Prevalence and diversity of bacteria in root-filled teeth associated with periradicular lesions

Abstract number: 1733_1192

Al-Ahmad A., Liebenow A-L., Wittmer A., Pelz K., Hellwig E., Schirrmeister J-F.

Objectives: Persistence of microorganisms or reinfection are the main reasons for failure of root canal treatment. The knowledge of bacterial diversity in root-filled teeth can help to find the adequate treatment plan to eradicate microorganisms associated with periradicular lesions. The aim of this study was to isolate and identify microorganisms of twenty different root-filled teeth associated with periradicular lesions.

Methods: All teeth studied had been previously root-filled and showed radiographic evidence of periradicular disease. After removal of the root-filling material, samples of 20 cases undergoing retreatment were collected using paper points which were immediately transferred to reduced transport fluid (RTF). A quality control was performed to exclude contamination of the samples with saliva or dental plaque. Serial dilutions were plated on Columbia Blood Agar (CBA) and on Yeast-Cystein Blood Agar (HCB) to isolate aerobic and anaerobic microorganisms, respectively. Bile Esculin Agar was used to cultivate enterococci. The bacteria were identified by morphological and biochemical analysis. Additionally, identification by 16S rRNA-gene sequencing was applied.

Results: The samples of eight patients did not contain bacteria. In samples of 12 patients microorganisms could be isolated. The colony forming units/mL (CFU/mL) were in the range of 103–107 on CBA and of 103–109 on HCB, respectively. A mixed culture was found in the samples of 10 patients. Species of Enterococcus, Streptococcus, Peptostreptococcus, Campylobacter, Veillonella, Fusobacterium, Dialister, Bulleidia, Bacteroides, Eubacterium, Actinomyces, Propionibacterium, Serratia, Klebsiella, Porphyromonas, Mycoplasma, Gemella, Corynebacterium, Capnocytophaga, Vagococcus, Megasphaera, Atopobium, and Flexistipes were detected. In samples of two patients E. faecalis was the only isolated species. In two samples similar bacterial species were also found in the quality control which indicates a contamination of the revision samples by saliva or dental plaque.

Conclusions: Microorganisms could not be isolated from all teeth. The majority of positive samples revealed a mixed culture of 2 to 9 species. E. faecalis was the only detected agent in two patients underlining its suggested important role in endodontic infections. A quality control was essential to avoid false positive results which could be easily caused the contamination with saliva or dental plaque.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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