Analysis of vertical loading forces on three different sagittal split ramus osteotomy modifications

The study aimed to compare and analyze the in vitro mechanical behavior of vertical load on three different sagittal split osteotomy designs proposed by Epker, Wolford, and Wyatt, focusing on the implications of each design on mandibular stability.

Synthetic polyurethane hemi-mandibular models were used to replicate the osteotomies according to the designs suggested by Epker, Wolford, and Wyatt. Each model group was subjected to linear vertical loading until system failure, with peak load and deformation recorded. The study utilized a controlled sample preparation and loading test to ensure standardization across all groups. Analysis of variance (ANOVA) and the Tukey test were applied to compare the mechanical responses among the different osteotomy designs.

The findings indicated no significant difference in displacement and vertical loading resistance between Groups 1 and 2; however, differences were found in Group 3 (Wyatt), where increased mandibular fragility was observed when screws were placed in thinner bone areas. Statistical analysis showed that the modifications in the osteotomy design led to significant differences in mechanical behavior, particularly in Group 3, highlighting the importance of bone thickness and osteotomy technique on postoperative early stability and mechanical stress distribution.

The study concludes that the choice of sagittal split osteotomy design significantly impacts the mechanical behavior under vertical loading, with particular emphasis on the importance of bone thickness at fixation points and the technique used. The findings suggest a preference for the modification proposed in group 1 and 2 in cases where increased mandibular stability and minimized postoperative complications are desired.