[Evaluation of the effect of invisible correction and SGTB in the treatment of mandibular retrusion].

PURPOSE: To compare the clinical effects of invisible correction and SGTB in two-stage treatment of mandibular retrusion. METHODS: Eighty-five patients with bony mandibular regression who did not pass the peak of growth and development were selected. Among them, 40 cases were guided by invisible correction and 45 cases were guided by SGTB functional correction. Lateral head X-rays before and after treatment were measured, and the effect before and after treatment was compared by SPSS 16.0 software package. RESULTS: After treatment, the SNB angle and NP-FH (face angle) increased and the ANB angle decreased in both groups, all of which had significant changes(P＜0.001). At T1, the changes of SNB angle, ANB angle and NP-FH angle in the invisible group were smaller than those in the SGTB group(P＜0.05). The difference between MP-FH angle and MP-SN angle before and after treatment was greater in the SGTB group than in the invisible group(P＜0.001). CONCLUSIONS: In patients with receding mandible before the peak of growth and development, the mandible was significantly moved forward after orthodontics. Both invisible orthodontics and SGTB promote changes in the position of the mandible, improves coordination between the upper and lower jaws. In the control of the posterior teeth in the vertical direction, the invisible group is stronger than the SGTB group.

MiR-146a-5p Promotes Dental Stem Cells Osteo/odontogenic Differentiation through NF-Kappa B Signaling Pathway by Targeting TRAF6.

OBJECTIVE: To screen miRNAs that could simultaneously regulate osteo/odontogenic differentiation of multiple stem cells, including dental pulp stem cells (DPSCs), stem cells from the apical papilla (SCAPs) and periodontal ligament stem cells (PDLSCs). METHODS: Differentially expressed miRNAs analysis on three miRNA microarrays data of dental stem cells undergoing osteo/odontogenic differentiation (GSE138180, GSE154466 and GSE159508) was performed, and miR-146a-5p were identified by bioinformatic prediction, dual-luciferase reporter assay and quantitative real-time polymerase chain reaction (PCR). In addition, differentially expressed genes between miR-146a-5p overexpressed group and control group (GSE79341) were applied for KEGG pathways enrichment analysis. RESULTS: MiR-146a-5p expression increased in the osteo/odontogenic differentiation of DPSCs, SCAPs and PDLSCs. Tumour necrosis factor receptor (TNFR)-associated factor 6 (TRAF6) was identified as the target gene of miR-146a-5p. Furthermore, miR-146a-5p could influence the NF-Kappa B signalling pathway. CONCLUSION: This study suggests that miR-146a-5p could promote differentiation in multiple dental stem cells through the NF-Kappa B signalling pathway by targeting TRAF6.

[Changes of the upper airway in children with Class â ¡ mandibular retrusion and snoring during night before and after functional treatment by sagittal-guidance Twin-block appliance].

PURPOSE: To study the changes of dimension and morphology of upper airway in children with ClassⅡ mandibular retrusion after functional treatment by sagittal-guidance Twin-block appliance. METHODS: Cone-beam CT (CBCT) data of upper airway of the subjects were measured by Dolphin 11.5 software and Mimics 17.0 software , and the changes of dimension and morphology of upper airway before and after functional treatment with sagittal-guidance Twin-block(SGTB) appliance were compared. SPSS 16.0 software package was used for data processing. RESULTS: After functional treatment，the volume of total upper airway，nasopharynx airway, oropharynx airway, the sectional area of tip of the epiglotti(TE), the lateral diameter of TE, the base of the epiglottis(EB) significantly increased (P<0.05) in children with SGTB appliance. CONCLUSIONS: SGTB functional treatment is effective in the treatment of skeletal ClassⅡ mandibular retrusion of children by increase of the upper airway and improvement of respiration．.

Role-play in Endodontic Teaching: a Case Study.

Objective: To investigate the role of the application of role-play in endodontic study in improving the communication skills of Chinese dental undergraduates prior to their direct interactions with patients at the Fourth Military Medical University's School of Stomatology, China. Methods: Students were recruited from the 5-year bachelor's programme (n = 36) and randomly divided into six groups, and from the 8-year DDS programme (n = 10) and randomly divided into two groups to participate in the role-play training. Cases selected randomly from the case pool were distributed to the groups. The teacher gave an outline of the roles in the simulation. Each member of each group randomly selected their own role for the role-play. Four types of surveys were distributed to students and faculty members at different points after the role-plays had taken place, to evaluate their attitude towards the use of role-plays in endodontic study. Frequency analysis and a one sample t test were used to describe and analyse students' acceptance of role-play as a teaching technique. The level of statistical significance was set at P < 0.05. Results: Students' performance and satisfaction as well as the supporting faculty responses were very favourable towards role-playing. In total, 93.5% of students responded favourably to the role-play, answering 'strongly agree' or 'agree' to the positive statements about their role-play performance. A total of 95.1% of students stated that they had benefited psychologically and technically from the role-play ('strongly agree' or 'agree') after their 1-year rotating internship. Conclusion: The application of role-play in endodontic study is an effective way of educating Chinese dental undergraduates and can be beneficial for their transition from students to dentists.

[Analysis of the biocompatibility of a new PLGA/fish skin collagen conjugated electrostatic spinning film].

PURPOSE: To study the biocompatibility of a new polylactic acid-glycolic acid(PLGA)/fish skin collagen conjugated electrostatic spinning film. METHODS: PLGA and medical-grade fish skin-I collagen were used as raw materials to prepare nanometer fiber films by conjugated electrostatic spinning technique. Mouse fibroblast L929 was used as a model to evaluate its cell and histocompatibility, which provided experimental basis for application in guided bone regeneration (GBR). RESULTS: Fibroblasts showed good adhesion and growth on the surface of fiber membrane; there were a large number of deep pseudopodias, which were arranged along the orientation of fibers. CONCLUSIONS: PLGA/fish skin collagen conjugated electrostatic spinning membrane is beneficial to fibroblast growth and is expected to be used for GBR.

[Morphological characteristics of upper alveolar bone around central incisor in Class II division 1 and division 2 malocclusion on cone-beam CT].

PURPOSE: During orthodontic treatment, the incisors in patients with Class II division 1 and division 2 malocclusion showed different clinical features, which determine the different ways to move the teeth to the suitable position. This study analyzed the morphology of alveolar bone around upper central incisor with cone-beam CT (CBCT). METHODS: The sample consisted of 20 normal malocclusion and 40 patients with Class II malocclusion （division 1 20 cases and division 2 20 cases）. CBCT images before orthodontic treatment were reconstructed by INVIVO 5.0 image processing software. Paired t test was used for statistical analysis with SPSS 19.0 software package. RESULTS: At the upper central incisors, the alveolar thickness between normal malocclusion and Class II division 1 and division 2 malocclusion had significant difference except the palate thickness between normal malocclusion and Class II division 2 malocclusion (P<0.05). CONCLUSIONS: Orthodontist should consider the relationship between the teeth position and alveolar bone shape comprehensively, choose the correct plan in order to avoid root desorption, alveolar bone loss, fenestration and other adverse reactions.

[Comparison of condylar position between Angle Class I and Class II malocclusion in teenagers].

PURPOSE: To analyze and compare the difference of condylar position between Angle Class I and Class II malocclusion patients using cone-beam CT (CBCT). METHODS: Thirty Class I patients, 30 Class II division 1 patients and 30 Class II division 2 patients were selected in this study. Each patient underwent CBCT. The images in the oblique position perpendicular to the condyloid process were reconstructed by Examvision software. The joint space was measured by Exam Vision software. The data were processed with SPSS17.0 software package. RESULTS: The upper joint space was larger in Class II, the posterior joint space was smaller in Class II patients; and in Class II division 1 patients, both of the upper and anterior joint spaces were larger than in Class II division 2 patients，the differences were significant (P<0.05). The length of condyle was longer in Class I patients than in Class II patients. CONCLUSIONS: The condylar position in Class II division 2 patients was lower and further backward. The length of condyle is shortest in Class II division 2 patients.

[The effect of core veneer thickness ratio on the flexural strength of diatomite-based dental ceramic].

PURPOSE: To evaluate the effect of different core veneer thickness ratios on the flexural strength and failure mode of bilayered diatomite-based dental ceramics. METHODS: Diatomite-based dental ceramics blocks (16 mm×5.4 mm×1 mm) were sintered with different thickness of veneer porcelains: 0 mm (group A), 0.6 mm (group B), 0.8 mm (group C) and 1.0 mm (group D). Flexural strength was detected and scanning electron microscope was used to observe the interface microstructure. Statistical analysis was performed using SPSS 17.0 software package. RESULTS: With the increase of the thickness of the veneer porcelain, flexural strength of group C showed highest flexural strength up to (277.24±5.47) MPa. CONCLUSIONS: Different core veneer thickness ratios can significantly influence the flexural strength of bilayered diatomite-based dental ceramics. Supported by Science and Technology Projects of Nantong City (HS2013010).

[A study on the thickness of buccal bone in the mandible of different vertical facial type in adults using cone-beam CT].

PURPOSE: To provide some references of using micro-implant anchorage in clinical orthodontic treatment, the thickness of buccal bone of mandible of different vertical facial type in adults with cone-beam CT (CBCT) were measured. METHODS: Initial 3-dimensional images of 45 adult patients (15 men, 30 women)were reoriented by using a standardized protocol, and divided into 3 groups by angle of mandibular plane (G1: high angle, 15 patients; G2: average angle, 15 patients; G3: low angle, 15 patients). After signing the informed consent form, three measurement points were defined at 4, 6, and 8mm from the alveolar crest in each measurement area. Statistical analysis was performed with SPSS11.0 software package. RESULTS: The thickness of buccal bone in mandible was thinner in G1 than in G2, and was thinnest in G3. The cortical bone thickness was thickest at the 8 mm level and thinnest at the 4mm level. CONCLUSIONS: The study suggested that the cortical bone thickness at 4mm level from the alveolar crest was safe for implantation. It is more stable when the distance of implants was more away from the alveolar crest. Patients with low mandibular plane angle should use self-tapping micro-implant anchorage. Supported by Nantong Science and Technology Fund (HS2013033).

[Preliminary study of bonding strength between diatomite-based dental ceramic and veneering porcelains].

PURPOSE: In order to choose the best veneering porcelain for diatomite-based dental ceramic substrate, the bonding strength between diatomite-based dental ceramics and veneering porcelains was measured, and the microstructure and elements distribution of interface were analyzed. METHODS: The coefficient of thermal expansion (CTE) of diatomite-based dental ceramics was detected by dilatometry. Three veneering porcelain materials were selected with the best CTE matching including alumina veneering porcelain (group A), titanium porcelain veneering porcelain (group B), and E-max veneering porcelain (group C). Shear bonding strength was detected. SEM and EDS were used to observe the interface microstructure and element distribution. Statistical analysis was performed using SPSS 17.0 software package. RESULTS: The CTE of diatomite-based dental ceramics at 25-500 degrees centigrade was 8.85×10-6K-1. The diatomite-based substrate ceramics combined best with group C. Shear bonding strength between group A and C and group B and C both showed significant differences(P<0.05). SEM and EDS showed that the interface of group C sintered tightly and elements permeated on both sides of the interface. CONCLUSIONS: The diatomite-based substrate ceramics combines better with E-max porcelain veneer.

Lentiviral-mediated short hairpin RNA silencing of APE1 suppresses hepatocellular carcinoma proliferation and migration: A potential therapeutic target for hepatoma treatment.

Apurinic/apyrimidinic endonuclease-1 (APE1) is a protein involved in DNA repair and transcriptional regulation of gene expression. APE1 expression was reported to be correlated with poor prognosis in hepatocellular carcinoma (HCC) patients. Based on our previous study, we hypothesized that APE1 may be involved in the metastatic progression of HCC. Thus, the present study aimed to investigate the knockdown effect of APE1 using shRNA in HCC and demonstrate that silencing of APE1 in MHCC97-H cells can decrease the oncogenic transforming potential in vitro and reduce the growth of HCC tumor xenografts in vivo. Silencing of APE1 expression decreased the cell proliferation and survival, reduced the cell adhesion ability in Matrigel or fibronectin-coated plates and suppressed the cell migration and invasion in a Transwell assay of HCC cells. In the xenograft study, tumor growth was markedly inhibited in the APE1-silenced group. Silencing of APE1 in MHCC97-H cells decreased the oncogenic transforming potential in vitro and reduced the growth of HCC tumor xenografts in vivo. Inhibition of APE1 may present a novel therapeutic approach for the treatment of HCC.

[Clinical effect of premolar extraction with high torque self-locking appliances].

PURPOSE: To analyze the clinical effect of extraction correction of patients with maxillary protrusion by using Damon high torque appliances. METHODS: Forty patients with extraction of four first premolars due to orthodontic treatment were selected. They had protrusion of maxilla and were randomly divided into two groups. Both arches of Damon group were treated with Damon high torque appliances and MBT group were corrected with traditional MBT straight wire appliance; patients in two groups received sliding mechanics for adduction of upper anterior teeth. Cephalometric radiophotographs were analyzed before（T0）and after adduction of upper anterior teeth（T1）. The difference between the two groups was analyzed with SPSS15.0 software package. RESULTS: The upper incisors showed a more retruded position in the two groups at T1,although they showed a similar amount in both groups. The backward movement of upper lip was 2.31mm in Damon group, which was significantly less than that of 2.81mm in MBT group(P<0.05). No significant difference in the first molar mesialization was detected between Damon group(2.33 mm) and MBT group(2.36mm) (P>0.05). For anterior teeth retraction, nasolabial angle (NLA) in MBT and Damon group were 107.44°and 106.33°, increase of NLA in MBT group was 9.17°,which was significantly larger than that of 7.22°in Damon group (P<0.05). U1-MxP in MBT and Damon were 110.61°and 114.11°. U1-MxP decreased 12.06°in MBT group, while significant change was deteced in Damon group of 7.61°(P<0.05). CONCLUSIONS: Application of Damon high torque appliances in extraction treatment of maxillary protrusion patients yielded better control of the labial crown torque of anterior teeth, and avoided excessive lingual inclination of anterior teeth compared with MBT in adduction of upper anterior teeth.

[Morphology and microRNA expression profiles of drug-resistant cells in hepatocellular carcinoma].

OBJECTIVE: To compare morphological differences of three drug-resistant hepatocellular carcinoma (HCC) cell subclones (Huh-7/ADM, Huh-7/CBP, Huh-7/MMC) and their parental Huh-7 cell line, to analyze differential microRNA (miRNA) expression profiles in these cells and, finally to screen for the abnormal expressed miRNAs in drug-resistant HCC cells. METHODS: Cellular morphology was observed by histology and transmission electron microscopy. MiRNA microarray was used to analyze the differential miRNA expression profiles in these cells (Huh-7, Huh-7/ADM, Huh-7/CBP, Huh-7/MMC) followed by real time quantitative PCR validation. RESULTS: The drug-resistant cells had more intracytoplasmic organelles and were larger in size along with increased cytological pleomorphism than the parental Huh-7 cells. Compared with the parental Huh-7 cells, 32 simultaneously up-regulated and 22 down-regulated miRNAs were found in three drug-resistant cells. Up-regulation of miR-15a, miR-16, miR-27b, miR-30b, miR-146a, miR-146b-5p, miR-181a, miR-181d and miR-194 was verified by RT-qPCR. CONCLUSION: Drug-resistant HCC cells have abnormal expressed miRNAs, which may be explored to further investigate the association of miRNA expressions with multidrugs resistance in HCC.

[An in vitro study of the relationship between KiSS-1 expression and hepatoma carcinoma cell proliferation, adhesion, and invasion].

OBJECTIVE: To investigate the impact of expression of kisspeptin-1 (KiSS-1) metastasis-suppressor gene on the proliferative, adhesive and invasive abilities of human hepatocellular carcinoma (HCC) using an in vitro cell system. METHODS: The highly metastatic human hepatoma cell line MHCC97-H was transiently transfected with the pcDNA3.1/HisC vector expressing the KiSS-1 gene (experimental group) or the vector without the KisS-1 gene (blank control group). Untransfected cells served as the negative control group. Proliferative abilities of the three groups were assessed by flow cytometry and MTT assay. Adhesive abilities were assessed by MTT assays using matrigel and fibronectin. Invasive abilities and cell motility were assessed by chemoinvasion chamber assay using reconstituted matrigel and migration chamber assay using polycarbonate filters, respectively. RESULTS: The experimental group showed significantly lower adhesion capacity to matrigel (0.257+/-0.029) than either the blank control group (0.374+/-0.016; t=-7.90345, P less than 0.01) or the negative control group (0.394+/-0.031; t=-7.22752, P less than 0.01). Similarly, the experimental group showed significantly lower adhesion capacity to fibronectin (0.292+/-0.004) than either the blank control group (0.394+/-0.010; t=-20.93138, P less than 0.01) or the negative control group (0.412+/-0.023; t=-11.31371, P less than 0.01). The experimental group also showed significantly lower numbers of cells with invasive capacity (42.40+/-1.14) than either the blank control group (66+/-1.58; t=-27.0711, P less than 0.01) or the negative control group (67.80 +/- 1.92; t=-25.4, P less than 0.01). Similarly, the experimental group showed significantly lower numbers of cells with chemotactic movement (65.80+/-1.92) than either the blank control group (93.80+/-2.28; t=-30.11750, P less than 0.01) or the negative control group (96.40+/-2.07; t=-24.19142, P less than 0.01). The experimental group showed slightly, but not significantly, lower cell proliferation (0.644+/-0.027) than either the blank control group (0.669+/-0.022; t=-1.60371, P?>?0.05) or the negative control group (0.678+/-0.027; t=-1.97828, P?>?0.05). In addition, there were no obvious differences between the three groups in the amounts of cells arrested in either the G1 phase or the S phase. CONCLUSION: KiSS-1 overexpression suppresses the adhesion, invasion and motility, but not the proliferation, of hepatoma carcinoma cells in vitro. These findings imply that KiSS-1 might represent a promising new candidate for gene therapy against human hepatocellular carcinoma.

Matrix metalloproteinase-3 inhibitor retards treadmill running-induced cartilage degradation in rats.

INTRODUCTION: The effect of intra-articular injection of matrix metalloproteinase (MMP)-3 inhibitor was investigated in a rat model to understand the role of MMP-3 in cartilage degradation induced by excessive loading from running. METHODS: A total of 24 male Wistar rats were randomly assigned into groups of sedentary control (SED), high-intensity running (HIR), HIR + low dosage of MMP-3 Inhibitor I (HIRI1), and HIR + high dosage of MMP-3 Inhibitor I (HIRI2). Rats in the HIR, HIRI1 and HIRI2 groups were intensively trained for six weeks on the treadmill. Those in HIRI1 and HIRI2 groups were provided bilateral intra-articular injections of 80 µL of 0.2 mM and 2 mM MMP-3 Inhibitor I in knee joints once a week, respectively. Blood samples were collected to measure serum MMP-3 level using ELISA. Femoral condyles were collected to observe cartilage characteristics by histochemistry, and MMP-3 as well as collagen II was measured by immunohistochemistry. In addition, cartilage samples were obtained to assess MMP-3 mRNA expression by RT-PCR. RESULTS: Histological examination showed osteoarthritic changes in rats after six weeks of high intensity running. In comparison to the SED group, significant decreases in glycosaminoglycans (GAG) and collagen content were found in the HIR group, which corresponded to significant increase in serum MMP-3 level, cartilage MMP-3 activity and gene expression. However, such a degradative process was considerably retarded by intra-articular injection of MMP-3 inhibitor at higher dosage. Statistical differences were found between the HIR and HIRI2 groups with regard to GAG and collagen II content, serum MMP-3 level, cartilage MMP-3 activity and gene expression. CONCLUSIONS: High-intensity running for six weeks may lead to cartilage degradation in a rat model. It was shown that the chrondroprotective effect was offered by the use of intra-articular injection of MMP-3 inhibitor. MMP-3 acts as the key mediator of this catabolic change under such mechanical condition. The results also showed that MMP-3 selective inhibitor may be an effective option for retarding such osteoarthritic changes.

[Improved sensitivity of gastric carcinoma cells to fluorouracil-related drugs by transfection of thymidine phosphorylase gene].

OBJECTIVE: To investigate the relationship between the expression of thymidine phosphorylase (TP) and the sensitivity of gastric carcinoma to 5-fluorouracil (5-FU) and its prodrugs. METHODS: Gastric carcinoma cell line AGS was transfected with recombinant plasmid pEGFP-N1-TP or control plasmid pEGFP-N1 by lipofectamin 2000. The expression of green fluorescence labeled protein was observed under fluorescence microscope. Positive clones AGS-p and AGS-pTP were selected by G418 treatment. Expression of TP protein and mRNA was detected by immunocytochemistry and RT-PCR, respectively. Drug sensitivity to 5-FU and its prodrugs was assessed by MTT assay. RESULTS: Cell clones with the expression of green fluorescent protein (AGS-p) and a clone with TP and green fluorescent fusion protein (AGS-pTP) were established. Immunostaining of TP protein was strongly positive in AGS-pTP and negative in AGS-p and AGS. The expression of TP mRNA was significantly higher in AGS-pTP (0.8090 ± 0.0450) than that in AGS (0.0490 ± 0.0046) and AGS-p (0.0610 ± 0.0069; P < 0.01). The sensitivity to doxifluridine and capecitabine in AGS-pTP was significantly increased, as compared with that in AGS-p. IC50 values of AGS-pTP to doxifluridine and capecitabine were estimated 1.7 folds and 2.2 folds as much as that of AGS-p, respectively. The sensitivity to 5-FU was not different between AGS-pTP and AGS-p. CONCLUSIONS: Enhancement of TP expression improves the sensitivity of gastric carcinoma cells to doxifluridine and capecitabine. But it does not affect the sensitivity to 5-FU.

[Finite element analysis of mechanical characteristics during retracting mandibular incisors through sliding mechanics].

PURPOSE: To analyze the mechanical characteristic changes of teeth and arch under different loading direction during retracting mandibular incisors through implant, simulating clinical loading system. METHODS: Three- dimensional finite element model, including brackets, archwire, crampable hooks and implants, was reconstructed. The force direction was determined by connecting the points in crampable hook and the center point of implant, and the force point and force direction were changed with the adjustment of the height of crampable hook and the height of implant. Then three-dimensional movement trend of teeth, stress distribution in periodontal membrane and the largest displacement of archwire nodes in each group were calculated and analyzed. SPSS13.0 software package was used for statistical analysis. RESULTS: It was found that the height of implant and the height of crampable hook were correlated with the movement of teeth and stress distribution in periodontal membrane (P<0.01). The movement trend of teeth in the condition of different height of implant and different height of crampable hook was illustrated as follows:(1)with the height increase of crampable hook, the movement trend of the central and lateral incisors varied from mesial lingual tipping to mesial labial tipping. However, canines tipped distally and lingually; the second premolars tipped mesially and lingually, and the first molar roots tipped distally and buccally with decreasing tipping angle. (2) The largest stress distribution in the whole arch was located in the labial apical one-third area of the lateral incisors, while that of canines and the first molars was located in the alveolar ridges and root bifurcations. CONCLUSIONS: These findings indicate that the different movement trend during retracting anterior teeth can be achieved through the adjustment of the height of crampable hook, and implant, anchorage can effectively control anterior movement of the posterior teeth. Supported by Research Fund of Bureau of Science and Technology of Nantong City (Grant No. S40023).

Multiple biomarkers of colorectal tumor in a differential diagnosis model: a quantitative study.

AIM: To evaluate the multiple biomarkers of colorectal tumor and their potential usage in early diagnosis of colorectal cancers. METHODS: Multiple biomarkers (DNA contents, AgNOR, PCNA, p53, c-erbB-2) in 10 normal colorectal mucosae, 37 colorectal adenomas and 55 colorectal cancers were analyzed quantitatively in the computed processing imaging system. Discrimination patterns were employed to evaluate the significance of single and multiple indices in diagnosis of colorectal cancers. RESULTS: The mean values of the analyzed parameters increased in order of the normal mucosa, adenoma and adenocarcinoma, and this tendency reflected the progression of colorectal malignancy. The parameters including DNA index, positive rates, densities of AgNOR, c-erbB-2, and p53, shape and density of nucleus were relatively valuable for diagnoses. Then a diagnostic discrimination model was established. The samples were confirmed with the model, the sensitivity rates in cancer group and adenoma group were 96.36% and 89.19%, respectively. The value of proliferating cell nuclear antigen (PCNA) in early diagnosis of colorectal cancers was uncertain. CONCLUSION: The quantitative evaluation of some parameters for colorectal tumor can provide reproducible data for differential diagnosis. The established diagnostic discrimination model may be of clinicopathological value, and can make the early diagnosis of colorectal cancer possible.