The effects of antitumor irradiation on mandibular opening and mobility: a prospective study of 58 patients.
OBJECTIVE
The purpose of this study was to analyze the effects of head and neck radiation therapy on jaw opening and mobility.


METHODS
Maximum jaw opening and mandibular mobility were measured before and after radiation treatment in 58 patients presenting for angle down wedge, homolateral wedge pair, and parallel pair head and neck radiation treatment.


RESULTS
As dose to the temporomandibular joint and pterygoid muscles increased, maximal jaw opening decreased linearly. Mandibular dysfunction appeared to increase as radiation dose to the pterygoid muscles increased. Similar effects were not observed with temporomandibular joint irradiation. Irradiation of the pterygoid muscles appeared critical in the development of trismus. Angle down wedge treatment irradiated the temporomandibular joint and pterygoid muscles with clinical effects similar to those seen in homolateral wedge pair and parallel pair patients. Doses as low as 1493 cGy resulted in functional impairment.


CONCLUSIONS
Future investigations into radiotherapy delivery and appropriate postradiation trismus treatment may reduce head and neck radiation morbidity.
Goldstein
M
M
Department of Dentistry, Ontario Cancer Institute/Princess Margaret Hospital, Toronto, Canada.
Maxymiw
W G
WG
Cummings
B J
BJ
Wood
R E
RE
D000704:Analysis of Variance; D016371:Cranial Irradiation / Q000009:adverse effects* / Q000379:methods; D006258:Head and Neck Neoplasms / Q000532:radiotherapy; D006801:Humans; D008334:Mandible / Q000503:physiopathology; D008409:Mastication; D011446:Prospective Studies; D011626:Pterygoid Muscles / Q000528:radiation effects; D011879:Radiotherapy Dosage; D016059:Range of Motion, Articular / Q000528:radiation effects; D012044:Regression Analysis; D013704:Temporomandibular Joint / Q000528:radiation effects; D014313:Trismus / Q000209:etiology* / Q000503:physiopathology; D014716:Vertical Dimension