RESUMEN
Fimbriae (fimA) of Porphyromonas gingivalis are filamentous components on the cell surface and are thought to play an important role in the colonization and invasion of periodontal tissue. P. gnigivalis fimA gene encoding fimbrillin, a subunit of fimbriae, has been classified into 5 genotypes (typesI to V) based on the nucleotide sequences. In the present study, we examined the prevalence of these fimA genotypes in patients with dental implant and the relationship between prevalence of these genotypes and peri-implantitis. Dental plaque specimens obtained from 80 peri-implant sulci of 50 patients with dental implants were analyzed by 16S rRNA fimA gene-directed PCR assay. P. gingivalis were detected in 74.4% of the samples of the control group (healthy peri-implant sulci; probing depth or =5mm). Among the P. gingivalis-positive samples of the control group, the most prevalent fimA type was typeI(29.3%), followed by typeII(26.8%). In contrast, a majority among the P. gingivalis-positive samples of the test group was typeII(56.5%), followed by typeI(43.5%). TypeII fimA genotype organisms were detected more frequently in the test group and a significant difference in the occurrence of typeII was observed between test and the control groups. A correlation between specific fimA types and peri-implant health status was found in typeII(OR 3.545) and only a weak relationship was revealed in typeIV(OR 3.807). These findings indicate that P. gingivalis strains that possess typeII fimA are predominant in peri-implant sulci with peri-implantitis and are closely associated with peri-implant health status. P. gingivalis with typeII fimA may be involved in peri-implantitis.