To evaluate low-level laser therapy (LLLT) as an adjunct to enhance postoperative mouth opening after orthognathic surgery. Prospective clinical trial of 82 patients allocated into an intervention group (laser, LG) and a control group (no laser, CG) and subgroups according to the procedure type : (1) surgically assisted rapid maxillary expansion (SARME); (2) maxillary surgery; (3) mandibular surgery; or (4) bimaxillary surgery. LG patients received LLLT immediately after surgery and every 24 h thereafter for 3 days, using a gallium-aluminum-arsenide (GaAlAs) diode laser (780 nm, 28 spots, 14 on each side of the face, output power 2 J/spot). Maximum mouth opening was measured using digital calipers at five time points: preoperative baseline and postoperative days 2, 7, 14, and 21. ANOVA was used to evaluate difference in mouth opening across groups. Significance was accepted at P ≤ 0.05. Final average mouth opening differed between women (GL1 = 94.24%, GC1 = 89.54%, GL2 = 69.39%; GC2 = 68.46%; GL3 = 65.11%; GC3 = 58.64%; GL4 = 61.85%; GC4 = 57.11%) and men (GL1 = 86.92%, GC1 = 102.44%, GL2 = 77.56%; GC2 = 81.65%; GL3 = 80.29%; GC3 = 67.63%; GL4 = 66.93%; GC4 = 55.31%). There were no significant differences between the SARME and isolated maxillary/mandibular surgery groups. In the bimaxillary groups, average mouth opening was increased in all patients who received LLLT, significantly so in male patients. LLLT with a GaAlAs diode laser (780 nm) did not affect postoperative mouth opening after SARME, isolated maxillary surgery, or isolated mandibular surgery. However, it improved mouth opening in men who had undergone bimaxillary orthognathic surgery.
Keywords: Low-level laser therapy; Mouth opening; Orthognathic surgery; Trismus.