Spatiotemporal cell landscape of human embryonic tooth development.

Understanding the cellular composition and trajectory of human tooth development is valuable for dentistry and stem cell engineering research. Previous single-cell studies have focused on mature human teeth and developing mouse teeth, but the cell landscape of human embryonic dental development is still unknown. In this study, tooth germ tissues were collected from aborted foetus (17-24 weeks) for single-cell RNA sequence and spatial transcriptome analysis. The cells were classified into seven subclusters of epithelium, and seven clusters of mesenchyme, as well as other cell types such as Schwann cell precursor and pericyte. For epithelium, the stratum intermedium branch and the ameloblast branch diverged from the same set of outer enamel-inner enamel-ALCAM+ epithelial cell lineage, but their spatial distribution of two branches was not clearly distinct. This trajectory received spatially adjacent regulation signals from mesenchyme and pericyte, including JAG1 and APP. The differentiation of pulp cell and pre-odontoblast showed four waves of temporally distinct gene expression, which involved regulation networks of LHX9, DLX5 and SP7, and these genes were regulated by upstream ligands such as the BMP family. This provides a reference landscape for the research on early human tooth development, covering different spatial structures and developmental periods.

Nifedipine-Influenced Enlargement of the Masticatory Mucosa in an Elderly Edentulous Patient: A Rare Case Report with a Two-Year Follow-Up.

Drug-influenced gingival enlargement is a common side effect associated with certain medications, particularly calcium channel blockers like nifedipine, which has been extensively documented. However, the occurrence of nifedipine-influenced masticatory mucosa overgrowth in edentulous patients is rare. Here, we present a case of nifedipine-influenced mucosal enlargement persisting in a 67-year-old edentulous patient 3 months after the extraction of all his teeth. The patient underwent flap surgery and alveoloplasty to excise the overgrown tissue, followed by complete denture restoration. The antihypertensive medication was replaced with valsartan. A 2-year follow-up revealed no recurrence of overgrowth, indicating the effectiveness of this management strategy for such clinical situation.

A novel concentrated growth factor (CGF) and bio-oss based strategy for second molar protection after impacted mandibular third molar extraction: a randomized controlled clinical study.

BACKGROUND: The extraction of impacted mandibular third molars might cause large bone defects in the distal area of second molars. A new strategy was innovatively employed here combining autologous bone, Bio-Oss, concentrated growth factors (CGF) gel and CGF membrane for bone repair, and the present study aimed at exploring safety as well as short- and long-term efficacy of this new protocol clinically. MATERIALS AND METHODS: A total of 66 participants were enrolled in this randomized single-blind clinical trial, and randomly allocated to control group (only blood clots), test A group (autogenous bone, Bio-Oss with barrier membrane) and test B group (autogenous bone, Bio-Oss, CGF gel with CGF membrane). The postoperative outcomes including PoSSe scale, periodontal probing depth (PD), degree of gingival recession and computed tomography measurements were assessed at 3rd, 6th, 12th month. A p-value < 0.05 was considered statistically significant. RESULTS: In PoSSe scale, no significant difference was observed except a significant alleviation of early-stage pain perception in test B group (p < 0.05). Also, test B group exhibited better effect on periodontal healing and gingival recession reduction after 6 months (p < 0.05). Both two test groups showed more new bone formation than the control group (p < 0.05). It is noteworthy that the bone repair of test B group was significantly better than that of test A at 3rd and 6th month (p < 0.05), yet no difference was observed at 12th month (p > 0.05). CONCLUSION: Both two test groups could achieve stable long-term efficacy on bone defect repair. The use of CGF gel and CGF membrane could accelerate early-stage bone repair, alleviate short-term pain after surgery, reduce long-term probing depth and relieve economic cost for patients. This new bone repair protocol is worthy of promoting by clinicians. TRIAL REGISTRATION: This study was registered with the identification number ChiCTR2300068466 on 20/02/2023 at Chinese Clinical Trial Registry. Also, it was ethically approved from the institutional ethics committee at the Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (No:2023-010-01), and has been conducted in accordance to the guidelines of the declaration of Helsinki. Written informed consent was obtained from all participants in the study.

PAP Polypeptide Promotes Osteogenesis in Jaw Bone Defect Repair by Inhibiting Inflammatory Reactions.

Jaw defects are common in oral and maxillofacial diseases and require surgical repair in extreme cases. Given the limitations in availability and efficacy of autologous bone grafts or allografts, great effort has been made in finding suitable, biocompatible, and effective artificial bone materials. Considering the key role of inflammation in bone resorption, we sought to identify a polypeptide with anti-inflammatory and bone-promoting effects. Rat bone marrow-derived mesenchymal cells (BMSCs) were treated with lipopolysaccharide (LPS) to induce an inflammatory environment, and 1,538 differentially abundant polypeptides were identified using mass spectrometry. Based on mass spectrometry signal intensity, multiple of difference, and structural stability, PAP was screened out as the polypeptide with the lowest abundance in the inflammatory condition. PAP showed no cytotoxicity to BMSCs with increasing concentrations. PAP (10 µM) also increased alkaline phosphatase activity and mRNA expression of Ocn, Bmp2, and Runx2 in a concentration-dependent manner, which confirmed that it can promote osteogenic induction of rat BMSCs. Moreover, PAP reduced LPS-induced expression of inflammatory cytokines (TNF-α, IL-1ß, IL-6) and reactive oxygen species and inhibited polarization of RAW 264.7 macrophages to the inflammatory type. Finally, a skull defect mouse model was established, and mice were injected with LPS and/or PAP. Micro-CT, histological analysis, and immunohistochemical staining showed that PAP significantly reduced the number of LPS-induced bone resorption pits and maintained bone integrity. Overall, the polypeptide PAP screened using LPS stimulation of BMSCs is not cytotoxic and can inhibit the inflammatory reaction process to promote osteogenesis. This study thus provides a basis for development of PAP as a new osteogenic material in the repair of jaw defects.

Characteristics of Chinese Costal Cartilage and Costa Calcification Using Dual-Energy Computed Tomography Imaging.

To assess characteristics of Chinese costal cartilage and costa calcification using Dual-Energy computed tomography(DECT). 154 patients who underwent chest DECT scanning were included in our study. They were divided into following groups: less than 30 years old, 31-40 years old, 41-50 years old, 51-60 years old and over 60 years old. The sixth, seventh and eighth costal cartilages and costas were evaluated. Calcification patterns of cartilage were classified as central(C), peripheral(P), mixed(M) and no calcification(N) types. Calcification degree of cartilage was distinguished as 1(0-25%), 2(26-50%) and 3(>50%). CT value, calcium and water concentrations were measured in costal cartilage, cortical or cancellous bone respectively. An increasing C pattern of cartilage was displayed in females, while P type preferred in males as age increased. Calcification degree generally changed from 1 to 2 or 3 in females. CT value and calcium concentration of cartilage went through a gradual rising course and peaked in their 40-50 years, while those two indices of cancellous bone decreased gradually since their 50 years in females. The findings suggest a gradual calcification of the costal cartilage took place before 40-50 years old and a sharp bone loss of the costa happened after 40-50 years old in females.