SNHG1 knockdown promotes osteogenic differentiation of hDFSCs through anti-oxidative stress mediated by autophagy.

The long noncoding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) plays a crucial role in tumorigenesis and is frequently employed as a prognostic biomarker. However, its involvement in the osteogenic differentiation of oral stem cells, particularly human dental follicle stem cells (hDFSCs), remains unclear. Our investigation revealed that the absence of SNHG1 enhances the osteogenic differentiation of hDFSCs. Furthermore, the downregulation of SNHG1 induces autophagy in hDFSCs, leading to a reduction in intracellular oxidative stress levels. Notably, this effect is orchestrated through the epigenetic regulation of EZH2. Our study unveils a novel function of SNHG1 in governing the osteogenic differentiation of hDFSCs, offering fresh insights for an in-depth exploration of the molecular mechanisms underlying dental follicle development. These findings not only provide a foundation for advancing the understanding of SNHG1 but also present innovative perspectives for promoting the repair and regeneration of periodontal supporting tissue, ultimately contributing to the restoration of periodontal health and tooth function.

LncRNA HOTAIRM1 promotes dental follicle stem cell-mediated bone regeneration by regulating HIF-1α/KDM6/EZH2/H3K27me3 axis.

Large bone defect reconstruction undergoes hypoxia and remains a major practical challenge. Bone tissue engineering with a more promising stem cell source facilitates the development of better therapeutic outcomes. Human dental follicle stem cells (hDFSCs) with superior multipotency, osteogenic capacity, and accessibility have been proven a promising cell source for bone regeneration. We previously identified a novel long noncoding RNA (lncRNA), HOTAIRM1, to be highly expressed in hDFSCs. Here we found that HOTAIRM1 overexpressed hDFSCs promoted bone regeneration in rat critical-size calvarial defect model. Mechanically, HOTAIRM1 was induced in hDFSCs under hypoxic conditions and activated HIF-1α. RNA-sequencing analysis indicated that HOTAIRM1 upregulated oxygen-sensing histone demethylases KDM6A/B and suppressed methyltransferase EZH2 via targeting HIF-1α. The osteogenic differentiation of hDFSCs was accompanied with demethylation of H3K27, and HOTAIRM1 overexpression decreased the distribution of H3K27me3 in osteogenic genes, including ALP, M-CSF, Wnt-3a, Wnt-5a, Wnt-7a, and ß-catenin, thus promoted their transcription. Our study provided evidence that HOTAIRM1 upregulated KDM6A/B and inhibited EZH2 in a HIF-1α dependent manner to enhance the osteogenesis of hDFSCs. HOTAIRM1-mediated hDFSCs may serve as a promising therapeutic approach to promote bone regeneration in clinical practice.

Mitochondrial Dysfunction in the Pathogenesis and Treatment of Oral Inflammatory Diseases.

Oral inflammatory diseases (OIDs) include many common diseases such as periodontitis and pulpitis. The causes of OIDs consist microorganism, trauma, occlusal factors, autoimmune dis-eases and radiation therapy. When treated unproperly, such diseases not only affect oral health but also pose threat to people's overall health condition. Therefore, identifying OIDs at an early stage and exploring new therapeutic strategies are important tasks for oral-related research. Mitochondria are crucial organelles for many cellular activities and disruptions of mitochondrial function not only affect cellular metabolism but also indirectly influence people's health and life span. Mitochondrial dysfunction has been implicated in many common polygenic diseases, including cardiovascular and neurodegenerative diseases. Recently, increasing evidence suggests that mitochondrial dysfunction plays a critical role in the development and progression of OIDs and its associated systemic diseases. In this review, we elucidated the critical insights into mitochondrial dysfunction and its involvement in the inflammatory responses in OIDs. We also summarized recent research progresses on the treatment of OIDs targeting mitochondrial dysfunction and discussed the underlying mechanisms.

Virtual reality used in undergraduate orthodontic education.

INTRODUCTION: Undergraduate dental students frequently have reduced clinical experience which presents a challenge for their dental education. Previously, we developed a virtual reality (VR) simulating the whole clinical treatment process of a patient with angle Class II division 1 malocclusion, and the VR also helped to explain some important orthodontic concepts. As a novel teaching tool, this study aims to compare the effects of VR versus traditional case analysis by Power Point (PPT) in inspiring student learning motivation and evaluating learning experience. MATERIALS AND METHODS: A randomized, cross-over, stratified sampling method was taken to divide the fourth-year undergraduate dental students equally into two groups. The two groups were crossed over to use VR and PPT. RESULTS: For the whole study, results indicated that students in the VR group showed higher learning motivation (including attention, relevance, confidence and satisfaction) than in the PPT group, but the differences between VR and PPT groups were not very big, and the median of the differences located at 0. For learning experience, students thought VR to be more useful, more enjoyable and more engaging, but the median of differences also located at 0. Notably, the majority of students had higher recommendations for VR than PPT, and the median difference located at 1. However, when the two phases were analysed separately, some items showed no significant differences between VR and PPT learning. CONCLUSION: VR is a very useful adjunct to education compared to traditional case analysis by PPT, but we cannot exaggerate its benefits. Educators should make good use of VR to solve the difficult problems in education.

Hydrogel composite scaffolds achieve recruitment and chondrogenesis in cartilage tissue engineering applications.

BACKGROUND: The regeneration and repair of articular cartilage remains a major challenge for clinicians and scientists due to the poor intrinsic healing of this tissue. Since cartilage injuries are often clinically irregular, tissue-engineered scaffolds that can be easily molded to fill cartilage defects of any shape that fit tightly into the host cartilage are needed. METHOD: In this study, bone marrow mesenchymal stem cell (BMSC) affinity peptide sequence PFSSTKT (PFS)-modified chondrocyte extracellular matrix (ECM) particles combined with GelMA hydrogel were constructed. RESULTS: In vitro experiments showed that the pore size and porosity of the solid-supported composite scaffolds were appropriate and that the scaffolds provided a three-dimensional microenvironment supporting cell adhesion, proliferation and chondrogenic differentiation. In vitro experiments also showed that GelMA/ECM-PFS could regulate the migration of rabbit BMSCs. Two weeks after implantation in vivo, the GelMA/ECM-PFS functional scaffold system promoted the recruitment of endogenous mesenchymal stem cells from the defect site. GelMA/ECM-PFS achieved successful hyaline cartilage repair in rabbits in vivo, while the control treatment mostly resulted in fibrous tissue repair. CONCLUSION: This combination of endogenous cell recruitment and chondrogenesis is an ideal strategy for repairing irregular cartilage defects.

Three-dimensional evaluation of soft tissues in hyperdivergent skeletal class II females in Guangdong.

OBJECTIVES: To establish the three-dimensional facial soft tissue morphology of adolescent and adult females in the Guangdong population and to study the morphological characteristics of hyperdivergent skeletal class II females in Guangdong compared with that of normodivergent class I groups. MATERIALS AND METHODS: The 3dMDface system was used to capture face scans of 160 patients, including 45 normal and 35 hyperdivergent skeletal class II adolescents (aged 11-14 years old) and 45 normal and 35 hyperdivergent skeletal class II adults (aged 18-30 years old). Thirty-two soft tissue landmarks were mapped, and 21 linear, 10 angular and 17 ratio measurements were obtained by 3dMDvultus analysis software. Data were assessed with a t-test of two independent samples between the normal adolescent and adult groups and between the normal and hyperdivergent skeletal class II groups. RESULTS: The linear measurements of the Guangdong adult females were larger than those of the adolescents in both Class I and Class II groups. However, the angular and ratio measurements had no significant difference. The vertical linear measurements were higher and the sagittal and transverse linear measurements were smaller in the hyperdivergent class II group (p < 0.05). The soft tissue ANB angle, chin-lip angle, and mandibular angle were significantly larger and the soft tissue facial convexity angle and nasal convexity angle were significantly smaller in the hyperdivergent class II group (p < 0.05). Additionally, there were significant differences in the ratio measurements between the hyperdivergent class II groups and the control groups (p < 0.05). CONCLUSIONS: The three-dimensional facial morphology of Guangdong adolescent and adult females was acquired. The facial soft tissue measurements of the adults were higher in the three dimensions except for the facial convexity and proportional relationships which were similar, suggesting that the growth pattern remained the same. The three-dimensional facial soft tissue features of hyperdivergent skeletal class II were characterized by the terms "long, convex, and narrow". Three-dimensional facial measurements can reflect intrinsic hard tissue characteristics.

Electromyographic features and efficacy of orofacial myofunctional treatment for skeletal anterior open bite in adolescents: an exploratory study.

BACKGROUND: Due to the multifactorial aetiology and unpredictable long-term stability, skeletal anterior open bite (SAOB) is one of the most intractable conditions for orthodontists. The abnormal orofacial myofunctional status (OMS) may be a major risk factor contributing to the development and relapse of SAOB. This study is aimed at evaluating the OMS and the efficacy of orofacial myofunctional therapy (OMT) alone for SAOB subjects. METHODS: Eighteen adolescents with SAOB (4 males, 14 females; age: 12-18 years) and eighteen adolescents with normal occlusion (2 males, 16 females; age: 12-18 years) were selected. The electromyographic activity (EMGA) associated with mastication and closed mouth state was measured. Lateral cephalography was used to evaluate craniofacial morphology. Wilcoxon signed rank tests and t-tests were performed to evaluate myofunctional and morphological differences. Pearson or Spearman correlation analysis was used to investigate the correlations between EMGA and morphological characteristics. SAOB subjects were given OMT for 3 months, and the EMGA was compared between before and after OMT. RESULTS: During rest, anterior temporalis activity (TAA) and mentalis muscle activity (MEA) increased in SAOB subjects, but TAA and masseter muscle activity (MMA) decreased in the intercuspal position (ICP); and upper orbicularis activity (UOA) and MEA significantly increased during lip sealing and swallowing (P < 0.05). Morphological evaluation revealed increases in the FMA, GoGn-SN, ANS-Me, N-Me, L1-MP, U6-PP, and L6-MP and decreases in the angle of the axis of the upper and lower central incisors and OB in SAOB subjects (P < 0.05). TAA, MMA and anterior digastric activity (DAA) in the ICP were negatively correlated with vertical height and positively correlated to incisor protrusion. MEA was positively correlated with vertical height and negatively correlated with incisor protrusion; and the UOA showed a similar correlation in ICP, during sealing lip and swallowing. After SAOB subjects received OMT, MEA during rest and TAA, MMA and DAA in the ICP increased, while UOA and MEA decreased (P < 0.05). CONCLUSION: SAOB subjects showed abnormal OMS features including aberrant swallowing patterns and weak masticatory muscles, which were interrelated with the craniofacial dysmorphology features including a greater anterior facial height and incisor protrusion. Furthermore, OMT contributes to OMS harmonization, indicating its therapeutic prospect in SAOB.

lncRNA HOTAIRM1 promotes osteogenesis of hDFSCs by epigenetically regulating HOXA2 via DNMT1 in vitro.

Dental follicle (DF) can develop into periodontal tissues including periodontal ligament, cementum, and alveolar bone. Possessing superior pluripotency and osteogenic capacity, dental follicle stem cells (DFSCs) have become a promising stem cell source for bone regeneration and periodontal engineering. However, the mechanisms underlying DFSCs-mediated osteogenesis remain elusive. Our previous long noncoding RNA (lncRNA) microarray revealed that lncRNA HOTAIRM1 was significantly higher expressed in human DFSCs (hDFSCs) compared with human periodontal ligament stem cells (hPDLSCs). lncRNA HOTAIRM1, an antisense transcript of the HOXA1/2 intergenic region, can epigenetically regulate proximal and distant HOXA genes through histone and DNA methylation. HOXA2, a target of HOTAIRM1, is crucial for cranial neural crest morphogenesis, branchial arches development, and osteogenesis. However, the roles of both HOTAIRM1 and HOXA2 in odontogenic stem cells remain unknown. Here, we investigated the functions and regulatory mechanisms of these two genes in hDFSCs. Both genes were confirmed highly expressed in hDFSCs compared with hPDLSCs, and they displayed similar expression patterns in the DF and surrounding periodontium during mice tooth morphogenesis. Knockdown of either HOTAIRM1 or HOXA2 inhibited osteogenic differentiation of hDFSCs, while overexpressed HOTAIRM1 inhibited hDFSCs proliferation and promoted osteogenesis. Furthermore, HOTAIRM1 inhibited both overall DNMT1 expression and DNMT1 enrichment on HOXA2 promoter, mechanically binding to the CpG islands of the HOXA2 promoter region, leading to hypomethylation and HOXA2 induction. These findings suggested that HOTAIRM1 promoted the osteogenesis of hDFSCs by epigenetically regulating HOXA2 via DNMT1. Taken together, HOTARIM1 and HOXA2 exerted pivotal functions in hDFSCs, and the regulatory mechanism of HOTARIM1 within the HOXA cluster was uncovered.

Down-regulated lncRNA MEG3 promotes osteogenic differentiation of human dental follicle stem cells by epigenetically regulating Wnt pathway.

Our previous long noncoding RNA (lncRNA) microarray results showed that lncRNA MEG3 (maternally expressed 3) was significantly downregulated in human dental follicle cells than human periodontal ligament cells. Latest studies show that MEG3 contributes to polycomb repressive complex 2 (PRC2) recruitment to silence gene expression. The enhancer of zeste homolog 2 (EZH2), a crucial catalytic subunit of PRC2, mediates gene silencing and participates in cell lineage determination via methyltransferase activity. In this study, we found that the expression of EZH2 and H3K27me3 (trimethylation on lysine 27 in histone H3) decreased during osteogenesis of human dental follicle stem cells (hDFSCs). Knockdown studies of MEG3 and EZH2 by siRNA showed that MEG3/EZH2 negatively regulated osteogenesis of hDFSCs. We investigated the role of Wnt signaling pathway during the osteogenesis of hDFSCs and its relationship with EZH2. Besides, we studied the key genes of the canonical/noncanonical Wnt signaling pathway which might be related to EZH2. ChIP (chromatin immunoprecipitation) analysis showed that these effects were due to the EZH2 regulation of H3K27me3 level on the Wnt genes promotors. We first demonstrated that the decrease of MEG3 or EZH2 activated the Wnt/ß-catenin signaling pathway via epigenetically regulating the H3K27me3 level on the Wnt genes promotors. Our research offers a new target for periodontal tissue engineering and osteogenic tissue regeneration.

Association between Dental Caries and BMI in Children: A Systematic Review and Meta-Analysis.

Research on the association between dental caries and body mass index (BMI) in children has shown contradictory results; thus we aimed to examine the association between dental caries and the full range of BMI classes among children. We comprehensively searched PubMed, Embase, and the Cochrane Library for studies published prior to March 2017. Articles comparing dental caries among the full range of BMI classes for children below 18 years of both genders were included. Fourteen studies were eligible for this study. Basic information - i.e., first author, published year, study design, country, sample size, age, type of dental caries index and BMI, main results and conclusions, and means and standard deviations of the dental caries indexes used - was pooled. The weighted mean differences and corresponding 95% confidence intervals for dental caries between children with abnormal weight and those with normal weight were analyzed. Generally, no significant differences in caries were found between any abnormal-weight group and the normal-weight group for both primary and permanent teeth. Sensitivity analyses showed that the obese group had more caries than the normal-weight group in their primary teeth. Significantly more caries was found among the overweight and obese children in both primary and permanent teeth in high-income countries, but not in low- and middle-income countries. We recommend that further studies use suitable sample sizes, unify the criteria for BMI categorization and the dental caries index, and investigate the confounding factors that might influence dental caries and BMI.

Relationship Between the Comprehensive Nutritional Index and the EORTC QLQ-H&N35 in Nasopharyngeal Carcinoma Patients Treated with Intensity-Modulated Radiation Therapy.

This study aimed to explore the relationship between the comprehensive nutritional index (CNI) and quality of life in nasopharyngeal carcinoma (NPC) patients receiving intensity-modulated radiation therapy (IMRT). The nutritional index, which includes total lymphocyte count, hemoglobin and albumin levels, body mass index, and usual body weight percentage, was evaluated pre-treatment and post-treatment in patients who underwent IMRT. The quality of life of NPC patients was measured by the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Head and Neck Cancer Module (EORTC QLQ-H&N35) at four time points: pre-treatment, post-treatment, and 3 and 6 mo after IMRT. A comprehensive nutritional model was used to assess the correlation with QLQ-H&N35. The nutritional index decreased significantly post-treatment. The CNI was associated with immunotherapy; the International Union Against Cancer (UICC) stage; concurrent chemotherapy; speech problems, trouble with social contact, feeling ill and having dental problems at pre-treatment; sexuality at 3 mos post-treatment; and sensory problems and xerostomia at 6 mo post-treatment (P < 0.05). The nutritional status and QLQ-H&N35 scores in NPC patients decreased during IMRT. Our study provides an alternative measure of the CNI to improve the QLQ-H&N35 evaluation system for patients with NPC.

Cationic Polyphosphazene Vesicles for Cancer Immunotherapy by Efficient in Vivo Cytokine IL-12 Plasmid Delivery.

To circumvent the severe toxicity of the systemic delivery of IL-12 protein and the limits of local administration of IL-12 gene, we constructed a polymersome system for systemic delivery of recombinant murine IL-12 plasmid (pmIL-12) based on amphiphilic polyphosphazenes containing weakly cationic N,N-diisopropylethylenediamine (DPA) as hydrophobic groups and monomethoxy poly(ethylene glycol) (mPEG) as hydrophilic tails. By simple dialysis method, pmIL-12 was successfully loaded into polymersomes due to the combination effect of physical encapsulation and electrostatic interaction. This pmIL-12 polymersome delivery system was validated with good biocompatibility and stability despite of serum protein and DNase challenging. The results of in vivo antitumor experiments showed that intravenous injection of pmIL-12 polymersomes achieved significant suppression of tumor growth in BALB/c mice bearing CT-26 colon carcinoma. The analysis revealed that the mechanism was related to the antitumor immune response induced by efficient transfection of pmIL-12 polymersomes, which maybe involved lymphocytes infiltration and angiogenic inhibition at the tumor site.

Unraveling ferroptosis in osteogenic lineages: implications for dysregulated bone remodeling during periodontitis progression.

Periodontitis is a highly prevalent disease characterized by inflammation and destruction of tooth-supporting tissues that leads to tooth loss in extreme situations. Elucidating the underlying mechanisms of periodontitis pathogenesis and progression will establish the groundwork for developing effective treatment strategies. Recently, evidence concerning the role of ferroptosis in periodontitis progression has emerged. Osteogenic lineage cells are key regulators of bone remodeling. Osteogenic cell death, as observed in experimental periodontitis models, disrupts the balance between bone resorption and bone formation. However, whether the osteogenic lineage undergoes ferroptosis during periodontitis and the corresponding effect on periodontitis progression remain elusive. Here, we investigated cell-specific ferroptosis within the alveolar bone in a murine periodontitis model. Through immunofluorescence double staining and immunohistochemistry, we identified ferroptotic osteocytes and osteoblasts in inflammatory alveolar bone. Next, in vivo administration of erastin or liproxstatin-1 was conducted to either induce or inhibit ferroptosis, respectively. Severe bone resorption and inflammation, accompanied by increased osteoclast formation and impaired osteogenic potential were detected following ferroptosis activation. Subsequently, we carried out in vitro experiments on osteocytes and further verified that ferroptosis enhanced the osteocytic expression of RANKL and IL-6. These findings suggest that ferroptosis occurring within the osteogenic lineage acts as a catalyst in the progression of periodontitis by stimulating osteoclastogenesis through the secretion of inflammatory cytokines and inhibiting osteoblastic function, providing insights into ferroptosis-induced alterations in microenvironment-based intercellular communication. Ferroptosis is a promising target for controlling inflammation and preventing bone resorption in periodontitis.

Cdc42 deletion yielded enamel defects by disrupting mitochondria and producing reactive oxygen species in dental epithelium.

Developmental defects of enamel are common due to genetic and environmental factors before and after birth. Cdc42, a Rho family small GTPase, regulates prenatal tooth development in mice. However, its role in postnatal tooth development, especially enamel formation, remains elusive. Here, we investigated Cdc42 functions in mouse enamel development and tooth repair after birth. Cdc42 showed highly dynamic temporospatial patterns in the developing incisors, with robust expression in ameloblast and odontoblast layers. Strikingly, epithelium-specific Cdc42 deletion resulted in enamel defects in incisors. Ameloblast differentiation was inhibited, and hypomineralization of enamel was observed upon epithelial Cdc42 deletion. Proteomic analysis showed that abnormal mitochondrial components, phosphotransferase activity, and ion channel regulator activity occurred in the Cdc42 mutant dental epithelium. Reactive oxygen species accumulation was detected in the mutant mice, suggesting that abnormal oxidative stress occurred after Cdc42 depletion. Moreover, Cdc42 mutant mice showed delayed tooth repair and generated less calcified enamel. Mitochondrial dysfunction and abnormal oxygen consumption were evidenced by reduced Apool and Timm8a1 expression, increased Atp5j2 levels, and reactive oxygen species overproduction in the mutant repair epithelium. Epithelium-specific Cdc42 deletion attenuated ERK1/2 signaling in the labial cervical loop. Aberrant Sox2 expression in the mutant labial cervical loop after clipping might lead to delayed tooth repair. These findings suggested that mitochondrial dysfunction, up-regulated oxidative stress, and abnormal ion channel activity may be among multiple factors responsible for the observed enamel defects in Cdc42 mutant incisors. Overall, Cdc42 exerts multidimensional and pivotal roles in enamel development and is particularly required for ameloblast differentiation and enamel matrix formation.

The prevalence of temporomandibular disorder and temporomandibular morphology among diverse chronotype profiles.

This study investigates the influence of chronotype on the prevalence of temporomandibular joint disorders (TMD) and the morphology of temporomandibular joint (TMJ). According to the Morningness-Eveningness Questionnaire-Self-Assessment, the participants were divided into morning group (n = 30), intermediate group (n = 83), and evening group (n = 30). Thirty participants were randomly selected from the intermediate group for subsequent examination and measurements. The morphology of TMJs was investigated using questionnaire and clinical examination form in Diagnostic Criteria for Temporomandibular Disorder. Meanwhile, the morphological results of TMJs were measured from cone-beam computed tomography images. The prevalence rate of TMD in the morning group (23%) was significantly lower than that in the intermediate group (56.7%), while there was no difference between the evening (53.4%) and intermediate groups. As to morphological measurements, there was no significant difference among three groups in mediolateral width of condylar process, anteroposterior width of condylar process, radius of condyle, medial joint space, lateral joint space, condylar stress angle, horizontal condylar inclination, width of glenoid fossa, depth of glenoid fossa, and posterior joint space, while there was a significant difference in horizontal condylar angle (p = 0.00490), articular eminence inclination (p < .0001), anterior joint space (p = 0.0163), and superior joint space (p = 0.0004). The morphology of TMJ in the morning group was better than that in the evening and intermediate groups. An association was found between TMD prevalence, temporomandibular morphology, and chronotype.

Development of predictive quantitative retention-activity relationship models of alkaloids by mixed micellar liquid chromatography.

The mixed micellar liquid chromatography is a mode that uses mixed micellar system of Brij35/SDS (85 : 15) as a mobile phase under adequate experimental conditions, can simulate the resting membrane potential and the conformation of the long hydrophilic polyoxyethylene chains remains unchanged. In this article, the applications of biopartitioning micellar chromatography, using mixed micellar system to describe and estimate bioactivities of alkaloids, has been focused. The BMC(Brij35/SDS)-QRAR models of half-life time, volume of distribution, plasma clearance and area under concentration-time curve were obtained using Brij35-SDS retention data. The aim is to take a look at the capability of the mixed micellar liquid chromatography model to describe and/or estimate the bioactivity of alkaloids.

Fixed orthodontic appliance therapy and its impact on oral health-related quality of life in Chinese patients.

OBJECTIVE: To determine changes in oral health-related quality of life (OHRQoL) during fixed orthodontic appliance therapy in Chinese patients. MATERIALS AND METHODS: Two-hundred fifty Chinese orthodontic patients completed six distinct intervals of the 14-item Oral Health Impact Profile (OHIP-14, Chinese version): before treatment (T0); after the placement of the fixed appliance at 1 week (T1), 1 month (T2), 3 months (T3), and 6 months (T4); and posttreatment (T5). RESULTS: The overall response rate was 88.8% (222 of 250). Significant differences of overall OHIP-14 scores could be found between any two time points (P < .001), except for between T0 and T2 (P > .05) and between T3 and T4 (P > .05). Overall scores at T1 were significantly higher than the scores at the other intervals (P < .001), with a significant change in the scores on physical pain (P < .001), psychological discomfort (P < .001), and physical disability (P < .001). Scores at T5 were lowest among the six time points (P < .001). CONCLUSIONS: Fixed orthodontic appliance therapy did affect Chinese patients' OHRQoL. Patients were considerably compromised in terms of their overall OHRQoL until approximately 1 month after insertion. The severity of the compromised condition in terms of overall OHRQoL was greatest at 1 week with the reported impact on physical pain, psychological discomfort, and physical disability. Patients' OHRQoL was better after they completed the orthodontic treatment than before or during treatment.

Defouling and cleaning using nanobubbles on stainless steel.

The present work demonstrates that nanobubbles can be used as cleaning agents on stainless steel (SS) surfaces. Cleaning efficiency has been quantified. Using an Atomic Force Microscope (AFM), it was demonstrated that nanobubbles can be produced by electrochemical treatment on a SS surface either with or without adsorbed bovine serum albumin (BSA). After allowing adsorption on SS overnight, radio-labeled BSA was removed by electrochemically generated nanobubbles, and then the remaining BSA on the surface was quantified by radioactivity measurement. The results indicate that nanobubbles can remove >10% of the protein in each 3-min electrochemical treatment while in a control group, washing with water and electrolyte resulted in no more than 3% of the protein being removed each time. Cleaning of conducting surfaces by nanobubbles is promising in any system where fouling occurs in biomedia.

Effect of microRNA-21 on hypoxia-inducible factor-1α in orthodontic tooth movement and human periodontal ligament cells under hypoxia.

Orthodontic tooth movement can lead to temporary hypoxia of periodontal tissues. Periodontal ligament cells (PDLCs) react to hypoxia, releasing various biological factors to promote periodontal tissue reconstruction. Hypoxia-inducible factor-1α (HIF-1α) is one of the most sensitive factors involved in the response to hypoxia. HIF-1α has been identified to be involved in osteogenic and osteoclast differentiation in vitro; however, few studies have investigated the expression of HIF-1α in the periodontal ligament (PDL) during orthodontic movement in vivo. In a previous study, microRNA-21 (miR-21) was demonstrated to be highly expressed in a rat model of orthodontic tooth movement. Additionally, miR-21 can increase the expression of HIF-1α in certain tumor cell types and is involved in tumor bioactivities. In the present study, HIF-1α exhibited expression patterns in a similar way to miR-21 in PDL samples from a rat model of orthodontic tooth movement, with expression initially increased and followed by a decrease over time. Furthermore, human PDLCs were exposed to a hypoxic environment in vitro, which induced significant upregulation of HIF-1α and miR-21 expression. Furthermore, miR-21 mimics increased HIF-1α expression and promoted osteogenic differentiation, indicated by upregulated expression of the osteogenic markers osteopontin, runt-related gene-2 and alkaline phosphatase. miR-21 inhibitors suppressed HIF-1α expression and downregulated the osteogenic markers. In conclusion, the results revealed that miR-21 has a positive effect on HIF-1α expression in PDLCs under hypoxia and has important roles in osteogenic differentiation during orthodontic tooth movement. These findings provide a theoretical basis by which to promote tissue reconstruction during orthodontic tooth movement.

Comparison of long non­coding RNA expression profiles in human dental follicle cells and human periodontal ligament cells.

The dental follicle develops into the periodontal ligament, cementum and alveolar bone. Human dental follicle cells (hDFCs) are the precursor cells of periodontal development. Long non­coding RNAs (lncRNAs) have been revealed to be crucial factors that regulate a variety of biological processes; however, whether lncRNAs serve a role in human periodontal development remains unknown. Therefore, the present study used microarrays to detect the differentially expressed lncRNAs and mRNAs between hDFCs and human periodontal ligament cells (hPDLCs). A total of 845 lncRNAs and 1,012 mRNAs were identified to be differentially expressed in hDFCs and hPDLCs (fold change >2.0 or <­2.0; P<0.05). Microarray data were validated by reverse transcription­quantitative polymerase chain reaction. Bioinformatics analyses, including gene ontology, pathway analysis and coding­non­coding gene co­expression network analysis, were performed to determine the functions of the differentially expressed lncRNAs and mRNAs. Bioinformatics analysis identified that a number of pathways may be associated with periodontal development, including the p53 and calcium signaling pathways. This analysis also revealed a number of lncRNAs, including NR_033932, T152410, ENST00000512129, ENST00000540293, uc021sxs.1 and ENST00000609146, which may serve important roles in the biological process of hDFCs. In addition, the lncRNA termed maternally expressed 3 (MEG3) was identified to be differentially expressed in hDFCs by reverse transcription­quantitative polymerase chain reaction. The knockdown of MEG3 was associated with a reduction of pluripotency makers in hDFCs. In conclusion, for the first time, to the best of our knowledge, the current study determined the different expression profiles of lncRNAs and mRNAs between hDFCs and hPDLCs. The observations made may provide a solid foundation for further research into the molecular mechanisms of lncRNAs in human periodontal development.