ABSTRACT
We compared the stability and stress analysis of four different fixation methods after sagittal split ramus osteotomy (SSRO) in mandibular models. In the first model (1P1B) we adapted a four-hole, 2.0 mm standard miniplate on the osteotomy line with one bicortical screw at the top. In the second (2P) we placed two four-hole 2.0 mm standard miniplates above and below the osteotomy line. In the third (3B), we applied three inverted L-shaped bicortical screws, and in the last (1RP1B) we used a four-hole miniplate with increased thickness on the osteotomy line with one bicortical screw at the top. A static vertical load of 200 Newtons (N) was then applied to each model from the occlusal of the first molar. The maximum and minimum principal stresses on the bone were observed more in the proximal segment close to the osteotomy line in all groups. Maximum von Mises stresses were 2705.21 Megapascals (MPa), 1633.56 MPa, 1121.4 MPa, and 1734.44 MPa for the 1P1B, 2P, 3B, and 1RP1B groups, respectively. Displacement values were 1.92 mm, 1.15 mm, 0.79 mm, and 1.42 mm for the 1P1B, 2P, 3B, and 1RP1B groups, respectively. The reinforced plate contributed to the stabilisation, but it was not as effective as three bicortical screws and a double plate.
