Abstract
Congenital hypoplasia of the masseter muscle is a rare condition most commonly associated with craniofacial or poly-malformation syndromes, with a small number of reported idiopathic cases. The condition is most commonly managed by orthodonture and later surgical intervention; however, surgery is not an option for all patients. Nonsurgical approaches to correcting asymmetry may be considered for patients for whom the functional impact of hypoplasia has been largely managed and the patient's concern is primarily aesthetic. In this case study, the patient presented for a consultation seeking a nonsurgical solution for marked facial asymmetry. The patient underwent physical examination and magnetic resonance imaging to confirm diagnosis of congenital masseter muscle hypoplasia. To treat the asymmetry, a total of 9.6 cc of polymethyl methacrylate (PMMA)-collagen gel (Bellafill; Suneva Medical, Inc., San Diego, CA) was injected along the border of the mandible from the gonial angle out to the area of the mental foramen and slightly above over the course of 6 months (2 visits spaced 3 months apart) to provide long-term, nonsurgical correction. The patient was very satisfied with the results, highlighting the potential for PMMA-collagen gel to be used in clinical situations in which durable, nonsurgical correction of lower-face asymmetry is needed.