efficacy of chemo-mechanical preparation with different substances and the use of a root canal medication in dog’s teeth with induced periapical lesion

Objectives: to evaluate the effect of instrumentation, irrigation with different substances and the use of calcium hydroxide on bacterial load and microbiota profile in dog’s teeth with pulp necrosis and periapical lesion. Methods: Fifty five root canals were divided into groups: I) Saline (SSL) (n=11); II) natrosol gel (n=11); III) 2.5% NaOCl (n=11); IV) 2% CHX-gel (n=11); V) 2% CHX-solution (n=11). Endodontic samples were cultured, microorganisms counted and the microbiota analyzed at different sampling times — s1, s2 and s3. Results: At s1, the mean CFU counts ranged from 5.5 x10 to 1.5 x 10. These values dropped significantly at s2 (p<0.05). No statistical significant difference was found between s2 and s3. Changes in root canal microbiota were found at s2 and s3. Conclusion: Regardless the use of calcium hydroxide as a root canal medication, 2.5% NaOCl and 2% CHX-gel demonstrated a potent antimicrobial activity against endododontic pathogens in vivo.