Abstract
Introduction
Patients who receive radical radiotherapy to the head and neck may suffer from the late side effect of trismus due to radiation of the jaw. Trismus is progressive once it starts, and can be debilitating due to difficulty eating and inability to perform proper dental hygiene. Although radiotherapy to the temporomandibular joint can restrict mouth opening, the pterygoid muscles-which are responsible for lateral and protrusive motions of the jaw-are more sensitive to radiation. Therefore, damage to these muscles will also limit mouth opening.Method
A series of simple jaw exercises was designed to help patients maintain jaw mobility and reduce the effect of trismus. In the study, one group of patients used the exercises and the other did not. To assess whether trismus was occurring, dental gap measurements (measurements taken with a ruler from upper incisor to lower incisor, or gum-to-gum) were taken at the start of radiotherapy treatment and again at scheduled follow-up appointments.Results
There was an overall statistically significant difference between the dental gap measurements of the jaw exercise and the no-jaw exercise group (P = .01, assuming the statistical significance level is .05). Patients who performed the jaw exercises were able to open their mouths wider than the patients who did not do them. Although there appeared to be a difference in decreasing dental gap across time between the two groups in the study, the Wald test did not find this to be statistically significant (P = .1). The use of chemotherapy was not statistically significant; that is, chemotherapy could not be linked with trismus in this study (P = .6171).Conclusion
The results of this study demonstrate that jaw exercises can be a useful aid to help prevent side effects of trismus due to radiotherapy treatment. Although it is not possible to accurately quantify the effect in this study due to the use of a compensator technique, this intervention was easy to implement and simple for patients to undertake. The jaw exercises continue to be used in the Cancer Centre for the Southern Interior, and a recent revision to the jaw exercises was made with the collaboration of the dental department.