['One of the operative complications of the sagittal split osteotomy of the mandible is a bad split, which describes an unfavorable or irregular fracture of the mandible in the course of the osteotomy. The purpose of this study is to identify previous studies which reported incidences of bad split occurrence during sagittal split osteotomy and to discuss its mechanisms and risk factors, based on a literature review, in order to minimize their occurrence. A few illustrative cases are also presented.', 'An electronic search was undertaken in January 2011. The titles and abstracts from these results (n\u2009=\u2009363) were read for identifying studies which reported incidences of bad split occurrence during sagittal split osteotomy procedures.', 'Twenty-one studies were identified and assessed. The incidence of bad splits from these studies varied between 0.21% and 22.72%. The buccal plate of the proximal segment and the posterior aspect of the distal segment were the most affected areas.'] Does risk factors and prevention of bad split during sagittal split osteotomy?