Simulation of osteotomy and support for surgery using VR haptic device.

A novel computer-assisted 3-D simulation for osteotomy and CAD/CAM fabrication of surgical splints consider the relative inter-bone interference and space after bone translation were developed. CT image of a patient for osteotomy was operated and simulation of surgery for deformation, segmentation, displacement of the bone was processed effectively by virtual reality haptic device PHANTOM. CAD of a bite splint before surgery and after bone displacement was done in the process of simulation. CAM of resin bite splints was done by precise Rapid Prototyping CAM machine. All fabricated splint were sufficiently functioned to determine the position of jaws.

Asymmetry of the face in orthodontic patients.

OBJECTIVE: To investigate the laterality of the normal asymmetry of the human face, examining differences in laterality in relation to sex, growth stage, and skeletal classification. MATERIALS AND METHODS: A total of 1800 Japanese subjects (651 males and 1149 females; mean age, 15 years 3 months; range, 4 years 2 months to 59 years 11 months) were selected. Individuals in the sample were categorized according to sex, one of three growth stages, and one of three skeletal patterns. Differences in length between distances from the points at which ear rods were inserted to the facial midline and the perpendicular distance from the soft-tissue menton to the facial midline were measured on a frontal facial photograph. Subjects with a discrepancy of more than 3 standard deviations of the measurement error were categorized as having left- or right-sided laterality. RESULTS: Of subjects with facial asymmetry, 79.7% had a wider right hemiface, and 79.3% of those with chin deviation had left-sided laterality. These tendencies were independent of sex, age, or skeletal jaw relationships. In this regard, during pubertal growth, the proportion of subjects with wider right hemiface decreased (P < .0001), whereas the proportion of those with a wider left hemiface increased (P < .01), despite a consistent tendency for right-sided dominance. CONCLUSION: These results suggest that laterality in the normal asymmetry of the face, which is consistently found in humans, is likely to be a hereditary rather than an acquired trait.

Craniofacial morphology in an unusual case with nasal aplasia studied by roentgencephalometry and three-dimensional CT scanning.

OBJECTIVE: To examine the three-dimensional morphology of internal structures of the craniofacial region and present the orthodontic problems in an unusual case with nasal aplasia. PATIENT: The patient was an 11.5-year-old boy with aplasia of the nose and nasal cavity with extremely constricted nasopharyngeal airway. He did not have mental or somatic retardation. The patient had dacryostenosis. The morphology of the craniofacial structures was characterized by absence of septal structures, including cribriform plate, perpendicular plate of ethmoid bone, vomer, and septal cartilage; bony hypotelorism; midface hypoplasia; short and retrognathic maxilla with Class III jaw relationship; average mandibular plane angle; high arched palate; severe anterior open bite with bilateral posterior crossbites; and dental anomalies (agenesis of four maxillary permanent teeth, microdontia, taurodontism, and short roots). Thus, the patient had characteristic dentofacial phenotype, which might be caused by a combination of the primary anomaly and the functional disturbances secondary to the nasal obstruction.

Craniofacial morphology in a patient with Simpson-Golabi-Behmel syndrome.

OBJECTIVE: We present the case of a 6-year-old boy with a coarse face, cleft palate, and malocclusion with anterior open bite who had been diagnosed with Simpson-Golabi-Behmel syndrome. Morphology of the craniofacial structures was examined on the basis of conventional radiographs, three-dimensional (3D) computed tomography (CT) and magnetic resonance (MR) scanning. PATIENT: This patient had 13 ribs on the right side, slight scoliosis, supernumerary nipples, a coarse face, hypertelorism, a short broad upturned nose, a wide mouth, a straight facial profile with incompetence of the lips, midline groove of tongue, and cleft palate. The patient also had severe anterior open bite, a distal step-type molar relationship, five congenitally missing teeth, and a supernumerary tooth. Lateral cephalometric analysis revealed a large anterior cranial base, a large maxilla and mandible, a large inferior face height, and skeletal Class I jaw relationship with a high mandibular plane angle and large gonial angle. The 3D CT image showed a large cranium, a long face height, and prominent skull sutures. The MR image showed a large tongue, midline groove of the tongue, and a small space between tongue and palate.