Three-dimensional finite element analysis of the stability of tooth-implant supported prostheses for mandibular anterior dentition defects

BACKGROUND: While tooth-implant supported prostheses (TISP) are commonly used in the posterior region, few studies report on their anatomical suitability or mechanical behavior in the anterior mandible. This study analyzed CBCT data from patients with mandibular anterior edentulism and constructed three-dimensional finite element models to investigate the anatomical constraints of this region and to compare the biomechanical behavior of different restorative designs involving TISP. METHODS: Based on CBCT images of 524 patients, 3D reconstruction using Mimics 21.0 was performed to measure available alveolar bone buccolingually at 1 mm, 3 mm, and 5 mm apical to the crest. Two finite element models were established to represent clinically relevant restorative strategies for extensive mandibular anterior tooth loss: an implant-implant supported fixed partial denture and a tooth-implant supported fixed partial denture. These models were compared in terms of stress distribution under different oblique loading conditions. RESULTS: Alveolar width generally increases with depth from the crest. The available mandibular anterior alveolar bone width is significantly influenced by gender and age. Specifically, bone width measurements were statistically significantly greater in male patients than in female patients, and the width at most measured depths showed a stable negative correlation with age. Biomechanically, stress concentrations were mainly observed at the implant-abutment neck and the crestal cortical bone, and stress increased with increasing loading angle (overjet). Within the assumptions of this simplified finite element model, the tooth-implant supported design showed a comparatively different stress distribution pattern and may provide biomechanical reference for selected mandibular anterior restorative scenarios. CONCLUSIONS: Mandibular anterior tooth-implant supported and implant-implant supported restorations showed different stress distribution patterns under oblique loading. Stress was mainly concentrated at the implant-abutment neck and adjacent crestal cortical bone, and greater loading angles were associated with higher stress levels. These findings may provide comparative biomechanical information for restorative planning in selected cases, but further experimental and clinical studies are needed to confirm their clinical relevance.