EVALUATION OF ROOT-CANAL BACTERIA AND THEIR ANTIMICROBIAL SUSCEPTIBILITY IN TEETH WITH NECROTIC PULP

This study aimed to evaluate the microbiota of necrotic pulp in teeth without carious lesions where the crown and root were intact and to te st the sensitivity of this microbiota to antibiotics in order to impro ve treatment. The necrotic pulp was sampled from 26 single-rooted teet h in intact pulp chambers. A total of 84 strains were isolated. The nu mber of species isolated per tooth varied from 2 to 8, with a strong c omponent (81%) of anaerobic bacteria. The most commonly represented sp ecies were Bacteroides gracilis, Propionibacterium acnes, Fusobacteriu m nucleatum, Prevotella buccae and Eubacterium lentum. The sensitivity of these organisms to amoxicillin, amoxicillin combined with clavulan ate and tetracycline was evaluated by Etest(R) on 38 isolates. For all strains tested, the minimum inhibitory concentration values obtained were low and substantially below effective serum concentrations for th ese antibiotics. These data enable us-to devise suitable treatments fo r acute development of apical lesions and to prevent dissemination of this source of infection to the rest of the host.