Background: The immediate loading technique requires a high primary stability. Resonance frequency analysis (RFA) has been proposed to assess this stability with a quantitative method.
Purpose: The aim of the present study was to evaluate if a good primary stability could be achieved in sites that had undergone a sinus augmentation procedure and also to evaluate the importance of different clinical factors in the determination of resonance frequency values at implant insertion.
Materials and methods: In 14 patients, 80 implants were inserted. Sixty-three implants were inserted in a site previously treated with a sinus augmentation procedure, while 17 implants were inserted in healed or postextraction sites. For each implant, diameter, length, bone density, insertion torque, RFA value, and percentage of implant fixed to a nongrafted bone were recorded.
Results: Grafted sites showed high RFA values. A statistically significant positive correlation was found between resonance frequency values and implant diameter (p=0.007), implant length (p=0.02), diameter of the last bur used (p=0.01). No statistically significant correlation between RFA values and all the other variables considered was found.
Conclusions: Sites treated with sinus augmentation procedures can offer good primary stability after 6 months of healing. The length and diameter of the implants, together with the geometry of the implant used, are important to obtain high RFA values.