Resonance Frequency Analysis Assessment of Implants Placed with a Simultaneous or a Delayed Approach in Grafted and Nongrafted Sinus Sites: A 12-Month Clinical Study.

BACKGROUND: Implant stability is one of the key factors for a successful osseointegration. At present, several techniques are available to regenerate bone tissue, but it is not clear whether implants placed in grafted bone are as stable as implants in native bone over time. PURPOSE: The aim of the present study was to compare, by means of resonance frequency analysis (RFA), the stability of implants placed in sinus-grafted and -nongrafted sites during 12-month follow-up. METHODS: Twenty-five patients received a total of 38 implants. Nineteen implants were placed in maxillary native bone (group A) and 19 implants following maxillary sinus floor augmentation using anorganic bovine bone and autogenous bone (group B) in a 50:50 ratio. Group B was divided into groups B1 and B2 depending on the timing of implant insertion, that is, B1 simultaneously and B2 6 months after sinus lift. The implants were inserted according to a two-stage procedure. RFA values were collected at baseline, 6 and 12 months after implant placement. RESULTS: Between the tested groups, no statistically significant difference was found in RFA values of implants placed in sinus-grafted and -nongrafted sites after the surgery as well as at 6 and 12 months, while a significant difference was recorded in group B1 (p = .0297) when RFA values were compared over time.