Changes in the lower lip soft tissue after bone graft harvesting from the mandibular symphysis

Following the surgical release of the mentalis muscle, lip incompetence and/or an increase in lower incisor exposure may be seen due to undesirable attachment of the muscle fibres. The aim of this study was to evaluate the extent of lip ptosis, lower incisor exposure, and other soft tissue changes following bone graft harvesting from the mandibular symphysis when the mentalis muscle is reapproximated precisely to its original position. Seventeen consecutive patients who underwent bone graft harvesting from the mandibular symphysis were included in this study. The mentalis muscle was isolated, identified, marked, and reapproximated precisely during the bone harvesting operation. Digital lateral cephalograms obtained preoperatively and at 6 months postoperative were analyzed and compared by paired samples t-test to determine the horizontal and vertical soft tissue changes in the lower lip and chin. Although the soft tissue thickness at soft tissue point B and at soft tissue pogonion had increased significantly at 6 months after chin bone graft harvesting, there were no significant changes in lower incisor exposure or other positional alterations of the lower lip (P < 0.05). Precise reattachment of the mentalis muscle in its original position helps to avoid significant vertical positional changes in the lower lip. Increases in soft tissue thickness can be observed following bone graft harvesting from the mandibular symphysis.