Peri-implantitis susceptibility as it relates to periodontal therapy and supportive care

Objective: To assess the long-term survival of implants inserted in periodontally susceptible patients and to investigate the influence of residual pockets on the incidence of peri-implantitis and implant loss.

Materials and methods: For 70 patients, comprehensive periodontal treatment was followed by installation of 165 Straumann Dental implants. Subsequently, 58 patients entered a University supportive periodontal therapy (SPT) program and 12 had SPT in a private practice. The follow-up time ranged from 3 to 23 years (mean 7.9 years). Bleeding on probing (BOP), clinical attachment level (CAL), and peri-implant probing depths (PPD) were evaluated at baseline (T0), completion of active treatment (T1), and at follow-up (T2). Peri-implant bone levels were assessed on radiographs at T2. Patients were categorized as having implants not affected by peri-implantitis (non-PIP), or affected by peri-implantitis (PIP).

Results: From 165 implants inserted, six implants were lost, translating into a cumulative survival rate of 95.8%. Solid screw implants yielded significantly higher survival rates than the hollow cylinder and hollow screw implants (99.1% vs. 89.7%). Implants lost due to peri-implant infection were included in the PIP groups. When peri-implantitis (PPD ≥ 5 mm, BOP+) was analyzed, 22.2% of the implants and 38.6% of patients had one or more implants affected by peri-implantitis. Using the peri-implantitis definition (PPD ≥ 6 mm, BOP+), the prevalence was reduced to 8.8% and 17.1%, respectively. Moreover, all these implants demonstrated significant (≥ 2 mm) bone loss at T2. At T1, the non-PIP group had significantly (P = 0.011) fewer residual pockets (≥ 5 mm) per patient than the PIP group (1.9 vs. 4.1). At T2, the PIP group displayed an increased number of residual pockets compared to T1, whereas in the non-PIP group, the number remained similar to T1. At T2, mean PPD, mean CAL and BOP were significantly higher in the PIP group compared with the non-PIP group. The prevalence of peri-implantitis was lower in the group that was in a well organized SPT at the University.

Conclusions: In periodontitis susceptible patients, residual pockets (PPD ≥ 5 mm) at the end of active periodontal therapy represent a significant risk for the development of peri-implantitis and implant loss. Moreover, patients in SPT developing re-infections are at greater risk for peri-implantitis and implant loss than periodontally stable patients.