The microbiologic approach in endodontics

The microbiologic

approach in endodontics

Aryeh Y. Kaufnmn, D.N.D., Pekcrh I’ikvah, (I& l’el-Aviv,

tr~td Niexer Ismel

PERIODONTIC

DEPARTMENT,

SCHOOL

OF

LABORATORY, MICROBIOLOGY,

AND

ENDODONTIC

DENTAL

MEDICINE,

BEILINSON TEL-AVIV

HEBREW

JERIXALEM

HOSPITAL, UNIVERSITY

Ii’. Hewig,

; THE

PETAH

TIKVA

MEDICAL

Ph.D.,

Jerustrlent,

UNIVERSITY

HADASSAH

MICROBIOLOGICAI~ ; DEPARTMENT

OF

HllMAN

SCHOOL

The results of an investigation of the microbiologic flora of gangrenous teeth arc presented. The rationale of the concept of the microlliologic approach is discussed. A possible explanation for the small differences in the success of endodonticallg treated teeth obturated after positive and negative bacteriologic cultures is suggested.

F

or years cultures have been made in order to estimate the microbiologic status of the root canal for effective endodont.ic treatment. of diseased and infected teeth. Diseased pulp tissue can provide a suitable environment for microbial existence and growth. A culture ma.y serve to determine t.he microbiologic status of the diseased pulp and also as a control in aseptic technique, an essential factor in successful root canal therapy. In general, a negative culture indicates effective removal of the ctiologie agents producing the infection. However, there is no agreement among authors as to the importanc*c of the microbiologic investigation concerning the effectiveness of the endodontic treatment. Reviewing the literature on this subject, one can find authors who consider the microbiologic culture to be important’-” and others who do not agree with this concept.‘-” In a series of investigations of the antibacterial effect of a preparation for root canal treatment (to bc publishecl), we studied the bacterial flora of the root canals of diseased teeth anti we present here our findings.

MATERIALS

AND

METHODS

The investigation was conducted on patients treated at the StomatSologic Institute at Tel Hashomer. The patients were soltlicrs, 1X to 45 years of age, ant1 their family members, who were referred to the Institute by a general clinic after an initial diagnosis and the decision that they needed endodontic treatment. The criteria for inclusion in the investigation were: nonvital, pulpless teeth, with or without periapical lrsion ; teeth that Hal IKXW untreated previously ; teeth that 810

I. Number and location of the treated teeth

Table

Molars 13 6 19

Upper Lower Total

Premolars 4 2 6

Canines

Incisors

1

6 1 T

i

II. Organisms isolated from root canal cultures

Table

Organism Streptococcus viridans Streptococcusjbecalis Staphylococcus aureus. Staphylococcus aureus, Proteus mirabilis Escherichia coli Coliform bacteria Dinhtheroids r ~~~ Candida albicans

coagulase coagulase

+ -

No.

Per cent

38 10

48 12.7 2.5 13.9 3.8 5.1 5.1

1: 3 t 3

3.8

4

5.1

could be treated with an aseptic technique. The teeth treated are listed in Table I. Sterilized instrument tray setups, including all intracanal instruments and absorbent paper points, were used. The tooth was isolated with a rubber dam. Entry into the pulp chamber was accomplished with sterile burs. A sterile absorbent paper point was inserted into the root canal and immediately transferred to a tube of thioglycollate cultural medium. 1)ifco fluid thioglycollate medium, which was used also as a transport medium, is generally accepted as especially useful for sterility testing of biologicals and other materials. It is particularly well suited for the growth of both acrobes and anaerobes because of the small amount of agar which it contains. The culture medium tubes thus inoculated were immediately incubated at 37O C.“.and the growth was checked daily for 11 days. All culture tubes showing any growth, a.s chcc*ked macroscopically and also microscopically by examination of smears prepared from the culture tube and stained, were submitted for further investigation, for identification of the organisms, and for testing of their susceptibility to antibiotics. The media nsed for further tliff’crcntiation of the organisms included: hloodagar plates preparcd from I)ifco bloo~l agar base with addition of 5 per cent stcrilc clefibrinated blood, i\lacConkc\- agar plates, Kliglcr iron agar tubcls, Tarious sugar mcltlia, ITrcw-Tntlol brot,h, an{1Wcllcotest agar. RESULTS

Out, of 291 cultures, including repeated follow-up ones, taken from root canals, 236 (81.1 per cent) wcro positive ant1 55 (18.6 per cent) were negative. The organisms isolated from thr root canal cultures were as shown in Table II. CASE CASE

REPORTS 1

A 31-year-old woman complained prared several times during the last

of pains in the right laxer quadrant. 7 months, accompanied by inflammation

The pains had apand swelling of the

Kaufman and Hewig

812

Oral December,

Fig. 1. Preoperative roentgenogram showing lesion penetrating t,he pulp chamber, rarefaction alveolar bone in the bifurcation area. Fig. 3. Roentgenogram showing the root canal Fig. 3. Eight-month follow-up roentgenogram areas.

Surg. 1976

the lower right first molar with deep carious areas in the periapieal regions, and a loss of filling. showing

regeneration

of

the

rarefaction

right side of the face, which disappeared after antibiotic treatment. On examination we found that the lower right first molar was gangrenous and very tender to both vertical and horizontal percussion. A roentgenogram revealed that, the lower right first molar had a deep caries penetrating into the pulp chamber. There was a loss of one third of the alveolar bone height, including the bifurcation. A rarcfaction area was present around the mesial root (Fig. 1). The diagnosis of chronic dentoalveolar abscess was established. The pret.reatment bacteriologic finding was StrPptococcw wiridnns. After completion of the biomechanical preparation and irrigation a second bacteriologic sample was taken from all three canals and the cultures were negative. Refore the second treatment bacteriologic examination of samples taken from the canals revealed, after a more prolonged incubation for 48 hours, only a scarce growth of Strqtococc~ts wiriduns. At the third session the tooth was obturated with gutta-percha points and AH 26* as a sealer (Fig. 2). A followup examination after 8 months revealed that the crown was broken, but there was a reduction in the rarefication areas and there were signs of bone regeneration in the furcation area (Fig. 3). CASE

2

A 26year-old woman came for replacement of a hrokeu crown on the lower right first molar. She had no complaint of pain or discomfort. A roentgenogram showed a radiolucent area around the mesial root of the lower right first molar (Fig. 4). A pretreatment bacteriologic culture revealed the presence of Streptococcus fnecalis. Two cultures made during the second session were negative. The obturation was performed at the third session (Fig. 5). A roentgmogram and examination taken 8 months after completion of the treatment showed that bone regeneration had taken place and the radiolucent area had disappeared (Fig. 6). *De-Tray

Fr&es,

S. A., Ziirich

(Switzerland).

Volume Numllrr

42 6

Fig. Fig. Fig.

CASE

4. Preoperative 5. Roentgenogram 6. Eight-month

Microbiologic

roentgenogram showing taken after completion follow-up roentgenogram

approach

in ettdodontics

rarefaction area around the me&l of obturntion. showing bone regeneration.

813

root.

3

A 32.year-old man was seen because of a broken filling in the upper left second molar. He did not complain of pain or discomfort. Physical examination revealed that the upper left second molar did not react to thermal and electric tests. No other symptoms were present. A roentgenogram showed widening of the periodontal ligament around the apices of the palatnl and mesiobuccal roots. Endodontic treatment was started. Pretreatment bacteriologic examination showed the presence of Streptococczts ciridnns. Another specimen taken after completion of the first treatment revealed the growth of Proteus mirnbilk An additional culture made before the second treatment revealed again the growth of Streptococcus viridnns, which grew repeatedly after the hiomechanical preparation at the second session. During the treatment a bloody exudate appeared in the mesiobuccal canal. A culture performed before the third treatment disclosed again the presence of Protw mirnhilti. At the end of this treatment the culture wm negative. Three days later the patient developed moderate pains, which became stronger during the next 2 days. Examination revealed a slight smelling of the left face and the periapical area was tender and fluctuating. Following the opening of the tooth a sample was taken for bacteriologic examination which showed the growth of Protws mircrbilis. During the treatment me faced a stream of hloody exudate from both buccal canals which could hardly be controlled. A second culture taken before sealing the tooth revealed again the growth of Proteus mirnbilis. The swelling persisted for 4 more days without any pain. Then the abscess opened spontnneously with a bloody exudate. We noticed the presence of a sinus tract. This fistula persisted for a week and cultures obtained from the root canals and from the sinus tract, taken before every treatment and upon completion of treatment, revealed a continuous infection by Proteus mirabilis. At the seventh treatment, after the sinus tract disappeared, the bacteriologic culture was still positive for Protects mirabilis. At the next treatment, while no signs of the fistula

tion root.

Pig. in

7. One-year the rarefaction

were present the treatment.

and the tooth still revded

rigation of the A roentgenogram cessory lateral rocntgenogram

follouup areas

roots, taken canal after

the

rofrntgenogram and the ol)turated

was completrly thv growth culture after the

in the middlrx 1 year ~110w~d

became filling

of

the Iatfwl

upper left c~+nal at

asymptomatic,

P,roteus

of of

the

mimbilis.

negative, the root

second molar, the rnidrllt~ of

bacteriologic Howww,

and the roots canals disclosed

after

showing reducthe distobuccd

culture taken cleansing

1)eforc and ir-

were sealecl permanently. the pwsenr~ of an

of the tlistolmcc~:~l root. .A followup an asymptornntir an11 functional tooth

rxamimltion iPi~. i ).

nr:md

DISCUSSION The debate about the ~Jccd for microbiologic culture in cndotlontics is still going 0~1. Many investigators c:oJJsidttr it to 1~ imlwrtant. As st.atctl by %eldow and Inglc,’ “the clinical uscfu~ness of ba~tcriologic control in entlodontic therap; has been t~~l1lOlJStr~tCX~ 1,~ llJc greatw suwcss rate which owurs in teeth fillet1 after obtaining a negative cultuw.” Engstriim and asso&ates,z in their investigation of the correlation of positive cultures with the prognosis for root canal treatment, reached the conclusion that persisting infection at the time of root filling is an important factor affecting adversely the prognosis in c*onservativr root treatment. Their results as well as those of other authors’ investigations support strongly the view that bacteriologic root canal wntrol is north carrying out a~1t1 that wreful asepsis is a necessary precondition for the reaching of optimal results. According to ?ulatusow,3 the rationale for root canal trcatmcnt is to retain teeth bp cffcct,iw removal of diseased and infcctcd pulp tissue. iIlicrobiolngic concepts in asepsis, dcl~ridcment, and 0htUrati0JJ i r(: fuJJdameJita1 to successful therapeutic results. similarly, Grossman 1 mcntioncd statistics showing that twth obturated after negative culture show 10 per writ grcatcr s~Jc’wss t.han those which have been obturated after a positiw cultuw. The same wnclusion was rcachctl by Shapira.” Naidorf” atlvised culturing in endodontk trcatmcnt as follows : “Since one cannot with an) assurance scparatc pathogclls from nonpathogens, and since eve~l nonpathogenic surface cwntaminants will interfcw \vith normal Iwaling, the elimination or the reduction of the total numlw of lnic,roorganisnis is clcsirahlc. Smears do not diffcrentiatc tlcatl from live bacteria. Sinw the o~ily practical index of bacterial viability is the capacity to rcprotiuw, the culture test is the only scientific method for determining sterility or at ieast the redwtion in t.hc microl~ial population t.o a point \\hrrc there is no gro\vth ~JI the inc~dium cm~~lo~~~cl.”

On the other hand, some authors have expressed their doubts about t,he value of bacterial cultures in cndodonties, Scliildcr,7 summing up the discussion on this subject, mentioned thoscl who ncgatc the value of the culturing with the claim that there exist many variables such as the culture media, the timing of taking cultures, and the possibility of transf’(~r of antibiotics or other antimicrobial agents into tlic culture mctliuni. The cultures may gi\c false-positive or false-negative results. E’alse-positive cultures may result from incomplete sterilization of instruments and absorbent. points, breath contamination, air contamination, rubber-dam leaks,” incomplete sterilization of the opcrativc field,” or air-leaking temporary fillings. The reasons for false-negatisc results may include a dry canal, incomplete penetration of the sampling point,4 insuficicnt time of incubation or only aerobic incubation,!’ reliance on visual determination of growth,” and the residual antimicrobial effect of intracanal medicaments.x. ‘* R’torsc,‘2 discussing the rationale of the culture concept, came to the conclusion that, although the culture is irrelevant in routine cndodontic therapy, it is essential to rcducc the microbial population to as low a level as possible, in order to help ensure that the host-parasite rclationship will be a favorable one for the host. However, he did not dismiss microbiologic considerations completely, bepause there are indications that in some instances, particularly in casts of acute apical abscesses and cellulitis, microbiologic evaluation is of value. Moreover, in such cases, not only the isolation and idcntification of the infecting organism arc important, but also the antibiotic sensitivit,y test should be performed. If an antibiotic is used at the onset of the disease and is not effcetice, the information will be available for selecting another drug which will be effective against the particular strain of organism. Knowing quite well all the pros and cons on the microbiologic approach to cndodontic treatment, we investigated our casts carefully. As mentioned, our investigation was directed toward an evaluation of the antimicrobial activity of a pertain preparation. We thercforc seleetod our patients for treatment in accord with clearly defined criteria. The microbial strains which WC found were isolated repeatedly several times with the help of culture media and culturing conditions suitable for the growth of aerobic and anaerobic organisms. Careful performance of the microbiologic investigation in all respects, including collection of the specimens, allowed us to keep to a minimum any possibility of false-positive or falsenegative results. At the end, on the basis of microbiologic control, we were able to ensure an effective endodontic treatment, even in cases with clearly persistent infection. In view of the case reports cited, it appears to us that from taking bacteriologic cultures before beginning and upon completing every session, one can obtain two kinds of reports. The culture taken before every session presents the real picture of the bacterial flora, whereas the culture taken upon completion of the biomechanical preparation and irrigation is negative most of the time and special precautions must be taken in order to grow a few colonies. However, while placing intracanal medication which will remain between sessions, a positive culture is most, often obtained before the nest session, Our impression is that thorough cleansing and irrigation produce a temporary state of sterility. If the final obturation is done in this condition we cut off the possibility for the remaining

germs to remultiply, and placing intracanal medication as a bactericitlal agent does not guarantee sterility of the canals.‘” On the other hand, most of the intracanal medications show strong q-totoxic affects.’ * It seems to us that between treatments the remaining germs may develop ant1 multiply once again. This observation ~ulcl explain the results of Shapira” and (Grossman,’ who found only small differences in the success of root canal fillings performed after negative and positive bact,erial mltuws. In conclusion, we advocate the microbiologic approach in endodontic treatment provided that the microbiologic investigation is performed with care to avoid any unreliable results. The microbiologic evaluation is, without doubt, important in cases of persistent infect.ions such as in cast No. 3, apical abscesses, cellulitis, a.nd so on, where it can be of great help to the patient, not only in the diagnosis of the infection, but also in the antimicrobial managemrnt. SUMMARY

The results of an investigation of the microbiologic flora of diseasedteeth in root canal treatment have been presentetl and the rationale of the concept of the microbiologic approach in cntlotlont~ieshas btlcn tliscussecl. REFERENCES 1. Zeldo~\:, 2. 3. 4. 3.

6. 7. 8. 9. 10. 11.

12. 13. 14.

Reprint

B. J., and Ingle, J. J. : Correlation of the Positive Culture to the Prognosis of EnJ. Am. Dent. Assoc. 66: 23-27, 1963. dodontxally Treated Teeth : A Clinical Study, G., and Frostrll, G.: Correlation of Positive CulEngstriim, B., Segerstad! I~., Ramstriim, tures With the Prognosis for Root Canal Treatment, Odontol, Rev. 15: 257.270, 1964. Matusow, R. J.: Microbiology of the Pulp and Periapical Tissues: Culture Control, Dent. Clin. North Am. 549-565, 1967. Grossman, I,. J. : Endodontics Practice, rd. 7, Philadelphia, 1965, Lea & Febigcr, Publishers, pp. 310-336. Shapirn, Y.: Roentgenological and Clinical Evaluation of Endodontically Treated Teeth n’ith or \$‘ithout Negative Culture, Thesis submitted to the Hebrew University Hadassxh School of Dental Medicine, Jerusalem, Nov. 1973. Naidorf, I. .J.: Clinical Microhiolog-y in Endodont,ics, I)cnt. Clin. North Am. 18: 329-344, 1974. Schilder, H. : The Vxluc of Culturing in Endodontic: Trratmmt, Dent. Clin. North Am. 12T, 1903. Miiller, A. J. R.: Microbiological Examination of Root Canals and Periapical Tissues of Human Teeth : Methodological Studies, Giitebore. 1966. Akademifarlaget.. Engstriim, B., and Frost&, G. : Rxp&ienw of”kacte&ological Root “Canal Controls, Acta Odontol. Stand. 22: 43-69. 1964. Zeldow, B. J. : Microbiological Considerations in Endodontics, In: Ingle, J. l., editor: Endodontics, Philadelphia, 1965, Lea & Febiger, Publishers, pp. 472-485. Bender, 1.. B., and Seltzer, S.: The Probability of Error of the Negative Culture With the Use of Combination of Antibiotics in Endodontic Trratment, ORAL SURC. 7: 1311-1319, 1954. Morse, I). H.: The Endodontic Culture Tc~chniqw: A Critical Evaluation, Oaar, S~~JRG. 30: 510-544. 1970. (Iwikla,’ .r. R.: The Vaporization and (lapillarity E:ffect of Entlodontic Medicaments, ORAL SUM:. 34: 117-121, 1972. Spangberg, I,., Engstriim, IX, and Langeland, K.: Biologic Effects of Dental Materials. 3. T0xicit.y and Antimicrobial Effect of Endodontic Antiseptics, ORAT. SVRG. 36: 856, 1973. requests

Dr. Arieh Kaufman 6, Hamaagal St. Ramat, Gan, Israel

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