Experimental comparison of fixation methods with different plates in sagittal split ramus osteotomy

Objective: The stabilization of segments should be good in mandibular movements where relapse is expected after sagittal split ramus osteotomy (SSRO). The aim of this study is to compare the stability of reconstruction plate, double miniplate, and single miniplate systems in cases requiring significant advancement of the mandible. Material and Method: We compared the stability of 3 different fixation methods applied to 45 sheep hemimandibles undergoing SSRO in our study. The fixation procedure was performed with segments advanced by 7 millimeters (mm). In the 1st group; 1 piece of 4-hole miniplate and 4 pieces of screws of 2 mm thickness and 7 mm length, In the 2nd group; 2 pieces of 4-hole miniplates and 8 pieces of screws of 2 mm thickness and 7 mm length, In the 3rd group; 1 piece of 4-hole reconstruction plate and 4 pieces of screws of 2.7 mm thickness and 7 mm length were used for fixation. The subjects were placed in a servo-hydraulic testing machine with a steel device. Forces ranging from 10 Newtons (N) to 200 N were applied to the molars. Displacement and standard deviation (SD) values in the segments were recorded on the computer. The normal distribution of the variables in the study was evaluated graphically and with the Shapiro-Wilks test. Kruskal-Wallis non-parametric variance analysis was used for comparisons between groups. Bonferroni correction was applied for pairwise comparisons, and analysis results were provided. The level of statistical significance was accepted as p <0.05. Results: The mean displacement amount in the single miniplate is significantly higher than the double miniplate and reconstruction plate in all forces applied. Similar displacement values were found in the double miniplate and single reconstruction plate groups. Conclusion: In mandibular movements where relapse is expected after SSRO; while the double miniplate and single reconstruction plate provide sufficient stability, the single miniplate cannot provide it. As a result of this study; it is suggested that the reconstruction plate and double miniplate can be used in mandibular movements where relapse is expected.