[Preliminary study on positioning of Damon Q self-ligating brackets in a digital integration model].

Objective: This study was performed to determine the feasibility of digital virtual positioning of braces in clinical applications.

Methods: We determined the positions of brackets in 28 teeth of 15 cases according to positioning methods that use bracket height or root information. Final status was generated by OrthoRx software.

A simple way to intrude overerupted upper second molars with miniscrews.

Various methods of using skeletal anchorage for the intrusion of overerupted maxillary molars have been reported; however, it is difficult to intrude the overerupted upper second molars because of the low bone density in the region of the tuberosity. This article illustrates a new treatment method using partial fixed edgewise appliances and miniscrews to intrude the overerupted upper second molars. The miniscrews were applied to reinforce the anchorage of the upper first molar.

[Condylar position of post-orthodontic patients with class II malocclusion].

Objective: To study the condylar position of post-orthodontic patients with class II malocclusion.

Methods: Forty four patients with class II malocclusion were recruited, among whom 22 were given orthodontic treatment and 22 without any treatment as controls. The condylar distractions between centric relation (CR) and centric occlusion (CO) were measured by an Panadent articulator with Measurement of Condylar Displacement (MCD).

Three-dimensional spiral computed tomographic imaging: a new approach to the diagnosis and treatment planning of impacted teeth.

Introduction: The aim of this investigation was to explore the validity of 3-dimensional (3D) spiral computed tomographic (CT) images to examine impacted teeth before surgical or orthodontic treatment.

Methods: Two patients with impacted teeth were examined with both spiral CT and traditional radiographs.

Results: 3D CT images clearly showed the impacted teeth, including crown, root neck, and root bifurcation; the labial or palatal location; and the eruption orientation and relationship to the dentition.

[Integrin 3 mRNA changes after orthodontic teeth movement in periodontitis rats].

Objective: To study the integrin beta3 mRNA changes after orthodontic treatment on normal teeth and periodontitis teeth in rats.

Methods: 96 adult SD rats of 10 weeks old were randomly divided into normal tooth move-ment group and periodontitis tooth movement group. The rats in the two groups were sacrificed after 0 d, 12 h, 1 d, 3 d, 5 d and 7 d of tooth movement.

[Effects of orthodontic force on tumor necrosis factor alpha protein expression in the inflammatory periodontal tissues].

Objective: To explore the combined effects of orthodontic force and inflammation on the remodelling of periodontal tissues.

Methods: The upper first molars underwent mesial orthodontic force on 48 rats suffering experimental periodontitis and 48 rats injected lipopolysaccharide, respectively.

Results: The TNF-alpha protein expression in the compressed periodontal tissues fluctuated during 0, 2, 12 hours and 2, 7, 14 days stages, the OD value got to the peak in the compressed periodontal tissues in 2 days.

[The integrin beta1 mRNA changes after orthodontic movement of teeth in periodontitis rats].

Objective: To study the integrin beta1 mRNA changes after orthodontic tooth movement in normal teeth and periodontitis teeth of rats.

Methods: The OD of positively stained osteoclasts for integrin beta1 mRNA using in situ hybridzation was detected after orthodontic tooth movement in normal teeth and periodontitis teeth groups.

Results: Integrin beta1 mRNA expression were detected on all osteoclasts in tooth movement samples of normal and periodontitis teeth.

[Logistic regression model analysis on Bolton ratio of orthodontic extraction model].

Objective: The purpose of this study was to evaluate the role of Angle's class, overall ratio and anterior ratio in the creation of tooth size discrepancies, and to determine whether any tooth extraction combinations create more severe discrepancies.

Methods: 166 dental casts of orthodontic patients were selected randomly. These models were classified according to angle's criterion.