resonance frequency analysis of implant stability in augmented and non-augmented sinus sites

background and aim:  although there have been substantial developments in dental implant therapies, achieving good implant stability (isq >60) for implants inserted in augmented sinus sites appears to be challenging in comparison with non-augmented sites due to the high prevalence of bone resorption in posterior regions of maxilla. this study aimed to evaluate and compare the time required to achieve good implant stability between implants inserted in sites that had undergone a sinus augmentation procedure with implants inserted in non-augmented similar regions of maxilla. methods: thirty stroman iti dental implants were inserted in 14 patients (8 females and 6 males) with average age of 55 ± 10 years. fourteen implants were inserted in sinus augmented sites (open sinus elevation and demineralized freezed bone allograft  or dfdba) 6 months after healing (test group), and 16 implants were inserted into non-augmented  posterior areas of maxilla (control group). the implant stability quotient (isq) for each implant was measured at the time of insertion (baseline, isq0) and at 1, 2 and 3 months later (isq1, isq2, isq3). residual and augmented bone heights were also recorded. results: the average residual bone height was 2.92 ± 0.63mm and 10.41 ± 1.46mm for the augmented bone height. the difference between isq values in the test and control groups was only significant at the baseline (p=0.023). no significant correlation was found between isq and bone height (residual and augmented), and there was no significant correlation between isq values and the implant diameter and length. in the test group, the differences between isq0 and isq1, isq1 and isq3 and isq2 and isq3 were all statistically significant (p=0.006, p=0.032, p=0.046). in the control group, the difference was only significant between isq0 and isq1 (p=0.002). conclusion:  isq values were not statistically significant between implants inserted in natural and augmented bone six months after sinus augmentation. in other words, within the limitation of this study, the time required to achieve good stability for implants inserted in augmented sinus sites is similar to those inserted in non-augmented sites.