Relationship between Implant Geometry and Primary Stability in Variant Bone Densities: An In Vitro Pilot Study

Abstract

Background and Aim: The success of dental implants largely depends on achieving primary stability, especially in varied bone densities. Primary stability is influenced by factors such as implant geometry and bone density, which play crucial roles in osseointegration and the overall implant stability over time. While various implant designs have been developed, the optimal geometry for different bone densities remains unclear. This study aims to investigate the effect of four implant geometries Bone Level Tapered (BLT), Bone Level (BL), Tissue Level Standard Plus (SP), and Tissue Level Standard (S) on primary stability in medium-dense (D2) and soft (D4) bone densities. Methods: An in vitro pilot study was conducted using 96 osteotomies on porcine ribs as a bone model to replicate human bone conditions. Each implant geometry was placed in D2 and D4 bone densities, and primary stability was measured using resonance frequency analysis (RFA) through the Implant Stability Quotient (ISQ). Descriptive statistics and a two-way ANOVA were applied to assess the main effects of implant geometry and bone density on primary stability, as well as their interaction. Results: The dense bone (D2) group showed significantly higher ISQ values compared to the soft bone (D4) group across all implant geometries, indicating a strong effect of bone density on implant stability (p < .001). However, no statistically significant differences were found among the four implant geometries in terms of primary stability (p = .627). Additionally, there was no significant interaction effect between implant geometry and bone density (p = .506), suggesting that implant geometry did not influence stability differently in the two bone densities. Conclusions: Bone density was identified as a critical determinant of primary stability, with denser bone providing superior stability outcomes. The findings suggest that while implant geometry did not significantly impact stability in this controlled in vitro setup, bone quality assessment should be prioritized in clinical settings. Future research should examine long-term stability, including secondary stability and osseointegration, to validate these results in varied clinical scenarios.