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

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.