Background: Magnetic resonance imaging (MRI) findings of temporomandibular joint (TMJ) in temporomandibular disorder (TMD) patients of different ages are still unclear. The aim of this study was to analyze and compare the characteristics of MRI features of TMJs in different age groups. Methods: A total of 1760 TMJs from 880 patients were included in the study and divided into three groups: ≤ 18Y (n = 195, 14.89 ± 2.35Y); 19-30Y (n = 475, 24.09 ± 3.23Y); and > 30Y (n = 210, 41.73 ± 10.45Y). T2-weighted image (T2WI) of MRI was obtained to evaluate the relationship between age and disc morphology, the degree of disc displacement, joint effusion, joint movement and changes of condylar bone morphology. Data were analyzed by Pearson Chi square test and Spearman correlation coefficient. Results: There was no statistical difference between left and right sides in all age groups. Except condylar morphology (χ2 = 0.943, P = 0.624), there were significant differences in the distribution of disc morphology, disc position, joint effusion and joint motion among different age groups (χ2 = 24.450, χ2 = 24.829, χ2 = 19.855, χ2 = 39.259, respectively). There were significant differences in the distribution of the degree of anterior disc displacement, condyle morphology and joint effusion in different types of disc morphology among the different age groups (except for joint effusion in > 30Y), among which the first two were significantly correlated with the disc morphology. Conclusions: The morphology and position of the articular disc changed significantly with age, but the proportion of abnormal condylar bone remained about 50%. The greater the degree of disc folding, the more prone to bone abnormalities. Trial registration This study was retrospectively registered on 28/03/2022 and endorsed by the Ethics committee (LCYJ2022014).

Human umbilical cord mesenchymal stem cells (hUC-MSCs) are a promising alternative source of mesenchymal stem cells (MSCs) that are enormously attractive for clinical use. This study was designed to investigate the effect of recombinant human bone morphogenetic protein-7 (rhBMP-7) and/or osteogenic media (OMD) on bone regeneration of hUC-MSCs seeded on nanohydroxyapatite/collagen/poly(l-lactide) (nHAC/PLA) in a rabbit model. The characteristics of stem cells were analyzed by plastic adherence, cell phenotype, and multilineage differentiation potential. Cell proliferation was examined using cell counting kit-8 assay. Osteogenic differentiation was evaluated by quantitative Ca²⁺ concentration, PO₄³⁻ concentration, alkaline phosphatase (ALP) activity, osteocalcin (OCN) secretion, and mineralized matrix formation. Bone regeneration was investigated in jaw bone defect repair in rabbit by microcomputed tomography, fluorescent labeling, and hematoxylin and eosin staining. Except for initial stress response, OMD and OMD + rhBMP-7 inhibited the proliferation of hUC-MSCs seeded on nHAC/PLA; rhBMP-7 inhibited cell proliferation in the nonlogarithmic phase and attenuated the inhibitory effect of OMD on cell proliferation. The inhibitory effects of OMD, rhBMP-7, and OMD + rhBMP-7 on cell proliferation were ranked as OMD > OMD + rhBMP-7 > rhBMP-7. OMD, rhBMP-7, and OMD + rhBMP-7 promoted Ca²⁺ concentration, PO₄³⁻ concentration, ALP activity, OCN secretion, and mineralized matrix formation of hUC-MSCs seeded on nHAC/PLA. The promoting effects of OMD, rhBMP-7, and OMD+rhBMP-7 on Ca²⁺ concentration, PO₄³⁻ concentration, ALP activity, OCN secretion, and mineralized matrix formation were ranked as rhBMP-7 > OMD > OMD + rhBMP-7, OMD > OMD + rhBMP-7 > rhBMP-7, OMD > rhBMP-7 > OMD + rhBMP-7, rhBMP-7 > OMD + rhBMP-7 > OMD, and OMD > rhBMP-7 > OMD + rhBMP-7, respectively. In rabbit jaw bone defect repair, OMD, rhBMP-7, and OMD + rhBMP-7 enhanced bone regeneration of hUC-MSCs seeded on nHAC/PLA, but the largest bone mineral apposition rate and bone formation were presented in cultures with rhBMP-7. These findings suggested that the combined use of rhBMP-7 and OMD may have no ideal synergistic effect on bone regeneration of hUC-MSCs seeded on nHAC/PLA in rabbit jaw bone defect.

Background:Joint click is a typical symptom for TMD and can be treated by anterior repositioning splint (ARS) therapy. However, the effect of treatment in different age groups has not been evaluated. To analysis of the effectiveness of ARS therapy in the management of TMJ click in different age groups based on the results of clinical and CBCT examination.Methods:Patients with TMJ click admitted to TMJ Diagnosis and Treatment Center in 2021 were included in this study. They divided into 2 groups according to ages: ≤22Y and >22Y. Clinical features included click severity, symptom duration and CBCT imaging characteristics (condylar position and condylar ratio) were analyzed.Results:169 patients with 338TMJs were studied in this study. The mean age of paitents was 18.78±2.8 in the ≤22Y group (78 patients) and 30.53±10.6 in the >22Y group (91 patients). Sex distribution, CSV, ratio of CSV=1, ratio of CSV=2, symptom duration showed no statistical differences between the two groups. Before ARS treatment, there was no significant difference in AJS, PJS and condylar ratio, but the proportion of posteriorly positioned condyle in ≤22Y group (72, 46.2%) was significantly smaller than that in the >22Y group (100, 54.9%). After ARS treatment, there was no statistically significant difference in AJS, PJS, condylar ratio and condylar position, but the change of condylar ratio in ≤22Y group (0.03±0.10) was significantly higher than that in >22Y group (-0.02±0.11). The positive results (39.7%) in ≤22Y group were greater than >22Y group (17.9%). The time required for CSV=0 in ≤22Y group (2.03±1.14) was significantly shorter than that in >22Y group (2.66±1.41). In the first and second months of follow-up, the ratio for CSV=0 (46.1%, 65.8%) in ≤22Y group was significantly higher than that in >22Y group (22.5%, 50.0%).Conclusions:ARS is more effective in joint clicking treatment in the group ≤22Y. Although AJS, PJS, condylar ratio and condylar position did not change significantly after ARS treatment, the rate of positive results in condylar position was higher in the ≤22Y group.Trial registration:This study was retrospectively registered On 28/03/2022 and endorsed by the Ethics committee (LCYJ2022014).