Tatsuo Kawamoto

Kyushu Dental University, Japan

More than 30 years ago, patients with mandibular protrusion began to undergo orthognathic treatment in Japan. Orthognathic treatment has been admitted in Japan's health insurance system, which covers all citizens, since 1996. As the number of patients with mandibular protrusion has increased, the number of intractable cases, such as protrusion-associated open bite or facial asymmetry, has also increased.
Establishment of stability by orthognathic treatment for an open bite in patients with mandibular prognathism can be difficult. Even if normal occlusion is acquired, an open bite easily relapses during retention. For patients with facial asymmetry secondary to mandibular protrusion, it is necessary to prevent relapse of the maxilla and mandible not only in the anteroposterior direction, but also with respect to the frontal dimension and rotation. An understanding of the long-term craniofacial changes that occur after orthognathic treatment is important for a correct diagnosis, effective procedure, and accurate prognosis.
With respect to the operative procedure, the number of patients undergoing two-jaw surgery is increasing and now accounts for approximately half of all patients who undergo orthognathic treatment. For patients with mandibular protrusion and an open bite or long face, superior repositioning of the maxilla is needed to improve the stability by preventing anticlockwise rotation of the mandible. Although such repositioning of the maxilla is not easy by Le Fort I osteotomy, some research suggests that a combination of Le Fort I and horseshoe osteotomy is a useful technique for reliable superior repositioning of the maxilla, especially in its posterior portion, and shows no difference in short-term stability compared with Le Fort I osteotomy.
The aim of this speech is to present the medium- and long-term craniofacial changes after orthognathic treatment for mandibular protrusion with respect to the following:
1) Craniofacial pattern and long-term stability.
2) Operative procedure and medium-term stability.