Masticatory muscle thickness provides objective measurements of the oral motor function, which may change in patients with oral myofascial pain. In this study, we aimed to establish a reliable ultrasound (US) protocol for imaging the superficial and deep masticatory muscles and to identify the potential influencers of the measurements. Forty-eight healthy participants without orofacial pain were enrolled. The intra-and inter-rater reliabilities of US measurements for masseter, temporalis, and lateral pterygoid muscles were assessed. Intraclass correlation coefficients for all muscles were greater than 0.6. The generalised estimating equation was used to analyse the impact of age, gender, laterality, and body mass index on the measurements, whereby age and body mass index were likely to be associated with an increase in masticatory muscle thickness. The thickness tended to be lesser in females. Laterality seemed to exert minimal influence on masticatory muscle thickness. Our study shows acceptable reliability of US in the evaluation of superficial and deep masticatory muscle thickness. Future studies are warranted to validate the usefulness of US imaging in patients with oral myofascial pain syndrome. Temporomandibular disorder (TMD) is frequently observed in patients seeking dental treatment. It comprises various findings concerning the stomatognathic system, involving the temporomandibular joints, masticatory muscles, teeth, and ears 1,2. The prevalence of TMDs in the general population ranges from 34.9 to 42.4% across different studies 3,4 , and the incidence is more prevalent in females 5. Of note, oral myofascial pain is commonplace in about 10-15% of patients with TMD 6. The aetiology of oral myofascial pain is still controversial. The proposed mechanisms include overuse of the masticatory muscles and a decrease in its pain threshold following central sensitization 7. While overuse might lead to hypertrophy of the masticatory muscles in the early stages, persistent pain could result in disuse atrophy in chronic cases 8. In this sense, masticatory muscle thickness provides objective measurements of the oral motor function 9 , which is supposed to change in patients suffering from oral myofascial pain. Several imaging modalities, such as computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US) have been used to image the masticatory muscles. CT allows precise delineation of the skull bone where the masticatory muscles attach. However, radiation and poor resolution of the soft tissues make it unsuitable for muscle thickness measurements. Nowadays, MRI serves as the gold standard for depicting soft tissue pathologies 10 , but it is limited by its high cost and contraindications in patients with metal implants. US has various advantages over CT and MRI, i.e. real-time evaluation, zero radiation, cost-effectiveness, portability, and ease of dynamic examination 11. Further, it is capable of delineating muscle fibres-making it highly effective for imaging muscle trauma and neuromuscular diseas...

Objective. To assess the effects of epigallocatechin-3-gallate (EGCG) on oncostatin M (OSM)-induced CCL2 synthesis and the associated signaling pathways in human osteoblastic cells. The therapeutic effect of EGCG on collagen-induced arthritis (CIA) in rats was also studied.Methods. CCL2 and c-Fos messenger RNA expression was analyzed by Northern blotting. The modulating effects of EGCG on the activation of Raf-1, Akt, and phosphatidylinositol 3-kinase (PI 3-kinase) were examined by coimmunoprecipitation, Western blotting, and PI 3-kinase activity assay. Interactions between c-Fos and CCL2 promoter were evaluated by electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay. The effect of EGCG on CIA in rats was examined clinically and immunohistochemically.Results Conclusion. By stimulating PI 3-kinase activity, EGCG promoted Akt/Raf-1 crosstalk, resulting in decreased AP-1 binding to CCL2 promoter, and finally reduced CCL2 production in osteoblasts. EGCG alleviated the severity of CIA, probably by suppressing CCL2 synthesis in osteoblasts to diminish macrophage infiltration. Our data support the therapeutic potential of EGCG on arthritis.

Butyric acid as a histone deacetylase (HDAC) inhibitor is produced by a number of periodontal and root canal microorganisms (such as Porphyromonas, Fusobacterium, etc.). Butyric acid may affect the biological activities of periodontal/periapical cells such as osteoblasts, periodontal ligament cells, etc., and thus affect periodontal/periapical tissue destruction and healing. The purposes of this study were to study the toxic effects of butyrate on the matrix and mineralization marker expression in MG-63 osteoblasts. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Cellular apoptosis and necrosis were analyzed by propidium iodide/annexin V flow cytometry. The protein and mRNA expression of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) were analyzed by Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR). OPG, soluble RANKL (sRANKL), 8-isoprostane, pro-collagen I, matrix metalloproteinase-2 (MMP-2), osteonectin (SPARC), osteocalcin and osteopontin (OPN) secretion into culture medium were measured by enzyme-linked immunosorbant assay. Alkaline phosphatase (ALP) activity was checked by ALP staining. Histone H3 acetylation levels were evaluated by immunofluorescent staining (IF) and Western blot. We found that butyrate activated the histone H3 acetylation of MG-63 cells. Exposure of MG-63 cells to butyrate partly decreased cell viability with no marked increase in apoptosis and necrosis. Twenty-four hours of exposure to butyrate stimulated RANKL protein expression, whereas it inhibited OPG protein expression. Butyrate also inhibited the secretion of OPG in MG-63 cells, whereas the sRANKL level was below the detection limit. However, 3 days of exposure to butyrate (1 to 8 mM) or other HDAC inhibitors such as phenylbutyrate, valproic acid and trichostatin stimulated OPG secretion. Butyrate stimulated 8-isoprostane, MMP-2 and OPN secretion, but not procollagen I, or osteocalcin in MG-63 cells. Exposure to butyrate (2–4 mM) for 3 days markedly stimulated osteonectin secretion and ALP activity. In conclusion, higher concentrations of butyric acid generated by periodontal and root canal microorganisms may potentially induce bone destruction and impair bone repair by the alteration of OPG/RANKL expression/secretion, 8-isoprostane, MMP-2 and OPN secretion, and affect cell viability. However, lower concentrations of butyrate (1–4 mM) may stimulate ALP, osteonectin and OPG. These effects are possibly related to increased histone acetylation. These events are important in the pathogenesis and repair of periodontal and periapical destruction.

Few studies have explored the feasibility of shear-wave ultrasound elastography (SWUE) for evaluating the upper airways of patients with obstructive sleep apnea (OSA). This study aimed to establish a reliable SWUE protocol for evaluating tongue muscle elasticity and its feasibility and utility in differentiating patients with OSA. Inter-rater and intra-rater reliability of SWUE measurements were tested using the intraclass correlation coefficients. Submental ultrasound was used to measure tongue thickness and stiffness. Association between the ultrasound measurements and presence of OSA was analyzed using multivariate logistic regression. One-way analysis of variance was used to examine if the values of the ultrasound parameters varied among patients with different severities of OSA. Overall, 37 healthy subjects and 32 patients with OSA were recruited. The intraclass correlation coefficients of intra‐ and inter-rater reliability for SWUE for tongue stiffness ranged from 0.84 to 0.90. After adjusting for age, sex, neck circumference, and body mass index, the risk for OSA was positively associated with tongue thickness [odds ratio 1.16 (95% confidence interval 1.01–1.32)] and negatively associated with coronal imaging of tongue muscle stiffness [odds ratio 0.72 (95% confidence interval 0.54–0.95)]. There were no significant differences in tongue stiffness among OSA patients with varying disease severity. SWUE provided a reliable evaluation of tongue muscle stiffness, which appeared to be softer in patients with OSA. Future longitudinal studies are necessary to investigate the relationship between tongue softening and OSA, as well as response to treatment.

Objective Cone‐beam computed tomography (CBCT) offers three‐dimensional structures in assessing upper airway of patients. This study aims to compare the cone‐beam computerized tomography scan measurements between children with obstructive sleep apnea (OSA) and primary snoring. Study Design Case–control study. Methods This prospective study was conducted in a tertiary referral center. Thirty‐six children with moderate‐to‐severe OSA (with apnea‐hypopnea index [AHI] > 5 events/hour) and 36 age‐, gender‐, and obesity‐matched children with primary snoring (AHI <1) were enrolled. The measurements in CBCT parameters were compared between children with moderate‐to‐severe OSA and primary snorers by conditional logistic regression model. Results A total of 72 children (mean age, 7.9 ± 2.8 years; 64% male) were included. Children with moderate‐to‐severe OSA had a significantly smaller nasopharyngeal (2900 ± 1400 vs. 3800 ± 1800 mm3, P = .017) and oropharyngeal airway volume (5600 ± 2700 vs. 7400 ± 4000 mm3, P = .026) than those with primary snoring. Children with moderate‐to‐severe OSA, as compared to primary snorers, also had a significantly smaller minimal airway area in nasopharynx (77.4 ± 37.7 vs. 107.7 ± 52.0 mm2, P = .006) and oropharynx (66.6 ± 61.9 vs. 101.6 ± 65.8 mm2, P = .023). Moreover, the airway length was not significantly different between children with moderate‐to‐severe OSA and primary snoring. Conclusions The three‐dimensional CBCT airway analysis could be used as a useful tool to evaluate upper airway in children with OSA. Level of Evidence 3 Laryngoscope, 131:680–685, 2021