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Methods of Testing for Bacterial Growth During the Treatment of Infected Root Canals
25
Coolidge— M ethods o f T esting for Bacterial Growth Periodontia. Philadelphia: P. Blakiston’s Son & Co., Inc., 1938, p. 536.
Soc. Exper. Biol. & M ed., 22:400-402, April
12. P e l z e r , R. H. : Report of Study on Etiology of Bleeding Gums. /. Periodontol., 9:25-39, January 1938.
14. W o l b a c h , S. B., and H o w e , P. R .: In tercellular Substances in Experimental Scor butus. Arch. Path. &. Lab. M ed., 1:1-2 4, January 1926. 15. A s c h o f f , L., and K o c h , W .: Der Skorbut. Jena: Gustave Fischer, 1919. 57 West 57th Street.
13. W o l b a c h , S. B., and H o w e , P. R. : Effect of Scorbutic State upon Production and Maintenance of Intercellular Substance. Proc.
1925 -
METHODS OF TESTING FOR BACTERIAL GROWTH DURING THE TREATMENT OF INFECTED ROOT CANALS By
E dgar
D.
C o o l id g e ,
A C T E R IO L O G IC examination of root canals under treatment, where the presence o f micro-organisms or infected material is suspected, has be come an important part o f the routine o f treatment before filling the canals. Present-day teaching o f therapeutic prin ciples that relate to the treatment of pulp and periodontal disease is based upon the biologic sciences and upon re search. Graduates in dentistry o f recent years are fam iliar with bacteriologic technic, although it is possible that m any graduates have not been taught to em ploy bacteriologic technic in the treat ment o f pulpless teeth.
B
A T T IT U D E T O W A R D
PU LPLESS TEETH
T h e attitude of many members of the dental and medical professions toward pulpless teeth indicates a loss of faith in the possibility o f successful handling of pulpless teeth by known methods of Read before the Section on Operative D en tistry, M ateria M edica and Therapeutics at the Eighty-First Annual Session of the Ameri can Dental Association, Milwaukee, Wis., July
19,From 1 939the Department of Therapeutics, C h i
cago College of Dental Surgery, Dentistry, Loyola University. Jour. A .D .A ., V ol. 27, January 1940
School of
M .S., D .D .S., Chicago,
111.
treatment. In many instances, this lack of faith represents a lack of knowledge of research work that has been done along these lines. T h e demands made o f the operator in the practice o f dentistry that he acquire and maintain technical skill in mechanical lines are so exacting that m any have not shown a desire to keep informed on the progress made in the biologic sciences, but have willingly accepted statements that are not scien tifically correct. It is necessary not only to keep informed o f important research along biologic lines, but also, and more important, to apply the findings o f re search to daily practice of the profes sion. There has been a widespread tendency to condemn pulpless teeth to extraction on the basis of suspicion rather than on direct evidence o f periapical disease or definite knowledge of the relation of pulpless teeth to systemic disease. M any reports of investigations in the past have been based upon the study of material obtained in hospitals and clinics. M any o f the conclusions drawn from evidence o f bacterial growth in cultures taken from extracted teeth were shown to be unsound by Fish and M aclean.1 Atten tion has been called b y Blayney2 and
26
T h e Journal of the Am erican D en ta l Association
others to the necessity of considering the case history which includes the record of treatment o f the tooth, in order to make a more scientific diagnosis, before extracting roentgenographically negative pulpless teeth. Tunnicliff and Hammond3 have shown that 33 per cent o f sound teeth with healthy pulps extracted carefully and completely sterilized on their external surfaces still give positive growth cultures from the pulps. Examination of m icro scopic sections taken from the areas of the pulps that gave positive growth in cultures revealed no inflammatory reac tions in the pulp tissue; which was interpreted as positive evidence of con-
higher in molars and bicuspids than in anterior teeth. T h e findings o f these investigators in dicate that the scientific solution o f the pulpless tooth problem is not to be found by the extraction of all pulpless teeth, and the mere fact that extracted teeth when sterilized on the surface and dropped into culture medium show a growth of micro-organisms is no longer accepted as proof that the tooth har bored infection when in the mouth. A tooth with a vital and healthy pulp is to be desired, but to condemn all roentgenographically negative pulpless teeth to extraction cannot be accepted as scientific treatment.
Fig. i.— Small electric, thermo-regulated in cubator 9 b y 9 by 1 2 inches, suitable for den tal needs. (Courtesy of V . M ueller & Com pany, Chicago.)
Fig. 2.— Thermo-regulated water heater showing thermometer suspended from arm from which two test tubes of culture media are also suspended. The temperature regulator is set to maintain a uniform temperature of the w ater at io o °F . In the test tube at the right, no growth is observed, while a heavy growth appears in the test tube at the left.
tamination during extraction. This in vestigation very definitely suggests that m any of the reports o f earlier investi gators upon positive cultures from ex tracted pulpless teeth m ay simply show the presence o f micro-organisms that was accidental and not necessarily a fact before those teeth were extracted. Stein4 also found in his studies that the pulps of 32 per cent of all sound teeth extracted with the greatest of care were contaminated during extraction. T he in cidence of contamination was much
SO U R C E S O F
E V ID E N C E IN INVESTIGATION
Investigations o f the root-canal prob lem should include teeth with a recorded history of treatment as well as those without a history o f treatment in order to properly evaluate the results of treat ment of pulpless teeth. Such a history should include the condition o f the pulp and periodontal tissue at the time of treatment. This, o f course, includes the roentgen-ray record, which is the usual
C oolidge— M eth o d s o f T esting for Bacterial Grow th
means of determining the condition of the periapical tissues before the extrac tion of the tooth. T h e record o f treat ment should be an essential part of the history. Bacteriologic tests made during treatment add substantial evidence which, although not infallible, is an im portant step in the approach to success ful treatment. T h e clinical history o f a tooth reveal ing functional efficiency and comfort to the patient is of little value, since m any teeth with gross pathologic areas around the apices give such clinical histories. However, the roentgen-ray record, year after year, furnishes an important link in the clinical history. T h e final source o f evidence of the success o f root-canal treatment is found in the histologic ex-
27
canals is possible. It depends on the complete sterilization and complete filling o f the canal and on the potentiality of repair o f the tissue surrounding the root. This potentiality of repair of the peri odontal tissue is greatest where a vital pulp is surgically removed. It is lowest where the periapical tissue is grossly pathologic. W hen the obstruction is re moved ; that is, when the infection is re moved and the root canal is completely filled so as to obliterate the open space
Fig. 3.— Equipment needed for cultural ex amination. From left to right: Q uart thermos bottle and cap, pencil for writing on glass, loop needle, Rosenow brain broth, “ hor mone” broth, blood-agar, thermometer stuck through cork o f thermos bottle. (Appleton.)
amination of extracted teeth that have satisfactory clinical records over a period of years. It is difficult to obtain this final evidence because those teeth which have a perfect clinical record are not willingly relinquished by their owners, and it is only in the event of fracture or loss o f a tooth from periodontal disease that such a tooth can be acquired for histologic study. PROGNOSIS
Successful treatment of infected root
Fig. 4.— Cross-section of thermos bottle in cubator. (Grossman.)
where fluid can accumulate and stag nate, the defense and repair mechanism o f the vital tissue surrounding the tooth will usually function. T h e proof o f the success of treatment is based upon the roentgenographic evi dence o f normal tissue in the periapical region. This evidence m ay be further substantiated by frequent microscopic ex amination of extracted teeth with a
28
T h e Journal o f the Am erican D en ta l Association
known history for comparison o f the histologic evidence with the roentgenographic evidence. Failure in the treat ment of gangrenous and pulpless teeth is often due to a lack o f sterilization o f in struments or to a break in the chain of asepsis during some part of the procedure of treatment and filling o f the root canals. It m ay be due to the injury of the periapical tissues from excessive use o f broaches, the use o f caustic drugs or overfilling of the root canal with an irri tating filling material. Failure m ay re sult from imperfect root-canal filling which does not com pletely seal the foramen against the ingress of exudates from the periapical tissues. It must be kept in mind that periapical inflamma tion, which m ay result in bone resorp tion, m ay occur from an excessive occlu-
A
in the apical region, the value o f the tooth to the patient and the possibility of successful drainage and complete fill ing of the root canal. In filling the canals o f teeth which have harbored infection and which are devoid of all living tissue, the complete filling o f the canals is the goal of the operator. No aid can be expected from new deposits o f hard substance where no living cells exist. Therefore, the com plete obliteration of the canals by the filling material is necessary. However, an overfilled canal is not desirable. There is much histologic evidence that protruding filling material is a constant source of irritation. Chronic inflam m atory areas will not entirely heal in the presence of irritation, and the results in root canals that have filling material pro-
B
C
Fig. 5.-— -A: Incisor teeth of woman of middle age. The right lateral incisor was lost in an acci dent and the pulps of the two central incisors became necrotic. T he pulp chamber of the right central incisor was opened and, because of pain, was left open and exposed to the saliva. The traumatized tissues were subjected to infection; which resulted in increased pain, swelling and loosening of the tooth. After sterility of the canals was obtained by treatment and verified by culture test, the canals were filled. B and C : The same teeth two years after treatment. The teeth were firm and comfortable. The improvement in the alveolar bone surrounding the central incisor is evident.
sal stress brought to bear upon any tooth containing a living pulp as well as upon one that is pulpless. Such areas of bone resorption are not easily differentiated from pathologic areas due to infection. Before instituting treatment of teeth o f this classification, it is necessary in all cases to make a careful diagnosis and to determine the advisability of treatment on the basis of the general health of the patient, the extent of the tissue changes
truding through the apical foramina and other apical areas and in which healing is incomplete after two years should be considered unsatisfactory, calling for sur gical assistance in the form of root re section. CO N TR O L O F IN FE C TIO N IN R O O T CANALS
T h e types o f organisms that concern the operator in the treatment o f exposed vital pulps or gangrenous pulps that are
29
C oolidge— M eth o d s o f T estin g fo r Bacterial Grow th
undergoing putrefaction and in treat m ent o f infected root canals with im perfect fillings are very similar on an alysis. According to Appleton,5 the organisms best fitted for pulp invasion are the streptococci. These organisms, which are both aerobic and anaerobic, are capable o f growth in closed root canals as well as in open root canals. T he treatment of infected root canals is mostly concerned with the various forms of c o c c i: streptococci, staphylococci and pneumococci. Germicides selected for the treatment of infected root canals should be those that will destroy the micro-organisms with a minimum of damage to the living tissue in accessory pulp canals or in the surrounding apical tissues. It is needless to say that germ i cides that coagulate albumen are limited
A
B
3. T h e germicide must have actual contact with the micro-organisms in or der to destroy them. In order that the germicide m ay have contact with the micro-organisms in all parts of an infected root canal, it must be selected with consideration for physical and chemical principles re lating to penetration. Such principles as capillary attraction, surface wetting, difference in surface tension and diffu sion can be employed. Tim e will not permit o f more than the mere mention o f these principles. Suffice it to say that the problem o f disinfecting root canals demands careful application of certain principles o f physics and chemistry. T h e use of chlorine in the treatment o f infected wounds has become a com mon practice. Chlorine m ay be applied
G
D
Fig. 6.— Complete healing of granuloma at apex of lateral incisor of woman in middle life. A , roentgenogram showing granuloma at time root was treated and filled. B, same tooth five years later. C , tooth ten years later. D , tooth twenty-five years later. The cementum layers were deposited over the apex of the root so that the gutta-percha filling appears to be shorter than the root, while it extended to the periphery in A and B.
in their ability to penetrate into inac cessible places in the root canal and are therefore disqualified for the treatment of infected root canals. Prinz6 suggested rules for the treat ment o f infected wounds which defi nitely apply to the treatment of infected root canals : 1. T h e germicide should be strong enough to destroy the organisms in a given time. 2. T h e germicide must have sufficient time for germicidal action.
in the treatment o f infected root canals by means o f ionization o f a solution o f sodium chloride or zinc chloride, or it m ay be obtained by the liberation o f nascent chlorine from a solution of monochlorphenol or a solution of chloramine. Chloramine ranks very high as an an tiseptic or a germicide in the treatment o f infected wounds. It is logical that this solution which is so useful in the control of infection in gunshot wounds should be applicable in the treatment of root
3°
T h e Journal o f the A m erican D en ta l Association
canals. It destroys infection with little injury to the living cells when used as a germicidal wash in intermittent contact with infected tissue. It does not coagu late albumen, although it is slightly irri tating to living tissue. Chlorine is linked to nitrogen in the chloramine molecule, which releases chlorine slowly in the presence of protein. F or the treatment of infected root canals, an aqueous solution of chlora mine of from 2 to 5 per cent strength is very effective. I have used the follow ing formula for m any years with entire satisfaction: Chloramine compound solution Chloramine 5.00 gm. Sodium chloride 0.80 gm. Sodium hydroxide 0.25 gm. Distilled water q.s. 100.00 cc.
ture in the treatment o f root canals gives greater assurance that the root canal is free from infection than can be obtained by any other method. Grossman7 has shown that attempts to determine when the infection has been destroyed by the appearance and odor o f the dressing removed from root canals m ay fail. In 150 cultured teeth which were considered ready to fill by the ordinary methods, the bacteriologic test revealed that 42 per cent o f the root canals still produced a growth on culture. This investigation shows that about four o f ten root canals considered ready for filling m ay be found infected on culture. Certainly the responsibility involved in the treatment and filling of root canals at the present time demands
A B Fig. 7.— A , gangrenous pulp with chronic periapical inflammation; mandibular cuspid of woman aged 35. B, same tooth eight years after treatment and root-canal filling. There is no evidence of periapical inflammation.
Chloramine compound solution is used m ainly as a germicidal wash dur ing the process of cleaning and enlarg ing the canal, which brings the germicide in contact with every portion o f the root canal during the treatment. It is also used as a dressing to be sealed in the root canal between appointments. It is, however, not advisable to attempt to wash the entire infected canal at the first sitting, but to withhold cleaning and washing the apical h alf of the canal until the second appointment.
that every means o f safeguarding the health o f the patient be employed. Every operator who attempts root-canal filling must assume the responsibility o f con trolling the infection in the field in which he operates. This investigation does not indicate that four out of ten infected root canals cannot be made sterile by proper treatment. It simply indicates that the bacteriologic test is far more reliable than the old method of determining sterility by the condition of the dressing removed from the canal.
BACTERIO LO GIC T E S T S FO R T H E PR E SE N CE
E Q U IPM E N T
OF IN FECTIO N B Y C U L T U R E
M aking the bacteriologic test by cul-
REQ U IRED
FO R M A K IN G
BAC -
TER IO LO GIC C U L T U R E T E S T S
T h e essential equipment for culturing
31
Coolidge— M eth o d s o f T estin g for Bacterial Grow th
root canals before filling them is quite simple. I f one has access to a commer cial bacteriologic laboratory or to a hos pital laboratory, arrangements can usu ally be made by which the laboratory will provide culture media and will incu bate the cultures, so that the dentist is not required to provide such equipment. Should it be desirable to have the incu bation carried on in the dental office, a small thermo-regulated incubator can be secured at a very small cost. T h e incu bation of cultures requires only a regu lated temperature at the level o f human temperature, which is 370 C ., or 98.6° F. A simple home-made incubator sug gested b y Appleton,7 and to which Gross man refers, consists o f an ordinary quart
A
until used. Rosenow’s glucose brain broth is most highly recommended. TE C H N IC O F T H E C U L T U R E T E S T
T h e test for the sterility of the canals is not m ade until the treatment is con sidered complete and the canal expected to be free from infection. Usually, this is at the third or fourth appointment, and instead o f filling the canal at this time, it becomes part o f the regular rou tine to m ake a culture test for sterility. Those who are fam iliar with bacteri ologic technic realize that it is very d if ficult to make a bacteriologic test w ith out contaminating the culture tube with organisms that are not obtained from the root canal.
B
Fig. 8.— A , imperfect root-canal filling and periapical bone destruction. B, same tooth ten years after treatment and complete root-canal filling. T he periapical tissues appear to be free from inflammation.
thermos bottle. T he stopper used is a large cork, through which a hole is made to permit a thermometer to be inserted in order to record the temperature of the contents at different intervals. The culture tubes are swung from hooks or strings inserted in the cork stopper. Another simple incubator can be made by using an electric water heater with a thermostatic control in which the desired temperature can be maintained for any desired length of time. Culture media can be obtained from commercial laboratories as needed, or can be obtained in greater quantities in sterile tubes and kept in a refrigerator
Before adjusting the rubber dam, the mouth is sprayed with an antiseptic and the rubber dam is applied with great care to thoroughly isolate the tooth. T h e surfaces o f the exposed tooth or teeth are very thoroughly washed with a germicidal solution several times and painted with L ugol’s solution. W ith sterile burs, the root canal is opened and the dressing removed from the canal. This dressing is discarded, and if there is any antiseptic remaining in the canal, it is absorbed with sterile absorbent points and discarded before the culture test is actually made. A sterile cone is carefully inserted in
32
T h e Journal o f the Am erican D en ta l Association
the root canal so that the point protrudes slightly through the apical foramen. A cone is left in the canal for a few mo ments, while the test tube containing the culture media is flamed. T h e ab sorbent point is carefully removed from the root canal and dropped into the culture medium, and the cotton plug is replaced in the test tube immediately. I f the foramen is so small that the ab sorbent point does not pass into the periapical tissue, a sterile root-canal file is passed into the canal and into the foramen a few times, after which another absorbent point is passed into the canal for the culture test. It is important that a little periapical tissue exudate moisten the tip of the cone, to insure the accuracy o f the test. T h e culture tube is now labeled, put in to the incubator and kept there for seventy-two hours at a temperature of 370 C. I f the thermos bottle incubator is used, the temperature will not remain at body temperature for seventy-two hours unless the bottle is carefully packed in a box with paper insulation. However, unless the room temperature is allowed to go considerably below 70°, the temperature in the thermos bottle will remain sufficiently high for twentyfour hours to promote growth in the cul ture tube. Usually, at the end of fortyeight hours, there is evidence o f growth if the culture is positive, but it is ad visable to allow seventy-two hours to elapse before filling the root canal, to be sure that the test is complete. A microscopic examination should be made o f the contents of the culture tubes to determine the type of organisms growing if the culture is positive. I f or ganisms are found, it is well to record on the patient’s history card the type predominating. Further treatment must be given and one or two negative cul tures obtained before the root canal is filled. Occasionally, the operator will en counter a tooth from which several suc
cessive positive cultures will be obtained. If, on investigation, he is convinced that the culture medium has not been con taminated by handling during the process o f taking the culture, and he is sure that there is no obscure leakage in the filling between appointments, the con clusion should be drawn that treatment is not successful. T h e percentage o f such instances is very low, but it is a precau tion against retaining a tooth that should be extracted. I f these precautions are taken, it is quite evident that teeth that are not susceptible to successful treat ment will be eliminated and the great number o f other pulpless teeth that many operators extract needlessly will be saved without jeopardizing health. SU M M A R Y
The employment o f bacteriologic tests by culturing root canals prior to filling, especially those which contained infec tious material, is a requirement in present-day clinical practice that can be met by every operator. Bacteriologic tests have proved to be far more accurate than the old method of determining the condition of the root canal and periapical tissue b y the con dition o f the dressing removed from the root canal. M any teeth, however, that were treated before bacteriologic meth ods were employed have given clinical evidence of being free from infection on roentgenographic examination and, after extraction, have given microscopic evi dence o f a healthy periapical tissue free from inflammatory cells. Histologic study of m any extracted teeth with good root-canal fillings has confirmed the evidence in m any cases of the possibility of saving pulpless teeth without danger of harboring a focus of infection in the periapical tissues. W ith improved methods o f technic, employing surgical asepsis during rootcanal operations and checking the treat ment by means o f bacteriologic tests, it is possible to eliminate the small per
33
O pp ice— D entistry and the N ational H ea lth Program
centage of infected teeth that are not susceptible to treatment. T h e solution of the problem o f the pulpless tooth is not in the extraction of all pulpless teeth, but in the differentia tion between those that can be saved by proper treatment and those that should not be saved because of failure to com pletely control the infection.
3. T
R uth , and H am m ond, Presence of Bacteria in Pulps of In tact Teeth. J.A .D .A ., 24:1663, October 1937. C
u n n ic l if f ,
arolyn
:
4. S t e i n , G e o r g : Ist jeder pulpakranke Z ahn infëziert? Z ts°hr. f. Stomatol., :1281,
33
1935-
5. A p p l e t o n , J. L. T ., J r : Bacterial Infec tion. Philadelphia: Lea & Febiger, 1933. 6. P r i n z , H e r m a n n : Diseases of Soft Struc tures of Teeth and Their Treatment. Philadel phia: Lea and Febiger, 2 Ed., 1937, p. 198. 7. G r o s s m a n , L. I.: Bactériologie Examina tion of Pulpless Teeth Before Filling Root Canals. J.A .D .A ., : , M a y 1938.
B IB LIO G R A PH Y
25 774
i. F i s h , E. W ., and M a c l e a n , I.: Distribu 8. A p p l e t o n , J. L. T ., Jr.: Bacteriological tion of Oral Streptococci in Tissues. Brit. D . Control of the Treatment of Periapical Infec J., 61:336, September 15, 1936. tion. D. Items Int., 49:589, August 1927. 2. B l a y n e y , J. R . : Present-Day Evaluation o f Pulpless Tooth. J.A .D .A ., 23:533, April 1936. 25 East Washington Street.
DENTISTRY AND THE NATIONAL HEALTH PROGRAM By
H arold
W.
O p p ic e ,
H E R E are those among our pres ent luxuriant crop of socio-eco nomic reformers who would lead us to believe that the United States has never had a national health program worthy of the name. There are even some dentists who speak and write in this fashion, demanding that adequate medical and dental care be provided by our government for all of its citizens. T h ey apparently do not understand the meaning or purpose of a national health program in a democracy, or they have done some wishful thinking in regard to the conditions that exist in the totali tarian state. A ll regulations and laws established or enacted by governmental agencies for the protection and promotion of individual and community health constitute the health program of any state or nation. History has recorded some program of
T
Read before the Cleveland Dental Society, Cleveland, Ohio, October 21, 1939. Jour. A .D .A ., V ol. 27, January 1940
D .D .S., Chicago,
111.
this type, no matter how simple, crude or ineffectual, since the beginning of gov ernment itself. It is quite possible that the “ forbidden fruit” in the Garden of Eden had an implication for health as well as for religion. B y far the most im portant and beneficial of all public health activities have been proposed, sponsored and carried out by members of the health professions as a result of their efforts to prevent and to treat disease. T h e profession of dentistry, although only now completing its first century of existence, has not been slow to recognize its responsibility toward the improve ment and maintenance of our national health program. It is unnecessary to do more than recall that the dental profes sion in the United States has fathered all the laws enacted by the several states and controlling and regulating the practice of dentistry in those states. Surely, the con tributions of the dental schools in the matter of public health cannot be ig
Coolidge— M ethods o f T esting for Bacterial Growth Periodontia. Philadelphia: P. Blakiston’s Son & Co., Inc., 1938, p. 536.
Soc. Exper. Biol. & M ed., 22:400-402, April
12. P e l z e r , R. H. : Report of Study on Etiology of Bleeding Gums. /. Periodontol., 9:25-39, January 1938.
14. W o l b a c h , S. B., and H o w e , P. R .: In tercellular Substances in Experimental Scor butus. Arch. Path. &. Lab. M ed., 1:1-2 4, January 1926. 15. A s c h o f f , L., and K o c h , W .: Der Skorbut. Jena: Gustave Fischer, 1919. 57 West 57th Street.
13. W o l b a c h , S. B., and H o w e , P. R. : Effect of Scorbutic State upon Production and Maintenance of Intercellular Substance. Proc.
1925 -
METHODS OF TESTING FOR BACTERIAL GROWTH DURING THE TREATMENT OF INFECTED ROOT CANALS By
E dgar
D.
C o o l id g e ,
A C T E R IO L O G IC examination of root canals under treatment, where the presence o f micro-organisms or infected material is suspected, has be come an important part o f the routine o f treatment before filling the canals. Present-day teaching o f therapeutic prin ciples that relate to the treatment of pulp and periodontal disease is based upon the biologic sciences and upon re search. Graduates in dentistry o f recent years are fam iliar with bacteriologic technic, although it is possible that m any graduates have not been taught to em ploy bacteriologic technic in the treat ment o f pulpless teeth.
B
A T T IT U D E T O W A R D
PU LPLESS TEETH
T h e attitude of many members of the dental and medical professions toward pulpless teeth indicates a loss of faith in the possibility o f successful handling of pulpless teeth by known methods of Read before the Section on Operative D en tistry, M ateria M edica and Therapeutics at the Eighty-First Annual Session of the Ameri can Dental Association, Milwaukee, Wis., July
19,From 1 939the Department of Therapeutics, C h i
cago College of Dental Surgery, Dentistry, Loyola University. Jour. A .D .A ., V ol. 27, January 1940
School of
M .S., D .D .S., Chicago,
111.
treatment. In many instances, this lack of faith represents a lack of knowledge of research work that has been done along these lines. T h e demands made o f the operator in the practice o f dentistry that he acquire and maintain technical skill in mechanical lines are so exacting that m any have not shown a desire to keep informed on the progress made in the biologic sciences, but have willingly accepted statements that are not scien tifically correct. It is necessary not only to keep informed o f important research along biologic lines, but also, and more important, to apply the findings o f re search to daily practice of the profes sion. There has been a widespread tendency to condemn pulpless teeth to extraction on the basis of suspicion rather than on direct evidence o f periapical disease or definite knowledge of the relation of pulpless teeth to systemic disease. M any reports of investigations in the past have been based upon the study of material obtained in hospitals and clinics. M any o f the conclusions drawn from evidence o f bacterial growth in cultures taken from extracted teeth were shown to be unsound by Fish and M aclean.1 Atten tion has been called b y Blayney2 and
26
T h e Journal of the Am erican D en ta l Association
others to the necessity of considering the case history which includes the record of treatment o f the tooth, in order to make a more scientific diagnosis, before extracting roentgenographically negative pulpless teeth. Tunnicliff and Hammond3 have shown that 33 per cent o f sound teeth with healthy pulps extracted carefully and completely sterilized on their external surfaces still give positive growth cultures from the pulps. Examination of m icro scopic sections taken from the areas of the pulps that gave positive growth in cultures revealed no inflammatory reac tions in the pulp tissue; which was interpreted as positive evidence of con-
higher in molars and bicuspids than in anterior teeth. T h e findings o f these investigators in dicate that the scientific solution o f the pulpless tooth problem is not to be found by the extraction of all pulpless teeth, and the mere fact that extracted teeth when sterilized on the surface and dropped into culture medium show a growth of micro-organisms is no longer accepted as proof that the tooth har bored infection when in the mouth. A tooth with a vital and healthy pulp is to be desired, but to condemn all roentgenographically negative pulpless teeth to extraction cannot be accepted as scientific treatment.
Fig. i.— Small electric, thermo-regulated in cubator 9 b y 9 by 1 2 inches, suitable for den tal needs. (Courtesy of V . M ueller & Com pany, Chicago.)
Fig. 2.— Thermo-regulated water heater showing thermometer suspended from arm from which two test tubes of culture media are also suspended. The temperature regulator is set to maintain a uniform temperature of the w ater at io o °F . In the test tube at the right, no growth is observed, while a heavy growth appears in the test tube at the left.
tamination during extraction. This in vestigation very definitely suggests that m any of the reports o f earlier investi gators upon positive cultures from ex tracted pulpless teeth m ay simply show the presence o f micro-organisms that was accidental and not necessarily a fact before those teeth were extracted. Stein4 also found in his studies that the pulps of 32 per cent of all sound teeth extracted with the greatest of care were contaminated during extraction. T he in cidence of contamination was much
SO U R C E S O F
E V ID E N C E IN INVESTIGATION
Investigations o f the root-canal prob lem should include teeth with a recorded history of treatment as well as those without a history o f treatment in order to properly evaluate the results of treat ment of pulpless teeth. Such a history should include the condition o f the pulp and periodontal tissue at the time of treatment. This, o f course, includes the roentgen-ray record, which is the usual
C oolidge— M eth o d s o f T esting for Bacterial Grow th
means of determining the condition of the periapical tissues before the extrac tion of the tooth. T h e record o f treat ment should be an essential part of the history. Bacteriologic tests made during treatment add substantial evidence which, although not infallible, is an im portant step in the approach to success ful treatment. T h e clinical history o f a tooth reveal ing functional efficiency and comfort to the patient is of little value, since m any teeth with gross pathologic areas around the apices give such clinical histories. However, the roentgen-ray record, year after year, furnishes an important link in the clinical history. T h e final source o f evidence of the success o f root-canal treatment is found in the histologic ex-
27
canals is possible. It depends on the complete sterilization and complete filling o f the canal and on the potentiality of repair o f the tissue surrounding the root. This potentiality of repair of the peri odontal tissue is greatest where a vital pulp is surgically removed. It is lowest where the periapical tissue is grossly pathologic. W hen the obstruction is re moved ; that is, when the infection is re moved and the root canal is completely filled so as to obliterate the open space
Fig. 3.— Equipment needed for cultural ex amination. From left to right: Q uart thermos bottle and cap, pencil for writing on glass, loop needle, Rosenow brain broth, “ hor mone” broth, blood-agar, thermometer stuck through cork o f thermos bottle. (Appleton.)
amination of extracted teeth that have satisfactory clinical records over a period of years. It is difficult to obtain this final evidence because those teeth which have a perfect clinical record are not willingly relinquished by their owners, and it is only in the event of fracture or loss o f a tooth from periodontal disease that such a tooth can be acquired for histologic study. PROGNOSIS
Successful treatment of infected root
Fig. 4.— Cross-section of thermos bottle in cubator. (Grossman.)
where fluid can accumulate and stag nate, the defense and repair mechanism o f the vital tissue surrounding the tooth will usually function. T h e proof o f the success of treatment is based upon the roentgenographic evi dence o f normal tissue in the periapical region. This evidence m ay be further substantiated by frequent microscopic ex amination of extracted teeth with a
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T h e Journal o f the Am erican D en ta l Association
known history for comparison o f the histologic evidence with the roentgenographic evidence. Failure in the treat ment of gangrenous and pulpless teeth is often due to a lack o f sterilization o f in struments or to a break in the chain of asepsis during some part of the procedure of treatment and filling o f the root canals. It m ay be due to the injury of the periapical tissues from excessive use o f broaches, the use o f caustic drugs or overfilling of the root canal with an irri tating filling material. Failure m ay re sult from imperfect root-canal filling which does not com pletely seal the foramen against the ingress of exudates from the periapical tissues. It must be kept in mind that periapical inflamma tion, which m ay result in bone resorp tion, m ay occur from an excessive occlu-
A
in the apical region, the value o f the tooth to the patient and the possibility of successful drainage and complete fill ing of the root canal. In filling the canals o f teeth which have harbored infection and which are devoid of all living tissue, the complete filling o f the canals is the goal of the operator. No aid can be expected from new deposits o f hard substance where no living cells exist. Therefore, the com plete obliteration of the canals by the filling material is necessary. However, an overfilled canal is not desirable. There is much histologic evidence that protruding filling material is a constant source of irritation. Chronic inflam m atory areas will not entirely heal in the presence of irritation, and the results in root canals that have filling material pro-
B
C
Fig. 5.-— -A: Incisor teeth of woman of middle age. The right lateral incisor was lost in an acci dent and the pulps of the two central incisors became necrotic. T he pulp chamber of the right central incisor was opened and, because of pain, was left open and exposed to the saliva. The traumatized tissues were subjected to infection; which resulted in increased pain, swelling and loosening of the tooth. After sterility of the canals was obtained by treatment and verified by culture test, the canals were filled. B and C : The same teeth two years after treatment. The teeth were firm and comfortable. The improvement in the alveolar bone surrounding the central incisor is evident.
sal stress brought to bear upon any tooth containing a living pulp as well as upon one that is pulpless. Such areas of bone resorption are not easily differentiated from pathologic areas due to infection. Before instituting treatment of teeth o f this classification, it is necessary in all cases to make a careful diagnosis and to determine the advisability of treatment on the basis of the general health of the patient, the extent of the tissue changes
truding through the apical foramina and other apical areas and in which healing is incomplete after two years should be considered unsatisfactory, calling for sur gical assistance in the form of root re section. CO N TR O L O F IN FE C TIO N IN R O O T CANALS
T h e types o f organisms that concern the operator in the treatment o f exposed vital pulps or gangrenous pulps that are
29
C oolidge— M eth o d s o f T estin g fo r Bacterial Grow th
undergoing putrefaction and in treat m ent o f infected root canals with im perfect fillings are very similar on an alysis. According to Appleton,5 the organisms best fitted for pulp invasion are the streptococci. These organisms, which are both aerobic and anaerobic, are capable o f growth in closed root canals as well as in open root canals. T he treatment of infected root canals is mostly concerned with the various forms of c o c c i: streptococci, staphylococci and pneumococci. Germicides selected for the treatment of infected root canals should be those that will destroy the micro-organisms with a minimum of damage to the living tissue in accessory pulp canals or in the surrounding apical tissues. It is needless to say that germ i cides that coagulate albumen are limited
A
B
3. T h e germicide must have actual contact with the micro-organisms in or der to destroy them. In order that the germicide m ay have contact with the micro-organisms in all parts of an infected root canal, it must be selected with consideration for physical and chemical principles re lating to penetration. Such principles as capillary attraction, surface wetting, difference in surface tension and diffu sion can be employed. Tim e will not permit o f more than the mere mention o f these principles. Suffice it to say that the problem o f disinfecting root canals demands careful application of certain principles o f physics and chemistry. T h e use of chlorine in the treatment o f infected wounds has become a com mon practice. Chlorine m ay be applied
G
D
Fig. 6.— Complete healing of granuloma at apex of lateral incisor of woman in middle life. A , roentgenogram showing granuloma at time root was treated and filled. B, same tooth five years later. C , tooth ten years later. D , tooth twenty-five years later. The cementum layers were deposited over the apex of the root so that the gutta-percha filling appears to be shorter than the root, while it extended to the periphery in A and B.
in their ability to penetrate into inac cessible places in the root canal and are therefore disqualified for the treatment of infected root canals. Prinz6 suggested rules for the treat ment o f infected wounds which defi nitely apply to the treatment of infected root canals : 1. T h e germicide should be strong enough to destroy the organisms in a given time. 2. T h e germicide must have sufficient time for germicidal action.
in the treatment o f infected root canals by means o f ionization o f a solution o f sodium chloride or zinc chloride, or it m ay be obtained by the liberation o f nascent chlorine from a solution of monochlorphenol or a solution of chloramine. Chloramine ranks very high as an an tiseptic or a germicide in the treatment o f infected wounds. It is logical that this solution which is so useful in the control of infection in gunshot wounds should be applicable in the treatment of root
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T h e Journal o f the A m erican D en ta l Association
canals. It destroys infection with little injury to the living cells when used as a germicidal wash in intermittent contact with infected tissue. It does not coagu late albumen, although it is slightly irri tating to living tissue. Chlorine is linked to nitrogen in the chloramine molecule, which releases chlorine slowly in the presence of protein. F or the treatment of infected root canals, an aqueous solution of chlora mine of from 2 to 5 per cent strength is very effective. I have used the follow ing formula for m any years with entire satisfaction: Chloramine compound solution Chloramine 5.00 gm. Sodium chloride 0.80 gm. Sodium hydroxide 0.25 gm. Distilled water q.s. 100.00 cc.
ture in the treatment o f root canals gives greater assurance that the root canal is free from infection than can be obtained by any other method. Grossman7 has shown that attempts to determine when the infection has been destroyed by the appearance and odor o f the dressing removed from root canals m ay fail. In 150 cultured teeth which were considered ready to fill by the ordinary methods, the bacteriologic test revealed that 42 per cent o f the root canals still produced a growth on culture. This investigation shows that about four o f ten root canals considered ready for filling m ay be found infected on culture. Certainly the responsibility involved in the treatment and filling of root canals at the present time demands
A B Fig. 7.— A , gangrenous pulp with chronic periapical inflammation; mandibular cuspid of woman aged 35. B, same tooth eight years after treatment and root-canal filling. There is no evidence of periapical inflammation.
Chloramine compound solution is used m ainly as a germicidal wash dur ing the process of cleaning and enlarg ing the canal, which brings the germicide in contact with every portion o f the root canal during the treatment. It is also used as a dressing to be sealed in the root canal between appointments. It is, however, not advisable to attempt to wash the entire infected canal at the first sitting, but to withhold cleaning and washing the apical h alf of the canal until the second appointment.
that every means o f safeguarding the health o f the patient be employed. Every operator who attempts root-canal filling must assume the responsibility o f con trolling the infection in the field in which he operates. This investigation does not indicate that four out of ten infected root canals cannot be made sterile by proper treatment. It simply indicates that the bacteriologic test is far more reliable than the old method of determining sterility by the condition of the dressing removed from the canal.
BACTERIO LO GIC T E S T S FO R T H E PR E SE N CE
E Q U IPM E N T
OF IN FECTIO N B Y C U L T U R E
M aking the bacteriologic test by cul-
REQ U IRED
FO R M A K IN G
BAC -
TER IO LO GIC C U L T U R E T E S T S
T h e essential equipment for culturing
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Coolidge— M eth o d s o f T estin g for Bacterial Grow th
root canals before filling them is quite simple. I f one has access to a commer cial bacteriologic laboratory or to a hos pital laboratory, arrangements can usu ally be made by which the laboratory will provide culture media and will incu bate the cultures, so that the dentist is not required to provide such equipment. Should it be desirable to have the incu bation carried on in the dental office, a small thermo-regulated incubator can be secured at a very small cost. T h e incu bation of cultures requires only a regu lated temperature at the level o f human temperature, which is 370 C ., or 98.6° F. A simple home-made incubator sug gested b y Appleton,7 and to which Gross man refers, consists o f an ordinary quart
A
until used. Rosenow’s glucose brain broth is most highly recommended. TE C H N IC O F T H E C U L T U R E T E S T
T h e test for the sterility of the canals is not m ade until the treatment is con sidered complete and the canal expected to be free from infection. Usually, this is at the third or fourth appointment, and instead o f filling the canal at this time, it becomes part o f the regular rou tine to m ake a culture test for sterility. Those who are fam iliar with bacteri ologic technic realize that it is very d if ficult to make a bacteriologic test w ith out contaminating the culture tube with organisms that are not obtained from the root canal.
B
Fig. 8.— A , imperfect root-canal filling and periapical bone destruction. B, same tooth ten years after treatment and complete root-canal filling. T he periapical tissues appear to be free from inflammation.
thermos bottle. T he stopper used is a large cork, through which a hole is made to permit a thermometer to be inserted in order to record the temperature of the contents at different intervals. The culture tubes are swung from hooks or strings inserted in the cork stopper. Another simple incubator can be made by using an electric water heater with a thermostatic control in which the desired temperature can be maintained for any desired length of time. Culture media can be obtained from commercial laboratories as needed, or can be obtained in greater quantities in sterile tubes and kept in a refrigerator
Before adjusting the rubber dam, the mouth is sprayed with an antiseptic and the rubber dam is applied with great care to thoroughly isolate the tooth. T h e surfaces o f the exposed tooth or teeth are very thoroughly washed with a germicidal solution several times and painted with L ugol’s solution. W ith sterile burs, the root canal is opened and the dressing removed from the canal. This dressing is discarded, and if there is any antiseptic remaining in the canal, it is absorbed with sterile absorbent points and discarded before the culture test is actually made. A sterile cone is carefully inserted in
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T h e Journal o f the Am erican D en ta l Association
the root canal so that the point protrudes slightly through the apical foramen. A cone is left in the canal for a few mo ments, while the test tube containing the culture media is flamed. T h e ab sorbent point is carefully removed from the root canal and dropped into the culture medium, and the cotton plug is replaced in the test tube immediately. I f the foramen is so small that the ab sorbent point does not pass into the periapical tissue, a sterile root-canal file is passed into the canal and into the foramen a few times, after which another absorbent point is passed into the canal for the culture test. It is important that a little periapical tissue exudate moisten the tip of the cone, to insure the accuracy o f the test. T h e culture tube is now labeled, put in to the incubator and kept there for seventy-two hours at a temperature of 370 C. I f the thermos bottle incubator is used, the temperature will not remain at body temperature for seventy-two hours unless the bottle is carefully packed in a box with paper insulation. However, unless the room temperature is allowed to go considerably below 70°, the temperature in the thermos bottle will remain sufficiently high for twentyfour hours to promote growth in the cul ture tube. Usually, at the end of fortyeight hours, there is evidence o f growth if the culture is positive, but it is ad visable to allow seventy-two hours to elapse before filling the root canal, to be sure that the test is complete. A microscopic examination should be made o f the contents of the culture tubes to determine the type of organisms growing if the culture is positive. I f or ganisms are found, it is well to record on the patient’s history card the type predominating. Further treatment must be given and one or two negative cul tures obtained before the root canal is filled. Occasionally, the operator will en counter a tooth from which several suc
cessive positive cultures will be obtained. If, on investigation, he is convinced that the culture medium has not been con taminated by handling during the process o f taking the culture, and he is sure that there is no obscure leakage in the filling between appointments, the con clusion should be drawn that treatment is not successful. T h e percentage o f such instances is very low, but it is a precau tion against retaining a tooth that should be extracted. I f these precautions are taken, it is quite evident that teeth that are not susceptible to successful treat ment will be eliminated and the great number o f other pulpless teeth that many operators extract needlessly will be saved without jeopardizing health. SU M M A R Y
The employment o f bacteriologic tests by culturing root canals prior to filling, especially those which contained infec tious material, is a requirement in present-day clinical practice that can be met by every operator. Bacteriologic tests have proved to be far more accurate than the old method of determining the condition of the root canal and periapical tissue b y the con dition o f the dressing removed from the root canal. M any teeth, however, that were treated before bacteriologic meth ods were employed have given clinical evidence of being free from infection on roentgenographic examination and, after extraction, have given microscopic evi dence o f a healthy periapical tissue free from inflammatory cells. Histologic study of m any extracted teeth with good root-canal fillings has confirmed the evidence in m any cases of the possibility of saving pulpless teeth without danger of harboring a focus of infection in the periapical tissues. W ith improved methods o f technic, employing surgical asepsis during rootcanal operations and checking the treat ment by means o f bacteriologic tests, it is possible to eliminate the small per
33
O pp ice— D entistry and the N ational H ea lth Program
centage of infected teeth that are not susceptible to treatment. T h e solution of the problem o f the pulpless tooth is not in the extraction of all pulpless teeth, but in the differentia tion between those that can be saved by proper treatment and those that should not be saved because of failure to com pletely control the infection.
3. T
R uth , and H am m ond, Presence of Bacteria in Pulps of In tact Teeth. J.A .D .A ., 24:1663, October 1937. C
u n n ic l if f ,
arolyn
:
4. S t e i n , G e o r g : Ist jeder pulpakranke Z ahn infëziert? Z ts°hr. f. Stomatol., :1281,
33
1935-
5. A p p l e t o n , J. L. T ., J r : Bacterial Infec tion. Philadelphia: Lea & Febiger, 1933. 6. P r i n z , H e r m a n n : Diseases of Soft Struc tures of Teeth and Their Treatment. Philadel phia: Lea and Febiger, 2 Ed., 1937, p. 198. 7. G r o s s m a n , L. I.: Bactériologie Examina tion of Pulpless Teeth Before Filling Root Canals. J.A .D .A ., : , M a y 1938.
B IB LIO G R A PH Y
25 774
i. F i s h , E. W ., and M a c l e a n , I.: Distribu 8. A p p l e t o n , J. L. T ., Jr.: Bacteriological tion of Oral Streptococci in Tissues. Brit. D . Control of the Treatment of Periapical Infec J., 61:336, September 15, 1936. tion. D. Items Int., 49:589, August 1927. 2. B l a y n e y , J. R . : Present-Day Evaluation o f Pulpless Tooth. J.A .D .A ., 23:533, April 1936. 25 East Washington Street.
DENTISTRY AND THE NATIONAL HEALTH PROGRAM By
H arold
W.
O p p ic e ,
H E R E are those among our pres ent luxuriant crop of socio-eco nomic reformers who would lead us to believe that the United States has never had a national health program worthy of the name. There are even some dentists who speak and write in this fashion, demanding that adequate medical and dental care be provided by our government for all of its citizens. T h ey apparently do not understand the meaning or purpose of a national health program in a democracy, or they have done some wishful thinking in regard to the conditions that exist in the totali tarian state. A ll regulations and laws established or enacted by governmental agencies for the protection and promotion of individual and community health constitute the health program of any state or nation. History has recorded some program of
T
Read before the Cleveland Dental Society, Cleveland, Ohio, October 21, 1939. Jour. A .D .A ., V ol. 27, January 1940
D .D .S., Chicago,
111.
this type, no matter how simple, crude or ineffectual, since the beginning of gov ernment itself. It is quite possible that the “ forbidden fruit” in the Garden of Eden had an implication for health as well as for religion. B y far the most im portant and beneficial of all public health activities have been proposed, sponsored and carried out by members of the health professions as a result of their efforts to prevent and to treat disease. T h e profession of dentistry, although only now completing its first century of existence, has not been slow to recognize its responsibility toward the improve ment and maintenance of our national health program. It is unnecessary to do more than recall that the dental profes sion in the United States has fathered all the laws enacted by the several states and controlling and regulating the practice of dentistry in those states. Surely, the con tributions of the dental schools in the matter of public health cannot be ig