Influence of Bone Mineral Density Reduction on the Biomechanical Stability of Miniplate Fixation in Sheep Mandibular Angle Fractures

Abstract

Background: This study aimed to evaluate the influence of chemically induced reduction in bone mineral density (BMD) on the biomechanical stability of monocortical miniplate fixation in sheep mandibular angle fractures (MAFs).

Methods: Forty fresh sheep hemi-mandibles (N=40) were scanned using dual-energy X-ray absorptiometry (DEXA) to determine baseline BMD. Twenty specimens were immersed in 5% acetic acid for 5-7 days to induce low BMD, while the remaining served as controls. Posttreatment DEXA scans confirmed an average 20% reduction in BMD in the low-density (LD) group; all specimens were then subjected to mechanical testing. Standardized unilateral angle fractures were fixed with 2.0-mm titanium plates and four 5-mm monocortical screws. Within each BMD category (n=20), half (n=10) were stabilized with a single superior plate (normal-density single-plate [NDs], low-density single-plate [LDs]) and half with double plates in a monoplanar configuration (normal-density double-plate [NDd], low-density double-plate
[LDd]). Specimens were mounted on a custom-designed holder and vertically loaded up to 120 N in 10 N increments using a universal testing machine. Displacement at each load increment and the force magnitudes required to produce 1-mm, 3-mm, and 5-mm displacements were recorded and statistically analyzed.

Results: Up to 30 N of loading, all groups showed similar displacement. Between 30 N and 120 N, displacement was significantly greater in the LDs group than in the NDs group (P < .05). Both single-plate groups (LDs and NDs) demonstrated significantly higher displacement values than the double-plate groups (LDd and NDd) within the same loading range (P < .05). The load magnitudes required to achieve 1 mm and 3 mm displacements were also significantly lower in the LDs group than in the NDs group, and both single-plate groups required lower loads than their
double-plate counterparts (P < .05).

Conclusion: Single-plate fixation may provide limited stability in MAFs with low BMD, suggesting that additional support could enhance construct stability.

Cite this article as: Şirin Y, Yıldırımtürk S, Can Ü. Influence of bone mineral density reduction on the biomechanical stability of miniplate fixation in sheep mandibular angle fractures. Essent Dent. 2026, 5, 0145, doi:140.10.5152/EssentDent.2026.25145.