Astaxanthin inhibits inflammation of human periodontal ligament cells induced by lipopolysaccharide. / è™¾é’ç´ æŠ‘åˆ¶è„‚å¤šç³–è¯±å¯¼äººç‰™å‘¨è†œç»†èƒžç‚Žç—‡ååº”.

OBJECTIVES: Human periodontal ligament cells (hPDLCs) are important source of periodontal tissue reconstruction. Under chronic inflammation, the multi-directional differentiation potential and chemotaxis in hPDLCs are decreased. Therefore, inhibiting inflammatory microenvironment and improving the functional characteristics of stem cells can better promote periodontal tissue reconstruction. This study was to investigate the effect of astaxanthin (AST) on lipopolysaccharide (LPS)-induced inflammation in hPDLCs and the underlying mechanisms. METHODS: hPDLCs were isolated and cultured in vitro, and vimentin and keratin immunocytochemical staining were used to identify hPDLCs. CCK-8 assay was used to measure the effects of AST (1, 5, 10, 20, 50, 100, and 200 µmol/L) on proliferation of hPDLCs. Quantitative RT-PCR (RT-qPCR) and ELISA were used to measure the mRNA and protein expression of inflammatory factors (IL-6, IL-1ß, and TNF-α) in the control (Con) group, the LPS group, and the LPS+AST (5, 10, 20, and 50 µmol/L) group. Western blotting was used to detect the protein expression of IKBα, phosphorylated IKBα (p-IKBα), and p65 in the Con group, the LPS group, the AST (20 µmol/L) group, and the LPS+AST (20 µmol/L) group. After 10 µmol/L PDTC treatment, the mRNA and protein expressions of IL-6, IL-1ß, and TNF-α were detected by RT-qPCR and ELISA. RESULTS: Cell morphology and immunocytochemical staining showed that the cells were in line with the characteristics of hPDLCs. Treatment with AST could promote the proliferation of hPDLCs, which reached the peak at 20 µmol/L. The mRNA and protein expressions of IL-6, IL-1ß, and TNF-α in the LPS group were higher than those in the Con group (all P<0.05). Compared with the LPS group, the mRNA and protein expressions of IL-6, IL-1ß, and TNF-α in the LPS+AST (5, 10, 20, and 50 µmol/L) group were down-regulated (all P<0.05). Compared with the Con group, the levels of IKBα and p65 in cytoplasm of the LPS group were significantly downregulated (both P<0.05), and the levels of p-IKBα in cytoplasm and p65 in nucleus of the LPS group were significantly up-regulated (both P<0.05). Compared with the LPS group, the levels of IKBα and p65 in cytoplasm of the LPS+AST (20 µmol/L) group were significantly upregulated (both P<0.05), and the levels of p-IKBα in cytoplasm and p65 in nucleus of the LPS+AST (20 µmol/L) group were significantly downregulated (both P<0.05). The mRNA and protein expressions of IL-6, IL-1ß, and TNF-α in the LPS+PDTC (10 µmol/L) group were lower than those in the LPS group (all P<0.05). CONCLUSIONS: AST promotes the proliferation of hPDLCs, which is related to suppression of LPS-induced the secretion of inflammatory factors via inhibiting the activation of NF-κB signaling pathway.

Prevalence of malocclusion in Chinese schoolchildren from 1991 to 2018: A systematic review and meta-analysis.

BACKGROUND: Malocclusion is a common oral health problem in schoolchildren. Literature describing the prevalence of malocclusion varies substantially across China. AIM: This study identified the epidemiological characteristics of malocclusion among Chinese schoolchildren from 1991 to 2018. DESIGN: Six English and Chinese electronic databases were searched through November 2018. The search was supplemented by hand searching to identify relevant surveys. The overall prevalence of malocclusion was estimated by a random-effects meta-analysis model, and variations in different groups were assessed by subgroup meta-analysis. RESULTS: Thirty-seven eligible articles describing 117 682 samples were investigated. The pooled national prevalence for malocclusion was 47.92% (95% CI: 58.6%-71.9%). For the Angle classification, the overall prevalence rates were 30.07% (95% CI: 25.37%-35.48%), 9.91% (95% CI: 7.41%-13.79%), and 4.76% (95% CI: 3.85%-6.54%) for Class I, Class II, and Class III malocclusion, respectively. A deep overbite (16.67%, 95% CI: 11.50%-23.08%) was shown to be the most common trait of malocclusion. When stratified by sex, males had a slightly higher prevalence than females (RR = 1.04, 95% CI: 1.01-1.06). More importantly, an ascending trend and substantial variations across the country were observed. CONCLUSIONS: Our results confirmed that malocclusion has become a serious oral health problem in Chinese schoolchildren, highlighting the need for proactive interventions at an early age. Moreover, high-quality epidemiological studies on malocclusion are still required.

Effectiveness of orthodontic temporary anchorage devices in canine retraction and anchorage preservation during the two-step technique: a systematic review and meta-analysis.

BACKGROUND: Temporary anchorage devices have been used for decades in orthodontic practice for many applications. The aim of this systematic review was to assess the effectiveness of orthodontic temporary anchorage devices in canine retraction during the two-step technique. METHODS: A search was systematically performed for articles published prior to June 30, 2019 in five electronic databases (PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, Scopus). The risk of bias was assessed using the Cochrane risk of bias tool for randomized controlled trials (RCTs) and the risk of bias in nonrandomized studies of interventions (ROBINS-I) tool for controlled clinical trials (CCTs). The Grading of Recommendation, Assessment, Development and Evaluation (GRADE) approach was used for the quality assessment. Data concerning the mean difference in mesial molar movement and extent of canine retraction were extracted for statistical analysis. The mean differences and 95% confidence intervals were analyzed for continuous data. A meta-analysis with a random-effects model for comparable outcomes was carried out. RESULTS: Three RCTs and five CCTs were finally included. Meta-analysis showed a significant increase not only in anchorage preservation in the implant anchorage group in both the maxilla (1.56 mm, 95% CI: 1.14 to 1.98, P < 0.00001) and the mandible (1.62 mm, 95% CI: 1.24 to 2.01, P < 0.00001) but also in canine retraction in the implant anchorage group in both the maxilla (0.43 mm, 95% CI: 0.16 to 0.69, P = 0.001) and the mandible (0.26 mm, 95% CI: 0.02 to 0.49, P = 0.03). CONCLUSIONS: There is very low-quality evidence showing that implant anchorage is more efficient than conventional anchorage during canine retraction. Additional high-quality studies are needed.

Prevalence of temporomandibular disorders and its clinical signs in Chinese students, 1979-2017: A systematic review and meta-analysis.

OBJECTIVE: This study intends to assess the prevalence of temporomandibular disorders and its clinical signs in Chinese students. MATERIALS AND METHODS: Search strategies were performed in seven electronic databases, and the reference lists from potentially relevant studies were searched manually. Only observational studies that met the eligibility criteria were selected. A validated instrument was used to evaluate the quality of the included studies. A random-effects model was used to calculate the pooled prevalence of temporomandibular disorders and its clinical signs. RESULTS: Twenty-three articles that met the eligibility criteria were included in this review and meta-analysis. The prevalence of temporomandibular disorders was 29.1% (95% confidence interval [CI], 23.7-35.1; n = 12,702), and a significant difference was observed between males and females. The most prevalent sign was temporomandibular joint sounds (17.4%; 95% CI, 13.8-20.6; n = 6,615) followed by abnormal jaw movement (12.3%; 95% CI, 9.1-16.7; n = 5,496) and pain (9.9%; 95% CI, 7.4-13; n = 4,552). CONCLUSIONS: The overall prevalence of temporomandibular disorders in Chinese students was approximately 29.1%, and a statistically significant difference was observed between males and females. The most prevalent sign was temporomandibular joint sounds (17.4%), followed by abnormal jaw movement (12.3%) and pain (9.9%).