Clinical effects of maxillary protraction in different stages of dentition in skeletal class III children: A systematic review and meta-analysis.

OBJECTIVES: This systematic review and meta-analysis aimed to evaluate the effectiveness of using maxillary protraction during different stages of the dentition by assessing changes in the jaws and inclination of incisors. MATERIALS AND METHODS: MEDLINE (PubMed), Embase, Cochrane, Web Of Science, China National Knowledge Infrastructure and Wanfang Databases were searched without time limitations up to 15 January 2022. Google Scholar was used to search grey literature. We included cohort studies that compared the effect of maxillary protraction by analysing primary outcomes and were grouped in age-related conditions. Mean differences and 95% confidence intervals were used for statistical analysis, followed by Grading of Recommendations Assessment, Development and Evaluation analysis. RESULTS: Six studies were finally included. The heterogeneity test showed P ≥ .1 and I2  ≤ 50%, and a fixed-effect model was applied. Patients in the early treatment group (ETG) were mainly in the early-mixed dentition stage, while patients in the late treatment group (LTG) were in the late-mixed and early-permanent dentition stage. Meta-analysis showed that there were no statistical differences (P > .05) between the ETG and LTG groups in terms of SNA (the angle composed by point Sella-Nasion-Subspinale), SNB (the angle composed by point Sella-Nasion-Supramentale), ANB (the angle composed by point Subspinale-Nasion-Supramentale), Wits, U1/SN (the angle composed by the axis of upper incisors and Sella-Nasion plane) and L1/MP (the angle composed by the axis of lower incisors and the mandibular plane). CONCLUSION: Our analysis showed that maxillary protraction applied in the late-mixed or early-permanent dentition stage did not cause different effects on the maxillary growth, the correction of the intermaxillary relationship, the inhibition of mandibular growth and dental tipping of skeletal class III patients when compared to that in the early-mixed dentition stage. Collectively, these data provide a theoretical basis for widening the applicable age period of maxillary protraction and choosing the best treatment opportunity for children patients after a comprehensive assessment.

Clinical effectiveness of different types of bone-anchored maxillary protraction devices for skeletal Class III malocclusion: Systematic review and network meta-analysis.

Objective: This study aimed to estimate the clinical effects of different types of bone-anchored maxillary protraction devices by using a network meta-analysis. Methods: We searched seven databases for randomized and controlled clinical trials that compared bone-anchored maxillary protraction with tooth-anchored maxillary protraction interventions or untreated groups up to May 2021. After literature selection, data extraction, and quality assessment, we calculated the mean differences, 95% confidence intervals, and surface under the cumulative ranking scores of eleven indicators. Statistical analysis was performed using R statistical software with the GeMTC package based on the Bayesian framework. Results: Six interventions and 667 patients were involved in 18 studies. In comparison with the tooth-anchored groups, the bone-anchored groups showed significantly more increases in Sella-Nasion-Subspinale (°), Subspinale-Nasion-Supramentale(°) and significantly fewer increases in mandibular plane angle and the labial proclination angle of upper incisors. In comparison with the control group, Sella-Nasion-Supramentale(°) decreased without any statistical significance in all treated groups. IMPA (angle of lower incisors and mandibular plane) decreased in groups with facemasks and increased in other groups. Conclusions: Bone-anchored maxillary protraction can promote greater maxillary forward movement and correct the Class III intermaxillary relationship better, in addition to showing less clockwise rotation of mandible and labial proclination of upper incisors. However, strengthening anchorage could not inhibit mandibular growth better and the lingual inclination of lower incisors caused by the treatment is related to the use of a facemask.

Distinct adverse outcomes and lipid profiles of erythrocytes upon single and combined exposure to cadmium and microplastics.

The growing accumulation of environmental microplastics (MPs) has become a global concern. MPs are capable to interact with other environmental contaminants leading to altered toxicity. Red blood cells (RBCs), are the target with highest priority for most of toxic xenobiotics after entering blood stream. Whether co-existence of MPs changes the toxicity of cadmium, a typical hemolysis inducer, in RBCs is unknown. We investigated the adverse effects of CdCl2 and Polystyrene-MPs (PS-MPs) on RBCs in mice. We found that CdCl2 induced mild microcytic hypochromic anemia while PS-MPs induced polycythemia vera, indicating distinct outcomes between them. Moreover, co-treatment of PS-MPs with CdCl2 did not change the phenotype of microcytic hypochromic anemia, indicating an antagonistic relationship between CdCl2 and PS-MPs. However, the lipid profiles were also distinct between single exposure and combined exposure to CdCl2 and PS-MPs. The significant changed lipids were mainly involved in altering the physiochemical or biological properties of RBCs, including decreased membrane components, disrupted bilayer thickness and intrinsic lipid curvature. These results indicated impaired membrane functions of RBCs. The altered lipid profiles observed in the current study may represent new and previously unrecognized harmful characteristics of cadmium and MPs on erythrocytes at low dose without apparent induction of anemia.

Enhanced hepatic cytotoxicity of chemically transformed polystyrene microplastics by simulated gastric fluid.

Microplastics pollution has emerged as one of the top-ranked global environmental issues, receiving worldwide attention in recent years. However, knowledge about the detrimental effects of microplastics on human health is still limited. In real-world settings, the physicochemical characteristics of microplastics were modified by environmental and biological transformation, largely changing their ultimate toxicity. Nonetheless, the toxicity change related to transformation of microplastics has not been considered in most published studies thus far. In the current study, we investigated the cytotoxicity of transformed polystyrene microplastics in hepatocytes. Our results revealed that 500 nm polystyrene microplastics, which were chemically transformed by simulated gastricfluid, exacerbated their adverse effects on SMMC-7721 cells at 20 µg/mL for 24 h treatment, including morphological alteration, membrane damage and increased cell apoptosis via oxidative stress. This exacerbated cytotoxicity could be at least partially explained by the degradation, changed surface charge and altered surface chemistry of these polystyrene microplastics after transformation. In conclusion, our study demonstrates that the hepatic cytotoxicity of polystyrene microplastics is enhanced after transformation.