[Effect and mechanism of miR-124 on osteogenic differentiation of dental pulp mesenchymal stem cells].

PURPOSE: To evaluate the effect of microRNA (miR)-124 on osteogenic differentiation of dental pulp mesenchymal stem cells (DPSCs) and to explore the possible mechanism. METHODS: Logarithmic DPSCs were collected and divided into blank group, no-load group, miR-124 inhibitor group, miR-124 inhibitor combined with N-[N-(3,5-difluorophenacetyl)-1-alanyl]-S-ph (DAPT, Notch signaling pathway inhibitor) group. The blank group was not treated, the empty group was transfected with negative control vector inhibitor-NC, the miR-124 inhibitor group was transfected with miR-124 inhibitor, the miR-124 inhibitor combined with DAPT group was transfected with miR-124 inhibitor, and DAPT was added to make the final concentration of 5 µmol/L. The proliferation ability was tested by CCK-8 method 48 h after transfection. Alkaline phosphatase (ALP) activity was tested by p-nitrophenyl phosphate (P-NPP) method after 2 weeks of induction. The area of calcified nodules was tested by alizarin red staining method. The protein expression of hair-like division-related enhancer 1 (HEY1), hair-like division-related enhancer 2 (HEY2), and cyclin D1 gene (CCND1) were tested by Western blot. The data was analyzed by SPSS 19.0 software package. RESULTS: Compared with the blank group and no-load group, the A450 value at 24, 48, 72 h detected by CCK-8 experiment, A450 value of ALP activity, the area composition ratio of calcified nodules, and expression of HEY1, HEY2, and CCND1 in the miR-124 inhibitor group were increased (P<0.05). Compared with miR-124 inhibitor group, the A450 value at 24, 48, 72 h detected by CCK-8 experiment, A450 value of ALP activity, the area composition ratio of calcified nodules, and the expression of HEY1, HEY2, and CCND1 in the miR-124 inhibitor combined with DAPT group were significantly decreased(P<0.05). CONCLUSIONS: Down-regulation of miR-124 can promote osteogenic differentiation of DPSCs. It is speculated that the mechanism of action is related to the activation of Notch signaling pathway.

[Prevalence of malocclusion among 5 387 12- to 14-year-old adolescents in Jiangxi province, China: an epidemiological study].

OBJECTIVE: We provided baseline data for oral public health through epidemiological surveys to investigate the prevalence of malocclusion and orthodontic treatment proportion in 12- to 14-year-old adolescents in Jiangxi province, China. METHODS: Multi-stage random cluster sampling was used. A total of 5 387 12- to 14-year-old adolescents were examined by three professional dentists according to Angle's classification of malocclusion. The subjects were recruited from 30 secondary schools in five counties in Jiangxi Province. Results were statistically analyzed by SPSS19.0. RESULTS: The prevalence of malocclusion was 79.67% among adolescents aged 12-14 years in Jiangxi province. The composition ratios of ClassⅠ, Class Ⅱ Division 1, Class Ⅱ Division 2, and Class Ⅲ malocclusion were 30.96%, 16.36%, 12.78%, and 19.13% respectively. ClassⅠmalocclusion had the highest composition ratio, and the most common clinical manifestation of malocclusion was dentition crowding with a prevalence of 91.30%. The prevalence rate of malocclusion was higher in boys than in girls at 81.16% and 78.21%, respectively (P<0.05). This condition had different prevalence rates in Nanchang, Yichun, Jiujiang, Shangrao, and Ganzhou (P<0.05) with the highest in Nanchang and lowest in Ganzhou. Malocclusion was related to caries, and its prevalence rate was higher in patients with caries than in those without caries (P<0.05). The orthodontic rate of malocclusion was 2.63%, and the value was higher for girls than that for boys (P<0.05). The rate of orthodontic in urban areas was higher than that in rural areas (P<0.05). CONCLUSIONS: Compared with local and international findings on malocclusion of adolescents, high prevalence and low orthodontic rate were found in Jiangxi province. Strengthening the combination of prevention and treatment is important for the physical and mental health of adolescents. We should actively conduct oral health education, popularize the knowledge of malocclusion, and actively treat caries.

[Status and strategies of oral health service demand and medical treatment utilization among 3- to 5-year-old preschool children in Jiangxi province].

OBJECTIVE: This study aimed to investigate the oral health service needs and dental treatment among 3-year-old to 5-year-old preschool children in Jiangxi province and provide data to support the development of relevant oral health policies, enhance the oral health service utilization and visit rate, and optimize oral manpower and service resources. METHODS: A total of 2 880 preschool children were selected via stratified cluster sampling. Dental examination methods and criteria according to the fourth national oral health epidemiological survey were adopted. Excel 2007 and SPSS 19.0 softwares were used for statistics analysis. Chi-square test and logistic regression analysis were performed. RESULTS: The caries prevalence was 49.13% (1 415/2 880) among the 2 880 cases of 3-
year-old to 5-year-old preschool children in Jiangxi province, approximately 53.37% (1 537/2 880) of which possessed oral health service needs. The parents of younger children assessed the oral situation better in older age than in their younger years (P<0.05), which was better in urban children than in rural children (P<0.05). The visiting rate of all the respondents was 12.33% (355/2 880), while the visiting rate of children with oral diseases was 17.31% (266/1 537). The top three reasons why patients did not visit the dentist were as follows: children's teeth have no problem, the teeth damage in teeth was considerably minimal, and primary teeth would be replaced without the need for treatment. The influencing factors included lower visiting rate in females than in males (OR=0.499, 95%CI: 0.411-0.606) and lower visiting rates in rural areas than in urban areas (OR=0.428, 95%CI: 0.353-0.519). Subjects with poor oral health and high oral knowledge scores possessed high dental service visit rates. CONCLUSIONS: The prevalence of caries in 3-year-old to 5-year-old preschool children in Jiangxi province is at a lower level than that in the national level. The proportion of the population actively seeking medical services is low, and their main purpose of treatment is to treat rather than prevention. Oral health education should be strengthened, and it should be incorporated to the contents of the kindergarten teacher training program to improve residents' awareness regarding children's oral health.

[Grape seed proanthocyanidin extracts inhibit lipopolysaccharide of Porphyromonas gingivalis].

PURPOSE: To study the inhibitory effect of grape seed proanthocyanidin extracts on 1ipopolysacharides of Porphyromonas gingivalis. METHODS: Grape seed proanthocyanidin extracts were double-diluted to different concentrations by two-fold dilution. The effect on Porphyromonas gingivalis was measured by minimal inhibitory concentration (MIC). The inhibition effect of grape seed proanthocyanidin extracts on lipopolysaccharide was measured by limulus assay with 6 concentrations below the minimal inhibitory concentration. SPSS 17.0 software package was used for statistical analysis. RESULTS: The value of MIC of grape seed proanthocyanidin extracts was 0.8 mg/mL to the strains of the experimental bacteria. The inhibitory effect on lipopolysaccharide enhanced with the increasing of the concentration of grape seed proanthocyanidin extracts within the scope of 0.05 to 0.4 mg/mL (P<0.05,0.01). CONCLUSIONS: Grape seed proanthocyanidin extracts have inhibitory effect on lipopolysaccharide of Porphyromonas gingivalis.

[The application of desocclusol and manual mechanical method in endodontic retreatment].

PURPOSE: To investigate the clinical method to remove a gutta-percha and root canal sealers. METHODS: 168 root canals which had been filled with gutta-percha were selected,all root canals needed endodontic retreatment.The root canal fillings were removed and the root canal was re-prepared with the method of desocclusol and manual mechanical method. Then the root canal was filled again with lateral condensation technique. RESULTS: With manual mechanical method and desocclusol,all original root canal fillings were removed completely. The combined method could effectively prevent the formation of step,root canal-side wear,broken equipment or other complications during the course of retreatment.The success rate of retreatment was 89.3%. CONCLUSIONS: Combined manual mechanical method with desocclusol could improve the success rate of recanalization of the root canal and saved time and effort. It is a method which could reduce the intensity and improve the efficiency of dentists, and worthy of wide clinical application.

[Dental caries and periodontal diseases in adult Jiangxi cohort: a sample investigation].

PURPOSE: To investigate the current status of dental caries and periodontal diseases in the population aged 35-44 and 65-74 years in Jiangxi province, and to provide information for prevention of these diseases. METHODS: 1584 people (aged 35-44 and 65-74 years) were selected by equal-sized stratified multi- stage and random sampling. Their dental caries and periodontal diseases were examined in routine epidemiologic surgery manner. Student's t test and Chi-square test were applied for statistical analysis using SPSS12.0 software package. RESULTS: In the age group of 35-44 and 65-74 years, the prevalence rate of dental caries was 59.4% and 85.5%, the mean DMFT was 2.19 and 4.91, the prevalence rate of root caries was 32.7% and 79.5%, the mean DFRoot was 0.28 and 1.25,the rate of healthy periodontal tissues was 0.1% and 5.3%. CONCLUSIONS: Dental caries and periodontal diseases are quite common diseases in Jiangxi Province. We should reinforce the oral health care and the propaganda for oral care knowledge in order to treat caries and periodontal diseases better and earlier, and improve the life quality of middle-aged and elderly citizens.