Biological Effects of Radiation
Temporomandibular Joint (TMJ) and Muscles of Mastication

Radiation portals that include the temporomandibular joint and/or muscles of mastication may affect the capsule or muscular integrity. Radiotherapy-induced cellular damage and eventual tissue fibrosis can lead to muscle spasm, trismus, and limited function as a function of radiation dose to the area.¹³ These effects manifest 3 to 6 months post radiotherapy and threshold doses of anywhere from 15 Gy to 50 Gy have been reported.¹³