Antimicrobial potential of medicaments used in healing process in dogs' teeth with apical periodontitis.

The objective of this study was to evaluate the influence of irrigants on the antimicrobial potential of calcium hydroxide paste in dogs' teeth with apical periodontitis. Forty-eight premolar teeth of adult mongrel dogs had their root canals opened to the oral environment for 6 months. The root canals were prepared and treated with different irrigating solutions and intracanal medicaments, according to the following groups: 1) 2.5% sodium hypochlorite (NaOCl) + calcium hydroxide paste (CHP); 2) 2% chlorhexidine (CHX) + CHP; 3) vinegar + CHP; 4) vinegar + vinegar. In group 4, both the irrigating solution and intracanal medicament were vinegar, which was renewed every 7 days. Each sample was collected by using two paper points maintained in position for 1 min, and individually transported and immersed in 7 mL of Letheen broth (LB), followed by incubation at 37 degrees C for 48 h. Microbial growth was analyzed by two methods: turbidity of the culture medium and subculture on a specific nutrient broth (brain heart infusion). After 21 days, all experimental groups had microbial growth, however, in different percentages: group 1 - 30%; group 2 - 30%; group 3 - 40%; group 4 - 60%. All materials tested had antimicrobial potential; however, the influence of calcium hydroxide paste on the control of microorganisms must be remembered.