Redefine the Anterior Limit of the Dentition in Case of Functional Genioplasty: A Clinical Protocol

Objectives: The purpose of this paper is to discuss the indications for “functional” genioplasty, as described by J. Delaire, and to analyze the implications of this surgical procedure on the choices the orthodontist must make regarding orthodontic treatment (extractions, anchorage, mechanics, etc.). In fact, this surgery modifies the position of the pogonion, the inferior reference point of the Apogonion line, which is fundamental for a correct calculation of spaces. Introduction: “Functional” genioplasty was first described by J. Delaire in 1983. This surgical procedure is indicated for individuals with Class II highangle malocclusion. The purpose of this procedure is not only to improve the aesthetics of patients with long, retruded chins, but also to promote labial competence by reducing the lower facial height. “Functional” genioplasty modifies both the labio-lingual neuromuscular balance and skeletal structure and, with it, some important cephalometric points and planes: Menton, Gnathion and pogonion, mandibular plane, facial axis, facial plane and A-Pogonion line. The orthodontist should carefully analyze these changes when evaluating treatment planning, especially when extractions are indicated and a new A-Pogonion line is to be drawn in the V.T.O (Visual Treatment Objectives). Materials and methods: The possibility of correcting a long, retruded chin by functional genioplasty and the reliability of cephalometric reevaluation with the described method are presented on a typical clinical case treated. The authors suggest specific timing for the orthodontic and surgical approach to high-angle Class II patients to achieve the best results. Results: The patient should undergo genioplasty as soon as the lower canines are erupted. Then it is important to wait 12–18 months to allow the improved labial competence to have an effect on the front dentition. Only at this point will it be possible to calculate orthodontic movements according to the new A-Pogonion line. Conclusions: “Functional” genioplasty is a low-impact, low-risk, and welltolerated surgical procedure. It corrects both neuromuscular and skeletal abnor- malities. However, the orthodontist must carefully consider these changes be- cause of the new orientation of the A-pogonion line.