Assessment of risk factors for early childhood caries at different ages in Shandong, China and reflections on oral health education: a cross-sectional study.

BACKGROUND: The high prevalence of early childhood caries (ECC) is widespread around the world, and oral health education (OHE) plays a vital role in preventing ECC. Numerous studies on ECC risk factor assessment have assisted us in enriching the content of OHE. The objective of this study was to further assess independent risk factors for ECC at different ages to provide evidence and insights for OHE. METHODS: Children aged 3-5 years old (N = 1301) in Shandong Province were enrolled in this cross-sectional study. Data about oral health status and caregivers' oral health knowledge, attitude, and practice (KAP) were extracted from the 4th National Oral Health Survey of China. The associations between ECC prevalence and various KAP variables were tested with chi-square tests, bivariate analysis and multivariable logistic regression analyses. RESULTS: The ECC prevalence in Shandong Province was 64.6%, and the dmft mean was 3.15. The independent variables with an increased risk for ECC were age, feeding method within 6 months of birth, bedtime sugar frequency, experience of toothache over the past year and dental visits (P < 0.05, chi-square tests). Complete breastfeeding within 6 months of birth primarily contributed to the high ECC risk of the 3-year-old group (OR: 3.39, 95% CI: 1.41-8.17), while high frequency bedtime sweet consumption mainly contributed to that of the 5-year-old group (OR: 3.22, 95% CI: 1.03-10.06; logistic regression analysis). Tooth brushing was not associated with ECC in this study, and some positive knowledge and attitude variables were positively correlated with a high risk of ECC. CONCLUSION: These data provide evidence to suggest that the ECC-related risk factors at different ages are inconsistent, which provides some insights for OHE. We should highlight the effects of feeding methods in the early stages of deciduous dentition and sugar habits in the late stages of deciduous dentition on ECC, as well as encourage preventive dental visit and supplemental training for oral health practices.

Less extrusion debris during the retreatment of curved canals using twisted files with higher rotational speeds: an ex vivo study.

BACKGROUND: Debris extrusion from the apical foramen can be problematic in severely curved canals. This study aimed to assess the use of Twisted Files (TF) at different rotational speeds during retreatment, compared with manual technique using Triple-Flex Files (TFF). METHODS: Forty-eight mesiobuccal root canals were randomized to four groups (n = 12 per group). In groups A, B, and C, gutta-percha was removed using TF at 500, 1000, and 1500 rpm, respectively, while it was removed using TFF in group D. Apical debris was collected in a pre-weighed centrifuge tube. The weight of dry debris was assessed by comparing the pre- and post-instrumentation weight for each group. RESULTS: Instrumentation in group D (0.69 ± 0.04 mg) extruded significantly more debris than any of the TF groups (A: 0.54 ± 0.05 mg; B: 0.48 ± 0.04 mg; C: 0.42 ± 0.03 mg; all P < 0.001). In addition, increasing the rotational speed of TF decreased the amount of extruded debris (A vs. B: P = 0.006; B vs. C: P < 0.001; A vs. C: P < 0.001). CONCLUSIONS: TF at 1500 rpm produced less apical extrusion debris than other TF operating speeds and TFF.

Physcion 8-O-ß-glucopyranoside induces mitochondria-dependent apoptosis of human oral squamous cell carcinoma cells via suppressing survivin expression.

AIM: A previous study has shown that physcion 8-O-ß-glucopyranoside (PG) derived from Rumex japonicusHoutt causes apoptosis and blocks cell cycle progression in human lung cancer cells. In the present study we investigated the molecular mechanisms underlying PG-induced cancer cell apoptosis. METHODS: Human OSCC-derived cell line KB was treated PG (10, 20, 50 µg/mL). Cell apoptosis was detected with flow cytometry. Mitochondrial membrane potential (MMP) and release of cytochome C from mitochondria were measured; the expression of relevant signaling proteins was analyzed using Western blotting or qRT-PCR. For evaluation of in vivo anticancer action, nude mice grafted with KB cells were treated with PG (10, 20, 40 mg·kg(-1)·d(-1), ip) for 24 days. RESULTS: PG dose-dependently suppressed cell proliferation and induced apoptosis in KB cells. PG-induced apoptosis was mediated via the intrinsic mitochondrial pathway, as evidenced by the decreased Bcl-2, increased Bax and Bax/Bcl-2 ratio, as well as the loss of MMP, caspase-9 activation, and increased cytosolic cytochrome c. Furthermore, PG suppressed the expression of survivin, whereas overexpression of survivin markedly attenuated PG-induced apoptosis. Meanwhile PG increased the expression of tumor suppressor PTEN, and decreased p-Akt, p-GSK3ß and miR-21 levels. Pharmacological activation of Akt/GSK3ß signaling or transfection with miR-21 mimic abolished PG-induced survivin reduction and cell apoptosis. Similar results were observed in PG-treated nude mice grafted with KB cells. CONCLUSION: Physcion 8-O-ß-glucopyranoside induces mitochondria-dependent apoptosis of human OSCC cells by suppressing survivin expression via miR-21/PTEN/Akt/GSK3ß signaling pathway.

Phenytoin Is Promoting the Differentiation of Dental Pulp Stem Cells into the Direction of Odontogenesis/Osteogenesis by Activating BMP4/Smad Pathway.

Background: The purpose of this study was the evaluation of the potential and mechanism of phenytoin to promote differentiation of human dental pulp stem cells (hDPSC) into odontoblasts/osteoblasts. Methods: Fourth-generation human hDPSC originating from healthy pulp of third molars was cultured in control as well as phenytoin-containing media (PHT) for 14 days. qPCR was applied to detect the expression of DSPP, DMP1, and ALP genes. Western blot analysis was used to confirm the findings. One-way analysis of variance (ANOVA) was used for statistical analysis (p < 0.05). Information about phenytoin was assessed from PubChem database, while targets of phenytoin were assessed from six databases. Drug targets were extracted based on the differentially expressed genes (‖logFC‖ ≥ 1, p < 0.05) in the experimental group (50 mg/L PHT, 14 days). GO BP and KEGG pathway enrichment analysis on the obtained drug targets was performed and the target protein functional network diagram was constructed. Results: A concentration below 200 mg/L PHT had no obvious toxicity to hDPSC. The expression of DSPP, DMP1, and ALP genes in the 50 mg/L PHT concentration group increased significantly. The WB experiment showed that the protein content of BMP4, Smad1/5/9, and p-Smad1/5 was significantly increased in 50 mg/L PHT in comparison with the NC group (the group without treatment of PHT) at 14 days. Conclusion: Phenytoin has the ability of promoting the differentiation of hDPSC into odontoblasts and osteoblasts. BMP4/Smad pathway, inducing odontogenic/osteogenic differentiation of hDPSC, appears a main process in this context.

Hydroxyapatite/NELL-1 Nanoparticles Electrospun Fibers for Osteoinduction in Bone Tissue Engineering Application.

BACKGROUND: As commonly bone defect is a disease of jaw that can seriously affect implant restoration, the bioactive scaffold can be used as potential systems to provide effective repair for bone defect. PURPOSE: A osteoinductive bone tissue engineering scaffold has been prepared in order to explore the effect of bioactive materials on bone tissue engineering. METHODS: In this study, NELL-1 nanoparticles (Chi/NNP) and nano hydroxyapatite were incorporated in composite scaffolds by electrospinning and characterized using TEM, SEM, contact angle, tensile tests and in vitro drug release. In vitro biological activities such as MC3T3-E1 cell attachment, proliferation and osteogenic activity were studied. RESULTS: With the addition of nHA and nanoparticles, the fiber diameter of PCL/BNPs group, PCL/NNPs group and PCL/nHA/NNPs group was significantly increased. Moreover, the hydrophilic hydroxyl group and amino group presented in nHA and nanoparticles had improved the hydrophilicity of the composite fibers. The composite electrospun containing Chi/NNPs can form a double protective barrier which can effectively prolong the release time of NELL-1 growth factor. In addition, the hydroxyapatite/NELL-1 nanoparticles electrospun fibers can promote attachment, proliferation, differentiation of MC3T3-E1 cells and good cytocompatibility, indicating better ability of inducing osteogenic differentiation. CONCLUSION: A multi-functional PCL/nHA/NNPs composite fiber with long-term bioactivity and osteoinductivity was successfully prepared by electrospinning. This potential composite could be used as scaffolds in bone tissue engineering application after in vivo studies.

Investigation of Interaction between Vitamin D Receptor Gene Polymorphisms and Environmental Factors in Early Childhood Caries in Chinese Children.

BACKGROUND: Early childhood caries is a multifactorial disease involving interactions between genetic and environmental risk factors. The aim of this study was to examine the effects of vitamin D receptor (VDR) gene polymorphisms and gene-environment interactions on the etiology of, and susceptibility to, caries in Chinese children aged 3-5 years. METHODS: Children (n = 549) were divided into three groups according to caries risk: high (decayed, missing, filled teeth (dmft) index > 4; n = 148), moderate (dmft = 1-4; n = 156), and caries-free (n = 245). A questionnaire was designed to collect demographic information, dietary habits, and oral hygiene practices, and dental plaque samples were collected to test acidogenic activity of bacteria. Genomic DNA was extracted from the buccal mucosa, and the VDR polymorphisms rs7975232, rs1544410, rs11568820, rs10735810, and rs731236 were genotyped using TaqMan assays. RESULTS: There were no differences among the caries risk groups in frequencies of the rs7975232, rs731236, rs1544410, or rs11568820 polymorphisms (χ 2 test, P > 0.05); however, the frequency of the rs10735810 CC genotype was clearly higher in the high caries risk group than in the control and moderate caries risk groups (39.2%, 25.6%, and 30.6%, respectively; χ 2 test, P=0.028). In multivariate analysis of genotypes and behavioral factors, rs7975232, rs731236, rs1544410, rs11568820, and rs10735810 were not associated with deciduous tooth decay (χ 2 test, P > 0.05). CONCLUSION: We conclude that these VDR polymorphisms cannot be used as markers for identification of Chinese children at increased risk of dental caries, when combined with environmental factors. Future studies are needed to replicate these initial findings and better assess the risk of caries in deciduous teeth.

PAR-2 promotes cell proliferation, migration, and invasion through activating PI3K/AKT signaling pathway in oral squamous cell carcinoma.

Objective: This research aimed to explore the function of protease activated receptor 2 (PAR-2) in oral squamous cell carcinoma (OSCC) development and progression, as well as underlying molecular mechanism.Methods: Tissue samples were collected from 115 OSCC patients. Quantitative real-time PCR (qRT-PCR) was performed to measure the expression of PAR-2 mRNA in OSCC tissues and cells. MTT and Transwell assays were used to detect the proliferation, migration, and invasion of OSCC cells, respectively. Western blot was performed to determine protein expression.Results: The expression of PAR-2 mRNA was up-regulated in OSCC tissue and cells (P<0.01), and its mRNA level was obviously correlated to tumor differentiation and TNM stage in OSCC (P<0.05 for both). The activation of PAR-2 with PAR-2AP (PAR-2 agonist) significantly promoted the proliferation, migration, and invasion of OSCC cells, while its knockout could inhibit malignant behaviors of OSCC cells (P<0.05). Excessive activation of PAR-2 enhanced phosphorylation level of PI3K, AKT, and mTOR revealing the activation of PI3K/AKT pathway. Moreover, LY294002, the inhibitor of PI3K/AKT pathway, could reverse oncogenic action caused by PAR-2 activation.Conclusion:PAR-2 can promote OSCC growth and progression via activating PI3K/AKT signaling pathway.

MiR-638 suppresses the progression of oral squamous cell carcinoma through wnt/ß-catenin pathway by targeting phospholipase D1.

Objective: The current study aimed to explore the function of miR-638 on the progression of oral squamous cell carcinoma (OSCC) and relevant molecular mechanisms. Methods: Expression profile of miR-638 in OSCC tissues and cells was detected using quantitative real-time polymerase chain reaction (qRT-PCR) method. Chi-square test was performed to estimate the relationship between miR-638 and clinical parameters of OSCC cases. Cell viability and motility abilities were estimated using MTT and transwell assays, respectively. Potential targets of miR-638 in OSCC were identified through bioinformatics analysis and luciferase reporter assay. Results: MiR-638 exhibited decreased expression in OSCC tissues and cells, compared to non-cancerous controls (P < .05 for both). Moreover, its down-regulation was closely correlated with lymph node metastasis (P = .044) and TNM stages (P = .001). Enforced miR-638 expression reduced cell proliferation, migration and invasion, while its knockdown exhibited opposite effects. Phospholipase D1 (PLD1) was confirmed as a target of miR-638 in OSCC. MiR-638 could inhibit wnt/ß-catenin pathway through targeting PLD1, thus realizing its anti-tumour action in OSCC. Conclusion: MiR-638 may be a tumour suppressor in OSCC by targeting PLD1/Wnt/ß-catenin pathway.

Nanosilver/poly (dl-lactic-co-glycolic acid) on titanium implant surfaces for the enhancement of antibacterial properties and osteoinductivity.

Background: Despite titanium (Ti) implants have been commonly used in the medical device field due to their superior biocompatibility, implant-associated bacterial infection remains a major clinical complication. Nanosilver, an effective antibacterial agent against a wide spectrum of bacterial strains, with a low-resistance potential, has attracted much interest too. Incorporation of nanosilver on Ti implants may be a promising approach to prevent biofilm formation. Purpose: The objective of the study was to investigate the antibacterial effects and osteoinductive properties of nanosilver/poly (dl-lactic-co-glycolic acid)-coated titanium (NSPTi). Methods: Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and the Gram-negative opportunistic pathogen Pseudomonas aeruginosa (PAO-1) were used to evaluate the antibacterial activity of NSPTi implants through the analysis of bacterial colonization in vitro and in vivo. Furthermore, we examined the osteoinductive potential of NSPTi implants by investigating the proliferation and differentiation of MC3T3-E1 preosteoblast cells. In vivo, the osteoinductive properties of NSPTi implants were assessed by radiographic evaluation, H&E staining, and Masson's trichrome staining. Results: In vitro, bacterial adhesion to the 2% NSPTi was significantly inhibited and <1% of adhered bacteria survived after 24 hours. In vitro, the average colony-forming units (CFU)/g ratios in the 2% NSPTi with 103 CFU MRSA and PAO-1 were 1.50±0.68 and 1.75±0.6, respectively. In the uncoated Ti groups, the ratios were 1.03±0.82×103 and 0.94±0.49×103, respectively. These results demonstrated that NSPTi implants had prominent antibacterial properties. Proliferation of MC3T3-E1 cells on the 2% NSPTi sample was 1.51, 1.78, and 2.22 times that on the uncoated Ti control after 3, 5, and 7 days' incubation, respectively. Furthermore, NSPTi implants promoted the maturation and differentiation of MC3T3-E1 cells. In vivo, NSPTi accelerated the formation of new bone while suppressing bacterial survival. Conclusion: NSPTi implants have simultaneous antibacterial and osteoinductive activities and therefore have the potential in clinical applications.

Chitosan-stablized bovine serum albumin nanoparticles having ability to control the release of NELL-1 protein.

The study was designed to prepare and evaluate chitosan stabilized-albumin nanoparticles as NELL-1 protein carriers(Chi/NNPs). The Chi/NNPs were prepared by desolvation method and then stabilized by chitosan through electrostatic interaction. The Chi/NNPs were characterized for drug loading efficiency, surface morphology, particle size, surface charge. Fluorescein isothiocyanate-labeled chitosan was used to confirm the homogeneity of chitosan coating on the BSA nanoparticles. The NELL-1 bioactivity of Chi/NNPs and the release kinetics were investigated in vitro. It was observed that the mean particle size with chitosan (0.075 wt%,0.15 wt%, 0.3 wt%, respectively) and the surface charge were 368.663 ±â€¯15.470 nm, 382.881 ±â€¯18.767 nm, 390.480 ±â€¯11.465 nm and +25.03 ±â€¯1.42 mV, +30.27 ±â€¯1.80 mV, +31.03 ±â€¯2.05 mV respectively. Drug entrapment efficiency ranged from 87.83% to 89.30%. The Chi/NNPs prepared with the 0.15 wt% chitosan were able to successfully control the release of NELL-1 and maintain a sustained release for up to 8 days. Furthermore, more than 82.67 ±â€¯8.74% of the loaded protein's bioactivity was preserved in Chi/NNPs over the period of the investigation. Our findings suggest that Chi/NNPs as promising protein delivery nanocarriers have the ability to maintain sustained release kinetics and to preserve the bioactivity of released NELL-1.

hsa-miR-485-5p reverses epithelial to mesenchymal transition and promotes cisplatin-induced cell death by targeting PAK1 in oral tongue squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is currently a highly prevalent disease worldwide. Cisplatin (CDDP) is widely used for the chemotherapy of OSCC. Yet, the molecular mechanisms responsible for cisplatin resistance have not been fully elucidated. In this study, we showed that overexpression of p21 (RAC1) activated kinase 1 (PAK1) induced epithelial to mesenchymal transition (EMT) and significantly promoted the invasion and migration of oral squamous cell carcinoma SCC25 cells. Emerging evidence indicates a strong link between resistance to therapy and the induction of EMT in cancer. We showed that overexpression of PAK1 induced cisplatin resistance in SCC25 cells. ERCC1 and YAP can promote cisplatin resistance in human OSCC. We showed that ERCC1 and YAP protein were upregulated by PAK1 in SCC25 cells. -We found that miR­485­5p inhibited PAK1 protein expression in the SCC25 cells. Contrary to PAK1, we demonstrated that overexpression of miR­485­5p reversed EMT and significantly inhibited invasion and migration. Moreover, its overexpression sensitized SCC25-CR cells (cisplatin-resistant cells) to cisplatin. Thus, we conclude that miR­485­5p reverses EMT and promotes cisplatin-induced cell death by targeting PAK1 in oral tongue squamous cell carcinoma. This study suggests that PAK1 plays an essential role in the progression of OSCC and it is a potential therapeutic target for OSCC.

A Cone-Beam Computed Tomographic Study on Mandibular First Molars in a Chinese Subpopulation.

The purpose of this study was to conduct a cone-beam computed tomographic (CBCT) investigation on the root and canal configuration of the mandibular first molars, especially the morphology of the disto-lingual (DL) root, in a Chinese subpopulation. A total of 910 CBCT images of the mandibular first molars were collected from 455 patients who underwent CBCT examinations as a preoperative assessment for implants or orthodontic treatment. The following information was analyzed and evaluated: tooth position, gender, root and root canal number per tooth, root canal type of the mesial root(s) and distal root(s), angle of the DL root canal curvature, distance between two distal canal orifices in the teeth with DL root, and angle of disto-buccal canal orifice-disto-lingual canal orifice-mesio-lingual canal orifice (DB-DL-ML). Most of the mandibular first molars (64.9%, n = 591) had two roots with three root canals, and most of the mesial root canals (87.7%, n = 798) were type VI. The prevalence of the DL root was 22.1% (n = 201). The right side had a higher prevalence of DL root than the left side (p<0.05). Additionally, the curvature of the DL root canal were greater in the bucco-lingual (BL) orientation (30.10°±14.02°) than in the mesio-distal (MD) orientation (14.03°± 8.56°) (p<0.05). Overall there was a high prevalence of DL root in the mandibular first molars, and most of the DL roots were curved in different degrees. This study provided detailed information about the root canal morphology of the mandibular first molars in a Chinese subpopulation.

[Scanning electron microscopic study on the use of traditional Chinese medical irrigant in ultrasonic root canal instrumentation].

PURPOSE: To evaluate the cleaning ability of traditional Chinese medicine Jieeryin used as ultrasonic root canal irrigant. METHODS: A total of 20 extracted human single-rooted teeth were divided into 4 groups: normal saline, 3.33% Jieeryin, 30% Jieeryin and 2.5% sodium hypochlorite. After ultrasonic root canal preparation a 15#-K type ultrasonic file was inserted into the root canal without contacting the root canal wall and the ultrasonic irrigation was kept for 10 seconds. The cleaning of the cervical, middle and apical thirds of the root canal walls was evaluated by scanning electron microscope. The data were analyzed statistically by ANOVA and Bonferroni test. RESULTS: The cleaning ability of 30% Jieeryin was similar to that of 2.5% NaClO (P>0.05) in the cervical third, and it was significantly better than 3.33% Jieeryin (P<0.01) and normal saline (P<0.05). There was significant difference between the cervical third and the middle or apical thirds (P<0.01) of 30% Jieeryin. There was no significant difference between the four groups in the middle third (P>0.05). In the apical third, 2.5% NaClO was significantly better than normal saline (P>0.05). No significant difference was found between 3.33% Jieeryin and saline in all thirds. CONCLUSION: Cleaning by 30% Jieeryin or 2.5% NaClO with ultrasonic technique was superior compared to the cleaning by 3.33% Jieeryin or normal saline in the cervical third.

[The effect of coronal preflaring on the working length measurement of root canals in molars].

PURPOSE: To study the influence of coronal preflaring of root canal on the working length measurement in molars. METHODS: 48 molars from 47 adult patients with pulpitis were divided into two groups randomly. 74 root canals of 24 molars were examined in Group 1. After preparing an access cavity, the root canal orifices were located. A 15# K-type file was inserted into root canal to detect resistance at the apical region. 75 root canals of 24 molars were examined in Group 2. Before testing the apical resistance,a size 25# and 20# ProFile.06 taper NiTi rotary instrument was used to enlarge the canal orifice and flare the coronal portion of the root canal. After placing 15# K-type files, a radiograph was taken with the bisecting-angle technique. The distance between the tip of the file and the radiographic apex was measured on the radiographs. Statistical analysis of univariate and multiple logistic regression were carried out for analysis. RESULTS: There was a significant difference between the two groups (P<0.05), there were more accurate measurements in Group 2 than in Group 1. No statistical correlation was found between X-ray measurements and age, sex and the position of molars,while there was significant correlation between maxillary molars and mandibular molars (P<0.05). CONCLUSION: Preflaring the coronal portion of the root canals could significantly increase the accurate measurements of the working length of root canals in molars.