Objective: To investigate the association between maxillofacial morphology and mandibular bone volume in patients with skeletal malocclusion. Materials and Methods: Subjects were 118 adult Japanese (58 males and 60 females). Skeletal malocclusion was classified, based on cephalometric analysis, into skeletal Classes I (21u # ANB , 4u), II (ANB $ 4u), and III (ANB , 21u). Using cone-beam computed tomography and threedimensional image analysis software, the dental crowns and mandible were separated, with only the mandible extracted. This was then reconstructed as a three-dimensional model, from which the mandibular volume was measured. Results: No significant difference in mandibular volume was noted among skeletal Classes I, II, and III, nor was there any significant correlation between mandibular volume and the ANB, SNB, or mandibular plane angles. There was occasional and limited correlation between mandible volume and gonial angle and certain cephalometric distance parameters. Conclusion: We conclude that proper understanding of the three-dimensional maxillofacial morphology requires not only cephalometric radiographic tracings but also high-resolution analysis of the mandibular area, width, and volume. (Angle Orthod. 2014;84:337-342.)

The Invisalign system is widely used to treat mild to moderate tooth crowding. Recently, Invisalign appliances have been used in orthodontic patients with increasingly complex malocclusions. When using an Invisalign appliance to correct severe tooth crowding, root positions must be carefully controlled during extraction space closure. We report our treatment of a 34-year-old man who presented with a Class I relationship, a midline deviation, severe overjet, and severe tooth crowding in the maxillary and mandibular anterior regions. The treatment plan involved extraction of the maxillary and mandibular fi rst premolars on both sides. We treated this patient with severe anterior tooth crowding using an Invisalign appliance combined with a fi xed appliance with power arms and elastics. Treatment by Invisalign as an application of computational calculated result, especially in extraction cases, doctors should have professional skill and experience as an orthodontist.