The three-dimensional assessment of dynamic changes of the proximal segments after intraoral vertical ramus osteotomy

• Published in: Cranio 2014-09, p.2151090314Y0000000023
• Main Authors: Ohba, Seigo, Nakao, Noriko, Awara, Kousuke, Tobita, Takayoshi, Minamizato, Tokutarou, Kawasaki, Takako, Koga, Takamitsu, Nakatani, Yuya, Yoshida, Noriaki, Asahina, Izumi
• Format: Article
• Language: English
• ISSN: 0886-9634

Objectives: The aim of this study was to assess the positional changes of the proximal segments after intraoral vertical ramus osteotomy (IVRO). Method: Fifteen patients underwent IVRO and were followed according to the authors' unique post-operative management regimen. The analyses of the positions and angles of the proximal segments were performed on frontal and lateral cephalograms, which were taken before surgery (T1) and within 3 days (T2), at 4 weeks (T3), and later than 6 months after surgery (T4). The three-dimensional positions of the condylar heads were also assessed by CT images, which were taken before and 1 year after surgery. Results : The proximal segments temporarily swung posteriorly and laterally with a center on the condylar head as a fulcrum point at T2 and T3, compared with T1, and they repositioned at T4. The condylar heads moved inferior approximately 2 mm with lateral rotation one year after surgery, as seen in the CT. Discussion : The condylar heads changed their positions physiologically for newly established jaw movement after IVRO with the authors' post-operative management regimen because the post-operative skeletal stability and the jaw function were good and stable using this method.