Unilateral sagittal split osteotomy: effect on mandibular symmetry in the treatment of class III with laterognathia

The bilateral sagittal split osteotomy is considered the standard surgery to correct facial asymmetries. More recently, unilateral sagittal split osteotomy (USSO) was used to treat such malocclusions.

To assess facial symmetry following USSO in the treatment of class III laterognathia.

Frontal facial photographs of four groups of patients were assessed: (1) pre-surgical group (n = 30) with skeletal asymmetry, (2) postsurgical group assessing patients of the first group 2 years after USSO, (3) control group (n = 30) of patients judged to have harmonious facial norms, and (4) mirrored group (n = 30) in which the control photographs were altered by duplicating the right half side of the face to replace the left half, thus creating perfectly symmetrical faces. All 120 photographs were distributed to 40 expert orthodontists to evaluate and score facial symmetry using the visual analog scale. Skin sensitivity and temporomandibular joint (TMJ) disorders were also assessed clinically pre and postsurgically.

Statistically significant differences were observed between the pre-surgical group and each of the postsurgical and control groups (p < 0.001). The control and postsurgical groups received similar scores of symmetry (p = 0.774). The mirrored group received statistically significantly higher symmetry scores than either of the control or the postsurgical groups (p < 0.001). A reduction in TMJ disorders was noted after USSO and all patients reported normal skin sensation 2 years post-surgery.

When indicated, USSO is a dependable and practical surgical approach to correct facial asymmetries associated with class III malocclusion.