Residual PPD>or=6 mm represent an incomplete periodontal treatment outcome and require further therapy.

In multivariate logistic regression analysis, a high-risk patient profile according to the PRA model at the end of APT was associated with recurrence of periodontitis. Another significant factor for recurrence of periodontitis was an SPT duration of more than 10 years.

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.

FI = 1 was not a risk factor for tooth loss compared with FI = 0. FI = 2/3, smoking and lack of compliance with regular SPT represented risk factors for the loss of MRT in subjects treated for periodontitis.