During radiation therapy, high doses of X-rays are used to destroy cancer cells, which can affect the patients' mouth, teeth and chewing muscles. X-rays can cause changes in the salivary glands. These changes can cause dry mouth, infections and tooth decay.
Trismus is a condition in which the movement of opening the mouth is restricted, which is frequently seen in patients receiving radiotherapy due to head and neck cancer and reduces the quality of life of the patients (Picture 1). Restricted mouth opening and decreased chewing functions affect patients' daily activities such as eating, chewing, swallowing and speaking, depending on the degree of trismus. These effects can lead to many problems such as severe pain, lack of proper dental care, weight loss, and poor oral hygiene. Although there is no definitive treatment for radiation-induced trismus, various treatment methods are used in its treatment (Picture 2). Stretching exercises are also used to increase mouth opening (Figure 3). If emergency surgical intervention is required, the presence of trismus may become life-threatening as the patient cannot be intubated easily.
The simplest way to determine whether there is a limitation in opening the mouth is to check whether your three fingers are placed between the lower and upper teeth (Picture 4). If the mouth opens wide enough to easily accommodate these three fingers, trismus is no longer a problem. However, if it does not open sufficiently, trismus may be diagnosed and the condition of these patients should be evaluated by a doctor. Therefore, routine dental checks have become more important, especially in patients receiving radiotherapy. Dental examination before radiotherapy is recommended to prevent future problems.
Picture 1: Restricted mouth opening of a patient who received radiotherapy due to nasopharynx cancer
Image 2: Mouth opening apparatus
Image 3: Finger stretching exercise
Picture 4: Three finger test
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