Biomechanical Evaluation of Locking Reconstruction Plates with Different Profile Thicknesses in Grafted and Non-Grafted Lateral Mandibular Segmental Defect Models

Objective: This study evaluated the biomechanical stability of locking reconstruction plates with different profile thicknesses in lateral segmental mandibular defects under incisal loading in grafted and non-grafted constructs.Material and Methods: A standardized 5.5-cm lateral segmental defect extending from the right canine to the right second molar was created in 40 polyurethane mandibular replicas (N=40). Specimens were randomly allocated into four groups (n = 10): LP (2.0 mm low-profile plate), LPg (2.0 mm low-profile plate with graft), HP (2.5 mm high-profile plate), and HPg (2.5 mm high-profile plate with graft). Fixation was performed using 2.4-mm locking reconstruction plates and 10-mm locking screws. In the LPg and HPg groups, a polyurethane segment served as a model for a fibula graft and was stabilized through the plate. All specimens underwent progressive uniaxial compressive incisal loading (10–250 N) using a universal testing machine. Load–displacement curves were recorded at 10 N intervals. Statistical analysis was performed using one-way ANOVA and Tukey HSD post hoc tests (p<0.05).Results: No significant differences were observed between the groups from 10 N to 80 N. Between 90 N and 250 N, a significant difference was found between the HP and HPg groups (p<0.05). No other pairwise comparisons demonstrated statistical significance.Conclusion: Within the limitations of this study, graft placement did not significantly affect the biomechanical stability of 2.0 mm low-profile reconstruction plates. Plate profile thickness alone did not result in significant displacement differences. In contrast, graft addition in 2.5-mm high-profile systems was associated with relatively greater displacement compared to graft-free constructs under incisal loading.