Identification of yeast and non-pigmented cultivable endodontic bacteria in adult portuguese patients

Abstract

Introduction This study has focused on the identification of the yeasts and non-pigmented bacteria present on adult patients with necrosis or apical periodontitis and the ones who resisted chemomechanical preparation and intracanal dressing with calcium hydroxide paste (Ca(OH)2) or 2% chlorohexidine digluconate gel (CHX). Methods 69 single-rooted teeth of adult patients with necrosis associated or not with apical periodontitis were selected (strict inclusion criteria); CHX group: 34 teeth; Ca(OH)2 group: 35 teeth. Bacteria samples were taken at baseline (S1), after chemo-mechanical preparation (S2) and after 14 days of intracanal dressing (S3). Bacteria and fungal presence was evaluate by means of culture in three atmospheres (aerobic, anaerobic, microaerofilic) in appropriate culture broads. Strict techniques were used for serial dilution, plating, incubation and identification. Results The most represented, abundant and prevalent strains of non-pigmented bacteria were Propionibacterium acnes (detected in S1, S2 and S3), Gemella morbillorum and Clostridium difficile. Candida albicans was found in 9 patients. The higher number of isolates proceeded from S1, being S2 the moment with lowest number of isolates. CHX had a worst performance in disinfection of the root canal system; consequently the number of isolates from S3 samples was bigger compared to Ca(OH)2. The number of identified bacterial species per canal/moment of sampling, varied from zero till 5, including yeasts (Candida albicans). Conclusions: Our findings confirm that the microbiota from primary endodontic infections is polymicrobial, and the anaerobes Gram-positive non-pigmented bacteria are well represented. CHX performed worse, consequently the number of isolates from S3 samples was bigger when compared to Ca(OH)2 as well as with diagnosis of necrosis.