Non-grafted sinus implants in periodontally compromised patients: a time-to-event analysis

This study reports the results of implant therapy involving a sinus membrane lift and of conventional implant therapy in 68 periodontally compromised patients treated between June 1990 and June 2002. Patients had at least two implants inserted, one of which was placed in the maxillary sinus region following fenestration of the lateral sinus wall and lifting of the sinus membrane. Two implant systems were used: a two-stage system (Astra) and a one-stage system (ITI). Annual follow-up visits included recording of plaque, probing pocket depth and measurement of the radiographic distance in millimeter from the implant shoulder to the alveolar crest. Survival analysis showed that the proportion of implants that had not been explanted after 5 years ranged between 88.7% for ITI sinus implants and 97% for ASTRA conventional implants. After 10 years, the proportion of implants remaining in situ ranged between 59% for ITI conventional implants and 97% for ASTRA conventional implants. Cox regression analyses showed that the factors influential for implant explantation were implant type (HR(ITI) = 2.8), implant length (HR(< or = 10 mm) = 3.1), patient being a smoker (HR(smoking) = 2.2) and patient having at least 20 natural teeth (HR(> or = 20 teeth) = 3.8). Our results demonstrate that sinus implants may be inserted with the same success as conventional implants in periodontally compromised patients.