Bacteriological study of roots canals associated to periapical abscesses

Author(s)

Ezilmara Leonor Rolim de Sousa

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2000-12-11

Examining board members

Caio Cezar Randi Ferraz; Clovis Monteiro Bramante; Brenda Paula Figueiredo de Almeida Gomes

• Advisor: Caio Cezar Randi Ferraz

Abstract

Infected dental root canais typically harbour a mixed flora, including many anaerobic species. The role of these microorganisms and their by-products in the development and perpetuation of pulp and periapical diseases has already been well established. Efforts have been made in order to correlate bacteria present in infected dental root canais to clinical signs and symptoms. The present study was outlined to identify microorganisms present in root canais associated to periapical a bscesses , the correlation specific bacteria species with the phases of this inflammatory acute process, signs and symtoms and, to test the susceptibility of this microbiota to antibiotics. Microbiological samples were collected from 30 root canais using sterile paper points, transported in VMGA and diluted, plated and incubated in an anaerobic chamber. Microbial colonies were then purified, characterised and identified by established methods. One hundred seven different bacterial species were recovered, being 75 (64.1 %) strict anaerobes or microphilic species. One or more (maximum of 10) bacterial species were recovered from 29 (96.6%) root canais, showing the polymicrobial characteristic of dental infections. The anaerobes most frequently isolated were: Peptostreptococcus prevotii (43.3%), Peptostreptococcus micros (30%), Fusobacterium necrophorum (23.3%). Although less frequent, facultative bacteria as Gemella morbillorum (30%) e Streptococcus mitis (20%) were also found. However, statistical analysis by a Pearson X2 test or a one-sided Fisher's exact test did not find statistical relationship between any bacterial specie identified and the presence of periapical abscesses (p>0.05). Antibiotic sensitivity of Peptostreptococcus prevotii e Fusobacterium necrophorum was accomplished with the E-test System. These bacterial isolates were tested for their susceptibility/resistance to benzylpenicilin, amoxiciln, amoxicilin combined with clavulanate and clindamycin. The species Peptostreptococcus prevotii and Fusobacterium necrophorum were susceptible to ali tested antibiotics. In spite of the lack of statistical significance, our results indicated predominance of Gram-positive anaerobic bacteria at the mixed microflora present in dental root canais associated with periapical abscesses. Antibiotic susceptibility data showed Peptostreptococcus prevotii and Fusobacterium necrophorum susceptibility to ali tested antibiotics (AU)