Roles of SP/KLF transcription factors in odontoblast differentiation: From development to diseases.

OBJECTIVES: A zinc-finger transcription factor family comprising specificity proteins (SPs) and Krüppel-like factor proteins (KLFs) plays an important role in dentin development and regeneration. However, a systematic regulatory network involving SPs/KLFs in odontoblast differentiation has not yet been described. This review examined the expression patterns of SP/KLF gene family members and their current known functions and mechanisms in odontoblast differentiation, and discussed prospective research directions for further exploration of mechanisms involving the SP/KLF gene family in dentin development. MATERIALS AND METHODS: Relevant literature on SP/KLF gene family members and dentin development was acquired from PubMed and Web of Science. RESULTS: We discuss the expression patterns, functions, and related mechanisms of eight members of the SP/KLF gene family in dentin development and genetic disorders with dental problems. We also summarize current knowledge about their complementary or synergistic actions. Finally, we propose future research directions for investigating the mechanisms of dentin development. CONCLUSIONS: The SP/KLF gene family plays a vital role in tooth development. Studying the complex complementary or synergistic interactions between SPs/KLFs is helpful for understanding the process of odontoblast differentiation. Applications of single-cell and spatial multi-omics may provide a more complete investigation of the mechanism involved in dentin development.

A novel simplified approach for endodontic retrograde surgery in short single-rooted teeth.

BACKGROUND: High technical thresholds, long operative times, and the need for expensive and specialized equipment impede the widespread adoption of endodontic microsurgery in many developing countries. This study aimed to compare the effects of a simplified, cost-effective, and time-efficient surgical approach involving orthograde obturation using biological ceramic material greater than 6 mm combined with apicoectomy for single-rooted teeth with short lengths with those of the conventional and current standard methods. MATERIALS AND METHODS: Forty-five premolars equally categorized into three groups: conventional surgery group, standard surgery group, and modified surgery group. A µCT scan was used to calculate the volume of voids. A micro-leakage test and scanning electron microscope (SEM) were performed to assess the sealing effect. Additionally, four cases of chronic periapical periodontitis in the anterior region were selected, and the patients received either the modified approach or the standard surgery for endodontic microsurgery. RESULTS: The volumes of voids in the apical 0-3 mm of the modified group and the standard group were comparable. The micro-leakage test and SEM examination demonstrated closely bonded fillings in the dentinal walls in both the modified surgery group and standard surgery group. The outcomes of the preliminary application of this modified procedure on patients were successful at the time of the follow-up cutoff. CONCLUSIONS: The modified surgery group exhibited similar root canal filling and apical sealing abilities with the standard procedure for single-rooted teeth with short lengths (< 20 mm). The preliminary application of this modified surgical procedure achieved favorable results.

Dental Caries Status and Caries Risk Factors in Students Ages 12-14 Years in Zhejiang, China.

BACKGROUND An accurate and valid caries prevention policy is absent in Zhejiang because of insufficient data. Therefore, the aim of this study was to investigate oral health status and related risk factors in 12- to 14-year-old students in Zhejiang, China. MATERIAL AND METHODS Using multi-stage, stratified, random sampling, we recruited a total of 4860 students aged 12 to 14 years old from 6 regions in Zhejiang in this cross-sectional study. Dental caries was measured using the Decayed, Missing and Filled Teeth (DMFT) index and the Significant Caries Index (SiC). Information concerning family background and relevant behaviors was collected in a structured questionnaire. Logistic regression analysis was used to study risk factors related to dental caries. RESULTS The overall prevalence of dental caries was 44% and the mean DMFT and SiC scores were 1.14 and 3.11, respectively. Female students had a higher level of dental caries than male students (P<0.01). The annual increase in caries prevalence was 3% with increasing age, and the DMFT score was 0.15. The results of logistic regression analysis showed that female sex, older age, snacks consumption once or more per day, fair or poor self-assessment of dental health, toothache experience, and dental visits were the most significant risk factors for dental caries, with odds ratios ranging from 1.24 to 2.25 (P<0.01). CONCLUSIONS The prevalence of dental caries in 12- to 14-year-old students in Zhejiang was low, with a tendency to increase compared with previous oral surveys. Female sex, older age, increased sugar intake, poor oral health self-assessment, and bad dental experience were the most important factors increasing dental caries risks.

Circ_0138960 knockdown alleviates lipopolysaccharide-induced inflammatory response and injury in human dental pulp cells by targeting miR-545-5p/MYD88 axis in pulpitis.

Background/purpose: Circular RNAs (circRNAs) have been shown to play important regulatory roles in many human diseases, yet their functions in pulpitis remain to be clarified. This study was designed to investigate the function of circ_0138960 in pulpitis progression and its underlying mechanism. Material and methods: Cell viability and proliferation were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and 5-Ethynyl-2'-deoxyuridine (EdU) assay. Flow cytometry and enzyme-linked immunosorbent assay (ELISA) were conducted to analyze cell apoptosis rate and the release of inflammatory cytokines. The activity of superoxide dismutase (SOD) was analyzed using a SOD assay kit. Dual-luciferase reporter and RNA-pull down assays were performed to verify the interaction between microRNA-545-5p (miR-545-5p) and circ_0138960 or myeloid differentiation primary response gene 88 (MYD88). Results: Lipopolysaccharide (LPS) treatment restrained the proliferation and promoted the apoptosis, inflammation, and oxidative stress of human dental pulp cells (hDPCs). LPS treatment dose-dependently up-regulated circ_0138960 expression in hDPCs. Circ_0138960 knockdown overturned LPS-induced inflammation and injury in hDPCs. Circ_0138960 could act as a molecular sponge for miR-545-5p, and circ_0138960 knockdown protected hDPCs from LPS-induced effects by up-regulating miR-545-5p. miR-545-5p directly interacted with the 3' untranslated region (3'UTR) of MYD88, and MYD88 overexpression reversed miR-545-5p-mediated effects in LPS-treated hDPCs. Circ_0138960 positively regulated MYD88 expression by sponging miR-545-5p in hDPCs. LPS could activate nuclear factor kappa-B (NF-κB) signaling by targeting circ_0138960/miR-545-5p/MYD88 axis in hDPCs. Conclusion: Circ_0138960 knockdown attenuated LPS-induced inflammatory response and injury in hDPCs by targeting the miR-545-5p/MYD88/NF-κB axis.

The effect of calcium phosphate ion clusters in enhancing enamel conditions versus Duraphat and Icon.

This study aimed to evaluate and compare the remineralisation, mechanical, anti-aging, acid resistance and antibacterial properties of calcium phosphate ion clusters (CPICs) materials with those of Duraphat and Icon. The remineralisation and mechanical properties were investigated using scanning electron microscopy, Fourier-transform infrared (FTIR) spectroscopy and nanoindentation. CPICs induced epitaxial crystal growth on the enamel surface, where the regrown enamel-like apatite layers had a similar hardness and elastic modulus to natural enamel (p > 0.05). Acid resistance and anti-aging properties were tested based on ion dissolution and surface roughness. CPICs exhibited similar calcium and phosphate ion dissolution to the control (p > 0.05), and its roughness decreased after thermocycling (p < 0.05), thereby decreasing the risk of enamel surface demineralisation. The minimum inhibitory concentration was 0.1 mg/ml, and the minimum bactericidal concentration ranged from 0.05 to 0.1 mg/ml. Overall, this biomimetic CPICs is a promising alternative to dental demineralisation.

KLF6 facilitates differentiation of odontoblasts through modulating the expression of P21 in vitro.

Multiple signaling pathways are involved in the regulation of cell proliferation and differentiation in odontogenesis and dental tissue renewal, but the details of these mechanisms remain unknown. Here, we investigated the expression patterns of a transcription factor, Krüppel-like factor 6 (KLF6), during the development of murine tooth germ and its function in odontoblastic differentiation. KLF6 was almost ubiquitously expressed in odontoblasts at various stages, and it was co-expressed with P21 (to varying degrees) in mouse dental germ. To determine the function of Klf6, overexpression and knockdown experiments were performed in a mouse dental papilla cell line (iMDP-3). Klf6 functioned as a promoter of odontoblastic differentiation and inhibited the proliferation and cell cycle progression of iMDP-3 through p21 upregulation. Dual-luciferase reporter assay and chromatin immunoprecipitation showed that Klf6 directly activates p21 transcription. Additionally, the in vivo study showed that KLF6 and P21 were also co-expressed in odontoblasts around the reparative dentin. In conclusion, Klf6 regulates the transcriptional activity of p21, thus promoting the cell proliferation to odontoblastic differentiation transition in vitro. This study provides a theoretical basis for odontoblast differentiation and the formation of reparative dentine regeneration.

Metal versus plastic stents for malignant biliary obstruction: an update meta-analysis.

BACKGROUND AND OBJECTIVE: The data on comparisons of stent patency, re-intervention rate and patient survival between metal and plastic stents in palliation of malignant biliary obstruction have never been pooled. We carry out a meta-analysis to summarise current evidence for clinical efficacy of metal and plastic stents in the treatment of malignant biliary obstruction. METHODS: A comprehensive search of several databases was conducted. A fixed-effects or random-effects model was used to pool data of all study endpoints. Sensitivity analysis and subgroup analysis (distal vs. hilar biliary obstruction) were also performed. RESULTS: Ten randomized clinical trials were identified. Compared with plastic stents, metal stents were associated with a significantly longer stent patency (HR=0.36; 95% CI: 0.28-0.47; I(2)=0%), fewer numbers of re-intervention (WMD=0.59; 95% CI: 0.28-0.90; I(2)=76.4%) and longer patient survival (HR=0.74; 95% CI: 0.64-0.85; I(2)=16.0%). These results were still significant by sensitivity analysis. All outcomes reached statistical significance except of the pooled WMD of number of re-intervention in the studies with hilar biliary obstruction. No publication bias was observed. CONCLUSIONS: Metal stents were associated with a significantly longer stent patency, lower re-intervention rate and longer patient survival in palliation of malignant biliary obstruction when compared to plastic stents.