A study on related factors affecting dental fear in preschool children.

This study aims to examine the manifestations of dental anxiety (DA) and its influencing factors during dental visits among preschool children. The data of 166 preschool children who visited the Department of Dentistry of our hospital from April 2021 to April 2023 with oral problems were retrieved. Their DA performance was investigated using the Children's Fear Survey Schedule-Dental Subscale (CFSS-DS). In addition, based on their general data and potential risk factor information, we performed logistic regression analysis to identify the factors influencing DA. Of the 166 questionnaires distributed, a total of 160 valid questionnaires were retrieved. The average CFSS-DS score was 35.57 ± 3.51 points. Sixty-six children had DA, resulting in an incidence rate of 41.25%. The top 5 items with the highest CFSS-DS scores were fear of needles, dentists, tooth extraction, drilling and oral anesthesia. When the 66 children with DA were classified into a DA group and a non-DA group, we observed significant differences in age distribution, dental experience, only child status, general anxiety symptoms, dental condition, family income and specific dental treatment procedures, particularly tooth extraction, between them (p < 0.05). Multivariate logistic regression analysis revealed that preschool children aged ≤4 years, those with prior dental experiences, single-child status, general anxiety symptoms, suboptimal dental health, family incomes below 100,000 yuan/year, and those undergoing specific dental procedures, such as tooth extractions, were independently associated with a higher risk of DA (p < 0.05). The incidence of DA in preschool children is high, and they exhibit substantial fear of needles, dentists, tooth extraction, drilling and oral anesthesia. Preschool children aged ≤4 years, with prior dental experiences, single-child status, the presence of general anxiety symptoms, suboptimal dental health, family incomes below 100,000 yuan/year, and those undergoing dental procedures, particularly tooth extraction, could be more predisposed to DA.

Metal-organic framework materials promote neural differentiation of dental pulp stem cells in spinal cord injury.

Spinal cord injury (SCI) is accompanied by loss of Zn2+, which is an important cause of glutamate excitotoxicity and death of local neurons as well as transplanted stem cells. Dental pulp stem cells (DPSCs) have the potential for neural differentiation and play an immunomodulatory role in the microenvironment, making them an ideal cell source for the repair of central nerve injury, including SCI. The zeolitic imidazolate framework 8 (ZIF-8) is usually used as a drug and gene delivery carrier, which can release Zn2+ sustainedly in acidic environment. However, the roles of ZIF-8 on neural differentiation of DPSCs and the effect of combined treatment on SCI have not been explored. ZIF-8-introduced DPSCs were loaded into gelatin methacryloyl (GelMA) hydrogel and in situ injected into the injured site of SCI rats. Under the effect of ZIF-8, axon number and axon length of DPSCs-differentiated neuro-like cells were significantly increased. In addition, ZIF-8 protected transplanted DPSCs from apoptosis in the damaged microenvironment. ZIF-8 promotes neural differentiation and angiogenesis of DPSCs by activating the Mitogen-activated protein kinase (MAPK) signaling pathway, which is a promising transport nanomaterial for nerve repair.

The optimal activation of plastic aligner for canine distal movement: a three-dimensional finite element analysis.

This study aimed to investigate the optimal activation of plastic aligner for the canine distal movement by combining the stress and strain of periodontal ligament. Computer-aided design models of the upper canine, periodontal ligament, alveolar bone, and plastic aligner were constructed. The stresses and strains of periodontal ligament were acquired by fitting plastic aligner on the canine, which will cause the canine distal-direction movement. The activation of plastic aligner was set into 12 groups, including 0.050, 0.100, 0.125, 0.150, 0.175, 0.200, 0.225, 0.250, 0.275, 0.300, 0.350, and 0.400 mm. Assuming the volume-averaged hydrostatic stress (VAHS) ranging from 4.7 to 16 kPa to be the optimal stress, and an average strain no less than 0.3 to be the optimal strain. The optimal activation of plastic aligner was acquired based on the optimal stress and average strain. As the activation increased, the stress and strain of periodontal ligament increased visibly. The degree of activation of plastic aligner was nonlinearly and positively related to VAHS and average strain. According to the fitted curves, the activation corresponding to the optimal stress was 0.07-0.24 mm and the activation was not less than 0.21 mm based on the optimal strain. The optimal activation of plastic aligner for the canine distal movement was 0.21-0.24 mm in this study. The degree of activation affects the force system of orthodontic tooth movement, and it should be taken into consideration to obtain healthy and efficient tooth movement. The activation with 0.21-0.24 mm seems optimal for orthodontic tooth movement in the plastic aligner system in this study.

Local Spinal Cord Injury Treatment Using a Dental Pulp Stem Cell Encapsulated H2S Releasing Multifunctional Injectable Hydrogel.

Spinal cord injury (SCI) commonly induces nerve damage and nerve cell degeneration. In this work, a novel dental pulp stem cells (DPSCs) encapsulated thermoresponsive injectable hydrogel with sustained hydrogen sulfide (H2S) delivery is demonstrated for SCI repair. For controlled and sustained H2S gas therapy, a clinically tested H2S donor (JK) loaded octysilane functionalized mesoporous silica nanoparticles (OMSNs) are incorporated into the thermosensitive hydrogel made from Pluronic F127 (PF-127). The JK-loaded functionalized MSNs (OMSF@JK) promote preferential M2-like polarization of macrophages and neuronal differentiation of DPSCs in vitro. OMSF@JK incorporated PF-127 injectable hydrogel (PF-OMSF@JK) has a soft consistency similar to that of the human spinal cord and thus, shows a high cytocompatibility with DPSCs. The cross-sectional micromorphology of the hydrogel shows a continuous porous structure. Last, the PF-OMSF@JK composite hydrogel considerably improves the in vivo SCI regeneration in Sprague-Dawley rats through a reduction in inflammation and neuronal differentiation of the incorporated stem cells as confirmed using western blotting and immunohistochemistry. The highly encouraging in vivo results prove that this novel design on hydrogel is a promising therapy for SCI regeneration with the potential for clinical translation.

Photosensitive Hydrogels Encapsulating DPSCs and AgNPs for Dental Pulp Regeneration.

OBJECTIVE: Pulp regeneration with bioactive dentin-pulp complex has been a research hotspot in recent years. Stem cell therapy provided an interest strategy to regenerate the dental-pulp complex. Hence, this study aimed to evaluate the effects of photosensitive gelatin methacrylate (GelMA) hydrogel encapsulating dental pulp stem cells (DPSCs) and silver nanoparticles (AgNPs) for dental pulp regeneration in vitro. METHODS: First, the AgNPs@GelMA hydrogels were prepared by lithium phenyl-2,4,6-trimethyl-benzoyl phosphinate (LAP) initiation via blue-light emitting diode light. The physical and chemical properties of AgNPs@GelMA hydrogels were comprehensively analysed via scanning electron microscopy (SEM), and mechanical characterisation, such as swelling ability, degradation properties, and AgNP release profile. Then, AgNPs@GelMA hydrogels encapsulated DPSCs were used to establish an AgNPs@GelMA biomimetic complex, further analysing its biocompatibility, antibacterial properties, and angiogenic capacity in vitro. RESULTS: The results indicated that GelMA hydrogels demontrated optimal characteristics with a monomer:LAP ratio of 16:1. The physico-chemical properties of AgNPs@GelMA hydrogels did not change significantly after loading with AgNPs. There was no significant difference in AgNP release rate amongst different concentrations of AgNPs@GelMA hydrogels. Fifty to 200 µg/mL AgNPs@GelMA hydrogels could disperse E faecalis biofilm and reduce its metabolic activity . Furthermore, cell proliferation was arrested in 100 and 200 µg/mL AgNPs@GelMA hydrogels. The inhibition of 50 µg/mL AgNPs@GelMA hydrogels on E faecalis biofilm was above 50%, and the cell viability of the hydrogels was higher than 90%. The angiogenesis assay indicated that AgNPs@GelMA hydrogels encapsulating DPSCs could induce the formation of capillary-like structures and express angiogenic markers CD31, vascular endothelial growth factor , and von willebrand factor (vWF) in vitro. CONCLUSIONS: Results of this study indicate that 50 µg/mL AgNPs@GelMA hydrogels encapsulating DPSCs had significant antibacterial properties and angiogenic capacity, which could provide a significant experimental basis for the regeneration of the dentin-pulp complex.

Orthodontic treatment with clear aligners for a patient with chronic periodontitis.

This case report describes the treatment of an adult female patient with a history of periodontal disease, Class I malocclusion with extrusion, dental spaces, and pathologic tooth migration. The patient was treated with clear aligners, which effectively controlled the strength and direction of orthodontic forces after 3 months of systematic periodontal treatment. The Peer Assessment Rating (PAR) index was calculated from study models before and after treatment. The pretreatment PAR score was 24, and the posttreatment PAR score was 4. The PAR score for this patient changed by 83%. Satisfactory appearance and good function were achieved for this patient.

Influence of Fluoride-Resistant Streptococcus mutans Within Antagonistic Dual-Species Biofilms Under Fluoride In Vitro.

The widespread application of fluoride, an extremely effective caries prevention agent, induces the generation of fluoride-resistant strains of opportunistic cariogenic bacteria such as fluoride-resistant Streptococcus mutans (S. mutans). However, the influence of this fluoride-resistant strain on oral microecological homeostasis under fluoride remains unknown. In this study, an antagonistic dual-species biofilm model composed of S. mutans and Streptococcus sanguinis (S. sanguinis) was used to investigate the influence of fluoride-resistant S. mutans on dual-species biofilm formation and pre-formed biofilms under fluoride to further elucidate whether fluoride-resistant strains would influence the anti-caries effect of fluoride from the point of biofilm control. The ratio of bacteria within dual-species biofilms was investigated using quantitative real-time PCR and fluorescence in situ hybridization. Cristal violet staining, scanning electron microscopy imaging, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay were used to evaluate biofilm biomass, biofilm structure, and metabolic activity, respectively. Biofilm acidogenicity was determined using lactic acid and pH measurements. The anthrone method and exopolysaccharide (EPS) staining were used to study the EPS production of biofilms. We found that, in biofilm formation, fluoride-resistant S. mutans occupied an overwhelming advantage in dual-species biofilms under fluoride, thus showing more biofilm biomass, more robust biofilm structure, and stronger metabolic activity (except for 0.275 g/L sodium fluoride [NaF]), EPS production, and acidogenicity within dual-species biofilms. However, in pre-formed biofilms, the advantage of fluoride-resistant S. mutans could not be fully highlighted for biofilm formation. Therefore, fluoride-resistant S. mutans could influence the anti-caries effect of fluoride on antagonistic dual-species biofilm formation while being heavily discounted in pre-formed biofilms from the perspective of biofilm control.

Effect of puerarin on osteogenic differentiation of human periodontal ligament stem cells.

OBJECTIVE: To investigate the effects of the flavonoid, puerarin, on osteogenic differentiation of human periodontal ligament stem cells (PDLSCs). METHODS: Human PDLSCs were isolated from patients undergoing orthodontic treatment, and the cell surface markers CD146, CD34, CD45, and STRO-1 were identified by immunofluorescence. Cell proliferation was detected by MTT assay; alkaline phosphatase (ALP) activity was measured, and calcium deposition was detected by alizarin red staining. PCR was then used to detect the distributions of COL-I, OPN, Runx2, and OCN, genes related to osteogenic differentiation. RESULTS: Staining was positive for cytokines CD146, CD34, CD45, and STRO-1 in the experimental group; staining was also positive for silk protein, but negative for keratin. After 7 days of culture, exposure to puerarin significantly promoted the level of intracellular ALP; increased puerarin concentration led to increased intracellular ALP. Red mineralized nodules appeared upon exposure to puerarin and the number of nodules was concentration-dependent. PCR analysis revealed that COL-I, OPN, Runx2, and OCN expression levels increased as puerarin concentration increased. CONCLUSIONS: Exposure to puerarin can promote proliferation and ALP activity in human PDLSCs, thus promoting both molecular and osteogenic differentiation; these findings may provide a theoretical basis for the clinical treatment of periodontal disease with puerarin.

Expression of Dickkopf-related Protein 1 in Patients with Temporomandibular Osteoarthritis after Treatment with Hyaluronic Acid.

We previously reported that the increased expression of Dickkopf-related protein 1 (DKK1) is positively related to vascular endothelial growth factor in the synovial fluid from patients with temporomandibular joint disorders (TMDs). DKK1 is involved in angiogenic activities in the TMD synovium in vitro, but the expression of DKK1 after treatment of TMD-osteoarthritis (TMD-OA) with hyaluronic acid (HA) remains unknown. In this study, we assessed the expression of DKK1 in the synovial fluid of TMD-OA patients before and after treatment with HA via enzyme-linked immunosorbent assay. We also investigated the role of DKK1 in TMD-OA via immunohistochemical staining. The relationship between the expression of DKK1 and the clinicopathological characteristics was determined by Pearson analysis. The results showed that the expression of DKK1 was significantly decreased after treatment with HA. Correlation analyses indicated that the expression of DKK1 in the TMD-OA samples was closely correlated with mouth opening and pain. These findings suggest that DKK1 could play an important role in the pathogenesis and treatment of TMD. Reduction of the pain by HA treatment may be correlated with the decreased expression of DKK1.

Knockdown RPL29 Gene Can Inhibit the Proliferation, Invasion of Squamous Cell Carcinomas.

OBJECTIVE: Gingival squamous cell carcinoma (GSCC) is one of the most common malignancies. Endogenous ribosomal protein L29 (RPL29) has been previously proven to be up-regulated in cancer tissues. However, RPL29 expression in GSCC has not been described. METHODS: The knockdown of RPL29 gene in GSCC cells was carried out to study the influence of RPL29 silencing on GSCC cells. RESULTS: We investigated the influence on cell proliferation, invasion, and related biomarkers, which led us to confirm that all were repressed by the knockdown of RPL29. CONCLUSION: The role of RPL29 should lead to a better understanding of the development and progression of human GSCC.