The Influence of Implant Macro-geometry in Primary Stability in Low-Density Bone: An in vitro Study.

Abstract

Aim: This study assessed the primary stability of implants featuring various geometries in polyurethane bone blocks simulating low-density bone types 3 and 4.

Methods: The study included 36 implants divided into three groups (Straumann BLT, n = 12; Zimmer TSV, n = 12; and Dentium Superline [DSL], n = 12). Implants featuring three different thread designs, a tapered body, a diameter of 4.0-4.1 mm, and a length of 10 mm were inserted into polyurethane bone blocks (20 and 15 PCF) to simulate bone types 3 and 4. Primary stability was evaluated using implant stability quotient (ISQ), insertion torque (IT), and removal torque (RT). IT and RT were compared using ANOVA, while ISQ was analyzed using the Kruskal-Wallis test. A P value < 0.05 was considered statistically significant.

Results: For bone type 3, the highest IT (30.21 ± 1.38 N cm) and RT (23.25 ± 2.30 N cm) value were observed for the Zimmer TSV, and the highest ISQ values (63.29 ± 0.54 N cm) were observed for DSL. For bone type 4, the highest IT (18.07 ± 1,71 Ncm) and RT (14.48 ± 1.81 Ncm) values were observed for the Zimmer TSV, and the highest ISQ values (58.46 ± 0.78 N cm) were observed for the DSL. The ISQ, IT, and RT values of the implant groups were significantly different (P < 0.001).

Conclusions: Implant geometry and bone density were key factors influencing primary stability in this study. The outcomes of the present study may help clinicians make decisions, especially when dealing with bone that has a less favorable quality. These findings may have important clinical implications related to immediate or early loading protocols, highlighting the critical role of implant design in attaining sufficient stability.