Bacterial Coronal Leakage after Obturation with Three Root Canal Sealers

Abstract

The purpose of this study was to compare the bacterial leakage of root canals obturated with three root canal sealers, using Endodontalis faecalis as a microbial tracer to determine the length of time for bacteria to penetrate through the obturated root canal to the root apex. Seventy-five, single-rooted teeth with straight root canals had the crown cut off at the cementoenamel junction. Root canals were instrumented by a step-back technique. The prepared teeth were randomly divided into 3 groups of 19 teeth each and another 2 groups as positive and negative controls (9 teeth each). The experimental groups were dependent on the sealer used: AH-Plus, Apexit, and Ketac-Endo. The root canals were obturated using a lateral condensation technique. After 24 h the teeth were attached to microcentrifuge tubes with 2 mm of the root apex submerged in Brain Heart Infusion broth in glass test tubes. The coronal portions of the root canal filling materials were placed in contact with E. faecalis. The teeth were observed for bacterial leakage daily for 30 and 60 days. With the chi2 test for comparing pairs of groups at the 0.05 level (p < 0.05), there was no statistical difference between Ketac-Endo and AH-Plus (p > 0.06), but Apexit had significantly higher leakage (p < 0.05) at 30 days. After 60 days there was no statistical difference between Ketac-Endo and Apexit (p > 0.05), but Apexit leaked more than AH-Plus. The conclusion drawn from this experiment was that epoxy resin root canal sealer was found to be more adaptable to the root canal wall and filling material than a calcium hydroxide sealer when bacterial coronal leakage was studied.

Influence of the length of remaining root canal filling and post space preparation on the coronal leakage of Enterococcus faecalis

“…Coronal leakage has been pointed out as one of the most important and challenging causes of endodontic failure because it compromises sealing of the root canal system (3,7,12,21,22).…”

“…It has been demonstrated that oral fluids, bacteria and their byproducts may infiltrate through the marginal gaps of defective restorations and penetrate the interface between the root filling material and the root canal walls, reaching the periapical region within a relatively short time (3,4,7,8,21,22). This scenario is worsened in case of teeth with extensive coronal tooth loss that implicates in the placement of intraradicular posts because of following factors associated with post space preparation and post cementation: break of the aseptic chain during procedures undertaken without rubber dam isolation, possibility of dislodging the obturation during removal of the coronal portion of the filling material, placement of temporary restorations between the prosthetic working sessions and length of the remaining root canal filling.…”

“…It has been demonstrated that tests using bacteria as tracer agents of leakage may simulate in a more reliable manner what actually occurs under clinical conditions, as they allow a dynamic interaction between the tested bacterial strain and the root canal sealer (11,14,20,21,24,25). E. faecalis is the most often retrieved pathogen in asymptomatic endodontic infections because of its capacity to invade dentinal tubules, compete with other microorganisms and resist nutritional privation.…”

“…It has been demonstrated that root fillings exposed to the oral cavity are invariably contaminated by fluids, bacteria and their byproducts. Long-term contamination may lead to failure of endodontics and compromise the restorative/prosthetic treatment as a whole (1,8,21,22,25).…”

<i>In vitro</i> microleakage of six different dental materials as intraorifice barriers in endodontically treated teeth

“…Timpawat et al 36) reported that the use of bacteria to assess coronal leakage is considered to be of clinical and biological relevance. However, those bacterial studies have been qualitative rather than quantitative.…”