The overlapping bone flap genioplasty.

The overlapping bone flap genioplasty is the transposition of the inferior part of the mandibular symphysis in front of the anterior mandibular cortex. The fragment remains attached to the medial fibres of the suprahyoid muscles. A study of long-term results (minimum 6 months) in 29 adults and 17 adolescents has shown a mean bone resorption of 24% in the first group, and 40% in the second group, with some unpredictable variations. The maximum resorption occurs between the 3rd and the 6th postoperative months and there is minimal change afterwards. The soft-tissue-osseous advancement is close to 75% in the adult and is comparable to the result of the standard sliding genioplasty.