Retrospective assessment of clinical and microbiological factors affectingperiimplant tissue conditions

An increasing numbs; of studies point to the detrimental effect of plaque b acteria on periimplant tissue health. The purpose of this retrospective stu dy was to explore a possible relationship between the clinical and microbio logical periimplant conditions of osseointegrated oral implants after sever al years of service and the dental and medical history, as well as the cond itions of the residual dentition. 45 partially edentulous patients (mean ag e: 51 years, range: 27-83 years), with a total of 64 implants participated in this retrospective analysis. The time between examination and the last d ental visit ranged from 6 to 24 months (mean: 13 months) and the time since the last maintenance therapy appointment with a dental hygienist ranged be tween 3 and 24 months (mean 7 months). During 5 to 10 years between implant installation and examination, 9 implants experienced one episode and an ad ditional 6 implants two episodes of periimplantitis. As a consequence of ex tensive bone loss associated with these infections, one of these implants, in a patient who had a history of diabetes, was lost. With this exception, the other episodes of periimplantitis were successfully treated employing t he principles of the Cumulative Interceptive Supportive Therapy (CIST) prot ocol. At examination, 42 implants (66%) showed a probing pocket depth excee ding 4 mm. Of the periimplantitis sites, four implants showed cultural evid ence for presence of Porphyromonas gingivalis, and 2 implants were positive for Actinobacillus actinomycetemcomitans. Statistical analysis revealed a significant relationship between periimplant probing depth and the total an aerobic cultivable microbiota as well as the frequency of detection of P. g ingivalis.