The evaluation of bacterial flora in progress of peri-implant disease

Background:  Cumulative interceptive supportive therapy (CIST) is currently used as a guideline for treating peri-implant diseases. The objectives of this study were to determine the detection rate and measure the number of periodontopathic bacteria in lesions of different CIST levels and thereby characterize peri-implant disease from a bacteriological viewpoint. Methods:  This study included 105 patients who had both residual natural teeth and implants with peri-implant disease. A total of 105 implants were divided into levels A, B, C and D according to the CIST classification. Bacterial samples were collected from peri-implant pockets and four periodontopathic bacteria were measured by PCR and PCR-Invader assay. Results:  The number of periodontopathic bacteria increased in line with CIST level, and the detection rate was also associated with CIST level. However, no difference was found in the bacterial detection rate of P. gingivalis and T. denticola between CIST-B and CIST-C. There was a higher detection rate of all periodontopathic bacteria for CIST-D. Conclusions:  The number of periodontopathic bacteria and detection rate increased as peri-implant disease advanced. However, there were no major differences in the detection rate between CIST-B and CIST-C. On the other hand, a higher detection rate of periodontopathic bacteria was seen for CIST-D.