From an anatomic and functional point of view, the stomatognathic system and the upper cervical spine are closely connected. Together with the complex neuromuscular relationships, this generates an important field of cooperation between dentists and orthopedics. The aim of this case report was to demonstrate the improvements of temporomandibular joint (TMJ) function after orthopedic surgery in case of a patient with idiopathic scoliosis. A 15-year-old female patient who had adolescent idiopathic scoliosis was surgically treated in 2016. Functional analyses of the TMJ were performed before the day of the operation and 10 months after the surgery. For detection, an ultrasound-based testing machine was used. The analyses of the data showed that almost all ranges of motions (ROM) were improved. The deviation to the right side was reduced from 8 mm to 2 mm during mouth opening. The patient had limited left lateral movement before the operation, however, after 10 months following the operation, there were free motions towards both sides. The originally asymmetrical protrusion became almost completely symmetrical. Regarding the functions of the TMJ, the surgery was successful; this in itself had a beneficial effect on the range and the path of the mandibular movements without any other treatment. These improved functions are indirect evidences for the connection of the function of the spine and TMJ. Orv Hetil. 2018; 159(50): 2144–2149.