METTL3-Mediated m6A Modification Regulates the Osteogenic Differentiation through LncRNA CUTALP in Periodontal Mesenchymal Stem Cells of Periodontitis Patients.

Objective: Periodontitis is a chronic inflammatory disease that causes loss of periodontal support tissue. Our objective was to investigate the mechanism by which METTL3-mediated N6-methyladenosine modification regulates the osteogenic differentiation through lncRNA in periodontal mesenchymal stem cells in patients with periodontitis (pPDLSCs). Material and Methods. We carried out a series of experiments, including methylated RNA immunoprecipitation-PCR, quantitative real-time polymerase chain reaction, and western blotting. The expressions of alkaline phosphatase (ALP), Runx2, Col1, Runx2 protein level, ALP staining, and Alizarin red staining were used to demonstrate the degree of osteogenic differentiation. Results: We found that METTL3 was the most significantly differentially expressed methylation-related enzyme in pPDLSCs and promoted osteogenic differentiation of pPDLSCs. METTL3 regulated the stability and expression of lncRNA CUTALP, while lncRNA CUTALP promoted osteogenic differentiation of pPDLSCs by inhibiting miR-30b-3p. At different time points of osteogenic differentiation, lncRNA CUTALP expression was positively correlated with Runx2, while miR-30b-3p showed the opposite pattern. The attenuated osteogenic differentiation induced by METTL3 knockdown was recovered by lncRNA CUTALP overexpression. The attenuated osteogenic differentiation induced by lncRNA CUTALP knockdown could be reversed by the miR-30b-3p inhibitor. Conclusions: In summary, METTL3/lncRNA CUTALP/miR-30b-3p/Runx2 is a regulatory network in the osteogenic differentiation of pPDLSCs.

Correlation between salivary cytokine profiles and white spot lesions in adolescent patients receiving clear aligner orthodontic treatment.

BACKGROUND: To explore the relationship between changes in salivary cytokine levels and the occurrence of white spot lesions in adolescents receiving clear aligner orthodontic treatment and investigate the predictive value of various factors for lesion occurrence. METHODS: We retrospectively analyzed sixthy eight adolescent in the permanent dentition period, who received clear aligner orthodontics in our hospital were randomly divided into two groups according to the occurrence or aggravation of white spot lesions after treatment. The general condition of the oral cavity was analyzed, saliva was collected, and inflammation-related cytokines with varying transcription levels between groups were screened by transcriptome analysis. The expression levels of inflammatory cytokines in the saliva of the patients in the two groups were measured, and the risk factors for white spot lesions were screened by correlation analysis and binary logistic regression analysis. The value of the independent and combined application of risk factors for predicting the occurrence of white spot lesions in adolescent patients after invisible orthodontic treatment was analyzed by receiver operating characteristic (ROC) curve analysis. RESULTS: Transcriptome and GO and KEGG pathway analyses showed that there were differences in the transcription levels of inflammatory cytokines such as CXCL1, CXCL2, CXCL8, CCL3, CCL4, IL-1ß and IL-2 between groups. The levels of CXCL8, CCL3, CCL4, IL-1ß and IL-2 in the saliva of patients with white spot lesions were significantly higher in patients after invisible orthodontic treatment (P < 0.05). Correlation analysis and binary logistic regression analysis showed that elevated levels of CXCL8, IL-1ß and IL-2 were independent risk factors for the occurrence of white spot lesions (P < 0.05). CXCL8 had the highest independent predictive value for the occurrence of white spot lesions (AUC = 0.773, P < 0.05), and the combination of IL-1ß and IL-2 was also of high value in predicting the occurrence of white spot lesions. CONCLUSION: After invisible orthodontic treatment, the oral microenvironment, including inflammatory cytokine levels, in adolescent patients changes; in particular, the levels of inflammatory cytokines such as CXCLs and ILs change. CXCL8 expression is significantly associated with the occurrence of white spot lesions and is an important potential target for the prevention and treatment of white spot lesions in the future.

Effective contribution ratio of the molar during sequential distalization using clear aligners and micro-implant anchorage: a finite element study.

INTRODUCTION: This study aims to investigate the biomechanical effects of anchorage reinforcement using clear aligners (CAs) with microimplants during molar distalization. And also explores potential clinical strategies for enhancing anchorage in the sequential distalization process. METHODS: Finite element models were established to simulate the CAs, microimplants, upper dentition, periodontal ligament (PDL), and alveolar bone. In group set I, the 2nd molars underwent a distal movement of 0.25 mm in group set II, the 1st molars were distalized by 0.25 mm after the 2nd molars had been placed to a target position. Each group set consisted of three models: Model A served as the control model, Model B simulated the use of microimplants attached to the aligner through precision cuts, and Model C simulated the use of microimplants attached by buttons. Models B and C were subjected to a series of traction forces. We analyzed the effective contribution ratios of molar distalization, PDL hydrostatic stress, and von Mises stress of alveolar bone. RESULTS: The distalization of the 2nd molars accounted for a mere 52.86% of the 0.25-mm step distance without any reinforcement of anchorage. The remaining percentage was attributed to the mesial movement of anchorage teeth and other undesired movements. Models B and C exhibited an increased effective contribution ratio of molar distalization and a decreased loss of anchorage. However, there was a slight increase in the undesired movement of molar tipping and rotation. In group set II, the 2nd molar displayed a phenomenon of mesial relapse due to the reciprocal force produced by the 1st molar distalization. Moreover, the efficacy of molar distalization in terms of contribution ratio was found to be positively correlated with the magnitude of force applied. In cases where stronger anchorage reinforcement is required, precision cuts is the superior method. CONCLUSIONS: The utilization of microimplants in conjunction with CAs can facilitate the effective contribution ratio of molar distalization. However, it is important to note that complete elimination of anchorage loss is not achievable. To mitigate undesired movement, careful planning of anchorage preparation and overcorrection is recommended.

Actual contribution ratio of maxillary and mandibular molars for total molar relationship correction during maxillary molar sequential distalization using clear aligners with Class II elastics: A finite element analysis.

INTRODUCTION: Class II elastics, in combination with clear aligners (CA), are efficient for molar distalization. However, the effects of this combination on intermaxillary molar relationship correction have yet to be investigated. This study aimed to investigate the actual contribution ratio of the maxillary and mandibular molars for total molar relationship correction during maxillary molar distalization using Class II elastics with CA and further explore therapeutic recommendations for clinical practice. METHODS: Finite element models (FEMs) were established, including the distalization of the second molars (Set I), followed by the distalization of the first molars (Set II). Model A simulated elastics attached by precision cutting, whereas Model B simulated elastics attached to buttons. Force magnitudes of 100 g, 150 g, and 200 g of force were applied. We recorded the contribution ratio of the maxillary and mandibular molars for total molar relationship correction, effective distalizing distance in 0.25 mm step distance, tipping and rotation angles, and the hydrostatic stress in the periodontal ligament. RESULTS: During maxillary molar distalization, mesialization of the mandibular molar had a notable contribution ratio for molar relationship correction. The mandibular first molar was mesialized with mesiolingual rotation tendency. Approximately half of the 0.25 mm step distance was occupied by maxillary molar distalization; the remainder was occupied by anchorage teeth mesialization and tipping or rotation. When traction forces increased, the total molar relationship correction and effective distalization increased; the mandibular molars mesialization contribution ratio also increased, as did rotation and inclination tendency. Precision cutting had a higher total molar relationship correction and more effective distalization than a button but also had a larger contribution ratio of mandibular molar mesialization and inclination or rotation. CONCLUSIONS: Mandibular molar mesialization should be considered when correcting the molar relationship using CA with intermaxillary elastics during maxillary molar distalization. It is also important to consider the anchorage teeth mesialization and undesired tipping or rotation.

Comparison of interleukin expression in gingival crevicular fluid between patients with invisible orthodontics treat-ment and fixed orthodontics treatment.

OBJECTIVES: To compare the expression levels of interleukin (IL)-1ß, IL-6, IL-8, IL-10, IL-16, and IL-18 in gingival crevicular fluid between patients with invisible orthodontics treatment and fixed orthodontics treatment. METHODS: A total of 67 patients with invisible orthodontic treatment were selected as the observation group, and 40 patients with fixed orthodontic treatment were selected as the control group. The expression levels of IL-1ß, IL-6, IL-8, IL-10, IL-16, and IL-18 in gingival crevicular fluid before, 24 h, and 12 months after orthodontic treatment were detected. RESULTS: No significant difference in basic characteristics and interleukin expression levels in gingival crevicular fluid was observed between the two groups before orthodontic treatment (P>0.05). After 24 h of orthodontic treatment, the expression levels of IL-1ß, IL-6, IL-8, IL-10, and IL-18 in gingival crevicular fluid increased in both groups; however, no significant difference was observed between the two groups (P>0.05). After 12 months of orthodontic treatment, the expression levels of IL-1ß, IL-6, IL-8, IL-10, and IL-18 in gingival crevicular fluid in the observation group were significantly lower than those in the control group (P<0.05), and no significant difference in the expression level of IL-16 was observed between the two groups (P>0.05). CONCLUSIONS: Compared with patients with fixed orthodontics treatment, those with invisible orthodontics treatment had weaker oral inflammatory response, which was conducive to the recovery of the oral microenvironment.