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Objective To study the histological change of microscrew-bone interface, detect the relative cytokine of gingival crevicular fluid, and explore the impossible mechanism of peri-implantitis. Methods Four male Beagles were collected. Randomly select one side of animals jaw as the experimental group to induce the peri-implantitis, and another side as the control group. Four microscrews were implanted on each side. In the 1st, 2nd, 3rd, 4th weeks after implantation, collect peri-implant sulcular fluid (PISF) and detect tumor necrosis factor-α (TNF-α) levels before sacrificed, and the harvest tissue were observed in histological ways. Results According to the extension of time after implantation, the experimental group showed visible progress of interface destruction: 1st week after implantation showed large numbers inflammatory cells collected at the neck but did not undermine the cortical bone; 2nd week after implantation, cortical bone were observed angular absorption; Bone resorption continued to develop and at the 4th week, bone resorption were enlarged to the second thread of microscrew and the interface was filled with a large number of collagen fibers. Conclusion The destruction of interface began at the neck of microscrew, and the further development was along the interface in depth. Both microscrews with peri-implantitis and the healthy controls showed the presence of TNF-α. Inflammation accumulation might trigger the up-regulation of TNF-α level, and the onset of inflammation would enhance the up-trend. [ABSTRACT FROM AUTHOR]

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. Comprehensive theoretical knowledge and a great wealth of practical experience are required to ensure the final treatment effect. The possible complications should be kept under control and fully informed to patients and their parents. In order to unify and standardize early orthodontic treatment protocol and help to promote healthy and orderly development of early orthodontic treatment, this consensus summarized the practical experience of orthodontic experts from many famous colleges and affiliated hospitals for clinical reference.

Porphyromonas gingivalis ( P. gingivalis ), a Gram-negative oral anaerobe, is considered to be a major pathogenic agent involved in the onset and progression of chronic periodontitis. P. gingivalis must be able to perceive and respond to the complicated changes in host to survive the environmental challenges, in which the two-component signal transduction systems (TCSs) play critical roles by connecting input signals to cellular physiological output. Canonical TCS consists of a sensor histidine kinase and a cognate response regulator that functions via a phosphorylation cascade. In this review, the roles of TCSs in P. gingivalis were demonstrated by illustrating the target genes and modulation modes, which may help elucidate the underlying mechanisms in future studies.

Orthodontic treatment is a time-consuming process whose duration usually takes 2-3 years. In general, long-term treatment duration possesses higher risks of complications, which may have adverse impact on patients. Therefore, exploring safe and effective adjunctive interventions to accelerate orthodontic tooth movement and shortening the treatment duration are of profound clinical significance. Currently, numerous adjunctive interventions have been generated and developed to accelerate orthodontic tooth movement, which can be divided into two main categories: surgical and non-surgical. However, an intervention that is widely accepted as a routine practice in orthodontic clinic is lacking. This article aims to review com-mon adjunctive interventions used to accelerate orthodontic tooth movement. This review can be used as a basis to guide clinical practice, shorten treatment duration, and improve patients' prognosis.

Centric relation (CR) is one of the core research contents in orthodontics, prosthodontics, and gnathology, acting as an important physiological factor in reconstructing the occlusion and adjusting the occlusal relationship. For over a century, CR is still a controversial subject in dentistry. CR has been redefined for several times, and recently, its application has been widened in orthodontics, including orthodontic diagnosis, clinical examination and analysis, and treatment goals. The purpose of this article is to review the definition of CR, its relationship with malocclusion, and the application of this relationship in orthodontic treatment.

Circular RNAs (circRNAs), novel endogenous non-coding RNAs with the special circular structure, have been found to play critical roles in various development of tissues and diseases. However, few studies have focused on the functions and mechanisms of circRNAs in the osteogenesis of human adipose-derived stem cells (hASCs). Here, we performed the circRNAs sequencing and bioinformatic analysis to investigate the expression profiles of hASCs during osteogenic differentiation. There were 150 upregulated circRNAs and 60 downregulated circRNAs expressed differentially. Among them, the expression of circPOMT1 and circMCM3AP were downregulated during the osteogenesis of hASCs. hsa-miR-6881-3p could promote the osteogenic differentiation of hASCs, while the expression of circPOMT1 and circMCM3AP were negatively correlated with it. Smad6 and Chordin, critical inhibitors of the BMPs signaling pathway, were predicted to be the targets of hsa-miR-6881-3p. Therefore, circPOMT1 and circMCM3AP might influence the osteogenic differentiation of hASCs by targeting hsa-miR-6881-3p via BMPs signaling pathway. CircPOMT1 and circMCM3AP are potential novel targets for the repairment of bone defects., Competing Interests: None.

Objective: To detect the expression of growth factors relating to bone reconstructions in microscrew-bone interface of implanted titanium microscrews near the extraction wounds, and to determine the influence of healing process on the growth factors., Methods: Eight male Beagle dogs (age 18 months) were divided into experimental and control groups. Titanium microscrews were implanted near an extraction wound in the dogs in the experimental group, while the controls had implantation without extraction wounds. The dogs were sacrificed at 1, 3, 8, 12 weeks, respectively. Immunohistochemistry and in situ hybridization sections were performed to detect the expression of TGF-beta, TNF-alpha, osteocalcin (OC) protein and Cbfal mRNA., Results: The experimental group had higher levels of expression of TGF-beta, TNF-alpha protein and Cbfa1 mRNA than the controls, with significant differences appearing at week one for TNF-alpha (P<0.05), week three for TGF-beta and TNF-alpha (P<0.05), and week eight for Cbfa1 mRNA (P<0.05). The expression of OC increased over time and reached peak at week eight (P<0.05)., Conclusion: Microscrews implanted near extraction wounds can maintain stability. Severe inflammation occurs in the early stage of healing, but does not sustain. Bone remodeling remains active over the healing process. But prolonged healing phase without force loading could weaken the remodeling.

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. The randomization of sampling and grouping were both generated by a pseudo-random number generator. According to the monomial and combined subjects, 69 orthodontic specialists were regarded as the raters to rank the 12 cases in each group, and to judge whether the case was qualified., Results: Correlation analysis: the Spearman r between Post-M + C and Post-M + C + P and the Spearman r between Post-M + P and Post-M + C + P were both greater than 0.950. The Spearman r between Post-M and Post-P and the Spearman r between Post-M and Post-C were about 0.300. The Spearman r between Post-P and Post-C was 0.505. Regression analysis: the linear regression results: M + C = 0.782M + 0.308C - 0.150, M + P = 0.804M + 0.233P - 0.091, M + C + P = 0.764M + 0.243P + 0.131C - 0.291. The r(2) of above three models was greater than 0.9., Conclusions: It was applicable to use M + C and M + P instead of M + C + P. Study casts could not replace cephalometrics or photographs when doing subjective evaluation. Cephalometrics and photographs could not substitute for each other either. In the combined materials evaluation, model accounted for the largest percentage. Based on the regression model, for the greater part, the integration of several monomial materials could replace the combined material assessment effectively.

In recent years, new approaches to the diagnosis and treatment of malocclusion have emerged. The diagnostic and therapeutic techniques of orthodontics have evolved from two dimensions to five dimensions with the development of computer technology, auto-machining and imaging. Furthermore, interdisciplinary study has become the driving force for the advancement of fundamental research in orthodontics. The mechanisms of malocclusion and orthodontic tooth movement have been extensively studied to the details at the level of cells and molecules.

Objective: To investigate the changes in the expression of Dlx5 and Msx2 in human periodontal ligament stem cells (hPDLSCs) loaded with cyclic tensile stress., Methods: hPDLSCs were subjected to cyclic tensile stress (0.5 Hz, 3000 microm strain) for 3, 6, 12, 24 h through a four-point bending strain system. The expressions of Dlx5 and Msx2 mRNA were determined by real time PCR., Results: Strong expressions of Dlx5 and Msx2 were found in the periodontal fibroblasts of the tension side 20 minutes after mechanical loading. The expression of Dlx5 mRNA decreased over time with the stress. The expression of Msx2 mRNA increased over time with the stress., Conclusion: Both Dlx5 and Msx2 are sensitive to mechanical stress. Cyclic tensile stress may induce differentiating of hPDLSCs towards mineralized tissue cells by promoting Dlx5 mRNA expression and decreasing Msx2 expression.

Objective: To identify the differences in maxillary growth vector with different vertical skeletal patterns of skeletal class I before and after growth spurts., Methods: One hundred and ninety four cases with different vertical skeletal patterns of skeletal class I were selected and categorized into six groups according to their vertical skeletal patterns and cervical vertebral stages: cervical vertebral maturation stage (CVMS)1,2-horizontal pattern (n=30); CVMS1,2-average pattern (n=32); CVMS1, 2-vertical pattern (n=33); CVMS5, 6-horizontal pattern (n=34); CVMS5, 6-average pattern (n=29); and CVMS5, 6-vertical pattern (n=36). Lateral cephalograms were taken on all of the cases. The angle SN-C axis (theta) and angel PP-C axis (alpha) were measured., Results: (1) The skeletal class I with a vertical growth pattern had larger angle SN-C axis than those with a horizontal or average growth pattern before growth spurts (P(average-vertical) < 0.05, P(horizontal-vertical) < 0.001). (2) The skeletal class I with a vertical growth pattern had the largest angle SN-C axis after growth spurts, followed by those with an average growth pattern. Those with a horizontal growth pattern had the smallest angle SN-C axis. The differences were statistically significant (P(horizontal-average) < 0.05, P(horizontal-vertical) < 0.001, P(average-vertical) < 0.001). (3) The skeletal class I with the same vertical growth pattern had slightly larger angle SN-C axis after growth spurts than before growth spurts, but without statistical significance. (4) The skeletal class I had relatively stable angle PP-C axis and no significant differences were found before and after growth spurts or among those with various vertical skeletal facial types., Conclusion: The magnitude of angle SN-C axis is closely associated with vertical growth patterns and is weakly influenced by maxillofacial growth and development.

Objective: To study the histological change of microscrew-bone interface, detect the relative cytokine of gingival crevicular fluid, and explore the impossible mechanism of peri-implantitis., Methods: Four male Beagles were collected. Randomly select one side of animals jaw as the experimental group to induce the peri-implantitis, and another side as the control group. Four microscrews were implanted on each side. In the 1st, 2nd, 3rd, 4th weeks after implantation, collect peri-implant sulcular fluid (PISF) and detect tumor necrosis factor-alpha (TNF-alpha) levels before sacrificed, and the harvest tissue were observed in histological ways., Results: According to the extension of time after implantation, the experimental group showed visible progress of interface destruction: 1st week after implantation showed large numbers inflammatory cells collected at the neck but did not undermine the cortical bone; 2nd week after implantation, cortical bone were observed angular absorption; Bone resorption continued to develop and at the 4th week, bone resorption were enlarged to the second thread of microscrew and the interface was filled with a large number of collagen fibers., Conclusion: The destruction of interface began at the neck of microscrew, and the further development was along the interface in depth. Both microscrews with peri-implantitis and the healthy controls showed the presence of TNF-alpha. Inflammation accumulation might trigger the up-regulation of TNF-alpha level, and the onset of inflammation would enhance the up-trend.

Objective: To measure the utility value of different skeletal malocclusion for patients receiving orthodontic treatment., Methods: Utility value of different skeletal malocclusion for patients was measured by rating scale and time trade-off., Results: The youth group had higher utility values than adult group for skeletal malocclusion Class II (protruding facial type) with median mandibular angle. The utility value of skeletal malocclusion Class III (concave facial type) with low mandibular angle was the lowest, and the utility value of skeletal malocclusion Class II (protruding facial type) with median mandibular angle was the highest. There was no difference in the utility values by rating scale and by time trade-off., Conclusion: For some skeletal malocclusion, the youth had different utility values with the adult.

Objective: To study the relationship between the mesiodistal tipping degree of maxillary and mandible posterior teeth and different vertical facial skeletal types of subjects with normal occlusion., Methods: 163 subjects with normal occlusion were selected, lateral cephalograms were taken and divided into three different facial skeletal types. The difference of the mesiodistal tipping degrees and intersection angles of upper and lower posterior teeth between the three different facial skeletal types were analyzed., Results: Among 163 subjects, vertical growth pattern, average growth pattern and horizontal growth pattern were 24, 96 and 43 respectively. There were statistic differences of mesiodistal tipping degrees of the first and second maxillary and mandible premolar and the first permanent molar between vertical growth and horizontal growth pattern, horizontal growth and average growth pattern (P < 0.05). But there were no statistically significant differences between vertical growth and average growth pattern (P > 0.05). The differences of the maxillary and mandible posterior teeth's intersection angle among three vertical facial skeletal types had no statistic significance (P > 0.05)., Conclusion: Different vertical facial skeletal type has its own normal and coordinated posterior teeth mesiodistal tipping degrees.

Objective: To figure out the differences of the morphological characteristics of mandibular symphysis between Class II and Class III adult skeletal malocclusions with different abnormal vertical skeletal patterns., Methods: 109 Chinese female adults of skeletal Class II and Class III were chosen and divided into four groups according to vertical and sagittal skeletal pattern: Class II--vertical-growth-pattern group (n=30), Class III--vertical-growth-pattern group (n=25), Class II--horizontal-growth-pattern group (n=29), Class III--horizontal-growth-pattern (n=25). Lateral cephalograms were taken. The symphyseal widths and heights, along with lower incisor positions were evaluated. Observation and statistics analysis were done to clarify the morphological characteristics of the symphyseal region of different skeletal patterns., Results: There were morphological differences of symphyseal region between Class II and Class III skeletal malocclusions, but not significant in width and total height. With a vertical-growth-pattern, Class II malocclusions had higher alveolus than Class III, but smaller chin prominence and lower basal bone (P < 0.01). With a horizontal-growth-pattern, Class II malocclusions had higher alveolus (P < 0.05) and larger alveolar top width (P < 0.001). With a same sagittal skeletal pattern, vertical-growth-pattern group had thinner but higher symphyseal region and bigger chin prominence (P < 0.001 in Class II while P < 0.05 in Class III). Besides, a vertical-growth-pattern malocclusion was prone to have a cucurbit-morph chin, of which Id width was larger than basal width (P < 0.01)., Conclusion: There are morphological differences in symphyseal region between Class II and Class III skeletal malocclusions with different abnormal vertical skeletal patterns. The influence of abnormal vertical skeletal pattern to symphyseal morphological characteristics is greater than that of abnormal sagittal skeletal pattern. There is a risk of orthodontic movement of low incisors in vertical-growth-pattern skeletal malocclusion.

HX straight-wire appliance (HX-SWA) is designed and adjusted by doctors of Orthodontic Department, West China College of Stomatology, Sichuan University. It is a set of appliance that is constructed according to normal occlusion features of the Chinese people, including the prescription of tip, torque, in/out, counter-tip, counter-rotation and overcorrection in brackets and buccal tubes. Some ingredients of the appliance are different from that of the most popular Roth straight-wire appliance in the world wide. Over a period of the last 10 years, doctors in our hospital kept on summarizing treatment experience with HX-SWA, which will help more doctors promote practice and results in orthodontic clinic.

Objective: To examine the histological discrepancies between juvenile and adult Beagle dogs at different concrescence times after miniscrew implants., Methods: Miniscrew implants were performed in six juvenile Beagle dogs and six adult Beagle dogs. The space between the fourth premolar root and first molar root, and the spaces in distal and mesial of M1 root were picked up for the implants of the 48 miniscrews. The lower jaw specimens including the miniscrews were harvested 3 and 12 weeks after the implants for the histological examinations and bone implant contact (BIC) calculations., Results: There was no miniscrew falling off or becoming loose. The miniscrews had favorable biological consistencies with the tissues around them. The osteoblasts and osteoclasts showed active functions in the peri-bones of the minisrews. The BIC became higher when the healing time was prolonged. The juvenile Beagle dogs had lower BIC than the adults 3 weeks after the implants. But the BIC of the juvenile dogs surpassed the adults 12 weeks after the implants., Conclusion: The osseointegration of the miniscrews is hindered by the poorer bone quality of the juvenile Beagle dogs. But the early osseointegration deficiency can be made up by the rapid development and growth of the bones of the juvenile dogs.

Objective: To determine the facial profile preference among four groups of persons and the influence of vertical proportion and skeletal anteroposterior relation on facial profile esthetics., Methods: One hundred and twenty persons, comprising of adult patients, adolescents' parents, laypersons and orthodontists, participated this study. The subjects were asked to rate 27 silhouettes which represented the male facial profiles with various vertical proportion and anteroposterior relation., Results: The silhouette II-1s scored highest while the one III-4s scored lowest (P < 0.05). The silhouette I-normal was rated highest by orthodontists while the ones II-normal and II-1s were rated highest by other three groups. The silhouette III-4s was scored lowest by all groups (P < 0.05)., Conclusions: Vertical discrepancy had influence on Chinese male facial profile esthetics and the influence was related to the degree of vertical malformation and skeletal anteroposterior relation. Class III skeletal pattern had the most negative influence on male profile esthetics. The four panels had different esthetic standard. The preference of facial profile esthetics was related to orthodontic education background rather than gender or age.

Objective: The aim of the study was to find the most reliable method used for space analysis for Chinese population., Methods: 140 study models in accordance with the conclusion standards were measured using a calibrated digital caliper with an accuracy of 0.01 mm and the statistic comparision and analysis had been done between the predictions and measurements. The methods were "West China Moyers", "Tanaka -Johnston", "Bachmann", "Gross and Hasund", "Trankmann"., Results: All the methods tend to under-estimate the mesiodistal crown diameters of the permanent canines and premolars(MDD). The under-estimated predictive scale in the method of Trankmann is the largest while in the method of Moyers is the least., Conclusion: The method proposed by Moyers that was improved by West China School of Stomatology, Sichuan University proved to be most reliable in this study which showed the greatest correltion. However, the reliability of the method of Trankmann which seems to be the most unfit for Chinese population is the lowest.