The essential role of masseter muscle is for adequate mastication. This bulky muscle is located laterally to the mandibular ramus, and thus plays an important role in facial aesthetics. Masseter hypertrophy is recognized as an asymptomatic enlargement of one or both masseter muscles. A hypertrophied masseter will alter facial lines, generating discomfort, and create negative cosmetic impacts in many patients. This leads to the prominent mandibular angle which is considered to be aesthetically unacceptable. The muscle function may also be impaired, thus resulting in conditions such as trismus, protrusion, and bruxism.
In most cases of masseter hypertrophy, it is bilateral and symmetric, but asymmetry is not unusual. In majority of the cases, the etiological factor is unknown therefore it is considered to be idiopathic. Unilateral occurrence can also be seen when patients chew or clench primarily on one side.
There are various treatment modalities for the management of masseteric hypertrophy. The aim of the treatment is to improve facial balance, change the shape of an overly square face and relief pain or discomfort as a result of an overly large masseter muscle.