Low-intensity pulsed ultrasound in the treatment of masticatory myositis and temporomandibular joint synovitis: A clinical trial.

BACKGROUND: Low-intensity pulsed ultrasound (LIPUS) is a non-invasive physical stimulation application for the therapy of articular cartilage injury. This study aimed to explore the therapeutic effects of low-intensity pulsed ultrasound in treating masticatory myositis and synovitis in temporomandibular joint disorders and to establish an evaluation system to evaluate the clinical efficacy. METHODS: TMD patients who met the inclusion criteria in the temporomandibular joint clinic of the affiliated Stomatological Hospital of Chongqing Medical University from April 3, 2021, to December 2021 were selected. Before the start and after 7 days of LIPUS treatment, the Fricton temporomandibular joint disorder index, Visual Analog Scale (VAS), and Pressure Difference of Precision Manometer (PD) were measured. A paired t-test was used to compare the values of the Fricton index, VAS, and PD before and after treatment in each group. One-way ANOVA analysis of variance was used to compare the differences between groups. RESULTS: After one week of LIPUS treatment, the PI, DI and CMI of the Fricton index in the masticatory myositis (PI: P < 0.001; CMI: P < 0.001; DI: P = 0.2641, ns) and the synovitis group (DI: P < 0.001; CMI: P < 0.001, PI: P = 0.9729, ns) significantly decreased. The VAS of the masticatory myositis group and the synovitis group were significantly reduced (P < 0.001). The PD between the affected and healthy sides of the masticatory myositis group and the synovitis group was significantly reduced (P < 0.001), and the reduction was more evident in the M group. CONCLUSIONS: LIPUS is effective in pain relief in patients with masticatory myositis and joint synovitis, meanwhile, masticatory myositis was more sensitive to LIPUS. A new comprehensive clinical efficacy evaluation system which includes PV, FI, and VAS was created to better 2 diagnose masticatory myositis and joint synovitis.

CT data analysis of temporomandibular joint morphology in patients with Open-mouth breathing.

OBJECTIVE: This study aims to investigate the correlation between open-mouth breathing and temporomandibular joint morphology by examining CT data in patients. METHODS: From January to December 2022, 31 patients with open-mouth breathing and 20 with normal breathing were chosen from those attending the Stomatological Hospital of Chongqing Medical University. We compared condylar measurements among normal breathers (NB), pre-operative open-mouth breathers (Pre-OB), and post-operative open-mouth breathers (Post-OB) to identify statistically significant differences. RESULTS: Upon comparing the measurement parameters of the NB with the Pre-OB, we found significant statistical differences in the bilateral condylar height, depth of the articular fossa, anterior joint space, and the anterior inclined plane length of the condyle (p < 0.05).Further examination of the Pre-OB, when considering duration of open-mouth breathing, revealed pronounced differences in the condylar mediolateral diameter, fossa depth, anterior joint space, condylar height, and the condyle's horizontal angle (p < 0.05).Regarding the A/N ratio, it showed no significant correlation with the preoperative oral breathing group. Lastly, compared with Pre-OB, Post-OB highlighted a distinct statistical increase in the anterior slope length of the condyle (p < 0.05). CONCLUSION: A discernible correlation between open-mouth breathing and condylar morphology exists. Continuous open-mouth breathing contributes to adaptive changes in the condylar morphology. Although limited post-operative data suggests that halting open-mouth breathing doesn't immediately result in condylar modifications, a relationship between the two phenomena remains evident.

Biomechanical effects of joint disc perforation on the temporomandibular joint: a 3D finite element study.

BACKGROUND: Disc perforation (DP) is a severe type of Temporomandibular Disorder (TMD). DP may induce changes in the internal stresses of the temporomandibular joint (TMJ). Herein, this study attempts to investigate the biomechanical effects of different positions and sizes of DP on the TMJ using a biomechanical approach, to explore the mechanical pathogenesis of TMD. METHODS: Eleven three-dimensional finite element (FE)models of the TMJ were constructed based on CBCT imaging files of a patient with DP on the left side. These models included the disc with anterior displacement and discs with different locations and sizes of perforations on the affected disc. FE methods were conducted on these models. RESULTS: Anterior displacement of the disc leads to a significant increase in the maxim von Mises stress (MVMS) in both TMJs, with the affected side exhibiting a more pronounced effect. DP occurring at the posterior band and the junction between the disc and the bilaminar region has a greater impact on the MVMS of both TMJs compared to perforations at other locations. As the size of the perforation increases, both sides of the TMJs exhibit an increase in the magnitude of MVMS. CONCLUSIONS: Unilateral disc anterior displacement results in an increased stress on both TMJs. Unilateral DP further affects the stress on both sides of the TMJs. TMD is a progressive condition, and timely intervention is necessary in the early stages to prevent the worsening of the condition.

Self-Healable and Reprocessable Polysulfide Sealants Prepared from Liquid Polysulfide Oligomer and Epoxy Resin.

Polysulfide sealants have been commercially applied in many industrial fields. In this article, we study the self-healing property of the epoxy resin-cured polysulfide sealants for the first time. The obtained sealants showed a flexible range of ultimate elongation of 157-478% and a tensile strength of 1.02-0.75 MPa corresponding to different polysulfide oligomers. By taking advantage of the dynamic reversible exchange of disulfide bonds, polysulfide sealants exhibited good self-healing ability under a moderate thermal stimulus. A higher molecular weight and a lower degree of cross-linking of polysulfide oligomer were helpful in improving the ultimate elongation and healing efficiency of the polysulfide sealants. After subjecting to a temperature of 75 °C for 60 min, both the tensile strength and ultimate elongation of a fully cut sample, LP55-F, were restored to 91% of the original values, without affecting the sealing property. Furthermore, the sample exhibited excellent reshaping and reprocessing abilities. These outcomes offer a paradigm toward sustainable industrial applications of the polysulfide-based sealants.