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Objective: N6‐methyladenosine (m6A) is the most prevalent modification of RNA in eukaryotes which is associated with many cellular processes and diseases. Here, our objective is to explore whether genetic variants in m6A modification genes are associated with the risk of non‐syndrome orofacial clefts (NSOCs). Methods: The transmission disequilibrium test (TDT) was performed to calculate the association between single nucleotide polymorphisms (SNPs) in m6A modification genes and NSOCs risk in 944 case‐parent trios. The function of SNP was predicted by HaploReg, RegulomeDB and histone enrichment data. The expression quantitative trait locus (eQTL) analysis was examined using Genotype‐Tissue Expression (GTEx) and eQTLGen. The role of gene in the development of NSOCs was assessed with correlation and enrichment analysis based on gene expression data in mice craniofacial tissue and zebrafish embryo. Results: We identified that rs8078195 (A > C) in METTL16 was suggestively associated with the increased risk of NSOCs (OR = 1.32, p = 1.80E − 03). The region surrounding rs8078195 was subjected to deoxyribonuclease hypersensitivity and enriched with multiple histone modifications. In addition, it had a significant eQTL effect with METTL16 in skin tissue and human peripheral blood, which played an important role in NSOCs development. Bioinformatic analysis indicated that METTL16 contributed to the development of NSOCs probably by regulating cell cycle process. Conclusions: Rs8078195 in METTL16 was associated with the occurrence of NSOCs. [ABSTRACT FROM AUTHOR]

Objective To observe the changes of soft tissue in patients with Angle class Ⅱ division Ⅰ malocclusion during mixed dentition treated with MRC functional appliance. Methods Twenty patients with Class Ⅱ division Ⅰ malocclusion of Angle were treated with functional MRC. The facial features before and after treatment were measured by software and the results were analyzed statistically. Results The patients′soft tissue profiles were improved signifi⁃ cantly before and after treatment, The OE⁃Prn⁃Pos angle, OE⁃N′⁃B′ angle, OE⁃N′⁃Pos angle, OE⁃Prn⁃N′angle, Cm⁃Sn⁃ UL angle, and N′⁃Sn⁃Pos angle increased significantly (P < 0.05). The OE⁃Sn⁃UL angle, and Sn⁃N′⁃B′ angle decreased significantly (P < 0.05); the distance between the lateral soft tissue line and the middle Sn⁃H line, UL⁃E line and LL⁃E line were significantly different (P < 0.05). The distances were all reduced, and the difference was statistically significant (P < 0.05). Conclusion The application of an MRC functional appliance can improve the relationship among nasolabial soft tissue, upper and lower lip soft tissue, and chin⁃lip soft tissue, thus improving the protrusion profile of patients.

Background: The BCL‐2 family is crucial for cell death regulation and is involved in development, tissue homeostasis, and immunity. This study aimed to investigate the association between genetic variants in BCL‐2 family genes and non‐syndromic cleft lip with or without cleft palate (NSCL/P) risk. Methods: A two‐stage case–control study was conducted in this association study. Gene‐based analysis using Multi‐marker Analysis of GenoMic Annotation was performed in the first stage cohort, which included 565 cases and 1269 controls. A logistic regression model was employed to assess the effect of single nucleotide polymorphisms (SNPs) on susceptibility to NSCL/P. Candidate SNPs were replicated by extra dbGaP case‐parent trios. Haploreg, RegulomeDB, and UCSC Genome Browser were used to identify enhancer effects of promising SNPs. Bulk RNA sequencing data obtained from the Gene Expression Omnibus was used to identify co‐expressed genes. Single‐cell RNA sequencing dataset was used to infer the cell population of the candidate gene. The "Monocle" package was used to analyze the pseudotime cell trajectories. Results: Rs3943258 located in the enhancer region was associated with the risk of NSCL/P (Pmeta = 5.66 × 10−04) and exhibited an eQTL effect for BCL2 (P = 3.96 × 10−02). Co‐expression and pathway enrichment analysis revealed that genes related to Bcl2 were significantly enriched in the PI3K‐Akt signaling pathway, MAPK signaling pathway, and Wnt signaling pathway. Five cell clusters were identified in single‐cell RNA sequencing, and Bcl2 was mainly located in the mesenchyme. Conclusion: The rs3943258 located within BCL2 was probably related to NSCL/P susceptibility. [ABSTRACT FROM AUTHOR]

Non‐syndromic skeletal Class III malocclusion is a major craniofacial disorder characterized by genetic and environmental factors. Patients with severe skeletal Class III malocclusion require orthognathic surgery to obtain aesthetic facial appearance and functional occlusion. Recent studies have demonstrated that susceptible chromosomal regions and genetic variants of candidate genes play important roles in the etiology of skeletal Class III malocclusion. Here, we provide a comprehensive review of our current understanding of the genetic factors that affect non‐syndromic skeletal Class III malocclusion, including the patterns of inheritance and multiple genetic approaches. We then summarize the functional studies on related loci and genes using cell biology and animal models, which will help to implement individualized therapeutic interventions. [ABSTRACT FROM AUTHOR]

This retrospective clinical study investigated the clinical changes of maxillary central incisor and alveolar bone in Class II Division 2 nonextraction treatment with fixed appliances or clear aligners on the basis of cone-beam computed tomography. Fifty-nine Chinese Han patients with similar demographic characteristics were collected from a conventional bracket group, a self-ligating bracket group, and a clear aligner group. All measurements about root resorption and alveolar bone thickness on the cone-beam computed tomography images were tested. Changes between pretreatment and posttreatment were evaluated by paired-sample t test. The variation among the 3 groups was compared by 1-way analysis of variance. The resistance center of the maxillary central incisor showed upward or forward movement, and the axial inclination was increased in 3 groups (P <0.0001). Root volume loss in the clear aligner group (23.68 ± 4.82 mm3) was significantly less than that in the fixed appliances group (28.24 ± 6.44 mm3 in the conventional bracket group, 28.17 ± 6.07 mm3 in the self-ligating bracket group) (P <0.05). All 3 groups showed a significant decrease in palatal alveolar bone and total bone thickness at all 3 levels at posttreatment. In contrast, labial bone thickness significantly increased except for crestal level l. Among the 3 groups, the clear aligner group had a prominent increase in labial bone thickness at the apical level (P = 0.0235). Clear aligner treatment for Class II Division 2 malocclusions could effectively reduce the incidence of fenestration and root resorption. Our findings will be beneficial to comprehensively understand the effectiveness of different appliances for Class II Division 2 malocclusions treatment. • This study investigated root resorption and alveolar bone changes in Class II Division 2 treatment. • Root resorption in clear aligners group was significantly less than in fixed appliance groups. • Clear aligners could reduce labial bone thickness loss at the apical level effectively. [ABSTRACT FROM AUTHOR]

Objective: Premolar agenesis is a common subtype of tooth agenesis. Although a genome‐wide study (GWAS) has identified some variants involved in tooth agenesis in Europeans, the genetic mutation related to premolar agenesis in the Chinese population remains unclear. Materials and methods: We present a GWAS in 218 premolar agenesis cases and 1,222 controls using the Illumina Infinium® Global Screening Array. 5,585,618 single nucleotide polymorphisms (SNPs) were used for tests of associations with premolar agenesis. Results: Four independent SNPs on chromosome 2 were identified as susceptibility loci, including rs147680216, rs79743039, rs60540881, and rs6738629. The genome‐wide significant SNP rs147680216 (p = 6.09 × 10−9) was predicted to change the structure of the WNT10A protein and interact with hedgehog signaling pathway components. Meta‐analysis showed that the rs147680216 A allele significantly increased the risk of tooth agenesis (p = 0.000). The other three SNPs with nominal significance are novel susceptibility loci. Of them, rs6738629 (p = 5.40 × 10−6) acts as a potential transcriptional regulator of GCC2, a gene playing a putative role in dental and craniofacial development. Conclusion: Our GWAS indicates that rs147680216 and additional three novel susceptibility loci on chromosome 2 are associated with the risk of premolar agenesis in the Chinese population. [ABSTRACT FROM AUTHOR]

Several genes associated with periodontitis have been identified through genome-wide association studies (GWAS); however, known genes only explain a minority of the estimated heritability. We aimed to explore more susceptibility genes and the underlying mechanisms of periodontitis. Firstly, a genome-wide meta-analysis of 38,532 patients and 316,185 healthy controls was performed. Then, cross- and single-tissue transcriptome-wide association studies (TWAS) were conducted based on GWAS summary statistics and the Genotype-Tissue Expression (GTEx) project. Risk genes were evaluated to determine if they were differentially expressed in periodontitis sites compared with unaffected sites using public datasets. Finally, gene co-expression network analysis was conducted to identify the functional biology of the susceptible genes. A total of eight single nucleotide polymorphisms (SNPs) within the introns of lncRNA LINC02141 approached genome-wide significance after meta-analysis. EZH1 was identified as a novel susceptibility gene for periodontitis by TWAS and was significantly upregulated in periodontitis-affected gingival tissues. EZH1 co-expression genes were greatly enriched in the cell-substrate junction, focal adhesion and other important pathways. Our findings may offer a fundamental clue for comprehending the genetic mechanisms of periodontitis. [ABSTRACT FROM AUTHOR]

Objective : To investigate the longitudinal influence of alveolar bone grafting on the oral microbiota of children with cleft lip and palate (CLP). Materials and methods : Twenty-eight children with nonsyndromic CLP were recruited and underwent secondary alveolar bone grafting at the first time. Unstimulated saliva and plaque samples were collected from the subjects preoperatively and at 2 days, 1 month, and 3 months postoperatively. The v3–v4 hypervariable regions of the 16S rRNA gene from bacterial DNA were sequenced using the Illumina MiSeq sequencing platform. Results : The alpha diversity of the saliva and plaque microbiota was significantly decreased at 2 days postoperatively and then increased at 1 and 3 months postoperatively. The saliva and plaque microbiota compositions at 2 days postoperatively differed from those at the other time points, and the microbiota compositions at 1 and 3 months postoperatively showed a gradual shift toward the preoperative composition. The saliva, but not plaque, microbiota composition 3 months postoperatively was similar to that preoperatively. Conclusion : The effect of secondary alveolar bone grafting on the plaque microbiota in children with CLP lasted longer than the saliva microbiota. Alveolar bone grafting altered the saliva microbiota in children with CLP within 3 months postoperatively. [ABSTRACT FROM AUTHOR]