Immediate provisional restoration of screw-type implants in the posterior mandible: results after 5 years of clinical function.

Objective: The aim of this prospective study was to evaluate the outcome of immediately provisionally restored implants in the posterior mandible after a minimum of 60 months in function.
Material and Methods: Twenty-four patients were treated with 40 screw-type implants replacing mandibular molars and premolars. Implants were provisionalized immediately after placement. Radiographic coronal bone levels, implant survival and success were evaluated 12, 24, 36, 48 and 60 months after the final restoration.
Results: Measurements of the mean marginal bone levels around immediately loaded implants after 12 months showed a significant bone loss (P<0.001) within the first year after the final restoration. Measurements of coronal bone levels after 24, 36, 48 and 60 months, respectively, showed no further significant increase of bone resorption. Two implants were lost within the first year after the final restoration, resulting in an overall survival rate of 95%; a total of three implants were recorded as failures (two implant losses and one excessive bone resorption above 50%), resulting in an overall success rate of 92.5 after an implant observation period of up to 8 years.
Conclusion: The present data revealed results comparable to conventionally loaded implants. Careful patient selection in combination with high primary stability seem to be key factors for immediately loaded implants. Larger long-term randomized clinical trials are needed to confirm the final evidence of this protocol as the standard treatment concept for the partially edentulous mandible.