[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. The first round of nested PCR was carried out with the bacterial universal primers, while a second PCR was conducted by using primers specific for the 16S rRNA gene of Streptococcus mutans. The TaqMan® MGB probe for Streptococcus mutans was designed from sequence analyses, and the primers were the same as nested PCR. Streptococcus mutans DNA with 2.5 mg/L was sequentially diluted at 5-fold intervals to 0.16 µg/L. Standard DNA samples were used to generate standard curves by TaqMan® MGB real-time PCR. RESULTS: In the nested PCR, the primers specific for Streptococcus mutans also detected Streptococcus gordonii with visible band of 282 bp, giving false-positive results. In the TaqMan® MGB real-time PCR reaction, only Streptococcus mutans was detected. The detection limitation of TaqMan® MGB real-time PCR for Streptococcus mutans 16S rRNA gene was 20 µg/L. CONCLUSION: We designed a new TaqMan® MGB probe, and successfully set up a PCR based method for detecting oral Streptococcus mutans. TaqMan® MGB real-time PCR is a both specific and sensitive bacterial detection method.

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. intermedia and P. nigrescens, respectively, were performed using Pan-genome Analysis Pipeline software (version 1.2.1; Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, PR China). Phylogenetic trees were constructed based on the entire pan-genome and single nucleotide polymorphisms within the core genome. The distribution and abundance of virulence genes in the core and dispensable genomes were also compared in the three species. RESULTS: All three species possess an open pan-genome. The core genome of P. gingivalis, P. intermedia and P. nigrescens included 1001, 1514 and 1745 orthologous groups, respectively, which were mainly related to basic cellular functions such as metabolism. The dispensable genome of P. gingivalis, P. intermedia and P. nigrescens was composed of 2814, 2689 and 906 orthologous groups, respectively, and it was enriched in genes involved in pathogenicity or with unknown functions. Phylogenetic trees presented a clear separation of P. gingivalis, P. intermedia and P. nigrescens, verifying the reclassification of the black-pigmented species. Furthermore, the three species shared almost the same virulence factors involved in adhesion, proteolysis and evasion of host defences. Some of these virulence genes were conserved across species whereas others belonged to the dispensable genome, which might be acquired through horizontal gene transfer. CONCLUSION: This study highlighted the usefulness of pan-genome analysis to infer evolutionary cues for black-pigmented species, indicating their homology and phylogenomic diversity.

[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. enzyme linked immunosorbent assay (ELISA) was used to quantify the concentration of OPG and sRANKL (soluble receptor activator of nuclear factor kappa B ligand) in GCF. Immunohistochemical staining was performed to identify the OPG and RANKL expression in periodontal tissues. RESULTS: The concentration of sRANKL in GCF increased statistically significant from baseline to T2 (P<0.05) while decreased significantly from T2 to T3 (P<0.05). The concentration of OPG had minimum fluctuation from baseline to T3 without any statistical significance (P>0.05). The sRANKL/OPG ratio in GCF and that in periodontal tissues during the three time points were similar which showed a prominent increase in T2 (P<0.05 and P<0.01, respectively) and sharp decrease in T3 (P<0.05). CONCLUSION: sRANKL/OPG ratio may be one of the predictors reflecting the remodeling of periodontal tissues in orthodontic retention.

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. RESULTS: From 13 to 18 years of age, significant differences of mandibular posterior space were found among ages and sexes. The total increases of available space were 5.12 mm in the girls and 5.79 mm in the boys. For girls before age 16 and boys before age 17, the increased available space was contributed mainly by resorption of bone on the anterior border of the ramus. Mesial drift of the dental arch did not occur until the eruption of the third molars. The average available spaces increased 1.22 mm in girls less than age 16 and 1.45 mm in boys less than age 17 per side per year. CONCLUSIONS: The prediction of available space in the posterior mandibular arch should be based on age and sex.

[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, 0.3 mg/L, 1 mg/L), and the antgonist Noggin(1 mg/L, 3 mg/L, 10 mg/L) medium; cultured for 3 days; fixed samples, observed tongues with scanning electronic microscope (SEM); measured the whole tongue length, anterior 1/8, 1/4 width and middle width of cultured tongues and analyzed data with SPSS 10.0. To further study the effects of BMP4 on epithelial and mesenchymal cell proliferation, Affi-gel blue gel beads were applied. Beads were soaked in PBS and BMP4 (667 mg/L), and implanted in the E13 embryonic tongues; then after cultured in standard medium for 3 days, tongues were embedded in O.C.T. and cut into 12 microm series sections. Ki67 was detected by immunohistochemical method. RESULTS: (1)Whole length of tongues changed greatly (P<0.05), the length was shortened in BMP4 groups (0.03 mg/L group 877.3+/-67.6 microm, 0.3 mg/L group 838.5+/-88.9 microm, 1 mg/L group 718.7+/-38.6 microm) compared with standard medium (1 037.8+/-126.2 microm), Noggin groups had no obvious change; the anterior 1/8 width of tongues changed significantly(P<0.05), the anterior 1/8 width was narrower in BMP4 groups (0.03 mg/L group 332.1+/-80.9 microm, 0.3 mg/L group 305.1+/-51.3 microm, 1 mg/L group 276.9+/-45.9 microm) compared with standard group(639.1+/-106.2 microm), except 10 mg/L group, Noggin groups were wider (1 mg/L group 815.5+/-90.3 microm, 3 mg/L group 857.6+/-87.1 microm, 10 mg/L group 807.1+/-113.8 microm); the anterior 1/4 width of tongue changed magnificently, also(P<0.05), BMP4 groups were narrower (0.03 mg/L group 421.3+/-43.8 microm, 0.3 mg/L group 407.3+/-15.6 microm, 1 mg/L group 363.7+/-24.7 microm) compared with standard group (653.7+/-101.6 microm), whereas, Noggin groups were wider greatly (1 mg/L group 838.0+/-130.5 microm, 3 mg/L group 947.2+/-34.9 microm, 10 mg/L group 889.4+/-74.6 microm); the middle width of tongue changed significantly(P<0.05), width of BMP4 groups were narrower (0.03 mg/L group 567.3+/-35.8 microm, 0.3 mg/L group 548.4+/-30.5 microm, 1 mg/L group 457.4+/-48.0 microm) compared with standard medium (683.1+/-79.8 microm), and Noggin groups had widening tendency, difference in 3 mg/L group is magnificent (1 mg/L group 776.2+/-134.1 microm, 3 mg/L group 964.3+/-44.3 microm, 10 mg/L group 777.2+/-46.7 microm). (2) The expression of Ki67 in both epithelium and mesenchym adjacent to BMP4 beads reduced greatly. CONCLUSION: BMP4 could effect morphological development of embryonic tongue, which could change spatula-shape tongue into short, narrow and tip-point one, the antagonist Noggin tongue was wider and longer; BMP4 inhibit cell proliferation in embryonic tongues.

[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. Using Procrusts standardization and cluster analysis, the samples were divided into different groups, discrimination equations were then established. RESULTS: The samples were divided into 11 subdivisions by Procrusts superimposition and cluster analysis. Three discrimination equations were established. The accuracy rate of cross-validated grouped cases was 80.17%. CONCLUSION: Procrusts standardization had certain advantages in morphological classification; cluster analysis could be used in classification of Angle class II malocclusion; For different types, the differentiate rate was not the same; the discrimination equations was the foundation for future research.

[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. This friction testing apparatus enables previously unattainable testing of the orthodontic archwire-bracket-ligation interface. In the passive configuration or the active configuration with second-order angulation, the friction in sliding mechanics was measured. CONCLUSION: The apparatus presented has the ability to allow for a high standard of basic hypothesis testing, product development and performance evaluation with relative ease. Furthermore, it will be the prototype of a computer-controlled multifunctional friction testing device in the near future.

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. Longitudinal lateral cephalograms for a set of 10 subjects (7 females and 3 males) at consecutive annual time points were selected and monitored. Data were analyzed on the basis of the superimpositions of serial tracings of lateral cephalograms on stable anterior cranial base, the anatomies of the maxillary and mandibular structures. The horizontal and vertical displacements of the first molar and incisor were assessed by t-test. The local and the secondary tooth displacements with growth contributed to the total horizontal and vertical displacements of the molars and incisors of the subjects. In the total tooth displacement, the horizontal growth of maxilla and mandible had the same contribution as the local tooth displacements. The vertical maxillary growth played a smaller role than the local drift, and mandibular remodeling went in a reverse direction with the local tooth drift. The first molars moved more forward than the incisors in the upper and lower arches. Both the upper and lower first molars showed forward tipping. The analysis of tooth displacement may be utilized in making orthodontic treatment plan, including anchorage or torque control.

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. RESULTS: The residual microbial community from the curettes-treated implant surface contained a variety of microorganisms, including periodontal pathogens, which showed no changes in their composition and structure. CONCLUSION: It is possible that the residual bacterial community remained unchanged and this was the cause of recurrent episodes of inflammation.

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. Sequential lateral cephalograms and hand-wrist films were taken once a year for 6 years. The lateral cephalograms of all subjects were divided into 11 maturation groups according to the Fishman skeletal maturity indicators. The morphologic characteristics of the second, third, and fourth cervical vertebrae at 11 developmental stages were measured and analyzed. RESULTS: Three characteristic parameters (H4/W4, AH3/PH3, @2) were selected to determine the classification of CVM. With 3 morphologic variables, the quantitative CVM system including 4 maturational stages was established. An equation that can accurately estimate the maturation of the cervical vertebrae was established: CVM stage=-4.13+3.57xH4/W4+4.07xAH3/PH3+0.03x@2. CONCLUSIONS: The quantitative CVM method is an efficient, objective, and relatively simple approach to assess the level of skeletal maturation during adolescence.

[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. By referring the image of aluminum stepwedge on each radiograph the equivalent aluminum thickness(EAT)and corrected gray level intensity(CGL)of the ROIs could be calculated as indicators of alveolar bone density. Nineteen specimens containing different amounts of hydroxy-phosphorite were radiographed. The precision of the system was tested by repeatedly measuring 2 of the specimens. The set of specimens was exposed under two different exposure time in order to test the system's validity to correct the gray level difference caused by different exposure time. RESULTS: After repeated measurement of specimens, we found the Relative Standard Deviation(RSD) of EAT and CGL was between 0.83%-2.15%; At the level of 95%, if the difference of EAT between the two ROIs was larger than 0.05 mm or the difference of CGL was larger than 3, the content of hydroxy-phosphorite in them was different; The two sets of data during different exposure time were processed with Wilcoxon Signed Ranks Test, and the result showed effective correction of the variation caused by different exposure time. CONCLUSION: The precision and validity of the quantitative alveolar bone density measuring system are acceptable. The system can be used to compare alveolar bone density longitudinally and cross-sectionally.

[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. Among them, Professor Mao of Beijing Medical College was regarded as the father of Chinese Orthodontics. Removable appliance was the main tool at that stage and Prof.Mao brought forward Mao's Classification of Malocclusion which is still used in China. The rapid developing stage began in the 1980's when China opened its door to the world. More and more orthodontists got further training abroad and brought back advanced techniques since then. Up to now, we have already had more than one thousand of orthodontic specialists and established its own organization--the Chinese Orthodontic Society (COS), which holds domestic orthodontic meetings and organize its members to attend international meetings. Right now, almost all advanced techniques in diagnosis and treatment are adopted in China, including 3D imaging, self-ligating bracket appliance, and implant anchorage. Chinese orthodontists have started to present or publish papers in international meetings and journals and more than that, started to develop new appliances, such as Driving-Force Straight Wire Appliance, which has shown advantages in treating skeletal Class III malocclusion.

[Comparative study on ordinary coordinates and standardized coordinates converted by general procrusts analyzation method in cluster analysis and discrimination analysis of Angle I malocclusion].

OBJECTIVE: To classify the Angle I malocclusion subgroups using lateral radiographic films according to their ordinary coordinates and standardized coordinates converted by general procrusts analysis (GPA), and to compare the two kinds of classifications and their valne in diagnosis of malocclusion. METHODS: 946 pretreatment lateral radiographic films of patients with Angle I malocclusion were chosen and their ordinary coordinates were acquired via soft ware. The ordinary coordinates were then converted into standardized coordinates by GPA. All of the films were classified by cluster analysis and discrimination analysis applying the upper two kinds of coordinates respectively. RESULTS: (1) Twenty one subgroups were identified according to the ordinary coordinates of the chosen films with the total differentiate rate of 92.7% and leave-one-out differentiate rate of 68.4% (Classification A). Correspondingly, 20 subgroups were identified according to the standardized coordinates with the two differentiate rates of 87.8% and 71.9% (Classification B). (2) If the ordinary coordinates were discriminated by Classification B, the total differentiate rate and leave-one- out differentiate rate were 79.8% and 60.2 % respectively. If the standardized coordinates were discriminated by Classification A, the two differentiate rates were 79.8% and 60.2 % respectively. (3) There were some subgroups having the similar form in Classification A and their difference mainly arose from the difference of the patient age, while there were no such subgroups like that in Classification B. (4)The proportion of the largest subgroup in total subjects is 15.9% and there were 8 subgroups having the number of subjects over 40 in Classification A, while the corresponding proportion and number of subgroups were 74.7% and 2 in Classification B. (5)Classification A and Classification B were both suitable to classify a new subject, but Classification B was required to standalize all of the subjects onc again, which was very complex, while Classification A was more simplified. CONCLUSION: Classification A and Classification B are interrelated. GPA could concentrate the subjects in cluster analysis, which reduces some influence of the age to the classification, but the process to classify a new subject is very complex. Thus if quick diagnosis is needed in clinics, Classification A should be recommended, but the influence of the age should be noted.

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). Here, we report a sporadic Chinese case presenting typical symptoms of CCD. METHODS: We made genetic testing on this sporadic Chinese case and identified a novel RUNX2 frameshift mutation: c.1111dupT. In situ immunofluorescence microscopy and osteocalcin promoter luciferase assay were performed to compare the functions of the RUNX2 mutation with those of wild-type RUNX2. RESULTS: RUNX2 mutation was observed in the perinuclear region, cytoplasm, and nuclei. In contrast, wild-type RUNX2 was confined in the nuclei, which indicated that the subcellular compartmentalization of RUNX2 mutation was partially perturbed. The transactivation function on osteocalcin promoter of the RUNX2 mutation was obviously abrogated. CONCLUSIONS: We identified a sporadic CCD patient carrying a novel insertion/frameshift mutation of RUNX2. This finding expanded our understanding of CCD-related phenotypes.

[Establishment and application of fetal rolling palate organ culture model of mouse].

OBJECTIVE: To investigate the effect of all-trans retinoic acid (atRA) on the development of mouse palates and its possible mechanism, a model of fetal mouse rolling plate organ culture was establishted. METHODS: Mouse embryonic palates were explanted on GD12 and cultured in a roller device for 72h induced by atRA in different concentrations from 10(-5) micromol/L to 10(-1) micromol/L. RESULTS: Similar to development in vivo, palates in control normal fused. Compared with the control, palates development and fusion were promoted in group of 10(-15) micromol/L, while were inhibited in groups of 10(-4) micromol/L or greater, resulting in cleft palate. The proportion of fusion was reduced in a significant dose-response pattern. CONCLUSION: In the model, the cultured palates continued developing and fusing. Palatal fusion was promoted by normally atRA in 10(-5) micromol/L level and were inhibited by atRA in 10(-4) micromol/L level or greater, which resulting in cleft palate. These mentioned confirm the validity and reliability of this model.

Osteoprotegerin Promotes Cementoblastic Activity of Murine Cementoblast Cell Line in vitro.

OBJECTIVE: To investigate the effect of osteoprotegerin (OPG) on the cementoblastic activity of a clonal population of immortalised murine cementoblasts (OCCM-30) in vitro. METHODS: OCCM-30 cells were transiently transfected with the mouse OPG using the Avalanche transfection reagent. The ectopic expression of OPG was confirmed by enzyme-linked immunosorbent assay and quantitative polymerase chain reaction. The cell counting Kit-8 assay was used to investigate the effect of OPG on cell proliferation. The expression levels of cementoblastic-related mRNA and protein in the transfected OCCM-30 cells were detected using real-time PCR, Western blotting and immunohistochemical staining. RESULTS: Satisfactory transfection efficiency was observed 48 h after transfection. The results of the cell proliferation assay indicated that the expansion rate of the OPG transfection group was greater than that of the control group at both 72 h and 96 h. The mRNA levels of osterix (Osx), protein kinase B (Akt1), cementum attachment protein (CAP) and osteopontin (Opn) were significantly upregulated (P < 0.05) in the OPG group. Protein levels of OPN, bone sialoprotein II (BSP II), osteocalcin (OC) and CAP, which are responsible for osteogenetic and cementoblastic activity, were significantly increased in the OPG-overexpressing group. CONCLUSION: Overexpression of OPG in OCCM-30 cells promotes cementoblastic activity.

[Preliminary study of treatment mechanism and stability in deep overbite malocclusion with hyperdivergent and hypodivergent skeletal pattern].

OBJECTIVE: Comparison of structural characteristic changes between deep overbite malocclusions with hyper- and hypodivergent skeletal pattern during treatment and follow-up stages. To discuss the difference between both in treatment mechanism and characteristic of relapse. METHODS: 59 cases out of 162 finished patients with deep overbite malocclusion followed for more than 2 years, selected from orthodontic clinic in school of stomatology Peking University, were filtered by cephalometrics (MP-SN>40 degrees or <29 degrees)and then two groups were formed. The hyperdivergent group (MP-SN>40 degrees) comprised 10 cases and the hypodivergent group (MP-SN<29 degrees) comprised 9 cases. Measurements and statistics were performed upon the two groups. RESULTS: After orthodontic treatment, the hyperdivergent group exhibited the extrusions of upper and lower molars [U6-PP increased from (10.69+/- 2.10)mm to (12.91+/-2.19)mm; L6-MP increased from (17.34+/-2.73)mm to (20.86+/-3.08)mm]. As to the skeletal change, a decrease of ANB angle from (5.86+/- 1.34) degrees to (4.62+/-1.67) degrees and NA-PA angle from (11.99+/-3.74) degrees to (8.76+/-4.45) degrees reflecting the sagittal change tendency from skeletal Class II to Class I. In vertical direction, the ratio of Ar-Go/ANS-Me increased from (0.58+/-0.03) to (0.62+/-0.05). Compared with the hyperdivergent group, the hypodivergent one only showed the extrusion of lower molars after treatment. The stability of overbite didn't show any statistically significant difference between two groups during the follow-up stage. Also in this stage the change of overbite in the hyperdivergent group was mainly due to the lingual inclination of upper incisors during the treatment stage and in the hypodivergent group it was due to the molar extrusion during treatment. CONCLUSION: The ramus showed great potential of growth in the hyperdivergent group during the treatment stage, which maintained the inclination of mandibular plane. The relapse of overbite was correlated with the changes of teeth during the treatment and follow-up stages.

[Retinoic acid induced cell cycle arrest and apoptosis in mouse embryonic palatal mesenchymal cells].

OBJECTIVES: To investigate the effect of all-trans retinoic acid (atRA) on proliferation activity and cell cycle distribution in mouse embryonic palatal mesenchymal (MEPM) cells and the underlying molecular mechanisms. METHODS: MEPM cells were prepared from palate shelves of mouse fetal on gestation day 13. Cell viability was determined by MTI assay. Cell cycle distribution and subdiploid population were analyzed by cytometry. The expression of cyclin D and E and phosphorylation of retinoblastoma protein was examined using Western-blot. RESULTS: atRA remarkably inhibited the growth of MEPM cells in a dose-dependent manner. atRA also caused an increase in the proportion of cells in G0/G1 and a decrease in the proportion of cells in S phase. atRA inhibited expression of cyclins D and E at protein level. Furthermore, atRA treatment reduced phosphorylated Rb. CONCLUSION: These data suggested that atRA had antiproliferative activity by modulating G1/S cell cycle regulators and by inhibition of Rb phosphorylation in MEPM cells, which might account for the pathogenesis of cleft palate induced by retinoic acid.

[Cephalometric comparison of soft-tissue morphology between extraction and non-extraction orthodontic treatment in borderline cases].

OBJECTIVE: To compare soft-tissue morphology changes by cephalometric measurements between extraction and non-extraction orthodontic treatment in borderline cases. METHODS: The samples consisted of 33 cases selected as borderline cases by 5 orthodontic specialists. They were divided into 21 extraction cases (including 13 four first premolar extraction cases and 8 four second premolar extraction cases) and 12 non-extraction cases by checking patients' treatment records. Conventional cephalometric analysis was made to compare soft tissue structures before and after orthodontic treatments and the same comparison was made between two different extraction patterns. RESULTS: No statistical difference was found in pretreatment soft-tissue morphology between extraction and non-extraction groups divided from borderline cases. The PosBs/FH of the four first premolars extraction group was smaller than that of non-extraction group, and the Ns-Sn-Pos of the four first premolars extraction group was smaller than that of four second premolar extraction group. None of the post-treatment soft-tissue measures showed significant statistical differences between four first premolars extraction group and non-extraction group, but there were 6 items showed significant statistical differences between four second premolars extraction group and non-extraction group. Compared with extraction and non-extraction treatments, the most significant soft-tissue changes were: PosBs/FH, LL-SnPos, and Bs-EP . CONCLUSION: Although pre-treatment soft-tissue morphology of second premolar extraction group was close to that of non-extraction group, the post-treatment soft-tissue morphology of first premolar extraction group became closer to that of non-extraction group. Compared with non-extraction treatment, the more significant changes caused by extraction treatment were located in the lower lip and chin, but not the upper lips.