Comparison of Chinese and white Bolton standards at age 13.

OBJECTIVES: To create a combined male-female Chinese Bolton standard for age 13 and to compare it to the combined Bolton standard for white 13 year olds. MATERIALS AND METHODS: Thirty-two Chinese and 32 white subjects (16 adolescent boys and 16 adolescent girls aged 13 years in each ethnic group) who fulfilled the selection criteria used to create the original Bolton standards were enrolled. Their cephalograms were traced and then averaged two at a time following the Bolton method. In addition to creating the template from the 32 subjects in each group, 43 linear and angular variables were measured and compared between the two ethnic groups and between the two sexes in each ethnic group using independent t-tests. A P value of .05 was used to assign statistical significance. The male-female combined templates for 13 year olds were also compared superimposing either in the Bolton relation or by soft tissue. RESULTS: No sexual dimorphism was found in the white subjects, whereas the Chinese girls had decreased upper face height (Na-ANS), more protrusive incisors (SNA-U1), and shorter cranial base (Ba-Na) and posterior cranial base (S-Ba) compared with the Chinese boys. In terms of ethnic comparison, the Chinese subjects presented shorter sagittal facial dimensions, a clockwise rotated mandible with a more acute gonial angle, and a convex facial profile with a less prominent nose and chin. However, overall vertical dimensions were similar. CONCLUSIONS: A 13-year-old combined male-female Chinese Bolton standard was created that demonstrated visually and with metric comparisons that Chinese and white clinically normal subjects have different craniofacial characteristics. These differences should be taken into consideration when an individualized orthodontic treatment plan is developed.

Mia-assisted orthodontic treatment for dental malocclusion secondary to periodontal disease.

In contemporary dental care, an increasing number of adult patients with periodontal disease are seeking orthodontic treatment. Achieving optimal results in such adult patients is difficult because decreased posterior tooth anchorage is risky. This case report demonstrates the use of miniscrew implant anchorage (MIA) in a Chinese male 21 years 5 months of age with maxillary and mandibular anterior dental spacing, bimaxillary protrusion, and severe bone loss caused by periodontal disease. Prior to orthodontic treatment, the patient underwent treatment to control his periodontitis. The patient was treated with 0.022-in straight-wire orthodontic appliances. After 17 months of active orthodontic treatment, the patient had healthier periodontal tissue with increased bone support, as well as improved facial esthetics and a functional occlusion. The results demonstrate that MIA is useful in enhancing anchorage in patients with bone loss associated with severe periodontal disease.

Orthognathic surgery outcome analysis: 3-dimensional landmark geometric morphometrics.

Traditional cephalometric analysis of 2-dimensional (2D) landmarks has been limited to distances, indices, and angles. Quantitative results vary depending on what baseline is chosen. Geometric morphometric techniques, such as Procrustes superimposition, assume all landmarks carry equivalent information. Using these methods, landmark coordinates (x, y, z) facilitate comparison of patients and "normative"shapes and assessment of pre- to postoperative outcomes. Pre- and postoperative lateral and frontal cephalograms and stereophotograms were taken of a 48-year-old Caucasian man and a 38-year-old Caucasian woman. Coordinates of 3D hard tissue landmarks were collected directly from scanned cephalograms, and 3D soft tissue landmarks were collected onscreen. Procrustes superimpositions of pre- and postoperative 3D craniodental landmark coordinates and 3D soft tissue coordinates were made, and scatter plots were created to show the surgical shape change separately for each patient. Procrustes superimposition of the preoperative and "normative craniodental data (18-year-old male and female Bolton standards) provided both qualitative and quantitative evaluations of the patients, allowing a better determination of the required treatment. Unlike traditional baseline-dependent methods, Procrustes shape analysis produces a single useful measure of surgical shape change or comparison to normative shape.