ISQ for Assessing Implant Stability and Monitoring Healing: A Prospective Observational Comparison between Two Devices

Background: With the growing use of dental implants, there is an urgent need to determine a prosthetic placement protocol by assessing implant stability and monitoring healing. Implant Stability Quotient (ISQ) values are produced using dental non-invasive devices through resonance frequency analysis, considered as indicators for measuring primary stability (i.e., at implant placement), monitoring biological stability (osseointegration), and prosthetic loading. A systematic and detailed comparison of ISQ measurement devices, for a given patient population, is lacking in the literature. This aspect is the subject of the present work, with the devices being two that are widely used in clinical practice (Osstell (R) and Osseo (R) 100). The aim of this study was to evaluate the reliability of ISQ measurement using two standard devices most commonly used in clinical practice and to highlight any differences when comparing measurements at undefined time intervals. Methods: We enrolled 50 patients (16 males and 34 females) with a mean age of 55.4 years, who indicated dental implant placement and met the inclusion criteria. The sample was divided into two equal groups based on bone density: A (D1-D2 bone density) and B (D3-D4 bone density); each had 25 patients with 40 implants. ISQ was measured using two devices: Osstell (R) and Osseo 100 (R), at different time points (A: three and B: four follow-ups). Results: All enrolled patients completed the study without adverse events; all implants placed were successful, with no implant failure. In each of the study groups, ISQ values increased gradually with increasing follow-up time, and there was no significant difference between Osstell and Osseo 100 values at follow-up times except for the T1 follow-up in group A. Temporal comparisons for the two devices revealed significant differences in T0 vs. T2 in group A, whereas significant differences existed in T0 vs. T1, T2, and T3 in group B. Our findings indicated that the overall effect significantly depended on bone density rather than on the device used to measure ISQ. Conclusion: Regardless of the devices used, the ISQ measurement effectively monitors healing after implant insertion and allows prosthetic load to be modulated according to the ISQ value, especially when prosthetizing implants placed in fine trabecular bone (D4 or regenerated bone).