de Olivera, Leandro BenettiSant'ana, EduardoManzato, Antonio José [UNESP]Guerra, Fábio Luis BunemerArnett, G. William2022-04-292022-04-292012-01-01Journal of Applied Oral Science, v. 20, n. 4, p. 419-426, 2012.1678-77651678-7757http://hdl.handle.net/11449/232098Among the osteotomies performed in orthognathic surgery, the sagittal osteotomy of the mandibular ramus (SOMR) is the most common, allowing a great range of movements and stable internal fixation (SIF), therefore eliminating the need of maxillomandibular block in the postoperative period. ObjectiveS: The purpose of this study was to evaluate the biomechanical resistance of three national systems used for SIF in SOMR in sheep mandibles. Material and Methods: The study was performed in 30 sheep hemi-mandibles randomly divided into 3 experimental groups, each containing 10 hemi-mandibles. The samples were measured to avoid discrepancies and then subjected to SOMR with 5-mm advancement. In group I, 2.0x12 mm screws were used for fixation, inserted in an inverted L pattern (inverted L group). In group II, fixation was performed with two 2.0x12 mm screws, positioned in a linear pattern and a 4-hole straight miniplate and four 2.0x6.0 mm monocortical screws (hybrid group). In group III, fixation was performed with two 4-hole straight miniplates and eight 2.0x6.0 mm monocortical screws (mini plate group). All materials used for SIF were supplied by Osteosin - SIN. The hemimandibles were subjected to vertical linear load test by Kratos K2000MP mechanical testing unit for loading registration and displacement. Results: All groups showed similar resistance during mechanical test for loading and displacement, with no statistically significant differences between groups according to analysis of variance. Conclusion: These results indicate that the three techniques of fixation are equally effective for clinical fixation of SOMR.419-426engBone platesBone screwsMandibleOsteotomyArtigo10.1590/S1678-775720120004000062-s2.0-84867144407