Microbiology and treatment of endodontic infections

Author(s)

Morgana Eli Vianna

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2006-10-31

Examining board members

Brenda Paula Figueiredo de Almeida Gomes; Izabel Cristina Froner; Alexandre Augusto Záia; Pedro Luiz Rosalen; Manoel Damião de Sousa Neto

• Advisor: Brenda Paula Figueiredo de Almeida Gomes

Abstract

The aim of the present study was to evaluate in vivo the microbial and endotoxins load after chemo-mechanical preparation (CMP) and after the use of intracanal medications (ICM), it was also aimed to evaluate in vitro the antimicrobial suscetibility from some microrganisms isolated. Samples were colected of single root teeth containing necrotic pulp tissue and periapical bone lesions, in several stage of the endodontic treatment. Transport medium, culture and incubation in favour of strict anaerobic microorganisms to grow were used. Microorganisms were identifyed by biochemichal tests and endotoxins quantified by Limulus Amebocite lysate (LAL) test. Antimicrobial susceptibility was evaluated by E-test method using the following antibiotics: benzylpenicillin, amoxicillin, amoxicillin + clavulanate, erythromycin, azithromycin, cephaclor, metronidazole, and clindamycin. Results showed that microorganisms were present in all teeth containing necrotic pulp tissue and periapical bone lesion, the colony forming unit (CFU/mL) ranged from 4x105 to 2.6x106. The microorganisms most frequent isolated were Propionibacterium acnes, Gemella morbillorum, Actinomyces naeslundii and Eubacterium lentum. Endotoxin was also present in all initial samples, ranging from 62.93 to 214.56 UE/mL. Post CMP samples showed more than 99% reduction of cultivable microbiota and 57% (mean value) of endotoxin concentration. After 7 days of ICM, residual microorganisms were still found in 54.1% of the cases and the endotoxin concentration increased considerably compared to the first CMP. No statistically significant differences among the intracanal medicament groups were found. In conclusion, the microbiological results sugested that CMP was responsible for the majority of the microbial and endotoxin reduction. Amoxicilin and amoxicilin plus clavulanic acid were the best antimicrobial agents, as all bacterial strains tested were susceptible to their action. Some Fusobacterium spp. showed to be resistant to eritromycin. In conclusion, the microbiologic results suggest that chemo-mechanical preparation was responsable for mainly microbial and endotoxin reduction. Amoxicilin and amoxicilin puls clavulanic acid are the first choice when required to use a systemic antimicrobial agent, as alternative to alergic patients the azitromicin is an option (AU)