Preparation and performance evaluation of a novel orthodontic adhesive incorporating composite dimethylaminohexadecyl methacrylate-Polycaprolactone fibers

This study addressed enamel demineralization, a common complication in fixed orthodontic treatment, by evaluating a novel orthodontic adhesive with DMAHDM-PCL composite fibers. These fibers, produced through electrospinning, were incorporated into orthodontic adhesive to create experimental formulations at different concentrations and a control group. The study assessed antimicrobial properties, biosafety, and mechanical characteristics. New orthodontic adhesive exhibited significant bacteriostatic effects, reducing bacterial biofilm activity and concentrations. Incorporating 1% and 3% DMAHDM-PCL did not affect cytocompatibility. Animal tests confirmed no inflammatory irritation. Shear bond strength and adhesive residual index results indicated that antimicrobial fibers didn't impact bonding ability. In conclusion, orthodontic adhesives with 3% DMAHDM-PCL fibers are potential antimicrobial bonding materials, offering a comprehensive solution to enamel demineralization in orthodontic patients.

Comparison of mandibular buccal shelf morphology between adolescents and adults with different vertical patterns using CBCT

OBJECTIVE

This retrospective study aimed to analyze the anatomical structure of the mandibular buccal shelf (MBS) in adolescents and adults with different vertical patterns to determine the optimal location for miniscrew insertion in orthodontic treatment.

METHODS

Cone-beam computed tomography (CBCT) scans of 230 patients were utilized for measurements. The morphology and thickness of alveolar bone at the MBS were measured. Two-way ANOVA and regression analysis were conducted to analyze the influencing factors on alveolar bone and cortical bone thickness.

RESULTS

Age had a significant effect on alveolar bone thickness (level I: F = 62.449, level II: F = 18.86, p < 0.001), cortical bone thickness (level II: F = 18.86, p < 0.001), alveolar bone tilt (F = 6.267, p = 0.013), and second molar tilt (F = 6.693, p = 0.01). Different vertical patterns also influenced alveolar bone thickness (level I: F = 20.950, level II: F = 28.470, p < 0.001), cortical bone thickness (level I: F = 23.911, level II: F = 23.370, p < 0.001), and alveolar bone tilt (F = 27.046, p < 0.001). As age increased, the alveolar bone thickness at level I decreased by 0.096 mm and at level II decreased by 0.073 mm. Conversely, the thickness of alveolar bone at level I and level II increased by 0.06 mm and 0.075 mm, respectively. The cortical bone thickness at level I and level II increased by 0.024 mm and 0.29 mm, respectively. However, the alveolar bone thickness decreased by 0.931 mm and 1.545 mm at level I and level II, and the cortical bone thickness decreased by 0.542 mm and 0.640 mm at level I and level II, respectively.

CONCLUSION

Age, different vertical patterns, alveolar bone inclination, and different shapes of MBS significantly affected the thickness of alveolar bone and cortical bone in the MBS area. Notably, only alveolar bone thickness and cortical bone thickness at level II were affected by age and different vertical patterns simultaneously. These findings can provide valuable insights for orthodontic practitioners in selecting the most suitable location for miniscrew insertion during treatment planning.

Iron level participates in the pathological damages of dental caries in infant rats by affecting enamel mineralization

Iron deficiency anemia (IDA) is a common nutritional disease associated with early childhood caries. This study aimed to explore the role of iron levels in pathological changes of dental caries in childhood. Rats were divided into four groups based on their iron content: IDA, positive control (PC), high iron (HI), and negative control (NC). Except for the rats in the NC group, rats in the other groups were inoculated with Streptococcus mutans and fed cariogenic high-sugar fodder to induce caries. Three months later, the caries status of the molars was evaluated at both the smooth and sulcal surfaces according to Keyes scores. Scanning electron microscopy (SEM) was performed to reveal microstructural changes in caries. Energy-dispersive spectroscopy (EDS) was used to determine the elemental composition of the enamel and dentin. In addition, the histopathology of the salivary gland was detected using hematoxylin and eosin (HE) staining.The results showed that rats in the PC group exhibited obvious carious lesions. The carious score was significantly higher in the IDA group than in the PC group but was lower in the HI group. SEM revealed complete destruction of the enamel and damage to the middle dentin in the IDA group. In contrast, the molars in the HI group exhibited some degree of enamel demineralization, but the underlying dentin was almost intact. In addition, the elemental compositions of the enamel and dentin were similar among the four groups, and iron was detected only in the HI group. No differences were observed in the morphological structures of the salivary glands of rats from the different groups. In conclusion, ID enhanced the pathological damage of caries, whereas HI weakened it. Iron may participate in the pathological damage caused by childhood caries by affecting enamel mineralization.

Effect of psoralen on the regulation of osteogenic differentiation induced by periodontal stem cell-derived exosomes

Periodontitis is a chronic inflammatory disease that is the main cause of tooth loss in adults, and the key to periodontitis treatment is the repair and regenerate of periodontal bone tissue. Psoralen is the main component of the Psoralea corylifolia Linn, which shows antibacterial, anti-inflammatoryand osteogenic activities. It promotes the differentiation of periodontal ligament stem cells toward osteogenesis. Exosomes secreted by stem cells play important roles in information transmission during the osteogenic differentiation process. The aim of this paper was to investigate the role of psoralen in regulating osteogenic miRNA information in periodontal stem cells and in periodontal stem cells exosomes and the specific mechanism of its action. Experimental results show that exosomes of human periodontal ligament stem cell origin treated with psoralen (hPDLSCs + Pso-Exos) were not significantly different from untreated exosomes (hPDLSC-Exos) in terms of size and morphology. Thirty-five differentially expressed miRNAs were found to be upregulated and 58 differentially expressed miRNAs were found to be downregulated in the hPDLSCs + Pso-Exos compared to the hPDLSC-Exos (P < 0.05). hsa-miR-125b-5p was associated with osteogenic differentiation. Among them, hsa-miR-125b-5p was associated with osteogenic differentiation. After hsa-miR-125b-5p was inhibited, the osteogenesis level of hPDLSCs was enhanced. In summary, the osteogenic differentiation of hPDLSCs was promoted by psoralen through the downregulation of hsa-miR-125b-5p gene expression in hPDLSCs, and the expression of the hsa-miR-125b-5p gene was also downregulated in exosomes. This finding provides a new therapeutic idea for using psoralen to promote periodontal tissue regeneration.

Osteogenesis promotion by injectable methacryloylated gelatin containing psoralen and its bacteriostatic properties

The treatment of periodontitis focuses on controlling the progression of inflammation, reducing plaque accumulation, and promoting bone tissue reconstruction. Among them, the reconstruction of irregular bone resorption caused by periodontitis is a long-standing challenge. At present, the local drug treatment of periodontitis is mainly anti-inflammatory and antibacterial drugs. In this study, psoralen (Pso), a Chinese herbal medicine with anti-inflammatory, antibacterial, and osteogenic effects, was selected for the local treatment of periodontitis. Meanwhile, an injectable methacrylate gelatin (GelMA) platform loading with Pso was constructed. Pso-GelMA had the properties of fluidity, light cohesion, self-healing, and slow release, which could be better used in the deep and narrow structure of the periodontal pocket, and greatly increased the effectiveness of local drug delivery. The pore size of Gelma hydrogel did not change after loading Pso by SEM. In vitro, Pso-GelMA effectively upregulated the expression of osteogenic genes and proteins, increased alkaline phosphatase activity, promoted the mineralisation of rat bone marrow mesenchymal stem cells (BMSCs) extracellular matrix, and had significant antibacterial effects on Staphylococcus aureus and Fusobacterium nucleatum. Therefore, Pso-GelMA has immense promise in the adjuvant treatment of periodontitis.