This in vitro study evaluated the efficacy of calcium hydroxide Ca(OH)2 pastes prepared with different vehicles in preventing bacterial infiltration in teeth exposed to human saliva. This study used 52 central incisors, of which 4 teeth were used as positive and negative controls (n = 2). The root canals were instrumented and filled with Ca(OH)2 paste prepared with different vehicles: saline solution (Group 1), polyethylene glycol (Group 2), or polyethylene glycol and camphorated paramonochlorophenol (Group 3). Only 6 teeth in Group 1 showed contamination. All teeth in Groups 2 and 3 were contaminated after 32 days of incubation. There were significant differences between Groups 1 and the other groups (P < 0.05) in terms of the mean time to contamination. By contrast, there was no such difference in terms of mean time to contamination between Groups 2 and 3 (P > 0.05). Based on the results, it was possible to conclude that calcium hydroxide paste prepared with saline solution was most effective for retarding microbial contamination.
Keywords: calcium hydroxide; endodontic; microbial infiltration; root canals.