There are different types of dentofacial deformities in the population. These may alter the function of the masticatory muscles, therefor, despite the esthetic assumption, the inadequate mastication had been considered to motivate these patients before performing the orthognathic surgery. . Many parameters had been used t to study the quantity of the mastication; including maximum bite force, electromyographic activity (EMG) of the masticatory muscles, chewing efficiency and maximum mandibular range of motion . The electromyographic activity can be expressed as a function of bite force to measure the musculoskeletal system efficiency
