The association between three attitude-related indexes of oral hygiene and secondary implant failures: A retrospective longitudinal study

Objective: This study evaluated the strength of the association between three widely used clinical indexes considered as distal behavioural indicators of attitude-related oral status (an index of oral hygiene, the plaque index [PI] and two periodontal indexes, that is the presence of bleeding on probing [BOP] and of pockets probing depth [PPD]) and secondary implant failure due to peri-implantitis in patients rehabilitated with cemented prosthesis. Materials and Methods: The study included patients who underwent implant-prosthetic rehabilitation and had joined the programme of maintenance of the same hospital. Implant failures, number of months between implant insertion and implant loading, and patients' surgical protocol were monitored and recorded. Further, PI, BOP and PPD-all attitude-related indicators of oral hygiene and periodontal inflammation-were recorded and related, in terms of odds ratios (ORs) and corresponding risk factors, to secondary implant failures. Results: A total of 1427 patients (2673 implants) were enrolled. The follow-up ranged from 1.5 to 9 years (mean 5.3 years±1.3). The cumulative survival rate was 98.01%. Thirty-two patients (36 implants, 1.36% of all implants) had implant failure. A statistically significant association between PI, BOP, PPD and secondary failures due to peri-implantitis was observed. Conclusion: Within the limitations of this study, all three attitude-related behavioural indicators-the plaque index (PI), bleeding on probing (BOP) and abnormal probing pocket depth (PPD)-proved to be significant risk indicators for secondary implant failure due to peri-implantitis, both from a clinical and from a socio-psychological attitude-related perspective.