New Generation of Orthodontic Elastomeric Ligature to Prevent Enamel Demineralization In Vivo.

This study aimed to synthesize a novel elastomeric ligature with dimethylaminohexadecyl methacrylate (DMAHDM) grafted, providing a new strategy for improving the issue of enamel demineralization during fixed orthodontics. DMAHDM was incorporated into elastomeric ligatures at different mass fractions using ultraviolet photochemical grafting. The antibacterial properties were evaluated and the optimal DMAHDM amount was determined based on cytotoxicity assays. Moreover, tests were conducted to evaluate the in vivo changes in the mechanical properties of the elastomeric ligatures. To assess the actual in vivo effectiveness in preventing enamel demineralization, a rat demineralization model was established, with analyses focusing on changes in surface microstructure, elemental composition, and nanomechanical properties. Elastomeric ligatures with 2% DMAHDM showed excellent biocompatibility and the best antibacterial properties, reducing lactic acid production by 65.3% and biofilm bacteria by 50.0% within 24 h, without significant mechanical property differences from the control group (p > 0.05). Most importantly, they effectively prevented enamel demineralization in vivo, enhancing elastic modulus by 73.2% and hardness by 204.8%. Elastomeric ligatures incorporating DMAHDM have shown great potential for application in preventing enamel demineralization, providing a new strategy to solve this issue during fixed orthodontics.

Risk prediction model of impacted supernumerary tooth-associated root resorption in children based on cone-beam computed tomography analysis: a case control study.

BACKGROUND: External surface resorption is pressure-induced resorption and occurs on the external surface of the root, pressure exerted by impacted teeth, is common causes of external surface resorption. Predictive risk factors of impacted supernumerary tooth-associated root resorption (ISTARR) mentioned in this article include supernumerary teeth and patient factors. To investigate the risk factors of impacted supernumerary tooth-associated root resorption and predict the incidence of root resorption. METHODS: This restrospective study enrolled 324 patients with impacted supernumerary tooth. All Cone-Beam Computed Tomography (CBCT) data and patient information were divided into two groups (without tooth root resorption and with root resorption). CBCT images and patient information (age and gender) of 133 patients had adjacent tooth root resorption and 191 did not. seven variables were analysed using binary logistic regression. RESULTS: Individual analysis of potential risk factors showed that age, crown mesiodistal direction, root formation, and odontotheca of the impacted supernumerary tooth were associated significantly with ISTARR. Binary logistic regression showed that impacted supernumerary tooth with odontotheca (Odd Ratio = 2.926), the crown is in the middle (Odd Ratio = 1.446), located at the middle third of the adjacent tooth root (Odd Ratio = 1.614), complete root development (Odd Ratio = 1.334), and patient's age (Odd Ratio = 1.261) were significantly associated with ISTARR risk. CONCLUSIONS: The risk factors of root resorption can be detected and predicted early according to the features of supernumerary tooth and patient's age. Still, more prospective studies with larger sample size are needed to validate the result.

Effects of interleukin-10 treated macrophages on bone marrow mesenchymal stem cells via signal transducer and activator of transcription 3 pathway.

BACKGROUND: Alveolar bone defects caused by inflammation are an urgent issue in oral implant surgery that must be solved. Regulating the various phenotypes of macrophages to enhance the inflammatory environment can significantly affect the progression of diseases and tissue engineering repair process. AIM: To assess the influence of interleukin-10 (IL-10) on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) following their interaction with macrophages in an inflammatory environment. METHODS: IL-10 modulates the differentiation of peritoneal macrophages in Wistar rats in an inflammatory environment. In this study, we investigated its impact on the proliferation, migration, and osteogenesis of BMSCs. The expression levels of signal transducer and activator of transcription 3 (STAT3) and its activated form, phosphorylated-STAT3, were examined in IL-10-stimulated macrophages. Subsequently, a specific STAT3 signaling inhibitor was used to impede STAT3 signal activation to further investigate the role of STAT3 signaling. RESULTS: IL-10-stimulated macrophages underwent polarization to the M2 type through substitution, and these M2 macrophages actively facilitated the osteogenic differentiation of BMSCs. Mechanistically, STAT3 signaling plays a crucial role in the process by which IL-10 influences macrophages. Specifically, IL-10 stimulated the activation of the STAT3 signaling pathway and reduced the macrophage inflammatory response, as evidenced by its diminished impact on the osteogenic differentiation of BMSCs. CONCLUSION: Stimulating macrophages with IL-10 proved effective in improving the inflammatory environment and promoting the osteogenic differentiation of BMSCs. The IL-10/STAT3 signaling pathway has emerged as a key regulator in the macrophage-mediated control of BMSCs' osteogenic differentiation.

Novel antibacterial orthodontic elastomeric ligature with oral biofilm-regulatory ability to prevent enamel demineralization.

OBJECTIVES: To synthesize a novel antibacterial orthodontic elastomeric ligature incorporating dimethylaminohexadecyl methacrylate (DMAHDM) for the first time to prevent enamel demineralization during orthodontic therapy. METHODS: Various mass fractions of DMAHDM (ranging from 0 % to 20 %) were grafted onto commercial elastomeric ligatures using an ultraviolet photochemical grafting method and were characterized. The optimal DMAHDM concentration was determined based on biocompatibility and mechanical properties, and the antibacterial efficacy was evaluated in a whole-plaque biofilm model. TaqMan real-time polymerase chain reaction and fluorescence in situ hybridization were used to assess the microbial regulatory ability of the multispecies biofilms. Furthermore, an in vitro tooth demineralization model was established to explore its preventive effects on enamel demineralization. Statistical analysis involved a one-way analysis of variance and LSD post hoc tests at a significance level of 0.05. RESULTS: The elastomeric ligature containing 2 % mass fraction of DMAHDM exhibited excellent mechanical properties, favorable biocompatibility, and the most effective antibacterial ability against microorganisms, which decreased by almost two logarithms (P < 0.05). It significantly reduced the proportion of Streptococcus mutans in the multispecies plaque biofilm by 25 % at 72 h, leading to an enhanced biofilm microenvironment. Moreover, the novel elastomeric ligature demonstrated an obvious preventive effect on enamel demineralization, with an elastic modulus 30 % higher and hardness 62 % higher than those of the control group within 3 months (P < 0.05). SIGNIFICANCE: The integration of DMAHDM with an elastomeric ligature holds significant promise for regulating biofilms and preventing enamel demineralization in orthodontic applications.