Publications by authors named "Yu-Xing Bai"

Early orthodontic intervention remains a controversial notion in current dental care regime. Whilst early orthodontic treatment for children is the province for orthodontic specialists, a growing number of general practitioners, who may not possess sufficient specialty knowledge, are also involved, raising the concerns about the propriety and quality of their treatment modalities. However, orofacial development of children and adolescents is in a very complicated environment.

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Background: Previous studies have reported incidence rates of dehiscence (DEH) and fenestration (FEN) as high as 36.51 and 51.09%, respectively.

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White spot lesions (WSLs), due to enamel demineralization, occur frequently in orthodontic treatment. We recently developed a novel rechargeable dental composite containing nanoparticles of amorphous calcium phosphate (NACP) with long-term calcium (Ca) and phosphate (P) ion release and caries-inhibiting capability. The objectives of this study were to develop the first NACP-rechargeable orthodontic cement and investigate the effects of recharge duration and frequency on the efficacy of ion re-release.

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Composites containing nanoparticles of amorphous calcium phosphate (NACP) remineralize tooth lesions and inhibit caries. A recent study synthesized quaternary ammonium methacrylates (QAMs) with chain lengths (CLs) of 3-18 and determined their effects on a bonding agent. This study aimed to incorporate these QAMs into NACP nanocomposites for the first time to simultaneously endow the material with antibacterial and remineralizing capabilities and to investigate the effects of the CL on the mechanical and biofilm properties.

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Objective: To characterise and compare the tensile characteristics after multi-proportional blending, to determine the proper blending ratio for new thermoplastic material and to compare its mechanical performance with commercial thermoplastics.

Methods: PETG and PC2858 aggregates were blended in five different ratios. Standard specimens of each ratio were molded and tested to determine their mechanical performance.

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Objective: To assess the accuracy of anterior tooth movement using clear aligners in integrated three-dimensional digital models.

Methods: Cone-beam computed tomography was performed before and after treatment with clear aligners in 32 patients. Plaster casts were laser-scanned for virtual setup and aligner fabrication.

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Secondary caries due to biofilm acids is a primary cause of dental composite restoration failure. To date, there have been no reports of dental composites that can repel protein adsorption and inhibit bacteria attachment. The objectives of this study were to develop a protein-repellent dental composite by incorporating 2-methacryloyloxyethyl phosphorylcholine (MPC) and to investigate for the first time the effects of MPC mass fraction on protein adsorption, bacteria attachment, biofilm growth, and mechanical properties.

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Objective: To evaluate the effect of orthodontic light force on the expression of Asporin, bone morphogenetic proteins-2 (BMP-2) and alkaline phosphatase (ALP) after auto-transplantation.

Methods: Thirty-two maxillary and mandibular incisors in four 13 month-old male Beagle dogs were auto-transplanted to the other side of the same jaw. The teeth were all endodontically treated and divided into four groups, control (group 1) and three experimental groups (groups 2, 3 and 4).

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Objective: To investigate the bond strengths of customized titanium bracket manufactured by selective laser melting.

Methods: Eighty human premolars which had been extracted for orthodontic purpose were collected and divided randomly (by random table) into two groups (customized bracket group and 3M bracket group, 40 molars in each group). The 35% phosphoric acid was used for etching and the brackets were bonded with 3M Unitek bonding adhesive.

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This study aimed to assess the reliability of experienced Chinese orthodontists in evaluating treatment outcome and to determine the correlations between three diagnostic information sources. Sixty-nine experienced Chinese orthodontic specialists each evaluated the outcome of orthodontic treatment of 108 Chinese patients. Three different information sources: study casts (SC), lateral cephalometric X-ray images (LX) and facial photographs (PH) were generated at the end of treatment for 108 patients selected randomly from six orthodontic treatment centers throughout China.

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Objective: To investigate the repeatability of three-dimensional (3-D) cephalometric measurements for the clinical application of 3-D cephalometry.

Methods: Forty-nine measurements that widely used in traditional cephalometric analyses were defined in 3-D cone-beam CT (CBCT) images. Three examiners identified landmarks on CBCT images of 17 subjects with normal occlusion, respectively, and 3-D measurements were exported automatically by software SimPlant.

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Introduction: Orthodontics in China has developed rapidly, but there is no standard index of treatment outcomes. We assessed the validity of the American Board of Orthodontics Objective Grading System (ABO-OGS) for the classification of treatment outcomes in Chinese patients.

Methods: We randomly selected 108 patients who completed treatment between July 2005 and September 2008 in 6 orthodontic treatment centers across China.

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Objective: To analyze craniofacial growth three-dimensionally for adolescents with normal occlusion in Beijing.

Methods: One hundred and twenty-six adolescents with normal occlusion were selected according to the criteria. The sample was divided into four age groups (53 within 4 years, 30 within 7 years, 27 within 10 years and 16 within 13 years).

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Objective: To investigate the effect of the continuous light force to the donor teeth on the periodontal healing after transplantation.

Methods: Thirty-two maxillary and mandibular incisors in four 10-month-old male Beagle dogs were autotransplanted. The pulps were removed in all teeth.

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Objective: To create an integrated digital maxillodental model and to apply it in computer aided design (CAD) of individualized lingual brackets in order to align both crowns and roots without fenestration and dehiscence.

Methods: Cone-beam computerized tomography (CBCT)-based maxillodental model and laser-scanned dental model were integrated by auto registration in 10 patients with malocclusions. The registration error was calculated automatically.

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Objective: To analyze the results of multiple Chinese orthodontic specialists' subjective evaluation of orthodontic treatment outcome, to investigate the relevance of different experiment items and to explore the weight of each monomial material.

Methods: As a randomized clinical trial, with six orthodontic treatment centers and Angle's classification being regarded as two stratification factors, it contained 108 cases with integrity data, which was random extracted from 2383 cases that received orthodontic treatment in six orthodontic treatment centers during the past five years, gathering post-treatment study casts, cephalometrics and photographs of 48 cases as the research subject. Similarly taking Angle's classification as a stratification factor, 108 cases were randomly divided into 9 groups.

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Objective: To design and build the micro-stress sensor measurement system for invisible aligner technique.

Methods: A measurement system based on silicon-on-insulator piezoresistive stress sensor was developed. A four-point-bending based experimental apparatus was constructed to calibrate the piezoresistive coefficients of this stress sensor.

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Objective: To compare the mechanical properties of different dental optimal material selection for orthodontic appliance.

Methods: Four commercialized thermoplastic products under different test conditions, and provide the suggestion of thermoplastic products were tested. The tear strength, elongation at break and stress relaxation of these materials were measured under different test conditions.

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Objective: To observe the microstructure changes of rat alveolar bone around tooth root under orthodontic force loading.

Methods: Ten 10-week-old rats were included in the study. Upper first molars were moved mesially with 0.

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Objective: To investigate the mechanical properties of Ni-Ti wires with direct electric resistance heat treatment (DERHT) method in three-point bending tests.

Methods: Two superelastic Ni-Ti wires (wire A: Smart SE, wire B: SENTALLOY SE, 0.406 mm × 0.

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Objective: To establish a three-dimensional digital dental model through scanning dental impression directly with micro-CT.

Methods: The polyvinyl siloxane (PVS) impression of the plaster model was taken and scanned with micro-CT. VGStudio MAX and Imageware softwares were used to obtain the digital dental model.

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Objective: To investigate the mechanical properties of various brands of thermoplastic materials under different test conditions so as to analyze their influencing factors so as to provide a reference for improving the effect of invisible orthodontics.

Methods: Three brands of thermoplastic materials, DR, Biolon and Erkodent, were selected. They were tested by Instron testing machine to measure their maximal stress and modulus under different processing modes, including pre-thermoforming, post-thermoforming and dipped in artificial saliva for two weeks after thermoforming.

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