J T Martinez1, T A Turvey, W R Proffitt. 1. Department of Oral and Maxillofacial Surgery, University of North Carolina, Chapel Hill 27599-7450, USA.
Abstract
PURPOSE: This study investigated the relationship of age at surgery and type of fixation to the pattern and extent of bone remodeling associated with inferior border osteotomy for chin augmentation. PATIENTS AND METHODS: Four groups of patients with similar chin advancement were established by age at the time of surgery: younger than 15, 15 to 19, 20 to 24, and older than 39 years. Cephalometric radiographs for immediate preoperative, immediate postoperative, and at least 9 months postoperative times were traced, digitized, and superimposed. RESULTS: The pattern of osseous remodeling was similar for all age-groups. This consisted of resorption of the superior-buccal aspect of the distal segment, bone apposition on the buccal surface of the proximal segment, and modest resorption at pogonion (mean change, 1 mm or less). There was no significant difference in stability of the chin advancement between wire and rigid (screw) fixation. There was a marked difference in the symphysis thickness regeneration of the youngest group (92% of the original symphysis thickness) compared with the rest of the groups (< or =66%, P < .001). CONCLUSIONS: Minimal remodeling at pogonion occurs in all age-groups with both wire and rigid fixation. Regeneration of symphysis thickness is much more complete in patients younger than 15 years at the time of surgery. This is potentially important for early treatment of severe chin deficiency, because it permits additional advancement of the chin later in life, if necessary.
PURPOSE: This study investigated the relationship of age at surgery and type of fixation to the pattern and extent of bone remodeling associated with inferior border osteotomy for chin augmentation. PATIENTS AND METHODS: Four groups of patients with similar chin advancement were established by age at the time of surgery: younger than 15, 15 to 19, 20 to 24, and older than 39 years. Cephalometric radiographs for immediate preoperative, immediate postoperative, and at least 9 months postoperative times were traced, digitized, and superimposed. RESULTS: The pattern of osseous remodeling was similar for all age-groups. This consisted of resorption of the superior-buccal aspect of the distal segment, bone apposition on the buccal surface of the proximal segment, and modest resorption at pogonion (mean change, 1 mm or less). There was no significant difference in stability of the chin advancement between wire and rigid (screw) fixation. There was a marked difference in the symphysis thickness regeneration of the youngest group (92% of the original symphysis thickness) compared with the rest of the groups (< or =66%, P < .001). CONCLUSIONS: Minimal remodeling at pogonion occurs in all age-groups with both wire and rigid fixation. Regeneration of symphysis thickness is much more complete in patients younger than 15 years at the time of surgery. This is potentially important for early treatment of severe chin deficiency, because it permits additional advancement of the chin later in life, if necessary.