In Vitro Bacterial Penetration of Coronally Unsealed Endodontically.pptx

A journal club on description of bacterial penetration coronally in prognosis of root canal treatment

1. In Vitro Bacterial Penetration of Coronally Unsealed Endodontically Treated Teeth AUTHORS : MAHMOUD TORABINEJAD , BORASMY UNG & JAMES D KETTERING JOURNAL OF ENDODONTICS, 1990

2. CONTENTS INTRODUCTION AIM OF THE STUDY MATERIALS AND METHODS RESULTS DISCUSSION

3. INTRODUCTION Sealed root canals can be recontaminated under several circumstances : (a) If the patient had endodontic treatment but has delayed placement of permanent restorations (b) If the seal of the temporary filling material has broken down (c) If filling materials and/or tooth structures have fractured or been lost. When these situations occur, the coronal portion of the root canal system is exposed to oral flora.

4. The question is how quickly the entire root canal system becomes contaminated again, to the point that retreatment of the canal may be necessary……..? Swanson and Madison in 1987 evaluated the length of time that the obturation material could be exposed to artificial saliva before compromising the integrity of the seal using a dye (Pelikan Ink) found that the dye penetrated from 79 to 85% of the root length in all exposed specimens. Madison et al in 1987 in a follow up study showed that in teeth exposed to artificial saliva for 7 days, the ink penetrated between 33 and 80% of the root length, depending on the type of sealer used.

5. Marshall F J, Massler M in 1961 stated that in addition to dyes, radioisotopes could be used to study microleakage but found that they could not give a true picture of the leakage which occurs clinically as ions used are much smaller than dye molecules and they diffuse much more rapidly than other small molecules. Mortensen et al in 1965 & Krakow et al in 1977 stated that microorganism penetration might be more appropriate than dye or isotope penetration for studying leakage in vivo. Goldman et al in 1982 pointed out that bacteria performed better than dye in testing for leakage of hydrophilic materials and that dyes could give a false positive reading if their molecules were small enough.

6. AIM OF THE STUDY The purpose of this experiment was to determine the length of time needed for bacteria to penetrate a standardized length of obturated root canals which were intentionally exposed to one of two species of microorganisms.

7. MATERIALS & METHODS Apparatus setup : Circular opening of 1mm through the cap. Alligator Clip 25mm length latex tubing over coronal portion of the tooth Obturated tooth 1o ml sterile phenol red broth with 3% lactose

8. Bacterial preparation 2 species of bacteria were used as contaminants for this experiment : Proteus Vulgaris Staphylococcus Epidermidis Both species were grown overnight In 30 ml of Trypticase Soy Broth

9. Preparation of teeth 45 maxillary incisors and cuspids with straight canals were used and stored in 10 % formalin and kept moist throughout experiment After Initial radiographs , standard access cavities were prepared and coronal enlargement done using #2 and #4 GG drills Apical foramina of teeth enlarged up to # 40 file with intermittent irrigation using 5.25 % NaOCl Prepared teeth were divided into Experimental and Control groups

10. Monitoring the Samples 2ml of bacterial suspension and 0.7 ml of sterile artificial saliva were added to the tubing Both organisms were acid formers and they expected the phenol red indicator solution to change to a yellow color when the bacteria reached it. The samples were monitored daily until the red indicator solution at the bottom of the flask turned yellow followed by which the yellow medium was plated on blood agar to assure that it contained the same type of bacteria as that placed in the tubing .

11. Experimental Groups Root canals of 33 teeth were obturated with Gutta percha and Roth's sealer using lateral condensation technique. To obtain a standardized length of filling, the coronal portion of the gutta-percha was removed with hot pluggers until only 10 mm of the filling material remained in the canal. To prevent bacteria from penetrating the root surfaces, two layers of fingernail polish were applied to the outside of the root except for 1 mm at the apex.

12. EXPERIMENTAL GROUPS GROUP 1 The coronal portions of the root canals of 16 teeth in this group were placed in contact with 2 ml of P. vulgaris in trypticase soy broth and 0.7 ml of sterile artificial saliva The tubing was then suspended over the phenol broth so that approximately 2 mm of the apex of the tooth was immersed in it . GROUP 2 The coronal portions of the root canals of the rest of the teeth in the experimental group (17 teeth) were exposed to 2 ml of S. epidermidis and 0.7 ml of artificial saliva. The apices of these teeth were also immersed in phenol red broth.

13. CONTROL GROUPS GROUP 3 The root canal in each of the eight teeth that were used as positive controls was filled with a single gutta-percha cone without sealer, simulating poorly obturated root canals. Each of the two species of bacteria were placed separately in the tubing to contaminate four root canals (per microorganism) GROUP 4 To verify that no contamination developed during the experiments (negative controls), four instrumented root canals were filled with gutta-percha and sealer. Coronal portions of the filling were exposed to sterile artificial saliva To test the reliability of their results, the rest of the prepared teeth were divided into two control groups.

14. RESULTS Group 1 : Time taken by P. vulgaris to reach the apex through 10 mm of the filling material.

15. Group 2 : Time taken by S. Epidermidis to reach the apex through 10 mm of the filling material.

16. Control Groups Group 3 : Positive Control Except for one sample , the rest of the samples caused a color change in the phenol red medium after 1 to 4 days Group 4: Negative Control The culture medium did not change color in teeth whose coronal segments were in contact with only sterile saliva (group 4) throughout the experiment (over 90 days).

17. This study evaluated bacterial leakage and determined the time needed for bacteria to penetrate a standardized length of obturated root canals which were intentionally exposed to one of two species of microorganisms. Over 85% of the teeth inoculated with P. vulgaris became completely penetrated in 66 days, whereas most (88%) of those inoculated with S. epidermidis were totally infected in 30 days, suggesting that motility may not be a factor in rate of penetration to the apices. DISCUSSION

18. Most of the samples in the positive control group with poorly filled canals showed leakage by 1 to 4 days and showed that sealers are needed to improve the apical seal and was a confirmation of similar studies by Marshall et al, Evans et al & Skinner et al. They found a significant variability in the time that took the bacteria to penetrate the entire root canal system which could be due to the shape of the prepared canal, type of sealer used, or the nature of the solution to which the coronal portions of the root canal were exposed.

19. Compared with clinical conditions, the model used in their study was static, its media for bacterial growth was not totally similar to saliva and for ease of management of experimental conditions and interpretations of the data, the bacterial contents were purposely limited to only two species.

20. Siqueira et al in 2000 evaluated the coronal leakage of bacteria from saliva to root canals filled by 3 obturation techniques and concluded that none of the techniques tested could predictably produce a coronal bacteria tight seal of the root canal after direct saliva challenge. Shashidhar et al in 2011 compared bacterial leakage using streptococcus mutans gutta percha and a thermoplastic synthetic polymer based root canal filling material (Resilon) and demonstrated that obturation using Resilon and epiphany sealer was significantly better than gutta percha. Oliveria et al in 2013 evaluated coronal microleakage of endodontically treated teeth prepared to receive an intra canal post and a teeth with an intracanal post without a crown exposed to fresh human saliva and found that tooth without prosthetic crown could be recontaminated when exposed to saliva.

21. CONCLUSION Endodontic therapy encompasses the complete sealing of the access cavity and the root canal apex . This eradicates the prospect of microleakage and the bacterial contamination leading to subsequent failure. For decades deficient obturation of root canals were was extensively considered as source of recurrent endodontic infection Lately the focus has shifted on the deficient post endodontic restoration after endodontic treatment and influence of this on the prognosis

22. Studies have shown that inadequate coronal restoration results in higher number of failures ( Lazarki et al 2001 , Friedman et al 2003, Lynch et al 2004, Pierre Machtou 2006, Mindola et al 2006 ) A successful endodontic therapy requires an integral coronal seal along with a good apical seal. Coronal microleakage must be deliberated as an impending etiological factor for failure of root canal therapy.

23. REFERENCES 1. Swanson KS, Madkson S. An evaluation of coronal microleakage in endodontically treated teeth. Part I. Time periods. J Endodon 1987;13:56-9. 2. Madison S, Swanson KL, Chile SA. An evaluation of coronal microleak- age in endodontically treated teeth. Part I1. Sealer types. J Endodon 1987;13:109-12. 3. Madison S, Wilcox LR. An evaluation of coronal microleakage in endo- dontically treated teeth. Part III. In vivo study. J Endodon 1988;14:455-8. 4. Marshall F J, Massler M. The sealing of pulpless teeth evaluated with In Vitro Bacterial Penetration radio-isotopes. J Dent Med 1961 ;16:172-84.

24. 5 . Evans JT, Simon JHS. Evaluation of the apical seal produced by injected thermoplasticized gutta-percha in the absence of smear layer and root canal sealer. J Endodon 1986 6. Bacterial leakage in coronally unsealed root canals obturated with 3 different techniques .J F Siqueira Jr 1, I N Rôças, A Favieri, E C Abad, A J Castro, S M Gahyva , 2000 7. The comparison of microbial leakage in roots filled with resilon and gutta-percha: An in vitro study C Shashidhar, Vasundhara Shivanna, GB Shivamurthy, and Jyothi Shashidhar , JCD 2011 8. Coronal microleakage of endodontically treated teeth with intracanal post exposed to fresh human saliva .OLIVEIRA ,Denise Jornada GOMES, Marcelo Hissé das Neves COSTA, Ezilmara Rolim de SOUSA, Rafael Guerra LUND , JAOS , 2013