Changes of the hyoid bone and tongue following advancement of the mandible.

Little is known concerning the adaptation of the tongue and hyoid bone after surgical mandibular advancement. This study was undertaken to evaluate the relationship between tongue and hyoid bone posture and their adaptation following mandibular advancement in fourteen adults. The data indicate that (1) there is no statistically significant correlation between changes in the posture of the tongue and hyoid bone; (2) the hyoid bone returns toward its presurgical posture; and (3) the tongue assumes a new position relative to both the cranial base and the mandible. The changes in tongue position occurred immediately after surgery and persisted 2 years postoperatively.