Changes of clinical parameters at implants: A retrospective comparison of implants versus natural teeth over 5 years of supportive periodontal therapy.

OBJECTIVES: To compare clinical parameters of implants versus natural teeth over a period of 5 years during supportive periodontal therapy (SPT). MATERIAL AND METHODS: A total of 421 SPT patients were screened for implants (I) and corresponding control teeth (C). Data (patient level [(P) ]: sex, age, smoking status, systemic diseases, adherence, oral hygiene indices, mean probing depth [PD](P) , bleeding on probing [BOP](P) , periodontal risk profile; implant/control tooth level [(I/C) ]: PD(I/C) , BOP(I/C) ; site level at implants [(SITE) ]: position, dental arch, aspect, BOP(SITE) ) were assessed at the first SPT session where the implant was probed (T1) and 5 years later (T2). The influence of patient and implant/control-related factors on PD(I/C) /BOP(I/C) was tested (linear mixed model) as well as the influence of site-specific factors on the PD(SITE) change (multilevel regression). RESULTS: A total of 70 patients (151 implants) were included. Mean PD(I) was 2.75 +/- 0.85 mm (T1) and 2.87 +/- 0.79 mm (T2). Mean PD(C) was 2.42 +/- 0.66 mm (T1) and 2.49 +/- 0.71 mm (T2). BOP(I) increased from 8.62 +/- 15.01% (T1) to 24.06 +/- 26.79% (T2) and BOP(C) from 9.97 +/- 17.78% (T1) to 15.52 +/- 22.69% (T2). The differences between implants and controls were significant for BOP (p = .0032). At T2, BOP(I/C) was associated with periodontal risk (p = .0351). The site-specific analysis revealed an association of BOP(SITE) at T1 with the progression of PD(SITE) (p = .0058). CONCLUSIONS: Probing depths of implants and controls seem to change similarly during SPT but retention of inflammation-free conditions at implants appears to be more difficult compared to natural teeth. Patients with a high-risk profile appear to have an increased susceptibility for BOP around implants, and BOP at implants seems to be a predictor for further PD increase.