Distraction osteogenesis promotes temporomandibular joint self-remodeling in the treatment of mandibular deviation caused by condylar ankylosis.

Craniofacial deformity and malocclusion are primary concerns following temporomandibular joint ankylosis (TMJa) in growing patients, and they pose even greater challenges in adult patients. The treatment objectives always involve restoring proper jawbone structure, achieving stable occlusion, and attaining satisfactory joint mobility. This report presents a 4-year follow-up of an adult patient with TMJa-induced mandibular deviation, who underwent a combined treatment approach involving distraction osteogenesis (DO) and orthodontic-orthognathic surgery. Orthodontic treatment resulted in favorable occlusion and improved facial esthetics. A new condyle with a reconstructed glenoid fossa in a forward position was established after mandibular DO and the damaged TMJ experienced self-remodeling owing to functional improvement. Thus, this case demonstrates the efficacy of DO in promoting adaptive TMJ self-remodeling with long-term stability when treating mandibular deviation caused by condylar ankylosis in adult patients.

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.

COL4A2 in the tissue-specific extracellular matrix plays important role on osteogenic differentiation of periodontal ligament stem cells.

Periodontal ligament stem cells (PDLSCs) can repair alveolar bone defects in periodontitis in a microenvironment context-dependent manner. This study aimed to determine whether different extracellular matrices (ECMs) exert diverse effects on osteogenic differentiation of PDLSCs and accurately control alveolar bone defect repair. Methods: The characteristics of PDLSCs and bone marrow mesenchymal stem cells (BMSCs) with respect to surface markers and multi-differentiation ability were determined. Then, we prepared periodontal ligament cells (PDLCs)-derived and bone marrow cells (BMCs)-derived ECMs (P-ECM and B-ECM) and the related decellularized ECMs (dECMs). Transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), and protein mass spectrometry were used to distinguish the ECMs. The expression of Type IV collagen A2 (COL4A2) in the ECMs was inhibited by siRNA or activated by lentiviral transduction of relevant cells. The stemness, proliferation, and differentiation of PDLSCs were determined in vitro in different dECMs. For the in vivo analysis, different dECMs under the regulation of COL4A2 mixed with PDLSCs and Bio-Oss bone powder were subcutaneously implanted into immunocompromised mice or in defects in rat alveolar bone. The repair effects were identified by histological or immunohistochemical staining and micro-CT. Results: B-dECM exhibited more compact fibers than P-dECM, as revealed by TEM, SEM, and AFM. Protein mass spectrometry showed that COL4A2 was significantly increased in B-dECM compared with P-dECM. PDLSCs displayed stronger proliferation, stemness, and osteogenic differentiation ability when cultured on B-dECM than P-dECM. Interestingly, B-dECM enhanced the osteogenic differentiation of PDLSCs to a greater extent than P-dECM both in vitro and in vivo, whereas downregulation of COL4A2 in B-dECM showed the opposite results. Furthermore, the classical Wnt/ß-catenin pathway was found to play an important role in the negative regulation of osteogenesis through COL4A2, confirmed by experiments with the Wnt inhibitor DKK-1 and the Wnt activator Wnt3a. Conclusion: These findings indicate that COL4A2 in the ECM promotes osteogenic differentiation of PDLSCs through negative regulation of the Wnt/ß-catenin pathway, which can be used as a potential therapeutic strategy to repair bone defects.

Evaluation of BMMSCs-EPCs sheets for repairing alveolar bone defects in ovariectomized rats.

The aim of this paper is to investigate the effect that bone marrow mesenchymal stem cells (BMMSCs) - endothelial progenitor cells (EPCs), BMMSCs and EPCs sheets have on repairing maxillary alveolar defects in ovariectomized (OVX) rats. In this study, after identification using multi-lineage differentiation and flow cytometry, BMMSCs and EPCs were isolated from female rats. The BMMSCs-EPCs, BMMSCs and EPCs sheets were detected by hematoxylin-eosin (H&E) staining, alkaline phosphatase (ALP) staining and qRT-PCR. Defects were created in maxillary alveoli and repaired with BMMSCs-EPCs, BMMSCs and EPCs sheets in OVX rats. The repair effects were determined by histological staining and micro-CT analysis at 2, 4 and 8 weeks after implantation. We aim to clarify whether BMMSCs-EPCs sheets are more effective in repairing alveolar bone defects than are BMMSCs and EPCs sheets in OVX rats. The results show that the osteogenic potential and the effect of bone repair are greater in the BMMSCs-EPCs sheet group and that this group has a higher ability to repair alveolar bone defects in OVX rats. These results suggest that BMMSCs-EPCs sheets have potential in clinical applications for treating humans with osteoporosis.