title: Evaluation of the antibacterial effect of calcium hydroxide in combination with three different vehicles: An in vitro study.
abstract: BACKGROUND
  Antimicrobial activity of interappointment intracanal medications is an important consideration in endodontics. Considering the fact that calcium hydroxide (CH) cannot sterilize the root canal system, completing its antimicrobial spectrum seems necessary. The aim of this study was to compare the antibacterial activity of CH combined with three different vehicles in root canal system.
  
  
  METHODS
  In this in vitro experimental study, 61 freshly extracted human single rooted teeth were used. After chemo-mechanical preparation, the teeth were dressed with CH in combination with: G1: Distilled water (DW); G2: 5.25% sodium hypochlorite; G3: 0.2% chlorhexidine solution. All teeth were mounted in a 2-chamber apparatus. After sterilization, the coronal chamber was exposed to bacteria and the apical chamber was filled with broth for 90 days. Leakage was recorded when turbidity was observed in broth. Mean times of leakage and turbidity percentage were recorded for each group. Data were analyzed by One Way ANOVA test (α=0.005).
  
  
  RESULTS
  The highest mean time of contamination was for chorhexidine/CH combination (M=66.76 days), and the lowest was for DW/CH combination (M=40.29 days). Statistically significant difference was observed between G3 and G1 (P=0.042), but the difference between G2 and G3 (P=0.76) or G1 and G2 (P=0.18) were not significant. 88.23% of the samples of G1, 70.58% of G2, and 64.70% of G3 were contaminated after 3 months.
  
  
  CONCLUSIONS
  As an intracanal medication, the chlorhexidine/CH combination had significantly more antibacterial activity than DW/CH combination.
authors.affiliation: Torabinejad Dental Research Center and Department of Endodontics, Isfahan University of Medical Science, Isfahan, Iran.
authors.forename: Ali Reza
authors.initials: AR
authors.lastname: Farhad
authors.forename: Behnaz
authors.initials: B
authors.lastname: Barekatain
authors.forename: Maryam
authors.initials: M
authors.lastname: Allameh
authors.forename: Tahmineh
authors.initials: T
authors.lastname: Narimani