Dentofacial Discrepancies Research Articles

Skeletal changes after modified intraoral vertical ramus osteotomy for correction of mandibular prognathism

Orthognathic surgery is widely used to correct congenital and acquired dentofacial discrepancies. Various surgical procedures have been advocated for correction of mandibular prognathism. In this study, a modified intraoral vertical ramus osteotomy has been developed for surgical correction of mandibular prognathism. The aim of this study is to identify contributing factors to skeletal change by analysing cephalometric changes after modified intraoral vertical ramus osteotomy. Forty-one patients, treated for absolute mandibular prognathism by bilateral modified intraoral vertical ramus osteotomy, were evaluated cephalometrically with reference to the menton point. A set of four standardised lateral cephalograms were obtained from each subject preoperatively (T1) and immediately postoperatively (T2), prior to removal of maxillomandibular fixation (T3), and at 1-year postoperatively (T4). The mean setback of the menton was 12.4 mm in the horizontal direction. Relapse was defined as forward movement of the menton during the 1-year follow-up. The highly significant backward movements in a horizontal direction were observed during the maxillomandibular fixation period (T3-T2). Moreover, highly significant forward movement was observed following the maxillomandibular fixation period (T4-T3). After 1-year follow-up (T4-T2), the mean changes of the menton were 0.1 mm backward in the horizontal direction. In this series, the mean skeletal change compared with the amount of setback was less than 1% (0.1/12.4 mm) in backward movement. The results suggest that the modified intraoral vertical ramus osteotomy technique is useful and the more stable approach for correction of severe mandibular prognathism.

A cost–utility analysis of patients undergoing orthognathic treatment for the management of dentofacial disharmony

Introduction: Management of dentofacial discrepancies using orthognathic treatment is now a common procedure in the United Kingdom. Although the benefits of orthognathic intervention are often considered, the cost implications have not been investigated to our knowledge. This study is a cost–utility analysis of orthognathic treatment. Patients and methods: Twenty-one patients were interviewed five times during treatment using the time trade-off (TTO) method to establish utility values. Quality adjusted life years (QALYs) gained as a result of treatment were calculated and discounted. The resource use was calculated for each of the 21 patients individually and the costs subjected to both a sensitivity analysis and discounting. The incremental mean cost per additional QALY was calculated (as compared with a ‘no treatment’ approach). Results: The incremental cost for each additional QALY was £561 for the groups combined, based on mean additional costs and QALYs (£546 for the bimaxillary group and £617 for the single jaw group). Discussion: Orthognathic treatment seems to provide good outcomes at relatively low cost. Even allowing for the uncertainty in mean costs and QALYs, there is a high probability of treatment being cost-effective. Cost–utility analysis is still a relatively new technique in dentistry and further studies should be encouraged.

Surgical correction of facial asymmetry with mandibular prognathism by Le Fort I osteotomy and obwegeser II method: Report of a case

Orthognathic surgery is widely used to correct congenital and acquired dentofacial discrepancies. Various surgical procedures have been advocated for correction of mandibular prognathism. In this study, a modified intraoral vertical ramus osteotomy has been developed for surgical correction of mandibular prognathism. The aim of this study is to identify contributing factors to skeletal change by analysing cephalometric changes after modified intraoral vertical ramus osteotomy.Forty-one patients, treated for absolute mandibular prognathism by bilateral modified intraoral vertical ramus osteotomy, were evaluated cephalometrically with reference to the menton point. A set of four standardised lateral cephalograms were obtained from each subject preoperatively (T1) and immediately postoperatively (T2), prior to removal of maxillomandibular fixation (T3), and at 1-year postoperatively (T4). The mean setback of the menton was 12.4 mm in the horizontal direction. Relapse was defined as forward movement of the menton during the 1-year follow-up.The highly significant backward movements in a horizontal direction were observed during the maxillomandibular fixation period (T3–T2). Moreover, highly significant forward movement was observed following the maxillomandibular fixation period (T4–T3). After 1-year follow-up (T4–T2), the mean changes of the menton were 0.1 mm backward in the horizontal direction.In this series, the mean skeletal change compared with the amount of setback was less than 1% (0.1/12.4 mm) in backward movement. The results suggest that the modified intraoral vertical ramus osteotomy technique is useful and the more stable approach for correction of severe mandibular prognathism.