Evolutionary and Pan-genome Analysis of Three Important Black-pigmented Periodontal Pathogens.

Objective: To analyse the pan-genome of three black-pigmented periodontal pathogens: Porphyromonas gingivalis, Prevotella intermedia and Prevotella nigrescens.

Methods: Pan-genome analyses of 66, 33 and 5 publicly available whole-genome sequences of P. gingivalis, P.

Changes of Microbial Community in Treated Peri-implantitis Sites: An Experimental Study in Beagle Dogs.

Objective: To investigate the changes of the bacterial community in the oral environment of beagle dogs to gain insights on the possible causes of failed therapy in peri-implantitis.

Methods: Beagles were used as models for experimental peri-implantitis. Samples from peri-implant soft tissue (supramargin and submargin), ligature and contaminated surface of peri-implantitis sites were collected and analysed by sequencing the bacterial 16S rRNA gene.

Longitudinal Quantitation of Tooth Displacement in Chinese Adolescents with Normal Occlusion.

This longitudinal study aims to analyze the different modes of the maxillary and mandibular tooth displacement in subjects, who were aged 12.5-17.5 years (150-210 months), with untreated normal (Class I) occlusion.

Posteroanterior cephalometric analysis of White-American and Chinese adolescents: a cross-sectional study.

: To characterize ethnic differences between Chinese and White-Americans between 8.5 and 17.5 years of age, with respect to transverse cephalometric characteristics and to establish transverse craniofacial normative values for Chinese adolescents.

Novel Mutation of Cleidocranial Dysplasia-related Frameshift Runt-related Transcription Factor 2 in a Sporadic Chinese Case.

Background: Cleidocranial dysplasia (CCD) is an autosomal dominant disease that affects the skeletal system. Common symptoms of CCD include hypoplasia or aplasia of the clavicles, delayed or even absent closure of the fontanels, midface hypoplasia, short stature, and delayed eruption of permanent and supernumerary teeth. Previous studies reported a connection between CCD and the haploinsufficiency of runt-related transcription factor 2 (RUNX2).

[A novel TaqMan® MGB probe for specifically detecting Streptococcus mutans].

Objective: To design a new TaqMan® MGB probe for improving the specificity of Streptococcus mutans's detection.

Methods: We extracted six DNA samples from different streptococcal strains for PCR reaction. Conventional nested PCR and TaqMan® MGB real-time PCR were applied independently.

[Indication of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL) in gingival crevicular fluid to remodeling of alveolar bone during retention].

Objective: To investigate the level of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL) in gingival crevicular fluid (GCF) during orthodontic retention and corresponding expression of OPG and RANKL in periodontal tissues.

Methods: Fifteen male Wistar rats (age, 6 weeks) were divided into three groups with 5 rats for each. GCF samples were collected at the baseline, 14 days after orthodontic force application, and 14 days after orthodontic force removal.

Longitudinal changes in mandibular arch posterior space in adolescents with normal occlusion.

Introduction: The purpose of this study was to investigate the changes of available mandibular space in the posterior dental arch of teenagers from 13 to 18 years old.

Methods: Longitudinal cephalograms of 28 adolescents (13 boys, 15 girls) with normal occlusion, selected from among 901 candidates, were taken annually from 13 to 18 years of age inclusively. Modified analyses with occlusal plane and occlusal plane perpendicular as reference planes were used to evaluate the changes of available space of the posterior mandibular arch.

[Preliminary investigation of Tip-Edge Plus technique in the treatment of Class III malocclusion].

Objective: To investigate the craniofacial and occlusal changes of Class III cases treated with Tip-Edge Plus Technique.

Methods: Thirteen Class III patients (6 girls and 7 boys, mean age 14.9 years) with mandibular protrusion were selected.

[Analysis of treatment templates of Angle's Class III malocclusion patients].

Objective: To analyze the morphological characters of Angle's Class III malocclusion patients and the relationship between characters and treatment options.

Methods: A total of 472 Class III patients were collected during 1997-2000. The standardized coordinates' values of the patients were obtained by Procrustes superimposition (PS).

[Intruding upper incisors using mini-screw anchorage in patients with gummy smile].

Objective: To evaluate the effectiveness of mini-screw anchorage on intruding upper incisors in patients with gummy smile.

Methods: Sixteen female patients (mean age: 23.8 years) were involved in this study.

[Development and preliminary application of orthodontic friction dynamic testing apparatus].

Objective: To design and assemble an orthodontic friction prototype testing apparatus and evaluate its performance.

Methods: Simulating progressive tooth tipping movement, results of the operating friction trials are reported at different archwire-bracket angulation.

Results: An orthodontic friction testing apparatus was designed and developed, by which the complexity of tooth movements observed with in vivo sliding mechanics was simulated and a series of in vitro friction experiments were conducted.

[Accuracy and sensibility of computer -aided alveolar bone density quantitative measuring system].

Objective: The alveolar bone density quantitative measuring system was established on the basis of grey level measuring on standardized-exposed direct digital periapical radiograph by referring to an aluminum step wedge with the aid of computer technique. We tested it's accuracy and sensibility by measuring a series of specimens and made it possible to estimate the area density of hydroxyl-phosphorite (HP) in the alveolar bone with the system.

Methods: The average grey level intensity of 19 specimens containing different amount of HP within certain area was measured with the system.

[Bone morphogenetic protein-4 regulates embryonic tongue morphogenesis].

Objective: To analyze the effect of Bone morphogenesis 4 and its antagonist Noggin on morphogenesis of tongue.

Methods: Dissected rats to get embryonic day 13 (E13) tongues; fed E13 tongues in standard medium, BMP4 (0.03 mg/L, 0.

[Craniofacial characters for Angle's class II malocclusion using Procrusts superimposition and multivariate statistics].

Objective: Cluster and discriminant analysis of the morphological characters of Angle's Class II malocclusion was performed using Procrusts standardization. The classification of craniofacial morphology with the help of morphometry and multivariate statistics was also discussed.

Methods: A total of 894 class II patients were collected from the department of orthodontic, Peking University School and Hospital of Stomatology during 1997-2000.

[Preliminary clinical application of Tip-Edge Plus appliance in the treatment of Class II patients].

Objective: To evaluate the craniofacial and occlusional changes of Class II patients treated with Tip-Edge Plus technique.

Methods: Twelve Class II patients (7 girls and 5 boys, mean age 14.3 years) with bimaxillary or maxillary protrusion were selected.

Quantitative cervical vertebral maturation assessment in adolescents with normal occlusion: a mixed longitudinal study.

Introduction: The purpose of this study was to establish a quantitative cervical vertebral maturation (CVM) system for adolescents with normal occlusion.

Methods: Mixed longitudinal data were used. The subjects included 87 children and adolescents from 8 to 18 years old with normal occlusion (32 boys, 55 girls) selected from 901 candidates.

[The differences of hard tissue changes and stability of Angle's Class II division 1 extraction cases treated by Begg appliance and Edgewise appliance].

Objective: The purpose of this investigation is to compare the differences of hard tissue changes and stability in patients with Class II division 1 treated with extraction of four first premolars by Begg appliance and Edgewise appliance.

Methods: The study was conducted using lateral cephalometric radiographs taken pretreatment, posttreatment and following-up. Thirty patients who had an Angle's Class II division 1 malocclusion were treated with first premolar extractions (19 by Begg appliance and 11 by Edgewise appliance).

[A system for quantitatively measurement of alveolar bone density and the evaluation of its precision and validity].

Objective: To establish a system for quantitatively measuring alveolar bone density and to test its precision and validity.

Methods: With the aid of computer technique, the system measured the average gray level intensity of regions of interest (ROIs) on standardized exposed direct digital periapical radiograph. To correct the variation resulting from exposure condition, an aluminum stepwedge was exposed simultaneously.

[History and development of Chinese orthodontics].

Orthodontics in China has experienced two important stages. At its early stage from 1950's to 1970's orthodontics was a division of prosthodontic department in China. There were 3 top professors in this field, who got partly training at one time or another in USA and returned to China working in Beijing Medical College, the Fourth Military Medical University and Shanghai Second Medical College.