Long-term implant prognosis in patients with and without a history of chronic periodontitis:: a 10-year prospective cohort study of the ITI® Dental Implant System

Aim: The aim of this 10-year study was to compare the failure, success and complication rates between patients having lost their teeth due to periodontitis or other reasons. Material and methods: Fifty-three patients who received 112 hollow screw implants (HS) of the ITI(R) Dental Implant System were divided into two groups: group A - eight patients with 21 implants having lost their teeth due to chronic periodontitis; group B - forty five patients with 91 implants without a history of periodontitis. One and 10 years after surgical placement, clinical and radiographic parameters were assessed. The incidences of peri-implantitis were noticed over the 10 years of regular supportive periodontal therapy. Results: Success criteria at 10 years were set at: pocket probing depth (PPD) less than or equal to 5 mm, bleeding on probing (BoP-, bone loss < 0.2 mm annually. The survival rate for the group with a past history of chronic periodontitis (group A) was 90.5%, while for the group with no past history of periodontitis (group B) it was 96.5%. Group A had a significantly higher incidence of peri-implantitis than group B (28.6% vs. 5.8%). With the success criteria set, 52.4% in group A and 79.1% of the implants in group B were successful. With a threshold set at PPD less than or equal to 6 mm, BoP- and bone loss < 0.2 mm annually, the success rates were elevated to 62% and 81.3% for groups A and B, respectively. Relying purely on clinical parameters of PPD less than or equal to 5 mm and BoP-, the success rates were at 71.4% and 94.5%, and with a threshold set at PPD less than or equal to 6 mm and BoP-, these proportions were elevated to 81% and 96.7% for groups A and B, respectively. Conclusions: Patients with implants replacing teeth lost due to chronic periodontitis demonstrated lower survival rates and more biological complications than patients with implants replacing teeth lost due to reasons other than periodontitis during a 10-year maintenance period. Furthermore, setting of thresholds for success criteria is crucial to the reporting of success rates.