[Long-term follow-up of microgenia treatment with natural coral].

[OBJECTIVE] To investigate the long-term effectiveness of microgenia treatment with natural coral, and the volume relationship between the implant and the new bone.

[METHODS] A retrospective analysis was made on the clinical data of 12 patients with microgenia treated by horizontal genioplasty with natural coral implantation between October 1998 and September 2004. There were 7 males and 5 females with the average age of 18.5 years (range, 15-28 years). The cephalometric data on the photo and X-ray films were collected at pre-operation, immediate after operation, and last follow-up. The vertical distance between lower lip point and inferior mental point, the vertical distance between inferior alveolar point and inferior mental point, the vertical distance of the osteotomic gap, and the distance between pogonion and the line between nasion and inferior alveolar point were measured, and the recurrence rates were caculated.

[RESULTS] All incisions healed by first intention, and no complication occurred. All patients were followed up 8-12 years (mean, 9.2 years). X-ray films showed that the natural coral was replaced by new bone formation in the mental osteotomic gap; the new bone had good strength and firmly attached to the mentalis and periosteum. At last follow-up, the vertical distance between lower lip point and inferior mental point, the vertical distance between inferior alveolar point and inferior mental point, and the vertical distance of the osteotomic gap were decreased when compared with the ones at immediate after operation, and the mean recurrence rates were 6.1%, 22.9%, and 31.7%, respectively; and no obvious change was observed in the vertical distance between pogonion and the line between nasion and inferior alveolar point. Nine patients were satisfied with operation effectiveness; chin morphology was adjusted again in 3 patients.

[CONCLUSION] Natural coral is a safe and effective bone substitute with enough stable new bone and good long-term effectiveness.