A Drop-By-Drop Self-Assembled All-Natural Hydrogel as a Desensitizer for Rapid and Enduring Management of Dentin Hypersensitivity.

Dentin hypersensitivity (DH) is a prevalent dental condition arising from the exposure of dentin tubules (DTs), leading to discomfort upon external stimuli. However, achieving swift and profound occlusion of these exposed DTs for immediate and enduring relief remains challenging due to the intricate dentin structure and oral environment. Herein, a pioneering and facile drop-by-drop strategy involving an in situ generated natural supramolecular hydrogel formed by self-assembling silk fibroin (SF) and tannic acid (TA) within the narrow DT space is proposed. When SF and TA aqueous solutions are applied successively to exposed dentin, they penetrate deeply within DTs and coassemble into compact gels, robustly adhering to DT walls. This yields a rapid and compact occlusion effect with an unprecedented depth exceeding 250 µm, maintaining stable occlusion efficacy even under rigorous in vitro and in vivo erosion and friction conditions for no less than 21 days. Furthermore, the biocompatibility and effective occlusion properties are verified through cell studies in simulated oral settings and an in vivo rabbit model. This study, for the first time, demonstrates the translational potential of hydrogel-based desensitizers in treating DH with prompt action, superior occlusion depth and enduring treatment benefits, holding promise as clinical-friendly restorative solutions for delicate-structured biosystems.

Graphene quantum dots promote migration and differentiation of periodontal ligament stem cells.

Graphene and its derivatives have attracted much attention as nanomaterials in bone tissue engineering because of their remarkable ability to induce cell osteogenic differentiation. However, graphene quantum dots (GQDs), as graphene derivatives, little is known about their osteodifferentiation- and osteoinduction-promoting capabilities, especially in the restoration of bone defect caused by periodontitis. Therefore, there is a growing need to investigate the effect of GQDs on periodontal ligament stem cells (PDLSCs). Here, we postulated that GQDs are a promising biocompatible nanomaterial that facilitated the migration and differentiation of PDLSCs, and use laboratory methods like CCK-8, transwell experiments, qRT-PCR, Alizarin red staining and immunofluorescence staining to evaluate. Our experiments confirmed that GQDs did not inhibit cell viability, with most cells remaining viable even at GQDs concentrations of up to 30 µg mL-1. Moreover, GQDs were found to significantly enhance PDLSC migration, with the peak effect observed at concentrations of 5 and 10 µg mL-1. Furthermore, GQDs accelerated osteoblastic differentiation in PDLSCs and induced the mineralization of calcium nodules. Additionally, GQDs were shown to promote fibroblast differentiation in PDLSCs compared to the control group. Thus, GQDs not only possessed low cytotoxicity and good biocompatibility, but also displayed the beneficial capability to migration and differentiation of PDLSCs, which indicated GQDs might be a potential nanomaterial for bone regeneration.

Impact of migration on oral health outcomes of children in multi-beneficial kindergartens in Nanning, Southern China: a cross-sectional study.

OBJECTIVE: To explore the effect of children's migration on their oral health outcomes in multi-beneficial kindergartens in Jiangnan District, Nanning, China, and to provide a basis for improving the oral health of migrant children. METHODS: A cross-sectional study was conducted among 470 children aged 5 years in Jiangnan District, Nanning, Guangxi. A questionnaire was used to collect information on their demographic and socioeconomic background, migration experience, eating habits, oral hygiene behaviours and utilization of dental care services. Dental caries of primary teeth was examined using the decayed, missing, and filled teeth (dmft) index recommended by the World Health Organization. Dental caries experience and oral health-related behaviours were compared between migrant and resident children. The impact of children's migration attributes on their oral health outcomes was examined by univariate and multivariate analyses. RESULTS: Among the examined children, 52.3% were migrant children. The prevalence of caries among the children in multi-beneficial kindergartens was 78.3%, and the mean number of dmft was 5.73 ± 5.00. The prevalence of caries was 81.7% for migrant children and 74.6% for resident children (p = 0.060). No significant difference was found in the mean numbers of DMFT between migrant children and resident children (5.96 ± 4.81 vs. 5.47 ± 5.20, p = 0.139). There were significant differences in the frequency of tooth brushing (p = 0.023) and parental help with tooth brushing (p = 0.008), typical use of fluoride (p = 0.012), regular dental check-ups (p = 0.003) and experience of dental fillings for caries (p < 0.001) between migrant and resident children. The multivariate logistic regression analysis showed that among the children with caries, the proportion of resident children who had regular dental check-ups was 1.720 times higher than that of migrant children (95% CI = 1.155 ~ 2.560), and resident children were more likely to have caries filled than migrant children (OR = 3.313, 95% CI = 1.585 ~ 6.927). CONCLUSION: Oral health status and oral health behaviours were poor among children in multi-beneficial kindergartens in Nanning, China, and migration might be a significant predictive indicator for the poor utilization of dental care services by children. The government departments should make special policy to promote the children's oral health in multi-beneficial kindergartens, and invest more to cover the migrant children's utilization of oral health services.

A multifunctional polymeric coating with self-adsorbed, antifouling and in situ remineralization properties for caries management.

Dental caries is a biofilm-induced bacterial infectious oral disease, where the early attachment of proteins and pathogenic bacteria to tooth surfaces has been known as the main cause of biofilm formation. Typically, dental caries is commonly accompanied by mineral depletion of enamels, thus causing dental demineralization. Multifunctional materials are highly attractive candidates for treating dental caries. Herein, we successfully synthesized diblock copolymers poly(ethylene glycol)-b-poly(aspartic acid) (PEG-PAsp) and modified them with alendronate sodium (ALN) to serve as bioactive bifunctional coatings (PEG-PAsp-ALN) on teeth. The PEG segments are employed for inhibiting proteins and bacterial adhesion. In addition, due to the presence of both PAsp and ALN, a synergistically strong binding capacity could be achieved with the tooth surface, thus promoting rapid and thorough remineralization in situ, while maintaining excellent safety. The combination treatment can significantly suppress the biofilm formation, which is beneficial for alleviating the demineralization of enamels caused by bacteria, and further, facilitate remineralization in situ. This approach thus demonstrates the potential of the copolymer PEG-PAsp-ALN coating as a multifunctional protecting layer on the tooth surface for high-efficiency prevention and treatment of dental caries.

Graphene quantum dots enhance the osteogenic differentiation of PDLSCs in the inflammatory microenvironment.

BACKGROUND AND OBJECTIVE: Graphene quantum dots (GQDs), a type of carbon-based nanomaterial, have remarkable biological, physical, and chemical properties. This study investigated the biological mechanisms of the proliferation and osteogenic differentiation of human periodontal ligament stem cells (PDLSCs) induced by GQDs in an inflammatory microenvironment. MATERIALS AND METHODS: PDLSCs were cultured in osteogenic-induced medium with various concentrations of GQDs in standard medium or medium mimicking a proinflammatory environment. The effects of GQDs on the proliferation and osteogenic differentiation activity of PDLSCs were tested by CCK-8 assay, Alizarin Red S staining, and qRT‒PCR. In addition, Wnt/ß-catenin signalling pathway-related gene expression was measured by qRT‒PCR. RESULTS: Compared with the control group, the mRNA expression levels of ALP, RUNX2, and OCN and the number of mineralized nodules were all increased in PDLSCs after treatment with GQDs. Moreover, during the osteogenic differentiation of PDLSCs, the expression levels of LRP6 and ß-catenin, which are Wnt/ß-catenin signalling pathway-related genes, were upregulated. CONCLUSION: In the inflammatory microenvironment, GQDs might promote the osteogenic differentiation ability of PDLSCs by activating the Wnt/ß-catenin signalling pathway.

The rs35874116 single nucleotide polymorphism increases sweet intake and the risk of severe early childhood caries: a case-control study.

BACKGROUND: Dental caries is one of the most prevalent chronic diseases worldwide among children. The rs35874116 single nucleotide polymorphism (SNP) in the sweet receptor gene TAS1R2 has been associated with dental caries at a high risk in permanent teeth among school children and adults. To date, little is known about the association of this SNP with sweet intake and caries risk in the primary school children. METHODS: Total of 236 children were included, namely 118 subjects in the non-caries (NC) group and severe early childhood caries (S-ECC) group, respectively. Oral mucosa cells were collected from all the selected children, and the full length of exon 3 in TAS1R2 was sequenced to analyse rs35874116 polymorphism. A questionnaire was used to collect information about socio-demographic information, frequency of sweet intake and oral hygiene habits. Multiple logistic regression models were applied to assess the relationship of rs35874116 polymorphism with frequency of sweet intake and S-ECC among the five-year-old children. RESULTS: Children with the TT genotype of rs35874116 had a higher frequency of sweet intake than CT/CC carriers (51.3% vs. 32.7%; x2 = 5.436, p = 0.020), and S-ECC individuals were more likely to be TT genotype carriers than NC individuals (53.5% vs. 46.5%; x2 = 4.353, p = 0.037). Multiple logistic regression analyses showed that the TT genotype of rs35874116 was not only significantly related to the frequency of sweet intake (OR = 2.25, 95% CI = 1.14-4.44) but also significantly associated with S-ECC (OR = 2.11, 95% CI = 1.01 ~ 4.42). CONCLUSIONS: The rs35874116 polymorphism might increase sweet intake and the risk of S-ECC among five-year-old children in Nanning, China.

Keratin-based wound dressings: From waste to wealth.

Keratin is a natural protein with a high content of cysteine residues (7-13%) and is widely found in hair, wool, horns, hooves, and nails. Keratin possesses abundant cell-binding motifs such as leucine-aspartate-valine (LDV), glutamate-aspartate-serine (EDS), and arginine-glycine-aspartate (RGD), which benefit cell attachment and proliferation. It has been confirmed that keratin plays important roles in every stage of wound healing, including hemostasis, inflammation, proliferation, and remodeling, making keratin-based materials good candidates for wound dressings. In combination with synthetic and natural polymers, keratin-based wound dressings in the forms of films, hydrogels, and nanofibers can be achieved with improved mechanical properties. This review focuses on the recent development of keratin-based wound dressings. Firstly, the physicochemical and biological properties of keratin, are systematically discussed. Secondly, the role of keratin in wound healing is proposed. Thirdly, the applications of keratin-based wound dressings are summarized, in terms of the forms and functionalization. Finally, the current challenges and future development of keratin-based wound dressings are presented.

A silk fibroin based bioadhesive with synergistic photothermal-reinforced antibacterial activity.

Bioadhesives have gained considerable popularity for application in wound closure. However, applying bioadhesives incurs risks associated with bacterial infection during wound healing. Hence, in this study, a silk fibroin based bioadhesive was constructed via employing natural macromolecule, silk fibroin (SF), to spontaneously coassemble with natural plant polyphenol, tannic acid (TA), and iron oxide nanoparticles (Fe3O4 NPs). In the system, the natural macromolecule SF plays a key role in fabricating the macromolecular network matrix due to the change of the secondary structure of SF (from random coil to ß-sheet) under the trigger of TA. Importantly, the strong hydrogen bonding interactions between SF and TA, and the coordination bonds between TA and Fe3O4 NPs endow the bioadhesive with high extensibility, self-healing properties, and considerable wet adhesion. Meanwhile, the synergy between the inherent photothermal properties of Fe3O4 NPs and TA/Fe3+ complexes under near-infrared (NIR) radiation enables the bioadhesive superior photothermal-reinforced antibacterial activity. The multifunctional natural macromolecule bioadhesive is a potential candidate in clinical wound management for improved outcomes, especially in infected wounds.

Impact of parental migration on oral health outcomes of left-behind school-aged children in Luchuan, southern China.

BACKGROUND: With rapid urbanization in China, an increasing number of rural adults have migrated to cities to seek job opportunities, leaving their school-aged children behind. These left-behind children (LBC) without one or both parents usually receive less attention from their caregivers. Whether the parental migration affects the children's oral health is not well understood. This study aimed to explore the differences in dental caries status and oral health-related behaviors between children with different parental migration experiences in a rural area of Southern China. METHODS: A cross-sectional study was conducted in Luchuan County of Guangxi Province in 2015. A total of 1085 school children aged 8-12 participated in this study. Participants' demographic characteristics, parental migration information, and eating and oral hygiene habits were collected using a self-administered questionnaire. Dental caries of permanent teeth was examined using the decayed, missing, and filled tooth (DMFT) index recommended by the World Health Organization. Dental caries experience and oral health-related behaviors were compared between LBC and non-LBC, as well as children with different experiences of parental migrations. The impact of various parental migration attributes on LBC oral health outcomes was examined by univariate and multivariate analyses. RESULTS: Among the school-aged children examined, 60.9% of them were LBC. Only 29.7% of the children brushed their teeth regularly; 86.5% of them did not know what fluoride toothpaste was. Caries prevalence was 51.4% for LBC and 40.8% for non-LBC (p < 0.001). The LBC experienced a greater DMFT mean (1.20 ± 1.59) compared to the non-LBC (0.85 ± 1.30) (p < 0.001). Oral health-related behaviors were not significantly different between LBC and non-LBC. Dental caries experience and oral health-related behaviors were not related to the type or duration of parental migration. Multiple regression analyses showed that parental migration was one of significant predictors of children's caries outcome; LBC had a higher risk to caries than non-LBC (95% CI =1.26, 2.09). CONCLUSIONS: These findings indicate that parental migration could be a significant risk factor for caries development among 8- to 12-year-old school children in rural China.

MicroRNA-661 Enhances TRAIL or STS Induced Osteosarcoma Cell Apoptosis by Modulating the Expression of Cytochrome c1.

AIM: Osteosarcoma (OS) is an aggressive bone malignancy that affects rapidly growing bones and is associated with a poor prognosis. Our previous study showed that cytochrome c1 (CYC1), a subunit of the cytochrome bc1 complex (complex III) of the mitochondrial electron chain, is overexpressed in human OS tissues and cell lines and its silencing induces apoptosis in vitro and inhibits tumor growth in vivo. Here, we investigated the mechanism underlying the modulation of CYC1 expression in OS and its role in the resistance of OS to apoptosis. METHODS: qRT-PCR, luciferase reporter assay, western blotting, fow cytometry, and animal experiments were performed in this study. RESULTS: MicroRNA (miR)-661 was identified as a downregulated miRNA in OS tissues and cells and shown to directly target CYC1. Ectopically expressed miR-661 inhibited OS cell growth, promoted apoptosis, and reduced the activity of mitochondrial complex III. miR-661 overexpression enhanced TRAIL or STS induced apoptosis and promoted the release of cytochrome c into the cytosol, which induced caspase-9 activation, and these effects were abolished by a caspase-3 inhibitor. Overexpression of CYC1 rescued the effects of miR-661 on sensitizing OS cells to TRAIL or STS induced apoptosis, indicating that the antitumor effect of miR-661 is mediated by the downregulation of CYC1. In vivo, miR-661 overexpression sensitized tumors to TRAIL or STS induced apoptosis in a xenograft mouse model, and these effects were attenuated by co-expression of CYC1. CONCLUSION: Taken together, our results indicate that miR-661 plays a tumor suppressor role in OS mediated by the downregulation of CYC1, suggesting a potential mechanism underlying cell death resistance in OS.

Genotypic diversity and cariogenicity of Candida albicans from children with early childhood caries and caries-free children.

BACKGROUND: The genotypic diversity and cariogenicity of C. albicans from the dental plaque of children are poorly understood. This study aimed to explore the genotypic diversity and cariogenicity of C. albicans from children with early childhood caries and caries-free children. METHODS: Dental plaque samples from 238 children with early childhood caries and from 125 caries-free children were collected for C. albicans isolation. A PCR method based on 25S rDNA was used to analyze C. albicans genotypes, and the strains with different genotypes were tested with regard to acidogenicity and aciduricity. RESULTS: Among 129 C. albicans isolates, 79 (61.2 %) belonged to genotype A. The distribution frequency of genotypes A and C or genotypes B and C showed no significant difference between children with early childhood caries and caries-free children (p = 0.178 and 0.148), whereas genotypes A and B exhibited significantly different distributions (p = 0.010). No significant differences in aciduricity were found among the three genotypes, but the acidogenicity of genotypes B and C differed significantly from that of genotype A at pH 4.0. CONCLUSIONS: The genotypic distribution of C. albicans is associated with the caries experience of children, and the genotype may be related to its acidogenicity at pH 4.0.