ABSTRACT
<p><b>BACKGROUND</b>Patients with maxillary tumor often suffer from trismus after maxillectomy, which could turn out to be a permanent sequela without proper intervention. In this study, the efficacy of mouth opening exercises in preventing and treating trismus was observed in patients with maxillary tumor early after their operations. At the same time, radiotherapy as an influencing factor for the mouth opening exercises was evaluated.</p><p><b>METHODS</b>In this study, 22 patients with maxillary oncology began their mouth opening exercises at an early stage (1-2 weeks) after maxillectomy. They were divided into two groups based on the principle of voluntariness: 11 patients in group 1 chose TheraBites as their instruments of mouth opening exercises, and the other 11 in group 2 chose stacked tongue depressors to help their exercises. All participants were trained to exercise 3-5 times a day, 30-40 oscillations at one time, with a 2-second pause at their maximum possible mouth open position. The maximal interincisor distances (MID) of patients were measured and recorded by a single investigator every week after the beginning of the mouth opening exercises. Medical information and the responses of patients were also recorded. Initial and final MIDs were calculated by SPSS 13.0.</p><p><b>RESULTS</b>The changes of the mouth aperture every week during exercises in both groups were described in figures, and there were statistical increases in the final MIDs compared with the initial ones. However, no significant differences were achieved between groups 1 and 2 (P > 0.05). Radiotherapy seemed to have no negative impact on the mouth opening results during the exercises.</p><p><b>CONCLUSION</b>Physical mouth opening exercises should be executed early after maxillectomy for the prevention and treatment of trismus, especially for those who had radiotherapy as part of antitumor treatments.</p>