Purpose The purpose of this study was to compare the effectiveness of manual and toothbrush approaches on the release of the lateral pterygoid muscle (LPM) for patients with temporomandibular joint (TMJ) deviation. Methods This is a crosssectional study design and randomized controlled trial. Fortytwo subjects who had TMJ deviation were involved in this study. This study used a toothbrush (length: 18.7 cm, head: 26 × 15 × 4 mm) made of polypropylene. Experimental subjects were randomly assigned to the manual intervention group (21 subjects) and the toothbrush group (21 subjects). All subjects were measured for the thickness of the LPM and the menton deviation in the mandible immediately after each selfrelease of the LPM using hand and toothbrush. Sonography was used to measure the thickness of the LPM. The ImageJ program was used to measure menton deviation in the mandible. Result The thickness of the LPM decreased, and menton deviation in the mandible slightly decreased after the intervention. The thickness of the LPM was significantly reduced when comparing post thickness with preintervention (p<.001). However, menton deviation in the mandible did not show a significant difference when comparing postmenton with preintervention (p>.05). The thickness of the lateral pterygoid muscle did not differ significantly between the two groups (p>.05). Conclusion Manual intervention and the toothbrush group were immediately effective in releasing the LPM in subjects with TMJ deviation. When releasing the LPM, the toothbrush is a proper alternative to manual intervention because of its convenient accessibility.