[Experimental study on the effect of tooth movement with thin and thick aligners in rabbits].

Purpose: To explore the effect of tooth movement on lower incisors of rabbits with thin and thick aligners.

Methods: A group of 6 male New Zealand rabbits were randomly divided into 2 groups, the experimental group(n=3) was designed to move the lower incisors distally by 3 steps with thin and thick aligners(0.625 and 0.

[Finite element analysis of clear aligners in extractive cases].

Purpose: This study analysed the mechanical features of the extraction space closure in clear aligners through mechanical research.

Methods: A patient with four first premolars extraction was chosen as sample, and four plans with clear aligners for space closure were designed, including anterior retraction entirely, anterior retraction dispersedly, posterior movement mesially and posterior movement dispersedly. Finite element analysis was performed separately.

[Maxillary protraction with and without maxillary expansion on unilateral cleft lip and palate model: a finite element analysis].

Purpose: The aim of this finite element study was to investigate biomechanical effects of maxillary protraction with and without maxillary expansion on unilateral cleft lip and palate(UCLP)model before and after alveolar bone graft (ABG).

Methods: Orthopedic force (30° downward and forward to the occlusal plane, 5N/side) with expansion and without expansion were loaded on models before ABG, and after ABG respectively. Initial displacement and sutural stress were analyzed by using ANSYS12.

Impact of rapid maxillary expansion in unilateral cleft lip and palate patients after secondary alveolar bone grafting: review and case report.

The purpose of this article was to analyze the effects and short-term stability of rapid maxillary expansion performed after secondary alveolar bone grafting in unilateral cleft lip and palate (UCLP) patients. Two UCLP patients with severe maxillary constriction who had previous bone grafting were involved in this study. A hyrax rapid expansion appliance was placed on 4 abutment teeth and activated twice daily.

[The reliability and accuracy of the digital models reconstructed by cone-beam computed tomography].

Purpose: To evaluate the reliability of the digital models scanned by cone-beam computed tomography (CBCT).

Methods: Forty plaster models of patients with orthodontic treatment were selected. These plaster models were scanned and measured by 3DX cone beam CT, compared with manual measurement via concordance correlation coefficient (CCC) and mean difference (MD).

[The effectiveness of asymmetric extraction in treatment of Class II division 1 malocclusions].

Purpose: To analyze hard and soft tissue profile changes before and after asymmetric extraction treatment of Angle Class II division 1 malocclusion.

Methods: Thirty patients of Angle Class II division 1 malocclusions (11 males, 19 females, average age 13.6 years) were divided into two groups according to their extraction approach.

The association between lower incisal inclination and morphology of the supporting alveolar bone--a cone-beam CT study.

Aim: To investigate the relationship between the positioning of the lower central incisor and physical morphology of the surrounding alveolar bone.

Methodology: Thirty-eight patients (18 males, 20 females), with mean age of 13.4 years, were included in this study.

[Sagital position of glenoid fossa in Angle Class II malocclusion with mandibular retrusion].

Purpose: To evaluate and compare the morphology and position of the glenoid fossa in patients with Class II malocclusion associated with mandibular retrusion and Class I malocclusion in the permanent dentition.

Methods: A sample of 26 subjects(12 males, 14 females, average age 13.4 years) with skeletal and dental Class II malocclusion associated with mandibular retrusion, was compared with a matched group of 31 subjects(12 males, 19 females, aged 12.

[Diagnostic value of dental implants in the posterior maxilla using cone beam computed tomography].

Purpose: To compare the diagnostic value of cone beam computed tomography (CBCT) with orthpantomography(OPG) for dental implants at the posterior maxilla.

Methods: 75 patients (89 positions) with dental implants in the posterior maxilla were assessed with CBCT and orthopantomography. The horizontal height from the top of the alveolar bone to the floor of sinus was measured through CBCT and OPG.

[A preliminary study of combined periodontal-orthodontic approach for treating labial displacement of incisors in patients with periodontal diseases].

Purpose: The purpose of this study was to evaluate the effect of combined periodontal-orthodontic treatment for patients who had chronic periodontitis with labial displacement of incisors and radiological evidence on migrated incisors.

Methods: Twenty-one adult patients were included in the study. Fifty-two migrated incisors were randomly assigned to treatment with circumferential supracrestal fibrotomy or non-surgery.

[Dental arch form reverting by four-point method].

Purpose: To explore a simple method of reverting individual dental arch form template for wire bending.

Methods: Individual dental arch form was reverted by four-point method. By defining central point of bracket on bilateral lower second premolar and first molar, certain individual dental arch form could be generated.

[Evaluations of self-perceived orthodontic treatment need using 2 different scales in adolescents].

Purpose: To evaluate the self-perceived dental aesthetics through visualized analogue scale (VAS) and aesthetic component (AC) of index of orthodontic treatment (IOTN) among adolescents in Shanghai area.

Methods: The investigation was carried out among 302 students (148 boys and 144 girls) aged 11-13 years. Self-perception of the dental aesthetic appearance was evaluated through VAS and AC.

[Current clinical studies on slow palatal expansion].

Palatal expansion is frequently applied in correction of maxillary transverse deficiency and upper dental arch constriction. Palatal expansion includes rapid palatal expansion and slow palatal expansion. Slow palatal expansion generated physiological expansion force compared to strong forces by rapid palatal expansion with some side effects.

[Analysis of the efficacy of Twin-block appliance on maxillofacial growth of six pairs of monozygotic twins].

Purpose: The purpose of this study was to investigate the efficacy of Twin-block appliance on maxillofacial growth by using monozygotic twins.

Methods: 6 pairs of non-high angle monozygotic twins aged 12.2 with class II division 1 malocclusion were selected from 32 pairs of twins.