Impact of CPAP treatment for obstructive sleep apnea on stomatognathic system function: a study on bite force, thickness, and temperature of the masseter and temporal muscles.

Obstructive sleep apnea (OSA) affects the body due to repeated obstruction of the upper airways. Continuous positive airway pressure (CPAP) is a treatment that can influence muscle function. This nine-month longitudinal study evaluated the effects of CPAP on molar bite force and on the thickness and surface temperature of the masseter and temporal muscles in adults. The study included 12 adults aged 20-70 with moderate or severe OSA, confirmed by polysomnography, all using CPAP. Molar bite force was measured with dynamometer; muscle thickness was evaluated by ultrasound at rest and during maximum contraction; and temperature was assessed using infrared thermography. Measurements were taken before treatment and at 3, 6, and 9 months. Data were analyzed using repeated-measures ANOVA with Bonferroni correction (p<0.05). Although no significant differences in bite force were observed, only a non-significant tendency toward increased maximum molar force on both sides was noted after nine months. Ultrasound showed a significant increase in right temporal muscle thickness at rest and during contraction, and a left-side increase at rest. Nine months of CPAP therapy in adults with moderate to severe obstructive sleep apnea resulted may influence craniofacial muscle morphology without significantly altering stomatognathic function.