In Vitro Antimicrobial Efficacy of Calcium Hydroxides in Root Dentin

Abstract

Enterococcus faecalis is the most commonly isolated bacteria in failed root canal treatment. Endodontic intracanal medicaments are commonly tested using standardized bovine cylinders infected with bacteria. The literature is not clear on whether calcium hydroxides are able to remove E. faecalis from the dentinal tubules. One reason for this is that there are several varying forms of calcium hydroxide commonly used. The purpose of the present experiment was to determine whether four commonly used calcium hydroxide products were able to reduce E. faecalis from four incremental samples of dentin and to determine if there was a statistically significant difference between each medicament in its ability to eliminate E. faecalis from bovine dentinal tubules. Ninety freshly extracted incisors from 22-24 month old cows were milled into standardized cylinders of the following dimension: 5 mm high, external diameter of 7 mm, and lumen diameter of 2.7 mm. The cylinders were sterilized and were all subsequently infected with Enterococcus faecalis ATCC4082, except for 15 which were set aside as negative controls. The remaining cylinders were divided into four treatment groups of 15 and a positive control group also consisting of 15 cylinders. The four treatment groups had the canal lumen filled with Calasept®, Diapex®, Ultracal®, or Pulpdent® for two weeks. After two weeks, round burs sized ISO 029, 031, 033, and 035 were passed through the lumens, dentin shavings were weighed, cultured and CFU/mg were enumerated. One-way ANOVA, Student-Newman-Keuls multiple comparison procedure, and Kruskal-Wallace tests were used for data analysis. Statistically significant reductions in CFU/mg E. faecalis were found between the four treatment groups and the positive controls (p \u3c 0.0001). Reductions in CFU/mg E. faecalis of 94.1%-100.0% were observed. There was no statistically significant difference between the medicaments. All p-values were \u3e 0.5