A Novel Dental Implant Nut System Designed to Enhance Primary Stability: Mechanical and Finite Element Analysis

Abstract

Purpose: The present study aimed to evaluate, in a preclinical setting, the biomechanical behavior and mechanical performance of a newly developed dental implant nut system designed to address primary stability challenges in the severely resorbed posterior maxilla. Materials and Methods: The evaluation consisted of two complementary stages: an in vitro mechanical experiment and a finite element analysis (FEA). In the experimental phase, polyurethane jaw models simulating a severely atrophic posterior maxilla with approximately 1 mm residual bone height were used. Four groups were prepared: single implant without nut, single implant with nut, double implant without nut, and double implant with nut (n = 10 per group). Primary stability was measured using resonance frequency analysis (RFA) with an Osstell device. In the computational phase, three-dimensional finite element models were constructed from cone-beam computed tomography (CBCT) data of the same configuration to evaluate detachment forces and stress distribution within the bone-implant complex under vertical loading. Results: In single-implant models, mean implant stability quotient (ISQ) values increased from 10.91 +/- 7.35 to 18.27 +/- 7.11 after nut application. In double-implant models, ISQ values increased from 11.13 +/- 4.14 to 19.24 +/- 4.24 (p < 0.05). FEA results revealed that the detachment force increased from 16.5 to 20.33 N in single-implant models and from 15 to 22.3 N in double-implant models. Compressive stresses on the bone were lower in nut-supported configurations, indicating a more favorable load distribution. Conclusion: The nut system was associated with increased implant primary stability and a more favorable stress distribution under the conditions of this preclinical study. These findings should be interpreted as preliminary biomechanical evidence, as no in vivo or clinical validation was performed. Therefore, this design may be considered a mechanical stabilization concept that warrants further investigation through in vivo and clinical studies.