Columbia ^nibetsiitp eo ^ in tbe Citp of iBteto Porfe Y g)cl)ool of Bcntal anb 0va\ ^urgerp leiefetence l^itirarp Digitized by the Internet Archive in 2010 with funding from Columbia University Libraries http://www.archive.org/details/practicablerootcOOcran A PRACTrCAP»I.R ROOT-CANAL TECILXIC BY ARTHUR BARTON CRANE, D.D.S. WASHINGTON, D.C. ILLUSTRATED WITH 48 ENGRAVINGS LEA & FEBIGER PHILADELPHIA AND NEW YORK 3 0^-;;^, Copyright LEA & FEBIGER 1920 this little book is dedicatp:d to the memory of the late J. J. KINYOUN, M.D. TO WHOSE PERSONAL INTEREST AND INSTRUCTION THE AUTHOR OWES HIS DESIRE FOR ACCURATE SCIENTIFIC KNOWLEDGE PREFACE The object of this little work is to jHTscnt in an orderly manner a complete root-canal technic which is paving a large percentage of successful results in the writer's practice. Tlie facts and theories set forth comi)rise a digest of the vari- ous methods advocated by the authorities, modified and supplemented by considerable study and some original research. Much of the matter included has already been made public in papers and clinics, but it is hoped that by thus gathering together in a consecutive manner the pro- cedures which have been most helpful to me, it may be pos- sible for others by comparison, to clarify their own technic. The subject will be treated in the following order: Diag- nosis, Asepsis, Instrumentation of the Canal, Therapy, Bacteriology, Obliteration of the Canal, and Surgery. It will be impossible at this time to give due credit for the many suggestions which ha\'e influenced me in arriving at this technic. Rhein, Callahan, Buckley, Coolidge, Ottolengui, Black, Prinz, (irieves. Moffit, McLean, and a host of others are the masters to \\h()ni the reader will owe any benefit which may be derived from a perusal of these pages. Before proceeding, let it be understood that ihe writer adrocdfrs the rct('>iti(ni af flic ininiiituni uinxber of non-vifdJ teeth, (ind then onli/ irlicN these are ueeessary to preserve an uut)roken areh, or to afford retention of prosthette apjdianccs. A. B. C. Washington. D. C. li)2(). CONTENTS. CHAPTER I. IXTKODUCTION 17 CHAPTER II. Diagnosis 20 CHAPTER III. Asepsis 41 CHAPTER IV. Instrumentation of the Canal .... 50 CHAPTER V. Therapy 65 CHAPTER VI. B.vcteriology SI CHAPTER VII. Obliter.vtion of the Canal .... 89 CHAPTER VIII. Surgery 104 IIOOT-CANAL TECHiNlC. CHAPTER I. INTIIODLXTIOX. In view of the divergence of opinion of the acknowledged leaders of dental thonght, there prevails in the average mind an uncertainty as to the efficiency of any method of dealing with pulpless teeth. While the medical profession in general contemplates with scepticism the attempts to retain non- \ital teeth in situ, the natural repugnance of most patients to submit to the mutilation of extraction places the burden of responsibility squarely upon the dentist. The happy day may come when universal ])roi)hylaxis will I)ractically eliminate the necessity for root-canal work, but the dentist of today must be prepared to render intelligent service to patients with diseases of the dental i)ul]>. lie must elect either to extract at once all teeth with exi>osed or non- vital pulps and absolutely avoid devitalization, or he must develop his root-canal teehnic to a ])oint which will insmv the patient, to a reasonable degree, against future extraction. The claim that no infected tooth can be retained with safety is as absurd as the attempt to save all teeth. There are men in every i)art of the country who can present an avalanche of roentgenograi)hie and ehnieal e\ idence ot bone 2 18 INTRODUCTION regeneration in periapical areas previously infected. The writer and others have determined by occasional cultural tests through the alveolus that such regenerated areas are commonly sterile. The question, then, is not one of feasibility but ability, and the reason dentists generally are not making such teeth safe is because they will not devote the infinite attention to detail which this work demands. Whoever has followed the progress of root-canal technic during the past few years must be gratified by the tendency toward standardization of methods among the recognized leaders. In spite of occasional diatribes against the wisdom of retaining pulpless teeth, the writer believes that the prob- lem of a satisfactory root-canal therapy is nearing a solution. Although the hopelessness of the reorganization of patho- logical periapical areas can be logically set forth, the fact remains that actual cures are being daily effected. The pages of surgical history are illumined by the narration of the over- coming of other seemingly insurmountable difficulties. In 1552, at the siege of Danvillers a shot passed through the tent of M. de Rohan, and hit the leg of one of his retainers. One of the most famous surgeons of all time finished cutting it off, to the wrath of his contemporaries, refusing to use either the red-hot irons or the boiling oil, then considered indispensable. Pare was ridiculed, but the simple treatment of wounds and the ligation of arteries which he taught, with slight modifications, are fundamental to the surgery of today. In 1864, sepsis following surgical operations was con- sidered inevitable. In defiance of all tradition. Lister by scientific deduction evolved the true theory of antisepsis. The wise men of the times who prided themselves upon the number of old blood stains on their operating coats ISTIiODlCTIOS 19 (•nii(l('iiiiu'(l his work as daiipTous ])r()cc(]urc, but to the ^M-cat uii(k'rlyintic. perhai)s we, too, may dejxMid upon the natural resistant forces to exert the same influence in the alveolus which contributes to the cure of infections elsewhere in the body. CHAPTER II. DIAGNOSIS. The foundation principle of a practicable root-canal technic is accurate diagnosis. Diagnosis is a scientific determination or discrimination of diseases by their symp- toms. It calls for a knowledge of cause and effect acquired only by a wide clinical observation. It is the embodiment of experience. Without a correct perception of conditions to be met any treatment becomes empirical. In the management of root-canals a careful diagnosis based upon methodical examination should precede any effort at treatment. Thereby much time and useless effort may be saved, and respect for the prognosis of the dentist increased. The diagnostic procedure should begin with a thorough physical examination. If this is properly conducted it will not only indicate suspicious teeth, but in many instances will classify those which may be expected to respond favor- ably to therapeutics, those whose only hope lies in surgery, and those which must be condemned to extraction. The following conditions if found indicate the advis- ability of further investigation: Color. — A tooth whose shade is not in harmony with its fellows is probably the seat of a pulp lesion. Translucence. — ^This is commonly called the live-tooth appearance. When it is absent the pulp is probably dead. TESriXd THE TKKTII 21 A small mouth lam]) held liMj,niall\ w ill he <»f j^rcat assistance in (Ictorinininj,' this j)()int. Large Cavities. — These should he carefully excavated and tested with a sliarj) e\]>lorer to determine ])roxinnty to the ])ul|) ( lianihcr. Large Fillings These are always suspicious, and should nex'cr he i)assed without thoroui^h tests. Gold Crowns. — Teeth under gold crowns are also always susi)ieious. The wonder is not that so many pulps die in such teeth, hut that any survive. The reason for this is that the freshly denuded dentin is left exposed to the fluids of the mouth until the crown or inlay is set. Infection invades the dentinal tuhuli, and is sealed in to continue its activity until at last the pulp becomes infected. As a precautionary measure a mild antiseptic should be sealed in contact with exposed dentin before the patient is dismissed. Cement should be used in cavities and aluminum shells for crowns. A cement of eugenol and oxid of zinc is excellent for this purpose. Post Crowns. — With rare exceptions these are ])laccd on puli)less teeth. Crownless Teeth. — These sometimes contain vital pulps, but unless treated prior to restoration will surely cause after-trouble. TESTING THE TEETH BY MEANS OF THE ELECTRIC CURRENT. Having marked all teeth which are suspicious by the fore- going tests, they should be further checked by means of the electric current. Either the Faradic or galvanic current 22 DIAGNOSIS may be used, the only requirement being some method of controlling the dosage. The high-frequency current is also useful in this connection, but it is more difficult to concen- trate this current upon given areas of the tooth crown, and thus a faulty diagnosis may result. "With any of the stand- ard galvanic switchboards, such as are used for electrolytic medication, the test is made as follows: A section of a broken broach is fitted into the needle- holder and attached to the positive wire. The sponge electrode is soaked with salt water and held by the patient in the palm of the hand. The tip of the broach is wrapped with cotton fibers, and this also is moistened with salt water. Several teeth which are unquestionably vital are now tested, and the tolerant dosage noted. With this as a control the suspicious teeth are tested. Machat warns against touching the electrode to metal fillings or crowns, but as the resistance of sound enamel varies so much in individual teeth, it is generally satisfactory to apply the electrode to a filling or crown where the metal does not come into contact with the soft tissues, especially where corresponding fillings or 'crowns on teeth of known vitality can be had as controls. It should be borne in mind that more current is required to penetrate enamel than metallic fillings, also that crowns and inlays have an intermediary of more or less non-con- ductive cement, which causes these teeth to respond only to an increased dosage. Recession of the pulp or thick deposits of secondary dentin in the pulp chamber must also be taken into consideration. When the canal is filled with the liquid products of decomposition, the tooth is often quite as sensitive to electricity as if the pulp were vital, and where hyperemia of the pulp exists, the tooth will often be more sensitive than the control. For teeth in which the electro- I PEIiCUSSlOM 23 (liaiiiiostic test is iiicoiiclusiNC llic (ild-tasliioiicd tlicrinal tests will often he of assistance in clearing; tlie diaf^nosis. IlaNiiiLi; i)y the forc^oin^ tests exclndcd llic teeth of iin(iuestional)le \itality, tlie next ste]) is a clinical examina- tion of the periapical region. Careful search sliould be made for fistuli? or scars where these have healed. The discovery of such will suggest more or less destruction of periapical tissue, hut there will often be as much or more disorganiza- tion where this evidence does not exist. PERCUSSION. The degree to which the apical attachments of the tooth ha\e been destroyed may be judged by percussion. The so-called " didl note" of the older practitioners requires a trained ear, but has a definite value. The percussion test of Talbot is of more universal utility. This is accom- plished by placing a finger of the left hand over the apex of the suspected root and striking the cusps of the tooth with a heavy instrument at different angles. If the bone has undergone destruction the ^■ibrations will be transmitted through the root to the finger. This test is of greater value on anterior teeth than on molars; where ])yorrhea exists it is utterly confusing. To ascertain the extent to which the houy plate of the alveolar ]>r()cess has been destroyed, take a small hard ])ledget of cotton in the cotton ])liers, and i)ress hard on the mucous nunihrani- oN'erlying the root apex. The tissues will sink into such an oi)ening, and slowly return when ])ressiu'e is i-cni(i\('(l. The ai)])earance is much the same as ])itting of the skin by ])ressin'e in edema. \Vhcne\cr the clinical tests classify any tooth as suspicious, 24 DIAGNOSIS the patient should be carefully questioned as to its history. Some patients have extremely good memories, and almost all can remember a prolonged toothache or the swelling of the face in the region of the tooth in question. THE X-RAY AS AN AID IN DIAGNOSIS. With the data now in hand all teeth recorded as non-vital or suspicious should be radiographed to complete the diag- nosis. Correct interpretation of dental radiographs cannot be made in the absence of good clinical data, and this point cannot be made too strong. Neither can radiographs be properly read by one deficient in the knowledge of normal dental anatomy. The density of the film, the angle from which the exposure has been made, the density of super- imposed structures, and the contiguity of other anatomical formations must all be taken into consideration. In reading a dental .r-ray film, the teeth known to be normal should first be studied (Fig. 1). The use of a good reading- glass, or dentiscope, will be of great help. It will be noted in the case of a normal tooth that the pericementum can be traced around the root as a continuous radiolucent line. Adjacent to and surrounding this will be seen the lamina dura or radiopaque line. It will also be noted that the trabeculse of bone about the apex are homogeneous with the bone which lies adjoining. Infection is microscopical, and cannot be radiographed. What we look for in the film is not infection, but the results of infection. Thus it may happen that a tooth recently infected or one long the habitat of organisms of low virulence may present a radiographic record in no way differing from the normal (Fig. 2) . Again, in the entire absence of infection TlfK X-h'AY AS A\ AID I.\ h/ACXOSIS 2."» there may hv a raretViii still a constant menace to the periapical tissues. At tliis])oint we are enabled to make a differential diagnosis and the tooth in ([Uestion nuist he i)lace(l in one of the following classes: A. Pulp normal. B. Pulp ex])osed, hut not infected (rare). (\ Pul]) ex])osed and infected. I). Pulp undergoing decomposition. 1''. Pul]) non-vital, but no ])eriai)ical disturbance. P. Pulp non-vital, with periapical disease. CLASSIFICATION OF PERIAPICAL DISEASE. A com})arative study of radiographs with the actual con- dition of the tissues, as disclosed by numerous root-resections, has led me to the conclusion that in periapical disease we are dealing with three distinct conditions, which may in most cases be differentiated in the film. For the sake of con- venience I have differentiated these conditions as follows (Fig. 5): Class I. Circumscribed radiolucent areas. (Primary granuloma). Class II. Diffuse radiolucent areas. (Advanced granu- loma.) Class III. Circumscribed radioparent areas. (Dental cyst.) (Figs. (■) and 7). The outstanding characteristics of these three classes are as follows: Class I (Fig. G, .1) : Circumscribed Radiolucent Areas. — At first glance this nui\' disclose no abnorinalit\' of the 28 DIAGNOSIS Class I. Class 11. Class III. Fig. 5. — I, circumscribed radiolucent area (granuloma) ; II, diffuse radiolucent area (granuloma) ; III, circumscribed radio parent area (dental cyst) . Class I. Class II. Periapical ilisoase, Cla.-^s 1/ circuniscril)C(l radioluccnt about second bicuspid. C Note area Periapical disease, Class II. Note diffuse radiolucent area about second bicuspid. D Periapical diesase, Class III. Xote circumscribed radioparent areas, sur- rounded by radiopaciue line. These cysts were sterile. Periapical disease. Class I, on mesial root; Class III, on distal root, lower first molar. Periapical disease. Class II, on Periapical disease. Class I, on left cuspid; Class III, on second bi- central; Class II, on right centnU; cuspid. Class III, on right lateral. Fia. 7. 30 DIAGNOSIS periapical tissues, except a slight thickening in the periapical pericementum, or it may present any extent of rarefying osteitis. There may or may not be evidence of previous attempt at root-canal filling. This condition, in the absence of such evidence, is too frequently passed with a glance, when a more prolonged study will reveal an absence of the apical lamina dura and an indefinitely circumscribed area, to a varying degree more radiolucent than the surrounding bone. To fall into Class I, however, no matter what the degree of periapical disturbance, the area must be circum- scribed, with the radiolucent area blending gradually into the normal bone. In cutting down upon these areas the alveolar plate will generally be found to be intact, but behind this a mass of soft granulations will be found investing the root apex. This class represents the primary results of infection, and the affected area is circumscribed, because the vital forces, while being slowly overcome by the invading organisms, are, as it were, making an orderly retreat. It often happens at this stage that proper root-canal treatment so attenuates the invading host that the balance of power passes to the tissues, and a cure results. For the better understanding of the statement just made the microscopical picture of primary granuloma must be studied (Fig. 8) . Under the low power may be seen a fibrous capsule surrounding a cellular central portion. Under high power the capsule is seen to be composed of dense white fibers of connective tissue, with numerous vessels and capil- laries. There is a scattering of wandering tissue cells and fibroblasts. The central portion is composed of plasma cells, fibroblasts, lymphocytes, and leukocytes, lying in an indefi- nite stroma of embryonic connective tissue. Careful exami- ri..\ssiFf(\\ri().\ OF I'Kin M'icM. dise.xsk ?A nation will n-vcal tlic (•:i])illan l()(ti)s often lined with a single layer of eiKlotlicliuin. It is from these delieate vessels that the iiitlainniatory eells })rol)ai)ly have tlieir distribution. Such a ])ath()l()gical arrangement is strongly indicative of nature's effort to wall olV the irritant. Fig. 8. — Photoniicrograiih of adxamcd granuloma, a, degenerative area; h, leukocj-tes and bacteria; c, fil)rinoiLs layer; d, granulation tissue; dd, capii- larj- loop; c, pericementum. rL.\ss 11 (Fig. G, B): Diffuse Kadioucknt Area. — This class shows in the film an irregularity of the radiolucent area, which ina\' \ary from a simple hreak in limitation to an entire loss of form. .\s in Class 1, the limitations of the abnormal area are ])oorly defined, and it is imjiossible to determine the borderline between normal and rarefied bone, 32 DIAGNOSIS so gradually does one blend into the other. The irregu- larity of general outline is caused by ramifications of inflammatory tissue which extend from the central mass into the surrounding bone. Wherever this abnormal tissue comes in contact with bone or cementum disintegration of the hard tissues takes place. The cementum becomes roughened and the bone becomes softened. This condition represents the absence of the reparative effort exhibited in Class I cases, and follows neglect or improper treat- ment of the primary infection. While it sometimes happens that Class II cases respond to treatment, the destructive process has reached so advanced a stage that it is seldom that teeth in this condition are restored to health, except by root resection. Indeed, the infection in this class of cases is rarely eliminated even by extraction unless exten- sive curettement is performed. Under the microscope the advanced granuloma shows areas of degeneration in the central mass, which appear as lumina containing fluid or cheesy matter. Class III (Fig. 6, C): Circumscribed Radioparent Areas. — In this class the film shows an intensely dark cir- cumscribed area surrounding the root apex. This dark area is outlined by a dense white line, which definitely separates radioparent from normal bone. Such a picture is always indicative of a dental cyst. In cutting down on these cases a definite cyst wall will be found attached to the root-end. By careful dissection this may be freed from its bony capsule and by resecting the root just below its attachment the whole cyst may be removed en masse. The limiting wall of bone, which shows in the radiograph as a dense white line, will be found to be smooth and hard. If the cyst be opened it will be found to contain a straw-colored fluid. Cysts are an expression of CLASSIFICATIUX OF I'F.ni M'lC .\ L DISEASE WW nature's effort to protect tlie or<^aiiisiM from tlie haiiefiil effects of certain noxious irritants. Microsco])ically the cyst wall will l)c seen to l)c formed of connectix'e-tissue fibers lined with cpitlicliid cells. In Lrrainiloniata which dcx'elo]) necrotic areas, epithelial strands may often he seen surround- ing the necrotic area. Thus certain Class I eases go on to cyst formation, while, on the othei- hand, the frequency with whicli radicular cysts api)ear as a late se(|uel to de\italization of the ])ulp from traumatism, suggests the possibility that in some instances these growths are not of infectious origin. Whether infected or not, cases of completed cyst formation as included in Class III are probably never eradicated by treatment through the canal. The cyst wall must lie entirely destroyed or the cyst will reform. FiG.'O. — Chronic abscess with fistula;. Note alxsence of periapical disturbance. A ty])e of ])eria})ical disease not mentioned above which is frequently encomitered is aKeolar abscess, either acute or chronic, with tendenc\- to Hstula formation. This may present a radiograi)hic record identical with any of the fore- going classes, or in extremely rai)id establishment of drainage may produce so little periapical destruction as to escape 3 34 DIAGNOSIS detection in the film (Fig. 9.) Where an abscess exists in conjunction with Classes I, II, or III of periapical disease, it is usually caused by the secondary invasion of Staphylo- cocci pyogenes. When acute alveolar abscess does not record proliferative tissue changes in the film, it is likely to be the result of infection by the Staphylococcus pyogenes, the Streptococcus hemolyticus, or both. A further important point for study in the radiograph is the condition of the root apex, and this is obviously of greater prognostic value than the condition of the surrounding bone. If the cementum is exposed and roughened it is certain that there is no present treatment by which this infected necrotic tissue can be restored to life, to say nothing of health. Fig. 10. — -Lower cells of antrum. Trace pericementum about apex of lingual root of molar. Fig. 11. — The nostrils superimposed upon root apices of centrals. ANATOMICAL CONSIDERATIONS. Anatomical points which seem to cause the most confusion are the lower cells of the antrum (Fig. 10), the nostrils (Fig. 11), and the anterior palatine foramen (Fig. 12) in films of AAA TOMICAL COS SI DERATIONS 35 tlic upper tcclli, nnd llic mental foramen (Fif^. V^) in films dl' tlic Idwcf. 'The (|iiesti(iii of infected areas in these re,i:ions can lie (piicklv (K'lci'niiiicd hy ti'acin^^ the line of liie jx'ri- A Fk;. 12. — .1, ahtciior palatine foramen; B, taken from furtlier to the right than .-1 clarifies the diagnosis. I'lo. 13. — Mental foramen. Note termination of inferior dental canal. eeinentnni around tlie root \\\n'\. If tliis is intact llic dark radiolucent area cannot l)e caused hy infection from tlie root-canal. Occasionally it is necessary to get an exposure from a dilTerent ande to verify the rcadinc: (Fi.t;. 12). 36 DIAGNOSIS CASES IN WHICH TREATMENT THROUGH THE ROOT- CANAL IS CONTRA-INDICATED. It may as well be acknowledged that there are many infected teeth which cannot be saved, but a selection of risks, through careful diagnosis, makes a favorable prognosis rea- sonably safe in many instances. For the sake of convenience, infected teeth which are rarely benefited by treatment through the canal may be classified in three groups as follows (Fig. 14): Group I Group II Group III Fig. 14. — Types unfavorable for canal medication. I, too much dead apical cementum; II, too much dead alveolar cementum (pyorrhea); III, canal opening within the antrum. Group I. — Teeth having considerable dead apical cemen- tum. Group II. — Teeth having considerable dead alveolar cementum. Group III. — Teeth having their apical opening within the maxillary sinus. Group I (Fig. 15). — A careful consideration of these three groups may have a tendency to prevent many unsuccess- ful attempts at tooth treatment. Recalling the classification of periapical disease previously referred to, it will be realized that most cases of Class II and all cases of Class III have so much denuded and therefore dead apical cementum that TREATMENT TUh'ordll THE ROOT-CAXAL V,t they must be iiicludrd in (irouj) I. After one has extracted a miinher of siicli teetli and curetted the ])eriai)i I (ill 'I'll /■' h'OOT-CA XA L 30 ])r()^Mi()si.s in root-canal treatment arc those with (lass 1 ])criaj)i('al disease, of limited deforce, and those in which the ])eriai)iciil coiiditions arc still normal. It often happens, after the most exhanstive cIVorts at diag- nosis, that there remains an nncertainty as to the necessity for interference with certain teeth. For the most ])art these are teeth with ])artially filled canals and no evidence of \wy\- i Fig. 17. — Coricll's trocar and cannula. apical distiirl)ance, or well-filled canals recently treated, which still show radiolucent bone areas about the root apex, I'litil some method is aiKanccd of dctcrmininii' when the ai)ical foramina have been sealed by a new jj;rowth of cemen- tum, any tooth with an incomplete canal filling should be considered a source of danger, no matter what the ])eriapical condition, ^^'e nuist constantK' bear in mind that the radio- 40 DIAGNOSIS graph is but a record of macroscopical conditions, while infection is the result of a microscopical invasion. An instrument has recently been devised by Coriell (Fig. 17), of Baltimore, which is of the greatest value in deciding upon the necessity for treatment in these extremely doubtful cases. This consists of a trocar drill and cannula, so con- structed that it can be used in the right angle hand-piece of the dental engine. By means of this instrument a hole may be made through the alveolus to the root apex, after which the drill may be withdrawn, leaving the cannula in place. Through this an uncontaminated culture may be taken, which will definitely determine the bacteriological condition of the periapical tissues. The operation can be performed with local anesthesia in a few minutes, but the utmost aseptic precaution is necessary to make the result of value. CIIArTER 111. ASEPSIS. TiiK object of asoi)sis is to reduce to a iiiiniiiiuiii the anioiiiit of infection wliicli may he introchiced into the fiehl by an operation. Any ase])tic technic gives at best only rehitively sterile results. The most careful surgeon cannot incise the skin without some contamination. Fortunately, most of the organisms thus introduced are non-pathogenic, and the natural resistance of the tissues defends them from the bane- ful effects of bacteria, if introduced only in limited amount. Natural resistance is dependent upon the elements of the blood stream, which is entirely absent from the dentin of a ])ulpless tooth. Thus the difficulty of an aseptic root-canal technic is augmented at the start. Add to this the natural (HsiiK liuatioii of the patient to submit to the inconvenience of sterile wrai)i)ings for the head and face, as well as his average inability to i)ay for the time thus consumed in many sittings, and the difficulty increases. Furthermore, consider that the use of rubber gloves robs the dentist of that delicate sense of touch so necessary to the ])r()i)er ])erformance of root-canal work, and that even with the greatest care the hands will usually ha\t' to come into contact with some unsterile object, and the achievement of an aseptic operation as it is generally understood by surgeons becomes next to im])ossible. Xotwithstanding these difficulties, the dentist i> no more justified in introducing infection by way of the 42 ASEPSIS root-canal, than the general surgeon is in doing so by way of the integument. The operative field in root-canal work is the smallest known to surgery and this to some extent offsets the danger of our somewhat loose technic. Bacteria can infect only the object with which they come into actual contact. Therefore the necessities of the case only demand that nothing shall enter the pulp chamber which may carry contamination. It is the belief of the writer that this result may be assured by the simple technic which follows. Before the canal is opened it is a wise precaution to attempt the sterilization of the coronal dentin. I am indebted to Grieves for suggesting a 10 per cent, solution of beechwood creosote in oil of cloves for this purpose. The clove oil is used as a penetrating menstruum to carry the creasote, which in 10 per cent, solution is not coagulant, in the dentin. Where the pulp chamber has not been opened or where the canals are blocked off by previous fillings, formocresol is a valuable agent. Either of these drugs must be sealed in for three or four days, as it requires that time to sterilize dentin by such means. Where discoloration of the tooth is not an objection, Howe's silver reduction method may be used and the delay avoided. STERILIZATION OF OPERATIVE FIELD. After the attempt to sterilize the coronal dentin, the tooth should be opened only when blocked off by the rubber dam, which should expose as few teeth as are necessary to give an unobstructed view. The dam should be adjusted in such a manner that there is no possibility of leakage of fluids froni STKh'iLizA'riox OF ori'h'ATni-: field 43 tlic moutli. Tlic teeth iiicliided should he ruhhed dry with gauze or cotton to remove the mucus, and the entire field then ])aint('d with tincture of iodin. After this has (h'ied it is washed oil' with alcohol to lighten the held. The coronal cavit>' may now be o{)ened. \\ here cavities extend below the ginf:;iva, or the crown is wanting, it is necessary to prepare the tooth for the reception of the rubber dam. This is most conveniently done with the manufactured co])])er l)ands which are su])plied for amalgam work. Tlu- band should be cut to conformity with the gin- gival margin and articulation and be securely cemented to })lace with a good crown-and-bridge cement. For anterior roots the band may be cut away labially in such a manner that a flat back facing may be ground to fit. By arranging the facing so that it does not come into contact with the ()l)l)osing teeth in mastication, and bending the pins together to form an arch, it will adhere to the gutta-percha reasonably well for two or three days. Cotton and dressings used in root-canal work are probably the most frequent sources of contamination. To avoid this the o])erator should ha\e available a sufficient number of sterilized ])ackages to meet his daily need. The ])ackage is prepared as follows: a thick towel, large enough to cover the operating table is folded evenly to a size about four by eight inches. Upon one end of this is laid a small J. & J. napkin folded twice upon itself. On the napkin are laid two sections of cotton rolls, about two dozen J. & J. absorbent ])oints, a number of small cotton balls and at least half a dozen smooth broaches wrai)ped with cotton. Three or four of the long Darby absorbent i)oints will also be found useful. These dressings are now covered with another folded nai)kin and the towel folded over it. The whole is now secureK' but 44 ASEPSIS not tightly wrapped in a piece of unbleached muslin, which is pinned to hold it together. As many of these packages as may be required are daily made up and sterilized. Fig. 18. — Sterilizing room made in closet. Autoclave for goods in packages and wet sterilizer for instruments. STERILIZATION OF DRESSINGS AND INSTRUMENTS. For the sterilization of dressings there is nothing so abso- lute as the autoclave or high pressure sterilizer (Fig. 18). STKUILIZATIOS OF hli'l'JSSfNGS AM) f XSTRl' M I':XTS 45 When subjected to stcMiii under fifteen ])(»iin(ls' i)ressure for twenty minutes jjositivc sterilization is assured. Then by sul)jeetinj:; to neji;ati\e i)ressure for about ten minutes, the ])aeka|;;es are rendered almost free from moisture. This is of great adxantaire in preNentinji; rust on tiie eotton wrapped broaches. I liuh-pi'essure sterilizers are somewhat ex])ensive, but the certainty of sterility makes the expenditure worth while for any dentist who does much root-canal work. Next in efheieney to the autoehive for this purpose is an ordinary gas cooking range. Ahnost any hirge vessel may be arranged to su])i)()rt a perforated platform on which the dress- ings may be sui)jected to live steam, without actually coming into contact with the l)()iling water. After thirty minutes of such treatment, the packages may be placed on a tray and ])ut ill the oven to be subjected to dry heat for an hour or two. ( 'are must be taken to prevent overheating the oven and thus burning the dressings. The Pent/, sterilizer is adxocated by many careful root- canal workers, and i)r()bal)ly is efhcient for cotton or gauze laid loosely on the tra\'. but if such a method of sterilization were satisfactory for goods in packages, one would expect to find it in use in our large hospitals. A mouth miri'or, two or three pairs of cotton ])liers, rubber- dam clani]) forcei)s and clamps, a ])air of collar ])liers. a few broach holders and lu-cessary exca\'ators. chisels and burs should l)e placed u])()n a perforated tray and sterilized by boiling for twenty minutes i)rior to the operatin Barbed broaches and smooth broaches for carrying cotton dressings may \n- kept in alcohol. \\ idc-iiecked bottles, such as the ordinary amalgam ixittle, are fitted with corks, into the under side of which the broaches are stuck in such a manner that when the cork is in the bottle the instruments 46 ASEPSIS will be immersed in the alcohol. The addition of one part of oil of sweet almonds to nine parts of alcohol, will prevent rusting, no matter how long the instruments are thus kept. Having made the foregoing preparations, we are now ready to set the table for the operation (Fig. 19). The ordinary bracket table is so unsteady that greater safety is assured by using a glass surgical table, so placed that it is within easy Fig. 19. — Table set for aseptic root-canal technic. reach of the operator and assistant. To the back of the table may be placed the medicaments likely to be of use, such as iodin, alcohol, canal antiseptics, peroxid of hydrogen, 30 per cent, sulphuric acid, xylol, temporary stopping, etc. At one end a Bunsen burner should be arranged, as it is frequently necessary to flame the cotton pliers or collar pliers. An open receptacle, such as a hair-receiver, for waste material should also be provided. l\STJaMK.\TAh'ir.\f 47 The tahlc top is wijH'd ofl' witli alcoliol and {•o\('rcd with a sterile towrl from one of the packages. The i)ackaf^e should be opened in such a maimer that the fiii,t,^crs do not eontami- nate its contents. The towel is then removed with two pairs of flamed forceps and spread U])on the table. The packapje of dressin caxity in tlu' vvvut that it is necessary to clianj^e the nihlxT (hiin a iiuiiiIxt of small cotton })ellets are (lr<»])])e(l into incited i)araliiii and allowed to l)oil for twenty minutes. They are then in(li\i(lually removed witli sterile cotton })Hers and laid on a sterile towel to cool. When the>' have hardened they are ])Iaced in a screw-top bottle and kv\)t in a coiix-eiiieiit place on the table. When needed it is only necessary to take one in the cotton pliers and hold it an instant in the Bunsen flame, when it may be pressed into the cavity effectively sealing it while the dam is being changed. Gutta-percha points should be prepared for use as follows: Dip in iodin and place on sterile glass slab to dry, wash oti' with alcohol, and then j)lace in an alcohol bath in a suitable covered container. CHAPTER IV. INSTRUMENTATION OF THE CANAL. OBTAINING FREE ACCESS. It has been pointed out that before entering the pulp chamber an attempt should be made to sterilize the coronal dentin. Thereafter the rubber dam should be applied and the coronal cavity so shaped that free direct access may be had to each canal in a line with its long axis. It is unfortu- nate that this often means extensive destruction of sound tooth substance, but even if the whole crown must be sacri- ficed the procedure is justified. The coronal opening corre- sponds to the primary incision in any other surgical operation, and as the object here is the safety of the root, as much of the crown should be sacrificed as may be necessary to prevent failure (Fig. 20) . Wherever possible, the natural walls of the pulp chamber should be preserved, as these will guide the broach naturally into the canals. The best method is to enlarge the cavity of access until the roof of the pulp chamber consists of only a thin layer of dentin, and then remove this with chisels and hoes (Fig. 21). In bicuspids and molars it is always necessary to enlarge mesial cavities well into the occlusal surface, and frequently, when the decayed or filled cavity is distal, it will be expedient to cut somewhat into the mesiobuccal surface as well. Those familiar with the Black system of cavity preparation will understand how to shape these cavities so as not to weaken OHTAIMXC FREE ACCESS 51 the tooth. The cutting is l)est done with a round or inverted cone bur, eare heiufj used to ])revent its phnifjiug into the pulp chamber. No overlianging walls should be left at any OPCMNG IN GORRLCT 0PCN1NG IN WRONG OPE.NIN& wlDt CNCXlGM POSITION BUT NOT PO&TION. BUT TOO OCtP WlOe ENOUGH Fig. 20. — Incorrect tcchnic. ])()int. In incisors and cuspids the lingual wall nuist generally be cut away, no matter where the cavity of decay exists. Enough dentin should be removed toward the incisal surface to completely expose the horns of the ])ulp. In either class of teeth, should the broach bind on any of the cavity walls, OPtNTOROOr BRCAK DOWN IN TOOTH CORRLCTLY or PULP CMAMBCR. TO PULP GMAMBCR. OPCNLD. Fig. 21. — Correct technic. when inserted in the canal, more cutting should be done in that direction until the broach is absolutely free. The conscientious operator will have made a careful study 52 INSTRUMENTATION OF THE CANAL of dental anatomy and be aware of the normal number and location of the canals in each type of tooth. Variations from the typical are to be expected and looked for. There are often two distal canals in the lower first molar. The mesiobuccal root of the upper first molar sometimes contains two canals. Thefe are not a few lower second molars with only one large canal and upper second molars with one or two canals only. Lower bicuspids are found with two canals and upper second bicuspids frequently have two. I have encountered three lower bicuspids with two well-defined canals and a few upper cuspids with a second canal running into a rudimentary root. The lower third molars may have from one to four canals and the upper as many as seven. The possible presence of such abnormalities should serve to keep the operator always on guard, for no matter how well the canals which are found are managed, an untreated canal will entirely vitiate the result. On the other hand, if a canal cannot be found it will do no good to form an artificial one, and this attempt generally results in puncture of the root. When difficulty arises in the search for the canals, it is generally because the floor of the pulp chamber has been mutilated. Other factors tending to impede progress are insufficient access, previous canal fillings or chips of dentin in the canal orifice. If the radiograph indicates that the canals are blocked by fillings, some solvent should be used. For gutta-percha the pulp chamber should be flooded with xylol, which in a few minutes will so soften this material that the finder will slip into the canal. If the obstruction is of cement or a proprietary root-filling, the canals may be located by painting the floor of the pulp chamber with iodin. When this is washed out with alcohol the root-filling will retain the stain. KXl'LOUATIUX OF THE CAXAL 53 If llic orifice nf tlic <-;iiiiil is filled willi (•liii)S of" dentin, pulp stt)iu's or lianleiied pnlp (issne, a small ]>ieee of sodinin- potiissinni slionld he |)laeed in the pulp cliamlx-r and s])read eMMily ()\'er the lloor. A hroken root pick sliai'pened to a ])oint is then nsed to systematically swee]) this snrl'aee until it becomes en^a^ed in the orifice of the canal. \Vhen this fails, occasionally a .")() ])er cent. snli)lnn'ic acid followed hy l)ieari)()nate of soda will succeed. Tlie temptation to use a i)nr in an nttemi)t to unco\-er the canal in these cases is some- times almost irresistihle, hut to do so is sure to complicate matters still further. EXPLORATION OF THE CANAL. Having located the canals by whatever means, the work ill the canal proper is begun by exploring to its apical extrem- ity. Upon the complete accomplishment of this task the success of the sul)se(|uent work depends. There are certain canals which cannot be so ex})l()rc(l by any technic at ])resent available, but the proportion of such is much less than it would seem to the inexperienced. A fine, smooth broach of ])iano wire is the only instrument which can be depended upon to do this part of the work with safety. The Khein root i)ick, the Twentieth Century ])ath- finder and the Kci'r root ])i-obe are all instruments designed for this i)urj)ose. The Kerr .set contains the finest instrument of this t,\pe, not much thicker than a hair, which is often \erv useful, but these probes are made of blued steel, w hich makt's thcni (li(Ii(iilt t(» sec in operation. The iiathhndcr is a long delicate instrument with which good work may be accom- ])lishe(l, but the flexibility of the long shank confuses the sense of touch to some degree. 54 INSTRUMENTATION OF THE CANAL Crane Canal Openers. — It is not unusual to encounter canals so plugged with organic debris or other obstruction, that when pressure is made upon the smooth broach the point buckles, thus retarding its progress. For the purpose of overcoming this I have recently had made by the Donaldson Broach Company a set of canal openers. This consists of four instruments of the root-pick type, the modification being that the working points are of varying lengths, thus increasing Fig. 22. — Crane opener for difficult canals. the relative length of the shanks. The No. 1 opener has a fine point one-eighth of an inch long; No. 2 is one-fourth inch; No. 3 is three-eighths and No. 4 one-half. If these instru- ments are used successively, beginning with the shortest, they will enable the operator to explore difficult canals without the buckling of the instrument interfering with the sense of touch. After the longest opener has been buried to its shank in the canal, the root-pick will usually complete the exploration. Hh:M()\ ISC ixdh'c.w/c M.\ri-:i:i.\L 55 Im)!- niutiiic work llic llliciii picks, wliidi (■nine in fonr si/i'S, aiT ;i(liiiii';ililc. Select iiiu' tlie sniallcst si/e the attemi)t is made to follow tlu' canal to the apical opeiiiiifi; l)y a scries of i)usiiiii^ and pickiiifi motions (Fig. 25, A). If the ])rogress of the hroach is sto])])e(l a comma-like turn given to the extreme point of the instnmient will frequently allow it to proceed. If this fails, sometimes a slight quarter-turn twisting motion given just at the imi)act of the picking motion will cause it to i)ass the ohstniction. Xo great force should be used, howc\'cr, and where ])urely mechanical exploration fails chemical aid is indicated. This should not be undertaken blindly, but the cause of the obstruction should be ascertained if possible. THE CALLAHAN METHOD OF REMOVING INORGANIC MATERIAL. Acids should be used for inorganic blockade, alkalies for organic, and suita])le solvents for previous canal fillings. The i)rincipal acids used for this ])urpose are 30 per cent, sulphuric, i)henolsul])lionic and hydrochloric. The life-work of Callahan with the sulphuric acid gives it preeminence and. where indicated, it renders a useful service. An appli- cator may be made of fine iridioplatinum wire, filed to a ta])er ]K)int and somewhat roughened with a coarse file. A satu- rated solution of bicarbonate of soda in sterile water should sul)se(|uently be used for the doultlc ])ni-i)ose of neutralizing any fn-e acid remaining, and forcing out the dei)ris i)y the bubblinii; which ensues. 56 INSTRUMENTATION OF THE CANAL THE SODIUM-POTASSIUM METHOD. The principal alkalies are sodium-potassium, sodium- dioxid and sodium-hydroxid. Of this group the sodium- potassium is easiest to handle and meets all the requirements. The best form is Schreier's paste, which was obtainable in Germany before the war, but the S. S. White Company makes a preparation which is quite satisfactory. It comes in a small glass tube which can be kept sealed with wax when not in use. In use the tube is nicked with a knife-edged file just above the point where the silver color shows the alloy unchanged, and the tube broken off at this point. A white substance forms at the top of the tube from contact with air and this should be discarded. The point only of the pick is dipped into the sodium-potassium and it should merely be painted with the alloy; that is, no lumps should adhere to the instrument. It may be more impressive to say, "Use sodium-potassium only in homeopathic doses." When this substance comes into contact with moist organic material there is a miniature explosion, attended by flame and smoke, caused by the rapid oxidation. In this reaction some of the organic material is actually consumed and some is saponified. The use of sodium-potassium in the canal is only occasionally attended by explosion, hence the saponified tissue must be washed out of the canal, for which purpose alcohol is an efficient medium. Repeated applications will eventually remove any organic blockade. As previously stated, alkalies are indicated for organic obstructions, but where the closure is caused by a calcific nodule or a constriction of the canal walls, sodium-potassium will more quickly effect a passage than acids. This is because it destroys the organic cementing stroma of the dentin as well Till': SonilM I'OTASSIIWf METHOD ."j? as till' ()rj,'iuiic nuittcr in tlic (Iciitin.il tiil)iili, Iciiviiijf flic iiiorUMiiic portion in such t'oi'ni that it is readily |)iil\cri'/.c(l l)y tlir hroacli. Tims it is the hcst clicniicai aid for routine use in removing natural obstructions. Gutta-percha is the most i"re(iuently encountered artificial obstruction. For dissohin<:j this, chloroform, eucaly])tol or xylol may Uc used. The latter ])ossesses many advantages over the other two and in a few minutes will so soften the hardest gutta-i)ercha that the pick will ])ass through it. Obstructions caused by ])roprietary root pastes will be slowly softened by sulphuric acid, in the rare cN'ent that they are hard enough to offer any resistance to the i)assage of the pick. Gold or cement nnist be ])ainstakingly ])icked out. A stiH", i)ointed instrmnent made of a broken root ])ick is most useful for this puri)ose. Broken instruments offer the greatest difficulty of any canal obstruction. It ma\' here be ])()inted out, however, that this does not ai)i)ly to smooth instruments broken otf in the picking and i)ushing motion. If these are sim})ly ignored for the time being and the ])icking and pushing resumed with a new instrument, the broken portion will soon ride out of tlie canal, but where an insti'ument is broken while being screwed into the canal further exploration is often im])ossil)le. By relocated use of sodium-potassium on a root ])ick, it is sometimes ])ossible to make a ])athway alongside of the obstruction, and then a twist broach nuiy be passed into this and twisted around and around to the right, without ]H'rmitting it to advance into the ()])ening. When this does not work it is feasible occasionally to continue the ])icking alongside of the broken instrument and reenter the canal at a i)oint ajjical to it. When the broken i)iece projects peri- apieally, extraction or root-resection is indicated. 58 INSTRUMENTATION OF THE CANAL THE DIAGNOSTIC WIRE. After the canal has been explored as far as possible by the foregoing method, successive sizes of root picks, carrying smallest quantities of sodium-potassium should be used, passing them to the farthest point of exploration and then pressing around the side walls of the canal (Fig. 26, A). In this way the opening may be made large enough for the insertion of a diagnostic wire (Fig. 23). For this purpose there is nothing better than a strand of ordinary braided Fig. 23. — Diagnostic mres. picture wire. Enough of this to last a life-time can be bought for five or ten cents, and it has all the qualities necessary for this use. Where the caliber of the canal permits, the diag- nostic wire may be wrapped with cotton fibers and saturated with any medicinal agent indicated. The end of the wire which is to remain in the pulp chamber should be given a turn around the beaks of the cotton pliers so that it may readily be grasped for withdrawal. After the insertion of the diagnostic wire a radiograph will indicate the extent to which the canal has been explored, and will be suggestive of subsequent procedure. If a portion I'lnC DIAMSOSTIC W IliE 59 of tlu' ciuiiil is uiK'Xi)l()r(>(l, wlicrc tliis is str;iif,'lit a still" ])ick or fine root file nia\' l)c used with coiisidcralilc lorct- to coin- plctc I lie (ipciiini;'. 1 1' 1 he canal is cui'xcd, the smooth hroadi should he curxcd to approximately the same decree and the Ucntle pushiiii;" and pickitiij: motions resumed, with the aid of the iiulieated chemical. A conunou cn-or in deahn^ with curxcd roots is to enlarge the eanal with burs or reamers in the (lirection of the lon ])assage of the smallest instru- ment, it may be worked through by alternately' giN'ing quarter turns and withdrawing the instrument. There are several sizes of apexograjihers, and by using them successively the 64 INSTRUMENTATION OF THE CANAL apical opening can be safely enlarged to meet the require- ments of the case. In curved or twisted canals, the smooth broach used in exploring will usually come out of the canal so bent to conformity that it may be readily reinserted. A broach so shaped should be laid aside as a pattern by which to bend A B Fig. 28. — The result of one hour's work by technic herein described. A, case as it presented; B, diagnostic wire in position. each instrument subsequently used in the canal (Fig. 28). Sometimes it is even expedient to bend the gutta-percha point to conform to this pattern. After enlarging the apical opening the canal is again washed out with hydrogen-peroxid and is then ready for the process of disinfection. , h CHAPTER V. THERAPY. TiiK upward ])r()gress of dentistry has been inai-ked from the be^iimiiig by a tendeney to perfect tlie ]>iir(ly mechanical and compromise with the t]iera])euticah In the struggle to reconstruct our root-canal technic to meet the requirements of adxanced medical thought history has repeated itself. While many operators are capable of opening and filling root-canals in a satisfactory manner, it is doubtful if any thoughtful dentist can approach root-canal work with the same degree of assurance that he would undertake the making of an inlay or a crown. The cause of this hesitancy lies in the uncertainty of accomplishing the eradication of the infec- tion. Tntil some scientifically correct method of making cultures in root-canal work is determined, the sealing of the canal will be fraught witli the dangerous ])(»ssii)ility that the infection still ])ersists. While awaiting this discovery a care- ful study should be made of the possibilities and limitations of sterilization in periapical disease. Such a study recjuires a visualization of the ])athological condition of the tooth and its investing tissues. In a typical case of pcria])ical infection the tooth is ])ul])less, and tile canal contains more or less infected organic matter. Tlic contents of the dentinal t iibuli lia\ c inidergone a change due to the action of the inxading bacteria. This degx-nera- tion may be confined to the inunediate region of the canal. 5 66 THERAPY but except in cases of short standing, it extends well toward, if not quite to, the dentocemental junction. Wherever this change has occurred the dentin is not only dead, but infected. Externally the cementum covering the root apex may be necrotic to a greater or less extent and saturated with the products of infection. Of the investing tissues the attachment of the apical fibers of the pericementum has been destroyed, and this destruc- tion often extends to the fibers of the oblique groups as well. To the extent to which this detachment has deprived the cementum of its blood nutrition, an irreversible change has occurred in the hard tissues. The cancellous bone surrounding this necrotic portion of the root has undergone a rarefying osteitis, in which process an infected granulation tissue has been substituted for the normal bone. The surface of this proliferating tissue which approximates the necrotic tissue has a tendency to undergo an indolent liquefaction, and in advanced granulomata this metamorphosis also takes place where the soft tissue comes into contact with the bone. In either instance the hard tissue deteriorates. The cementum becomes roughened and the bone becomes softened. If the foregoing clinical picture is in accordance with the facts, it must be acknowledged that, in cases of periapical infection, infection exists in the following sites: (1) The canal and canal walls; (2) the dentinal tubuli; (3) the apical cementum; (4) the granulation tissue investing the apex; (5) often in the bone adjacent to the granuloma. Further, it must be recognized that each of these areas is dependent upon or contributory to the others, hence it cannot be assumed that sterilization is complete until the infection in each of these sites has been eliminated. t/*S7i OF UISIM'ECTASTS 1 .\ ROOT f'.l.V.iy.,S 07 The difficulty of tliorouijlily stcrili/jiif^ tlicsc iiitcnh'jxMulciit s(>iits of iiif('<-tioii is ;uit,MiuMit('(l l)y tlic fact tliiit hotli lixiiij; and dead tissues arc inxoKcd. The researches of (and, ralif\ iiii;" and ainphfyini:,- t he HikHiii^^s of many |)re\ioiis in\cs- ti^^ators, ai'e decidedly con\iiiein^^ in the conchision that infections in h\inon the germicidal efl'ect of poisons l)rou<,dit into actual contact with the invading organisms. It would ai)])ear, then, that the attempt to sterilize both lixiiig and dead tissue b\' the same agency is irrational and im])ractical)le. With these facts in mind let us proceed to a consideration of the most widely accepted methods of tooth treatment in an efiort to determine why they are successful and wherein thev fail. USE OF DISINFECTANTS IN ROOT CANALS. For the i^urpose of disinfecting dentin de|)endence has always been placed on the action of drugs. At first em])ir- ically, and latterly more scientifically, the dentist has sought to aceomi)lish with disinfectants in the teeth what the general surgeon has also attemi)ted in other tissues. The trend of niddein surgery, however, is to place more and more depend- ence upon tlie vital resistance of the tissues. By control of the inlhiimnatory reaction, infection is inhibit(>d and rei)air ensues. In dead tissue, on the contrai'y, thei'e is no inflam- matory reartioii to control, and sterilization can only be elfected by the direct action of bactei-ial poixnis. TJu' greatest drawback to success in this necessity is the dilJicultx- of confining the treatment to the canal, for agents wlp'h 68 THERAPY might be depended upon to sterilize the canal and dentin are generally so inimical to the vitality of the periapical tissues that we have been repeatedly warned by careful investigators to discontinue the use of all irritating drugs. Other investi- gators, equally careful, claim that only by the use of such drugs can dentin be sterilized, and that periapical damage is due to faulty technic, rather than the inherent property of the medicament. Light may be thrown upon this controversy by a considera- tion of the theory that, in destroying bacteria by the use of drugs, there is most probably a definite chemical reaction by which the characteristics of both bacterium and drug are lost and inert substances produced. As in any chemical reaction an excess of either of the factors will remain unchanged with all its original character- istics. In the nice reactions which Buckley has worked out to show the rationale of formocresol medication this pos- sibility is not accentuated, although he is insistent upon the use of minimum quantities of this drug. It would be fatuous to deny that many teeth have been restored to health and usefulness b}^ the aid of this and other powerful drugs, but this result has been obtained by a chance happening upon just the proper amount of the remedy for the particular case; where used in excess nothing but harm has resulted. THE HOWE SILVER NITRATE METHOD. The treatment of root-canals by a silver reduction method, as suggested by Howe, is a valuable therapeutic agency in many cases. The chemical reaction which occurs, however, is subject to the possibility of excess of either reagent. Howe therefore advises that after the mixture of the two solutions THE l).\KIN SOLUTIONS G9 ill tlio canal is (■()ini)l('t(', the cxcrss should he aUsorlx'd with cotton ])oints, and the canal aj^ain flooded with the sih'cr solution lo take care of any excess of foniialiii i-einainin<;. The dense black stain which inevitably follows its use tends to limit the employment of this treatment to certain posterior teeth. This statement is made in full knowledge of the methods which ha\c been dexised to protect the coronal dentin from the stain, and at the same time also j)re\ent its stt'rilization. If eiigenol or any other drufj; can be deijended upon to sterilize the coronal dentin it would seem that it might be equally efficacious in the dentin of the root. Silver reduction by means of eugenol has been advocated by some, and it offers the advantage of less irritation in event of its passage through the ai)ical foramen. ]\Iany teeth have been treated in past years with silver nitrate, and the writer has seen a number of most favorable results. Whether the silver reduction methods are in any way superior to the straight silver nitrate is an open cpiestion. THE DAKIN SOLUTIONS. A group of substances studied by Dakin and elaborated by others has made ])ossible a new technic in the surgery of sii])])urating wounds. The attem])t to make use of these drugs in root-canal thera])y has not been an astonishing success, for the reason ])rincipally that, when the solution comes into contact with the secretions from the peria])ical region or the lluid debris of the dentinal tubuli, it is so diluted that in fifteen or twenty minutes no actixe substance remains, ("oncentration can only be maintained by constant renewal of the au;ent. H\- niixtniH' with stearates or lU'Utral oil this 70 THERAPY tendency to dilution is somewhat overcome, and this is one reason for the more favorable results with dichloramin-T. Dichloramin-T should be used not stronger than 5 per cent. For dressing the canal with this medicament it is better to use the prepared cotton points thus avoiding the use of metallic instruments. It should be securely sealed in the canal and be renewed at frequent intervals. It is probable that the best results would be obtained by changing the dressings three or four times daily for a couple of days. POTASSIUM-SODIUM AND SULPHURIC ACID. Happily the organisms with which we have to deal in root- canal work are not highly resistant. If a mild germicide can be brought into actual contact with the bacteria in proper concentration for a sufficient period of time, all that can be expected in the control of the infection will be accomplished. To achieve this end it is necessary to first deplete the tubuli of the organic content as thoroughly as possible. If sodium- potassium alloy has not already been used, it should be used now for this object, the debris scraped from the canal walls with Donaldson broaches, and the canal washed out with alcohol. With a Sauser irrigator the canal is then gently flooded with hydrogen peroxid. This is dried out with cotton points and the canal walls painted with 30 per cent, sulphuric acid, worked with a roughened platinum broach. This in turn is absorbed with cotton points. This treatment tends to deplete the dentinal tubuli of their organic content, and goes far toward sterilizing the dentin. Possibly in many cases this can be completed by dressing the canal with antiseptic oils. According to Black the oils possess the property of soaking into dentin and displacing its watery content. Whether lOMZM'IOX 71 such weak j^cnnicidrs as 10 jkt cent, solution of bcochwood cri'asoti' in oil of clows, Black's "1-2 ."')," or apinol retain tlieir potency w licii tlicy thus saturate the decix-r i)ortions of the dentin is a subject for further investiji;ation. ClinieuUy the\ seem to answer the reciuirenients, and at least their use is not attended with danger to the periapical tissues. Dead dentin, like other necrotic tissues, when retained in situ must he considered a foreif^n hody. It can he made innocuous only by sterilization and the obliteration of the canal. The sterilization of the periai)ical region presents an entirely different problem. For this purpose formaldehyd gas released from various solutions, ])henol, and other caus- tics, haxe ])ro\ed too treacherous to be longer (le])ended u})on for routine practice, and non-coagulant drugs have appar- ently little effect on granulomatous tissue. IONIZATION. There has been nnich discussion of late of so-called " ioniza- tion," fostered assiduously by the manufacturers of switch- boards to be used for this ])urp()se. Owing to lack of a proper conception of electrochemistry and electrobiology much confusion has resulted from the spread of questionable theories. Notwithstanding this, the clinical results of electro- lytic medication are so encoin-aging that it is i)eing aihocated as the best ])resent means of treating i)eriapical granuloma. Whether the dentin is sterilized to any considiTable depth by this agency is open to serious doubt. In order to under- stand the rationale of this method of treatment certain chemical and eli>ctrical phenomena must be studied. It will be recalU'd as one of the earlx' lessons in cliemistrv 72 THERAPY that certain elements are classed as positive and the others as negative. In the union of the elements to form compounds the negative unites with the positive. Thus when the chlorin atom, which is negative, unites with the sodium atom, which is positive, the result is a molecule of sodium chlorid, which is neutral; that is equally positive and negative. It is now accepted that the attraction which holds atoms together to form molecules is electrical, and is accomplished by the transfer of one or more electrons from the positive to the negative element. These electrons may be expressed as the bands which bind the elements into compounds. When a substance such as sodium chloride enters into solution there is a dissociation or loosening of the attach- ment between the positive and negative atoms, by which they have more independent freedom of movement than when combined in sodium chloride in the solid state. A compound decomposable by the electric current is called an electrolyte. When an electrolyte is dissolved in water the atoms which form the molecule become dissociated to an extent which permits their orderly movement with the electric current when it is passed through the solution. This movement may be more easily understood by a com- parison of the "all hands around" of the old quadrille. The dancers on the ballroom floor represent the electrolyte in solution. The men represent positive atoms and the ladies negative atoms. Each man (or positive atom) faces his partner (or negative atom) and gives her his hand (or elec- tron), and thus the molecule is formed. Now the music starts (corresponding to the making of the electric current), and the man passes his partner and gives his hand to the next lady, at the same time letting go the hand of his partner. Thus a new molecule is formed and this change of partners lOMZATION 73 continues until tlic music (or cU'ctric current) ceases. The ladies (or nci^atixc atoms) are always traveling in one dinc- tioii and the men (or ])ositive atoms) are always traveling; ill tlie other. 'I'o more nearly sinuilate the moxement of ions, we nuist coiieeix'e of the "all hands around" as taking; ])lace in a straight line rather than in the customary circle. Thus, w hen tlie man (or positi^■e atom) reaches the end of the line he will find no ])artner and will be set free, and the same holds true of the lady (or nefj;ative atom), so that men (or positive atoms) are made free at one end of the line, while ladies (or negative atoms) are released at the other. These traveling atoms are called ions. When an electrolyte enters into solu- tion, so that the attachment of the electrons is sufficiently loosened to render its constituent ions capable of thus traveling with the electric current, it is said to be ionized. Ions are electronegative or electropositive. For general purposes it will be sufficient to remember that the metals form positive ions, while the halogens and acidic radicals form negative ions, but it must not be assumed that all com- pounds can be ionized. The electronegative ions are con- ducted against the current and flow toward the positive pole, thus constituting what is known as the negative current. The positive ions conduct the positive current and flow toward the negative pole. With the foregoing comment as a basis we may now comprehend the clinical application of electrolytic medication. The root-canal must lune been opened and the a])ical foramen enlarged. The rubber dam is adjusted and all asei)tie ])recaiitions observed. The canal is now flooded with an electrolyte, that is to say, a watery solution of the chemical from which the ions are to be derived. If treatment with metallic ions is desired, the positive 74 THERAPY electrode must be placed in the electrolyte and vice versa. This is done by means of a needle, which fits into the root- canal, held in an insulated terminal on the desired pole of the battery. The opposite electrode must now be brought into close contact with the skin or mucous membrane of the patient. The usual method is to attach or hold it on the cheek, adjacent to the tooth. The current is now turned on and, by manipulation of the controllers, is cautiously passed through the tissues and gradually increased in strength until the point of tolerance is reached. This will usually be around two milliamperes. Care must be exercised that the current is not short-circuited by contact of the needle elec- trode with adjacent teeth, metal fillings, or moisture leaking through the rubber dam. Multirooted teeth may have all roots treated simultaneously by passing a separate needle into each canal and twisting or clamping them together. In this event the amount of current which will pass through the various apical openings will differ, and for this reason it is better practice to treat each root separately. If the indicator on the milliamperemeter vibrates with coincident painful shocks, it is an indication that somewhere along the path of the current there is a loose connection which should be looked for in the switchboard or terminals, between the electrolyte in the canal and the periapical fluids, or between the indifferent electrode and the tissues. Enough of the electrolyte should be added from time to time to com- pensate for evaporation. When the treatment is completed the current should be very gradually reduced to zero and then turned off. The most disagreeable shock is caused by the making and breaking of the current, hence the electrodes should only be applied or removed when the current is turned off at the switch. After removal of the electrodes any excess lOXIZATfON 7.") Ill' elect I'olylc ^ll(llll(| lie iih^oi'hed tVoiii the e;ili;il willi sterile cot toil points het'ofe drcssiii^f and sealiiif^ the tooth. It is ])i-ol);il)le thilt electrolysis only carries the ions ot" the ch'cti-olyte a shoi't dislaiice into the |)eria|)ical tissues, for the cni'i'cnt ii])oii reachini:,' the inulti])licity of ions contained in the hody lluids is <;i\'en U]) to them. '1 hus if ions of zine are earryinu" the current tln'oufj;h tiie apical oixMiint;, tliey will shortly transfer it to sodium ions or calcium ions or ot her electro])ositi\ i> ions already existing in the tissue juiees, nuich the same as the baton is transferred from one set of runners to another in a relay race. It is by such transfer- ence that the electric current })asses through the body from one electrode to the other. Cousidering this phenomenon it is doubtful, as has just been stated, if ions from the electrolyte are deposited to any appreciable distance beyond the ai)ical end of the root l)y electrolytic medication. This does not ex])ress the limit of their distribution, however, for provided ])reci])itation does not occur, ditl'usion begins as soon as the ions arc introduced into the tissues, and continues actively for upward of twenty- four hours. The maximum beneficial effect, if any, produced by the ions, is therefore not immediately upon their intro- duction, but after diiVusion has ensued. Tiie two leading American dental writers on electrolytic medication, Fette and Frinz, are at variance in their selection of an electrolyte. The former, adhering to the technic of Stin-ridge, advises the use of zinc chloi-ide with a needle of zinc as the positixc electrode; the latter, the use of sodium chloride with a ])latimnn needle on the ])()siti\'e ])ole. Sur- ])rising as it may seem, both claim the sanu> eflicient results. To avoid confusion let us examine each of these methods separately, and see what takes ])laee. 76 THERAPY Fette's Technic of Ionization. — When Fette's technic is used, as soon as the current begins to flow zinc ions pass through the apical opening, and at the same time chlorine ions begin to collect about the zinc needle, with which they unite to produce additional zinc chloride. It will be seen that any antiseptic action due to this technic must depend alone upon the zinc ions. According to Kronig and Paul the germicidal value of a metallic salt depends not only upon its specific character, but also upon its electronegative ions. Zinc ions as such have no demonstrable antiseptic value, hence if they contribute to sterilization it must be that during the process of diffusion they unite with certain preexisting negative ions in the periapical fluids, to produce a solution of an antiseptic salt. Prinz's Technic of Ionization. — In the method advocated by Prinz, when the current begins to flow sodium ions pass through the apical opening, while chlorine ions collect about the platinum needle. As platinum is not ionized, the chlorine ions unite with each other to form free chlorine, with the possible formation of infinitesimal quantities of hydrochloric acid as a by-product. In this technic the deposition of sodium ions can only add to the abundant supply of those already existent in the tissues, therefore the antiseptic value, if any, must be dependent upon the chlorine ions. Price claims that these have no antiseptic value, but as free chlorine is produced in the canal by their union the argument is hard to follow. The relative sterilizing value of chlorine thus pro- duced, compared to chlorine released from Dakin solution irrigations for the same period of time, or from treating with chlorinated lime and acetic acid according to the old bleach- ing method of Truman, would depend upon the amount of free chlorin available by each procedure. lO.MZATION 77 The Author's Technic of Ionization.- M.\ own ])ractice has becMi a conihiiKition of the two methods just studied, usinj; zinc elUoride as the eU'ctroIyte and a i)Uitinuni needle on the positive ])ole, and thus zinc ions pass through the ajHcal opening and free chk)rine is released within the canal, Evi- dently any therajieutical result which may accrue from either is obtained. 'J'here is little scientific e\'i(lence, however, to indicate any inherent sterilizing value in dissociating either of the foregoing electrolytes with the amount of current which tlie average patient can bear, A third electrolyte which presents a somewhat different aspect is Lugol's solution. This consists of iodin crystals, 5 parts, iodide of ])()tassium 10 ])arts, and water 100 parts by weight. ^Vhen the negative electrode is introduced into this solution in the canal, the ion I3 is carried into the peri- apical tissues. Iodine as such is not ionized, hence the neces- sity for adding iodide of i)otassium to the solution. In this connection the well-proved antisei)tic value of tincture of iodine should not be mistaken as an index of the value of I3. However, I am each day becoming more fa\()rably impressed with the clinical value of this electrolyte. The direct inherent sterilizing value of electrolytic medica- tion being so inconsiderable, it would ai)i)ear that the well- recognized clinical benefits following its use must be depend- ent upon some change produced in the tissue cells. It is reasonable to believe that granulomata persist at the root apex without objective sym])toms, because the strain of streptococcus, which is uniformly conceded to be the infect- ing organism, is so low in \irulence that iiiHannnatory reaction is only ])assi\e. The abscMicc of all the classic symj)toms of inflammation is confirmatory of this l)elief. The vital resistance of living tissue to infection is developed 78 THERAPY and increased by the inflammatory reaction, provided it does not proceed to a point of excessive activity. There is a pour- ing out into the infected area of white blood cells which have the power of ingesting the invading organisms, and of a blood plasma of high bacterial power. The inflammatory process and repair are very similar and often coincident. Electrolytic medication offers an easily controlled means of thus calling to our aid the defensive forces of nature. While the limited antiseptic action of the ions may serve to some extent to attenuate the invading organisms and thus aid in the ultimate result, it is a clinical fact that the use of the current is often followed by a varying degree of inflammation, signalized by pain, heat, redness, and sometimes swelling. The inflammatory reaction may be and often is induced in other ways and by other agencies. Indeed it is doubtful if the treatment of many cases of periapical disease is carried to successful completion without the tooth becoming sore at some stage of the treatment, no matter what the technic. Controlling the Inflammatory Reaction from Ionization.^ — The inflammatory reaction having been induced must be con- trolled. This may be contrived in mild cases by the use of counter-irritants, such as iodine, mustard, or capsicum. A method which not only tends to control the inflammatory process but also has a gratifying inhibition on pain symptoms is the electrolytic use of Fisher's salts, as described by Fette. A 4 or 5 per cent, solution of magnesium sulphate is applied through the apical mucous membrane with the positive current. The dosage is about 20 M. a. m. The instant there is an indication of excessive reaction, however, recourse should be .had to drainage. The recogni- tion of the value of this expedient dates back to Hippocrates at least, and this is Nature's own method of fighting pyogenic CONCLUSIONS 70 infect inn. \v\, strange as it may seem, many dentists fail to ii\ail themseKcs of so simple ii remedy. The j)romotion of the inflammatory ))roeess and the establishment of drainaf^e by means of a >mall window cut throuf^h the aKcolar plate into the canccllons hone of the jx-riapical i-e,t,non will in many eases mai'k the hei^dnnini;" of re])aii- in ])eriapical disease. INFECTED APICAL CEMENTUM. Infected a])ical cement nm ])resents the most inaccessible and troublesome factor in loot-canal therapy. For reasons already referred to, this dead tissue caimot be bathed in chemicals strong enoufjh to destroy the microorganisms, nor has it any power of inflammatory reaction. It may be that to some extent it is acted upon by the inflammatory exudate, or by drugs which inadxertently escape from the canal, but if so the effect must be very su])erficial. Hence, unless the denuded area is small enough to be successfully covered in the root-filling operation, its surgical removal is indicated, CONCLUSIONS. 1. No sterilization of infected teeth can be said to be (•om])lete unless it includes the canal and tu])uli, thedi'iuided cementum, and the jjcriapical tissues. 2. The same agency cannot be depejided ujxju to complete sterilization in all these sites. :'). The canal and dentinal tubuli can ]irobably be satis- factorily sterilized by the thorough use of sodium potassium alloy and ilO pel- cent, sulphuric, acid, followed by dressings of mild antiseptic oils; or by Howe's sil\er reduction method. -i. The i)eriai)ical region may be sterilized by inducing the 80 THERAPY inflammatory reaction by means of electrolytic medication, followed by immediate and sufficient control. 5. The apical cementum can at best receive but superficial sterilization, and unless the denuded portion is small enough to be successfully capped with gutta-percha, it must be surgically removed. 6. The establishment of scientifically correct culture methods and media is the crying need of the moment. Until this is accomplished the filling of the canal must be a proba- tionary expedient. CHAPTER VI. BACTERIOLOGY. The leaders of the medical profession are waitiiifj with open minds for conclusive evidence that periapical infection can he eliminated hy root-canal treatment. ^Meanwhile, knowing full well that extraction and curettage will he fol- A B IiG. 2'J. — liadiographic check reasonably co iviucing. lowed hy a healthy condition of the tissues, it is small wonder that many i)hysicians are demanding such treatment for all infected teeth. This attitude will continue and increase until some tangible method of pro\ing the ettectiveness of root- canal therai)y is available. The ])resent dei)en(lence upon radiograi^hic check, while reasonably con\incing in some cases (Fig. 29j, requires from 6 82 BACTERIOLOGY three to six months for demonstration. In cases attended by serious metastatic lesions this interval may be sufficient, if periapical infection persists, to so increase the malady that Fig. 30. — New bone growth in presence of streptococcus infection filling-in area once occupied by resorbed root apex. all chances of recovery are lost. This method is further con- trovertible on the ground that evidence exists that new bone Fig, 31. — New bone growth in presence of infected root apex left in by incomplete extraction. Note radiolucent area surrounding fragment. growth may occur in the presence of dangerous infection. This may be observed where new bone fills in the area once occupied by an absorbed root (Fig. 30), or the formation of Di':ri':h'.\ri.\i.\(i sTEun.iry of m'ical tissies S3 new I)()iic in the alveolus over a root tip left in by fracture (luriiiti; extraction (Fig. :U). Even eliminating tliese objec- tions, the check-up method is inelTectual because of the dis- iiicliiial idii of dentists ;iiid piiticiits ;ilikc to make use of it. Hence if we are to lia\e a method of i)ro\ing the elimination of ])(M-ia])ical infection which will be uni\ersally valuable, it must be cai)able of e.xhibitioii jjrior to filling the root-canal. The time has come to give preeminence to this requirement. Intil the sterility of the tissues can be reduced to demonstra- tion the filling of root canals remains an em])irical ])roccdure, worthx' of the coiidcnination it is recei\ing in many (juarters. A study of culture methods and culture media is the foun- dation upon which must be builded any attempt to pre- determine the successful outcome of root-canal therapy. CULTURE METHODS FOR DETERMINING STERILITY OF APICAL TISSUES. The first difficulty to present is that of obtaining reliable material for the culture. Two methods are in vogue. One consists in aspirating some of the periapical fluids through the root-canal. This method is difficult and its scientiiic \alue is lessened by the possibilities of contamination. The other ])lan is to gather on the tip of an apexographer or platiinun broach some of the periapical content by passing the instrument through the canal. This method also is open to scientific objection in that the material is gathered in a direct line with the canal where the greatest force of anti- septic treatment is expended, while t he little (•ryi)ts surround- ing the area of disturbance arc the ])oints most liable to remain infected, and these cannot be reached by this method. The finding of a negative culture may thus only mean that the 84 BACTERIOLOGY material has been gathered from a part of the field tempo- rarily under the influence of antiseptics. Another possibility is that some of the antiseptic used in treatment may remain in the canal and be carried over into the culture tube and inhibit growth. For about four years now the writer has taken cultures prior to filling the canal in practically every tooth treated. Until recently the technic of obtaining the material for cul- ture was as follows: The canal was dried as thoroughly as possible with sterile cotton points to absorb any excess of antiseptic present. A sterile apexographer was then passed through the apical opening until pain was experienced. Upon withdrawal the instrument was made to scrape the side walls of the canal and then used to inoculate the media. For the purpose of checking the value of this method the following experiments have been made. In one series of cases sterile cotton points were immersed in a sterile 25 per cent, solution of glycerin and sealed into the canal with gutta-percha, rendered sterile in the fiame. These were left in place for four days or longer, dependence being placed upon the hygroscopic action of the glycerin to induce osmosis and thus draw into the cotton the fluids of the periapical region. At the following sitting the cotton points were removed and dropped into culture tubes. Immediately thereafter cultures were made with the apexographer as described. In another series of cases similar experiments were performed with cotton points saturated with glucose broth, thus furnishing a rich pabulum for the propagation of any vital bacteria present. There was nothing in the results from either of these series to indicate any advantage of the cotton points over the apexographer. More recently a third series of cases has been tried as f ol- i>i:ri:ir\ii \ i\(. sri:i:ii.rry or M'kwl tissues 85 lows: A (iiltiii'c was first taken I)\ tlic a|ic\(i.uTa|)lici' ind IkmI. This was t'(i!l()W('(l hy a>|>ii'at inn' mhiic of tlic |)ci'ia|>i<-;il (iiiid into the canal, w lien a second culture was luade hy the apex- o,ijra])her method. The as])irating needle was r()Uj,dily made by solderin.u' a cu])i)ed disk of 30-gage ])latinum plate about three-eifihts of an inch from the end of the i)latinum point of a Berlin absc(>ss syrinii'c, in such a manner that it would aet as a platform upon which to carry temi)()rary stopping Fig. 32. — Aspiniting needle to be attached to Elgin casting machine. to automatically seal the caN'ity when the syrinue ])()int was introduced into the canal. \Vhen the tem])orary sto]ii)in,u' has hardened the syringe ])oint is connected to the I'-luin castinu; machine by means of rubber tubing and about tweh'C pounds negative ])ressure used. The needle is then w ithdrawn and most of the tem])orary stopping comes awa>' with it. If the a])ex()gra])her is now parsed through the i)ei-iapiial tluid wliicli has been t reliable culture 86 BACTERIOLOGY will be obtained. Based upon twenty cases in which compara- tive tests were made, this method is somewhat more efficient than the simple apexographer method. While it is possible that some more certain method of taking the culture may be developed, with such an easy means at our command, there is no present justification for an empirical acceptance of unreliable clinical evidence in deter- mining when the canal is ready for filling. Even though the finding of a negative result by this method is not absolute evidence of sterility, the finding of a Gram-positive coccus is a sure indication that sterilization has not been accom- plished, and by this guide alone we shall be prevented from filling the canals of many teeth which would otherwise seem to justify that procedure. For those who have not taken the routine precaution of making cultures prior to root-canal filling a surprise is in store, for positive growths will be recovered from about 30 per cent, of all cases which give every clinical indication of successful termination of the treatment. Selection of Culture Media. — Next in difficulty only to obtaining the culture is the selection of a practicable culture media. In the overwhelming majority of cases we have to deal with the streptococcus and some media especially acceptable to its growth must be selected. At the beginning I used an ordinary agar slant. This was inoculated with a stab and smear, the idea being to culture both the aerobic and anaerobic organisms. Growth developed very slowly in these tubes and too large a number remained negative. This led to the opinion that sufficient of the anti- septic used in canal treatments must be carried over with the culture material to cause inhibition. It was, therefore, decided to use a liquid culture medium and in such volume as to dilute this inadvertent antiseptic to a neutral state. DETERMINING STERILITY OF M'K'M. TISSUES 87 (llucosc hrotli was tricil, hut the lai-.^c i)crcentage of nega- tive results made us suspicious of its efHcicncy. Besredka's eij:cii)itate of metallic silver, and this is exactly what would exist in any tube no matter how small. Substances flow into the dentinal tubuli (.lily 1)\ cai>illar\- atti-action, and this ])h\sical force is exerted u])ou litjuids. Until some more convinciu.ii evidence is presented for these or some other sul)stances for filliu<;- the tubnli, it would seem wise to place dependence in soaking the dentin with a mild antiseptic oil as offering more defense against reinfection than is possible by any other present means. Fig. 33.— .1, B, iimltiple caiud emlin^iis, HUcJ l.y technic herein described. In order to obliterate the accessory foramina anil inequali- ties of the canal it is necessary that part of the filling material should l)e introduced in liquid form. (Miloroperchaof proper consistence not only will How into such accessory foramina and inequalities as have been opened, but possibly into the orifices of the tubuli as well (Fig. 33). The addition of resin to the chloroform makes the chloropercha more adhesive and it ina\- be used for this purpose. 92 OBLITERATION OF THE CANAL After the canal has been made as dry as possible with sterile cotton points, a drop of chlororesin is introduced from the flamed beaks of the cotton pliers and pumped into the canal with a smooth broach. A gutta-percha point considerably smaller than the canal is now pushed into it and agitated in such a manner that it is dissolved, thus forming chloropercha within the canal. This is the method suggested by Callahan and leaves nothing to be desired. The bulk of the filling may be made of undissolved gutta- percha. This is not an absolutely ideal material for root- canal filling, but has more points in its favor than any other material proposed for this purpose. When properly intro- duced and condensed it serves the clinical requirements. The most satisfactory form for routine use is the so-called "points" or, more properly speaking, cones. Those prepared by the Mynol Company are comparatively uniform and free from inequalities. They are also flattened on the end, which makes them easier to grasp in the cotton pliers. EFFECT OF OVERFILLING THE CANAL. Since the necessity for completely filling all canals has become an accepted policy, the desire of conscientious men to surely accomplish this end has led in many instances to grotesque overfilling, which at best serves no useful purpose (Fig. 34). Granted that in many cases this causes no par- ticular damage other than a temporary trauma, nevertheless in lower molars and bicuspids a periapical projection of gutta- percha may impinge on the mandibular nerve, and in upper bicuspids and molars a piece of gutta-percha extending into the antrum would surely invite reinfection (Fig. 35) . The amount of filling material, if any, which should be EFFECT OF OVEliFILLIXC THE CANAL 93 Fig. 34. — Grotcsinie overfilling- Fig 35— .1, Kiitta-percha point, probably projected into antrum; B, giitta-percha point impinging ou inferior dental nerve, causing sensory paralysis of lower lip. Fig. 3G.— .4, crater at apex should be filled; B, apex should be capped; C, too much dead ccmentiun to be capped. 94 OBLITERATION OF THE CANAL forced through the apical opening depends upon the extent to which the apical cementum has been denuded of its life- giving membrane (Fig. 36). In a very few cases of Class I and in all cases in which there is as yet no periapical disturb- ance the line of the pericementum as disclosed by the radio- graph is practically continuous. In such teeth to be ideal the filling should stop at the apical extremity of the canal (Fig. 37 A and Fig. 43). A careful examination of the apical termination of the canal in a number of extracted teeth will reveal the fact that in a goodly proportion there exists a crater-like depression in the ABC Fig. 37. —A, filled to the end; B, crater filled; C, apex capped. cementum at this point. This should be considered an integral part of the canal in so far as the filling operation is concerned, except in cases of recent operative devitalization. The radiographic evidence of the filling of this crater would indicate a little ball at the root apex (Fig. 37 B and Fig. 38). In no case is it necessary or even desirable to project a solid gutta-percha point beyond the root end, but wherever denuded apical cementum exists the attempt should be made to cover this with a cap-like film of chloropercha (Fig. 37, C). A careful study of the radiograph will indicate the amount of filling material which will be of value beyond the canal TKCIIMC OF I'lLLISC Tllh: CANAL 95 proper, and hy did'crent methods of inserting the filling about to be eN])laiii('(l this ;nn()iiiit can l)e coiitrollod to a r('as()nal)l(' degree. Vv 4§ C D Fig. 38. — Crater filled. Correct technic only in cases of pulp decomposi- tion, attended with no periapical disturbance. TECHNIC OF FILLING THE CANAL. The method of filling just to the end is as follows: In l)re])aring the canal for this ]iurpose the a])ical foramen should not be enlarged. The canal is flooded with chloro- resiii \aniisli and a xcry fine cone introduced and ])assed toward, but not quite to, the root end. This is dissolved with a stirring, not a ])umi)ing motion, which will coat the canal 96 OBLITERATION OF THE CANAL walls with a sticky chloropercha. A somewhat larger cone is now selected, but not so large as to impinge on the canal walls in its passage to the apex. This is dipped in chloro- resin and slowly insinuated into the canal almost to the end. At this stage time must be allowed for the chloroform to dissipate before proceeding with the operation. Part of the chloroform will evaporate and part will combine with the gutta-percha of the cone. As this process progresses the chloropercha becomes thicker and the gutta-percha cone becomes softer until at last the whole mass in the apical end of the canal will be homogeneous. When the gutta-percha in the pulp chamber is about the consistence of unvulcanized rubber a blunt plugger, too large to go far into the canal, is slightly warmed and used to gently pack the filling material toward the apex. At the first suggestion of pain the packing should cease. A fine plugger which will freely pass into the canal is now warmed and carefully passed through the center of the mass until it enters the apical third of the canal. It is then moved about in such a manner that the filling material is packed against the side walls of the canal, after which the deficiency thus caused is filled with a suitable cone packed to place. This procedure should be repeated until the canal is full. If the radiograph shows the filling to be incomplete, this can be corrected at a subsequent sitting by placing a drop of chloroform in the pulp chamber and passing a root pick through the filling toward the apex until pain is experienced. The opening thus made is then filled with a suitable gutta- percha point first dipped in chloroform To prevent overfilling the following points should be observed : 1. Do not enlarge the apical opening. TECHXir OF CAPPfXa A DEXl'DED APEX 07 2. Use a stirring" iiiotioii in iiuikiiiu" tlic dilDroix-i'dia. r?. Tnsci't the cdiic ill such a niaiiiicr as iiol to I'oi'cc tlie chloroiXTclia ahead of it . 4. Patiently wait tnr tlie whuh- mass in the apical end of the canal to hecoiue homogeneous before befi;inning to pack. 5. Discontinue ])acking toward the apex at the first indi- cation of pain. Thereafter pack against the side walls only. TECHNIC OF CAPPING A DENUDED APEX. In order to ca]) a denuded root apex, and this is necessary in most cases of periai)ical disease, the apical foramen should be somewhat enlarged. Too much zeal in this direction, how- ever, will result in a persistent seepage into the canal, which is most difficult to control. The ca])])ing of a denuded apex is usually much easier than filling just to the end, and the amount of filling material extruded can be controlled to a reasonable degree (Fig. 39) . Depending u])on the amount of capping desired, the canal should be lined or even filled with chloropercha in the manner prcN'iously described, only now the cone should be dissolved by a ])uni])ing motion, as many cones and as much chloro- resin being used as may be necessary to furnish a suitable amount. A little experience will soon e([uii) the operator to judge this with a fair degree of accuracy. A cone which approximately fits the canal is then selected and dipped in chlororesin, and gently pumj)ed through the chloro])ercha to the end of the canal. During these puni])ing oj)erations there will often be slight twinges of pain, but t he-e are caused by the irritation of the chloroform and should l»e disregarded. When the cone iiiially seems to ha\"e reached the end of the canal, time must be allowed as before for the chloroform to 7 98 OBLITERATION OF THE CANAL diffuse, but it is not necessary to wait quite so long as when the filling is to be confined to the canal. Usually when the blunt end of the cone begins to be plastic the point will not be solid enough to penetrate tissue. If pressure is then brought to bear, the mass in the apical end of the canal will Fig. 39.- -Apex capped. Correct technic only in cases attended with exposed apical cementum. flow through the apical opening at such a consistence as to distend the granulation tissue and flow in the direction of the least resistance. In other words, it will fill the space where tissue is missing. It is possible that the natural elasticity of the granulation tissue will have a tendency to force this gummy mass back toward the denuded cementum, thus TKCIIMC OF CAPPIXa A DENUDED APEX 00 increasinji; the intiinacy of its attachment. Tliis may be further assisted by making pressure on the crowTi of the tooth with the finger, or better by allowing the patient to bite hard witli the tooth on an ortlinary lea(l-])encil eraser. Tlie well- known tendency of cliloropercha to shrink n])on the e\aj)ora- tion of the chloroform will result in a properly placed capping hugging the root ai)ex tighter than ever. The amount of filling material passed through the apical opening may be controlled as follows: 1. The degree to which the ai)ical opening is enlarged. 2. The amount of chloropercha formed in the canal. 3. The gradation of the pumping motions, both in making the chloropercha and inserting the filling. 4. The accuracy of the fit of the gutta-percha cone. 5. The consistence of the mass in the apical end of the canal when pressure is brought to bear. If pressure is exerted too soon, the liciuid chloropercha will be forced into the meshes of the granulation tissue by the piston-like action of the cone (Figs. 40 and 41); or the point of the cone may be so solid as to penetrate the chloropercha cap (Fig. 42). Only when the filling material is gummy may it be confined between the granulation tissue and the cemen- tum. By careful study of the foregoing features it will be possible in most instances to confine the extruded filling material to the immediate utility of capping the root apex. When the root apex is capped the i)acking of the filling against the side walls of the canal should be done as previously described, and then the whole mass forcibly packed with a warm plugger, too large to go far into the canal. If pain is exhibited during the packing more time should be allowed as this is an indication that the gutta-percha caj) is still soft enough to flow. A few teeth thus capped have been extracted 100 OBLITERATION OF THE CANAL several months after the insertion of the filHngs. In these cases the cap was very adherent to the cementum and about as hard as gutta-percha becomes in coronal cavities. Fig. 40. — ^Filling in mesial root caps a large denuded area of apical cemen- tum. Filling in distal root projected by too precipitate pressure forcing the chloropercha ahead by its piston- like action. Fig. 41. — Runaway chloropercha resulting from pressure on cone while chloropercha was too fluid. Note beautiful result in distal root, in which the chloropercha became gummy. Fig. 42. — Solid gutta-percha point penetrating the chloropercha cap. (Distobuccal root.) DEVITALIZING UNINFECTED TEETH. Before leaving the subject of the treatment of root-canals to consider the surgical treatment of periapical disease, it may be wise to consider the subject of devitalization of unin- fected teeth. DEVir.MJZfXG UNINFECTED TEKTII 101 I-'(ir many years the dental ])r()t'essi()ii i^iioraiitly destroyed normal ])ulj)s in order to make l)ridij;e ahntments more seeure. The (HseU)siires of tlie dental radio.uraph of ])eriai)ic-al eon- C D Fig. 43. — Canals filled to the end. Correct tcchnic only in recently de\italized teeth. ditions whieh sn])er\ened ii;a\"e such a shoek to the })rot'ession that tlie conscientious dentist now looks w ith fear and tremb- ling ii})()n the necessity for such an o])eration. Yet until some more satisfactory abutment for Nital teeth is devised, the de- 102 OBLITERATION OF THE CANAL mand of an educated public for removable bridge work will continue to make devitalization necessary. In view of the holocaust wrought by this agency in the past, how may it now be undertaken with safety? The crux of the whole matter lies in asepsis. Provided the pulp may be extirpated and the canal obliterated without introducing infection no untoward result should follow. Teeth are not a source of danger because they are pulpless hut because they are infected. With the most painstaking technic a tooth once infected may be rendered safe, but the aseptic devitalization and filling of non-infected teeth offers the greater sense of security. As in any surgical operation of choice, the prime considera- tion is the selection of cases in which conditions will not fore- stall a happy termination. Teeth with deep-seated decay or pyorrhea or those in close proximity to, periapical areas of infection should be avoided. Preference should be given to teeth with unbroken enamel covering. The extirpation of pulps accidentally exposed in operating should be delayed until -a mild antiseptic dressing has been sealed in contact with the pulp for a couple of days. TECHNIC OF DEVITALIZATION. With the strictest aseptic technic the pulp chamber is uncovered and all debris cleaned away with alcohol. A fine, smooth broach is used to explore the canal. The pulp is extirpated with a fine Donaldson pulp-canal cleanser. This should be insinuated in the path made by the smooth broach until it appears to have reached the apex. It is then with- drawn just a trifle to avoid the possibility of binding and twisted around slowly a couple of times. The sense of touch will be more acute if no broach holder is used. When the TECHS ic or i)E\ rr.\Liz.\ri()\' 103 l»r(i;i(li i> w it lidraw II llic |)ul|) will iisiiiiliy \)v foiiiid t\\istc(| ;it)iiiii it. ir (iiily |);ift ol' it coines away the ri'inaiiidcT will 1)(" rc!iu)\(.Hl cluriii^^ the t'iilarj,niiK and sliapin^ of the canal by the technic previously described. Repeated wasliiniis with hydrogen peroxide, using the sterile cotton ])()iiits or cotton wrapped broaches as swabs, will remove all the blood and debris and leave the canal walls clean. An ai)ex curette is then used to clean the extreme end of the canal, but no InstruDient must pass through into the peri- apical tissues. The canal is again w^ashed with hydrogen- perioxide and dried as thoroughly as possible with cotton ])()ints. A strand of ])icture wire, wra])])ed with cotton fibers and placed in apinol prior to the operation, is now passed into the canal and sealed there with gutta-percha rendered sterile in the flame. A radiograph is made and studied as a guide to the length of the root. No attempt should be made to fill the canal while anes- thesia persists for fear of overfilling, which in such cases is entirely undesirable. Indeed, it is less dangerous to fall slightly short of the apical extremity than to have the filling protrude into the periapical tissues (Fig. 40). For the extirpation of vital i)uli)s slow subperiosteal injec- tions of cocain immediately o\er the root apex will generally be satisfactory, but in bicuspids and molars it is often well to support this wdth conduction anesthesia. Pressure anes- thesia is responsible for much of the infection which has followed extirpation, because the possibilities of contami- nation are infinite. It is wiser to avoid it entirely, but if einj)loyed some of tlu' aiiestlu'tics which will stand boiling should be used and base-plate gutta-percha softened in the flame should be substituted for red vulcanite rubber as a plunger. CHAPTER VIII. SURGERY. Many infected teeth which fail to respond to root-canal treatment, as well as those which the diagnosis eliminates as unfavorable for the attempt, may be saved by surgical pro- cedure. As any surgical operation is rendered more certain of successful termination when performed under satisfactory anesthesia, a word upon that subject may not be amiss. Conduction anesthesia raises dentistry to the nth power, yet many will not take the pains to thoroughly master the comparatively simple technic. There are a number of books published which place this modern method within the easy reach of all. For any surgical interference in the periapical region it at once furnishes a prolonged anesthesia, and avoids the possibility of scattering the infection. For root resections, in addition to conduction anesthesia, there should be an extremely slow infiltration of novocain solution rich in suprarenin immediately under the apical periosteum. This will make anesthesia more prompt and give a comparatively bloodless operation. PERIAPICAL DRAINAGE. As previously stated the establishment of periapical drain- age is often a valuable aid in root-canal procedure. Depend- ence upon antiseptics to accomplish in the mouth that which ROOT RKSECTION 105 has ])r()V(.'(l to \w iinpossiljlc in other i)arts of tlu- body will lead only to faiiiur. Success lies in a more universal adoption of surjiical ])rincii)les. To establish ])eriai)ical drainage a horizontal incision about half an inch in length is made over tiie root end. The soft tissues are reflected u])ward and downward ex])osing the alveolar pUite. With small sharp chisels a window is then made about one-eighth of an inch in diameter, exposing the cancellous bone. With a stifl' sharp probe punctures are made to the root end, thus permitting drainage. The lips of the wound should be i)revented from uniting by means of a gauze wick changed daily, until all discharge ceases. This treatment is indicated whenever the inflammatory reaction becomes excessive and in all pus cases whether acute or chronic. ROOT RESECTION. It is imi)robable that any periapical infection which has once reached the stage of pus formation or liquefaction of tissue can long persist without destruction of the ai)ical fibers of the pericementum. Proliferating uifections have the same result and in the presence of much dead apical cementum thus produced little is to be expected of medicinal treatment. We may heal the sick but we cannot raise the dead, and an infected necrotic area calls for surgical interference. Root resection is not a panacea for all teeth with peri- apical areas of infection. In selected cases, however, it gives a reasonable percentage of successes. It is unwise to attempt it in teeth whose gingival cementum has been ex])osed to any extent by pyorrhea, or in teeth which cannot be freed of the odor of putrefaction. Several days ])rior to the operation, 106 SURGERY the canal should be opened as thoroughly as possible, and treated by Howe's silver reduction method or a dressing of formocresol. Powerful and escharotic drugs may here be used, as any tissue which may be deleteriously affected is to be surgically removed. Just prior to the operation the canal should be filled with copper amalgam, using the utmost care to secure a thorough condensation. PREPARATION OF PATIENT. An aseptic operation is possible and desirable. The patient's head should be covered with a sterile cap and the chest and shoulders covered with sterile towels. A folded sterile towel should be laid over the eyes and nose and another across the chin under the lower lip, and both secured to the cap with safety pins. An oblong sponge made by sewing a wad of absorbent cotton in a small J. & J. napkin is now placed between the jaws and the patient instructed to close the teeth upon it. This will serve to absorb saliva and blood and make the use of a saliva ejector unnecessary. A square of gauze folded once on the bias is now placed over the nos- trils and under the upper lip, the free ends being tucked under the towel which covers the eyes. The teeth and mucous membrane in the neighborhood of the infection are now rubbed dry wdth gauze to remove the mucus, and the whole field painted with tincture of iodin. It is understood, of course, that the hands of the operator and assistant have been sterilized and that sterile gowns, or at least sleeves, are worn; also that all instruments used are sterile and handled in an aseptic manner. ri'iciixic OF liicsECTisa nil': hoot 1(i7 TECHNIC OF RESECTING THE ROOT. Tlic incision >li()ul(l he nuidc ratluT low, that is to say, below the \\\\v of tlic al\c'ohir-hil)ial juncture, and shouhl he from a half to three-quarters of an inch in Icnulh. It shonM he uiade straight and the point of tlie knife sliould sink to the bone so as to incise the periosteum. By })lunt dissection the niucoperiosteuni is freely loosened from the hone, uj)\\ard and downward. The labial flap should be retracted. This may be done with a fork retractor, but the method advanced by Sausser of passing a silk suture through the edge of the flap and making a loop of this to retract the tissue is often more satisfactory and causes less, traumatism. The blood should now be sponged away by the assistant until the wound is dry enough to give a clear view of the condition of the alveolar plate. This may be intact or may have undergone any degree of disintegration depending upon the t\pe of disease present. In cyst cases it will often be thinned out to a ])archment-like consistence. In Class II cases it will often be cheesy and discolored. ^Yhatever its condition a sufficient amount should be removed to assure ready access to the root apex. If the bone is normal this is best done with a bone gouge and mallet. The operator should direct the gouge, while the assistant uses the mallet. Where the bone is softened or thinned out, the window may be nicely made with large spoon excavators. The field should be again dried of blood and the periapical condition studied. Usually the infected tissue which invests the root apex will now be disclosed to view. In cases of (Mass 1 and ( 'lass II it will ai)i)ear as a \el\et-like mass of gi-ainila- tion tissue. This should be thoroughly curetted away with small curettes or large si)oon excavators. The wound is then 108 SURGERY washed out with small sponges soaked in Ringer's or physio- logical salt solution, exposing the root apex to careful exami- nation. Not infrequently the infected tissue will lie lingually to the root apex, in which case the root apex must be resected before the soft tissue can be curetted. When the disease is of Class III, upon the removal of the overlying thin plate of bone, the cyst wall will be readily recognized by its homogeneous structure and yellow or bluish-gray color. The attempt should be made to enucleate the cyst in its entirety without rupture. In order to accom- plish this it is essential that the window in the alveolar plate should be made large enough for its passage. The thinned portion of the bone may be readily lifted out with spoon excavators but the thicker bone surrounding must be cut away with bone gouges and mallet until the full extent of the cyst is visible. The root apex is now resected just below the point of attachment of the cyst wall. By careful blunt dis- section the cyst may now be freed from its bony capsule and removed unbroken. Suitable blunt dissectors for this work may be selected from the ordinary amalgam instruments. In cases of Class I and Class II the apex should be resected just coronally to the point where healthy pericementum begins. This will be indicated by intimate contact between the bone and root. The best instrument to use for this pur- pose is the cross-cut fissure bur. Chisel and mallet have been advised, but these do not permit of the same nicety of con- trol as does the bur. If an amalgam filling in the stump is desired the cut should be made in such a manner that the stump is shorter labially than lingually. This will facilitate the preparation of the cavity. After the apex has been removed, the whole diseased area should be curetted down to healthy bone. In some cases of Class II projections of TECHNIC OF RESECTING THE ROOT 100 t^M'aimlatioii tissur will Ix' louiid cxtciKliii.ic tVoni the central mass into the hone in xarious directions. These should all l)e followed up until no vesti^U' of a})normal tissue remains. The ea\ity thus made is a,t,'ain washed out with wet s])onf^es and then ])acked firnil\- with dvy ^^luze until hemorrhage is eontroih'd. Fig. 44. — Some ragged amalgam fillings. A final insi)ection is now made for diseased tissue which may remain, and assurance that every vestige of necrotic cementum has been removed. When the wound is clean, the cavity for the amalgam filling may be prej^ared with inverted cone burs, starting at the canal and working to the cementum. Much skill is necessary to confine the amalgam within the cavity, and often the edges of the filling will be ragged and small i)articles will fall into the wound from which it is practically impossible to recover them (Fig. 44). There is considerable difference of o])inion as to the advantage of this procedure and after three years' trial, I have abandoned it in favor of the following method: The root stump is dried and carefully i)ainted with a saturated solution of silver nitrate, being careful to avoid contact with the surrounding 110 SURGERY tissue. The cut surface of the dentin is then thoroughly burnished with a silver burnisher and the wound washed out with salt solution. CLOSING THE WOUND. Before closing the wound a careful examination should be made to be certain that no foreign body, such as sponges, scraps of amalgam or bone chips, remains. In case of Class 111 where the cyst has been enucleated without rupture, pro- vided asepsis has been maintained, the wound may be imme- diately completely sutured. In other cases, however, it seems more in keeping with surgical principles to only par- tially suture the wound, leaving space for the insertion of a gauze wick for drainage. The wound should be closed by interrupted sutures of black silk and these may be removed on the fourth or fifth day. Where indicated, drainage should be maintained until the wound will no longer retain the gauze. This will require that the patient be kept under observation for a month or even longer. A radiograph should be made soon after the operation and another, after six months or more have elapsed (Fig. 45). A regeneration of bone will be indicative of a successful outcome (Fig. 46) . Technic of Tooth Bisection. — ^Molar teeth are often extracted because one root is hopelessly diseased, although the other root or roots may be curable. If such a tooth can be made valuable by a crown or used as an abutment for bridge work it is generally worth saving by tooth bisection (Fig. 47) . In preparing a tooth for this operation the root which is to be eliminated should have its canal dressed with formo- cresol sealed in with permanent cement. This will prevent contamination of the other canal or canals while they are CLOSING rill': worsi) Fig. 45.— a good rcsvilt with amalgam filling: .1, few days after root resec- tion; B, same, one year later. r \ A B Fig. 46. — Apparent bone regeneration about resected roots (new tcchnic): A, a few days after root resection; B, same, four months later. .1 />' Fig. 47. — Examples of tooth bisection. 112 SURGERY being treated and filled. A good radiograph made after the root filling will be of great assistance in planning the operation. Straight incisions should be made in the buccal and lingual gum from the gingiva at the point of bifurcation toward the root end, about one-eighth of an inch. Deflecting the soft tissues the tooth is bisected with a pointed cross-cut fissure bur. The cutting should begin in the bifurcation and proceed coronally. It is more satisfactory when this can be done by cutting from one side only, but it generally will be necessary to cut alternately from the two points of incision. If the bisection does not start exactly at the point of bifurcation a Fig. 48. — Spike left by failure to start bisection exactly at point of bifurcation. small spike of root will be left which will make the tooth permanently tender (Fig. 48). The cutting should continue through the crown including all that part which is imme- diately supported by the diseased root. When completely severed, the root may be extracted, and the socket curetted and wiped out with tincture of iodin. The portion of the tooth which remains should now be made as smooth as possible subgingivally, which completes the operation. In crowning bisected teeth it is best to cut them off to the gingiva and use post and plate crowns with an occlusal rest on the tooth proximal to the missing root. M)E.\. AccESSOHY foniiniiia, filling of, 91 Alveolar al)sc('ss, '.V.i inicroiir^anisins of, 3-1 ra(lioM;rai)h of, 33 Amalgam filling in root resection, 109 Anatomical considerations, 34 Anosthosia, conduction, 104 for divitalization, 103 Antrum of Ilighmorc, canal open- ing in, .'•i()-3S dental films of, 3S A])exogra])lu'r, 47 method of using, 63 Ai)ical opening, enlarging of, 63 Asej)sis, 41 difficidty of, in dentistry, 41 for surgical operations, 106 wounds, 19 Aspirating periajiical fluids, 85 B I') \M)i\(, Icclli Id JKild iiil liter dam, \:\ Bisection of teeth, 110 indications for, 110 preparatory treatment for, 110 technic of. "112 liiood home infection, S9 I'loodless opeiations, 104 i'one growth in infection, 82 liroaches, method of keeping,4.5-4S Broken instruments in canal, 57 Callahan's method of introducing chloropercha, 92 Callahan's method of introducing solution of resin, 90 sidphuric acid, 55 Canals, exploration of, 53 locating, .")2 number and location, 52 Capping root ajiex, 97 Case history, 24 ('avity of access, 50 Cementum, exposed or roughened, 34 perforation of, 38 infected, 79 Chip blower, method of using, 63 Classification of periajiical disease, 27 Color test, 20 Coriell cannula, 40 Cotton rolls, use of, 48 Crane canal openers, 54 Culture media, 87-88 methods, 83 experiments in, 84 value of, S()-SS CuH'ttage after extraction, o2-81 ( "urved root method of enlarging, 64 of exploring, 59 Cyst, dental, 27 enucleation of, 32 liistopathology of, 33 oi)eration for, 108 prognosis in, 33 radiograph of, 32 Dakin solutions, 69 Dental cyst, 27 operation for, 108 Destruction of alveolar bono, 23 114 INDEX Devitalization, dangers of, 101 technic for, 102 Diagnosis, definition of, 20 differential, 27 physical, 20 Diagnostic wire, 58 Dichloramin-T, 70 Disinfection of dentine, 67 Drainage, 78 technic for, 104 E Electrical test for vitality, 21 method of making, 22 Electrolyte, 72 Electrolytic medication, 73 Crane's technic of, 77 Fette's technic of, 75-76 limitations of, 75 Prinz's technic of, 75-76 Enlarging canal, 53 Exploring canal, 53 Extraction, indications for, 36 Favorable prognosis, 38 FiUing canal to the end, 95 Finding the canal, 52 Fisher's salts, electrolytic use of, 78 Formocresol, 68-71 G Granuloma, advanced, 27 histopathology of, 30 operation for, 108 primary, 27 prognosis in, 30-32 radiograph of, 27-31 Gutta-percha as root filling, 92 method of dissolving, 57 Mynol points, 92 H High frequency current test, 22 Howe silver method, 68 Howe silver as root filling, 90 Hydrogen peroxide, method of using, 63 Incomplete root filling, 39-89 correction of, 96 Incubation, 88 Infection without radiographic evi- dence, 24 Inflammatory reaction, 78 control of, 78 excited by electrolytic medica- tion, 78 Instrumentarium, 47 Ionization, 71 Ions, movement of, 72 K Kerr root canal files, 47-61 method of using, 62 probes, 53 Lamina dura, 24 absence of, 30 Limitation of canal filling, 94 Lugol's solution, 77 N Normal tooth, radiograph of, 24 Operating table, 46 setting of, 47 Overfilling the canal, 92 Paraffine pellets, 49 Pathfinder, Twentieth century, 53 /.\7)/^.Y Pon-ussion tost, "dull iioto," 2:} 'r:ill)ot's, 2:i I'crfdratioii of ('ciiu'iituin, '.',\) ri-riapicMl disease, 2(') (l") areas of iiifecl ion in, (i() I'ericenientuni, infected, 2(1 normal, 21 Trottnosis, favorable, M'.i unfavorable, 3(1 Protection of exjjosed dentin, 21 Pul]) chamber, preservinfj; walls of, 50 R KAnioucKNT areas, 27 Kadioparent areas, 27 Karefyins osteitis, 30 without infection, 25 Removing canal fillinjis, 60 Khein canal enlarjiers, -47 root picks, 47-53 method of usin^, 55 Root resection, jireliminary treat- ment of, 106 postoperative treatment of, 110 suturing in, 110 technic of, 107 value of, 105 Rubber dam, adjustment of, 42 S Sciireiek's paste, 56 Short handled broaches, method of kee])in