RFA Values of Implants Placed in Sinus Grafted and Nongrafted Sites after 6 and 12 Months

Background: Maxillary sinus floor elevation surgery is widely used as a preimplantology method to permit implant insertion. Nevertheless, very few data are available about long-term stability of dental implants inserted in grafted sites. Purpose: The aims of the present study were to evaluate the evolution of resonance frequency analysis (RFA) values at 6 and 12 months from the implant insertion in sinus grafted sites and nongrafted sites. Materials and Methods: In 14 patients, 80 Xive implants (Dentsply Friadent GmbH, Mannheim, Germany) were inserted. Sixty-three implants were inserted in a site previously treated with a sinus lift; 17 implants were inserted in healed or postextraction sites. For each implant diameter, length, bone density, insertion torque, and percentage of implant fixed to a nongrafted bone were recorded. RFA values at implant insertion after 6 and 12 months were recorded. Results: After 6 and 12 months, grafted sites showed higher RFA values than the control sites; after 12 months, the difference was statistically significant (.007). A statistically significant positive correlation was found between resonance frequency values and bone quality after 12 months (.05). No statistically significant correlation between RFA values and all the other variables considered was found. Conclusions: Sites treated with sinus lift can offer good long-term stability. After 6 and 12 months, the geometric characteristics of the implant are no longer important to obtain high RFA values, and the bone-implant interface seems to be determinant.