No abstract

BackgroundMyopia is one of the major public health problems worldwide. However, the exact pathogenesis of myopia remains unclear. This study proposes using voxel-based morphometry (VBM) to investigate potential morphological alterations in gray matter volume (GMV) in form-deprivation myopia (FDM) rats.MethodsA total of 14 rats with FDM (FDM group) and 15 normal controls (NC group) underwent high-resolution magnetic resonance imaging (MRI). Original T2 brain images were analyzed using VBM method to identify group differences in GMV. Following MRI examination, all rats were perfused with formalin, and immunohistochemical analysis of NeuN and c-fos levels was performed on the visual cortex.ResultsIn the FDM group, compared to the NC group, significantly decreased GMVs were found in the left primary visual cortex, left secondary visual cortex, right subiculum, right cornu ammonis, right entorhinal cortex and bilateral molecular layer of the cerebellum. Additionally, significantly increased GMVs were found in the right dentate gyrus, parasubiculum, and olfactory bulb.ConclusionsOur study revealed a positive correlation between mGMV and the expression of c-fos and NeuN in the visual cortex, suggesting a molecular relationship between cortical activity and macroscopic measurement of visual cortex structural plasticity. These findings may help elucidate the potential neural pathogenesis of FDM and its relationship to changes in specific brain regions.

Objective To compare the effectiveness of micro-implant (MI) and conventional anchorage (CA) in vertical control during orthodontic treatment of Class II malocclusion. Materials and Methods Literature search was conducted through Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, EMBASE, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang Database, VIP, and China Biology Medicine (CBM) from inception to December 2021. Randomized clinical trials (RCTs) and Compared clinical trials (CCTs) were included. Mean differences (MDs) with 95% confidence intervals (CIs) were conducted. A meta-analysis concerning change of mandibular plane, vertical change of upper and lower molar, change of occlusal plane, SNB, chin position and profile was carried out. Results A total of 10662 records were identified in the database search, A total of 19 studies (10 RCTs and 9 CCTs) were included in the final analysis. MI significantly decreased mandibular plane angle and intruded upper molars compared to CA. No significant difference was found in vertical change of lower molars, occlusal plane, SNB, chin position and profile. Conclusion MI seems to be more effective than CA in vertical control during orthodontic treatment of Class II malocclusion. Clinical Relevance MI should be given priority when considering the vertical control of Class II patients, which is beneficial to the counterclockwise rotation of mandible or at least prevention of deterioration of the profile.