This study evaluated and compared the Therabite Jaw Motion Rehabilitation System (Therabite Corporation, Bryn Mawr, PA) to tongue blades as a technique for maintaining and/or improving mandibular range of motion in post-irradiated patients. Three groups of patients were evaluated and compared: 1) unassisted exercise, 2) mechanically assisted mandibular mobilization with stacked tongue depressors combined with unassisted exercise, and 3) the Therabite System combined with unassisted exercise. The initial average maximum incisal opening (MIO) for the study population was 21.6 mm, and did not vary significantly among the groups. Measurements were recorded at 2-week intervals for 10 weeks. At week 6 and thereafter, the net increase in MIO of group 3 (13.6 mm [+/- 1.6 mm]) was significantly greater than group 1 (6.0 mm [+/- 1.8 mm]) and group 2 (4.4 mm [+/- 2.1 mm]) (P < .05). The rate of improvement leveled after 4 week in group 1 and group 2. However, the rate of gain in MIO in the Therabite group (group 3) remained constant at 10 weeks. There was no statistical difference between groups 1 and 2.