Polymerase chain reaction-based simultaneous detection of selected bacterial species associated with closed periapical lesions.

Purpose: The aim of this study was to identify microorganisms which might be present in closed periapical lesions and to determine their relationship to conventional clinical parameters. -

Methods: In 11 patients, samples were taken with paper points from 14 teeth with periapical radiolucency, in seven cases two samples were taken from two different sites of the same tooth (n=21). Clinical parameters were determined. The 16S rDNA of eleven bacterial species could be simultaneously detected via a modified polymerase chain reaction (PCR) based technique. -

Results: All samples contained more than one bacterial species. Most frequently, M. micros was detected alone or in combination with E. faecalis, P. aeruginosa, E. coli, F. nucleatum or S. sanguinis. When apical palpation was positive, often M. micros and F. nucleatum were both present. Other clinical symptoms like tenderness to percussion were not associated with a particular microflora. -

Conclusions: In closed periapical lesions detected by radiography, specific bacteria were identified by means of a modified PCR technique. No clear associations between clinical symptoms and these bacteria were found. Surgical intervention might be indicated for some of the persistent lesions.