Evaluation of the Effects of Dental Implant Dimension and Design on Primary Implant Stability Using Different Stability Measurement Devices

Background/Objectives: Dental implants are an established treatment for functional and aesthetic rehabilitation of partially or completely edentulous patients. This in vitro study evaluates the effects of dental implant design, diameter, length, and bone density on primary implant stability using Osstell ISQ and Penguin Resonance Frequency Analysis (RFA) devices. Materials and Methods: A total of 96 dental implants were included in this study. Combinations of two implant designs (T6 Standard and T6 Torq), two implant diameters (3.5 mm and 5.0/4.8 mm), and two implant lengths (8 mm and 14 mm) were placed into synthetic bone blocks with densities of PCF15 and PCF30. Implant stability was measured twice from two different directions using Osstell ISQ and Penguin RFA devices. The data were statistically analyzed. Results: Both RFA devices demonstrated high measurement reproducibility. When all measurements were evaluated collectively, the intraclass correlation coefficient (ICC) reached 0.999 for both devices. Bone density was identified as the most influential factor affecting primary implant stability. Significantly higher ISQ values were obtained in the high-density bone model (p < 0.001). Increases in implant length and diameter significantly enhanced primary stability (p < 0.001). T6 Torq implants exhibited significantly higher ISQ values than T6 Standard implants in low-density bone and small-dimension implant combinations (p < 0.001). Conclusions: Under the present experimental conditions, bone density showed the greatest influence on primary implant stability, followed by implant length and implant diameter. In low-density bone, particularly with short and narrow implants, more aggressive implant macrodesigns may contribute to higher primary stability. However, the clinical relevance of these findings requires further investigation.