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 significantly 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.

Objective:To explore the mechanisms of prickle planar cell polarity protein 1 (PRICKLE1) involved in the occurrence of skeletal Class Ⅲ malocclusion.Methods:After extracting the genomic DNA of all family members of the skeletal Class Ⅲ malocclusion pedigree with maxillary hypoplasia collected in the Department of Orthodontics at the Affiliated Stomatological Hospital of Nanjing Medical University in October 2021, whole exome sequencing and Sanger sequencing were performed to screen pathogenic genes/mutation sites and validate the mutations. Jaw tissue was collected during the operation of orthognathic patients who were treated in the Department of Oral and Maxillofacial Surgery at the same hospital from October 2021 to December 2022. Following the extraction of human jaw bone marrow mesenchymal stem cells and transfection with overexpressing lentivirus (lentiviruses overexpressing the gene of interest served as the wild group, lentiviruses overexpressing mutation site served as the mutant group) and knockdown lentivirus (divided into knockdown group 1 and 2, with transfection interference negative lentiviruses as the control group). Various assays including real-time fluorescence quantitative PCR (RT-qPCR), Western blotting, proliferation and Transwell assays, alkaline phosphatase staining and alizarin red staining were performed. Construction of zebrafish animal model, morpholino oligonucleotide (MO) were injected to knock down the expression of prickle1a and prickle1b in zebrafish (co-knocking group), and the control group was injected with standardized MO as a reference. Transcriptome sequencing, enrichment analysis and co-expression analysis were performed on the zebrafish craniofacial tissues of the two groups.Results:Two patients of this family carried this mutation PRICKLE1 c.113C>T. The transfection experiments showed that compared with the wild group (relative expression of PRICKLE1 was 21.97±0.60), the relative expression of mutant group (5.05±0.05) was significantly reduced ( P<0.05), and cell proliferation and migration ability significantly enhanced ( P<0.05), and osteogenic differentiation ability was significantly reduced ( P<0.05). Compared with the control group, the proliferation and migration ability of cells in the two knockdown groups were significantly enhanced ( P<0.05), and the osteogenic differentiation ability was significantly reduced ( P<0.05). Zebrafish model experiments showed the width of the ethmoid plate was significantly reduced in the co-knocking group (282.50±61.77, t=5.29, P<0.001) compared with the control group (338.80±24.92). Transcriptome data and enrichment analysis showed that the differentially expressed genes were significantly enriched in the mitogen-activated protein kinase (MAPK) signaling pathway after the simultaneous knockdown of prickle1a and prickle1b in zebrafish. Conclusions:PRICKLE1 c.113C>T mutation might suppress the osteoblastic differentiation ability of jaw bone marrow mesenchymal stem cells by downregulating the MAPK signaling pathway, thereby involving the development of skeletal Class Ⅲ malocclusion.

Objective To study the distolingual space of mandibular molars in adult patients with different sagittal skeletal patterns,and to analyze the main bony anatomical sites that restrict molar distalization,in order to provide guidance for the treatment plan of mo-lar distalization.Methods A total of 97 adult patients according to the inclusion criteria were selected from the Department of Ortho-dontics,the Affiliated Stomatological Hospital of Nanjing Medical University.The patients were divided into skeletal Class Ⅰ group(n=28),skeletal Class Ⅱ group(n=49)and skeletal Class Ⅲ group(n=20)according to the ANB angle.CBCT of the patients were im-ported into Dolphin software for 3D reconstruction.The width of the distal root of the second molar,the width of alveolar bone,the dis-tance between the most convex point of the distal and lingual side of the distal root and the inneredge of the lingual cortex of the mandi-ble were measured at the 2,4,and 6 mm plane from the root furcation to the root apex.Statistical analysis was performed using SPSS 26.0 software,and univariate analysis of variance and LSD-t test were used to compare the difference.Results Root width was significantly narrower than alveolar bone width at all measurement planes(P＜0.01).Molar distolingual space in patients with different sagittal skeletal patterns was smaller than molar distal space,and the size of the space gradually decreased with the deepening of the measurement level,reaching the minimum value at the R4 and R6 measurement planes.Measurement results of this study showed that at the R6 level,the molar distolingual space in skeletal Class Ⅱ group was the minimum(2.30±2.45)mm;on the contrary,skeletal Class Ⅲ group was the maximum(4.17±2.38)mm.Conclusion When designing the plan of molar distalization in clinical practice,CBCT should be used,and more attention should be paid to the lingual alveolar bone mass of the mandibular molar.It is a safe and effective treatment method for skeletal Class Ⅰ and Ⅲ patients with mild to moderate dental crowding.

The biological samples of oral genetic diseases and rare diseases are extremely precious. Collecting and preserving these biological samples are helpful to elucidate the mechanisms and improve the level of diagnose and treatment of oral genetic diseases and rare diseases. The standardized construction of biobanks for oral genetic diseases and rare diseases is important for achieving these goals. At present, there is very little information on the construction of these biobanks, and the standards or suggestions for the classification and coding of biological samples from oral and maxillofacial sources, and this is not conducive to the standardization and information construction of biobanks for special oral diseases. This consensus summarizes the background, necessity, principles, and key points of constructing the biobank for oral genetic diseases and rare diseases. On the base of the group standard "Classification and Coding for Human Biomaterial" (GB/T 39768-2021) issued by the National Technical Committee for Standardization of Biological Samples, we suggest 76 new coding numbers for different of biological samples from oral and maxillofacial sources. We hope the consensus may promote the standardization, and smartization on the biobank construction as well as the overall research level of oral genetic diseases and rare diseases in China.