OBJECTIVETo investigate the effect of muscular rehabilitation on recovery after sagittal split ramus osteotomy.

METHODSTwenty-seven patients undergoing sagittal split ramus osteotomy received passive motion training and muscle endurance training after surgery using the new-developed mouth-opening trainer. The passive motion training began 2-3 days after the removal of inter-maxillary elastraction. The instrument was inserted into the inter-maxillary space for 5 min per time, 3-4 times per day. When the mouth opening reached a range of 20-25 mm, the muscle endurance training initiated. The results of the training were compared with another 20 cases who received the same surgery.

RESULTSThe mouth opening of the patients who received muscular rehabilitation achieved the pre-surgical level 4 weeks after surgery [(34.72 ± 3.75) mm], the bite force reached the pre-surgical level 8 weeks after surgery [(231.08 ± 62.52) N], but in the 20 cases without training the mouth opening [(28.42 ± 4.11) mm] in 4 weeks and the bite force in 8 weeks [(210.90 ± 73.40) N] were lower after surgery than before surgery.

CONCLUSIONSThe systematic and standard muscle function training, accompanied with the use of the new-developed mouth-opening trainer could improve the functional recovery of the patients who receive sagittal split ramus osteotomies.