Synovial fluid niche promoted differentiation of dental follicle mesenchymal stem cells toward chondrogenesis in rheumatoid arthritis

Objectives: In this study, we aimed to investigate the differentiation potential of dental follicle mesenchymal stem cells (MSCs) in the synovial fluid (SF) niche of early-onset or end-stage rheumatoid arthritis (RA). Patients and methods: Between May 2020 and January 2021, six patients (1 male, 5 females; mean age: 57.5±11.2 years; range, 49 to 65 years) who were diagnosed with RA with the indication of SF aspiration were included in the study. The third passage dental follicle stem cells (DFSCs) were cocultured with fresh SF samples of end-stage or early-onset RA patients in micromass culture system for 21 days. SF samples were analyzed for secreted cytokines. Chondrogenic markers (CD49e, CD49f) were analyzed in DFSCs, gene expression analysis was performed for the expressions of Col I, Col II, Aggrecan and Sox-9, and histochemical analysis was performed by staining three-dimensional pellets with anti-collagen II antibody. The neutralization assay was performed with anti-interleukin (IL)-6, anti-interferon-gamma (IFN-g), and anti-IL-1beta(b). Results: The high levels of IL-1b and IL-6 were observed in end-stage RA patients’ SF samples compared to the early-onset patients (p<0.05). The CD49e and CD49f expressions in DFSCs were significantly higher in the SF samples of end-stage RA patients (p<0.05). Also, the Col II, Sox-9 and Aggrecan messenger ribonucleic acid (mRNA) expressions increased in the DFSCs, when cultured with end-stage RA patients’ SF samples (p<0.01). Collagen-II expression in histochemical analysis of micromass pellets was higher in the DFSCs cultured with end-stage RA patients’ SF samples. The neutralization of IL-6 significantly decreased the CD49e and CD49f expressions (p<0.05). Conclusion: The high levels of IL-6 in SF niche of end-stage RA patients were found to differentiate DFSCs toward chondrogenesis. Based on these findings, DFSCs can be used as a new cell-based treatment in RA patients for the cartilage damage.

Long-term follow-up in lower right second premolar tooth with a dental follicle but no tooth bud: A case report

Aim: The patient was followed up in consultation with the orthodontist, and after a long-term follow-up, it was found that the dental germ developed, but the position of the tooth was horizontal. When the follow-ups were continued, it was observed that the position of the tooth also improved, and it progressed smoothly along the tooth eruption path. Methodology: In the panoramic radiography of an 8-year-old male patient who applied to the clinic complaining about the left upper first primary molar tooth, the right lower permanent second premolar tooth follicle developed, but there was no tooth development in the follicle. Results: When follicle formation is observed, only following the patients without directing them to orthodontic treatment, which is expensive and difficult, positively affects their dental structure. Following patients without affecting their lives can be significant. Conclusion: We emphasize the importance of long-term follow-up when follicle formation was observed. We predicted that this situation was caused by the disconnection in the interaction of transcription factors and signals in the tooth development stage. How to cite this article: Sukurica Y, Çakır A. Long-term follow-up in lower right second premolar tooth with a dental follicle but no tooth bud: A case report. Int Dent Res 2021;11(Suppl.1):312-5. https://doi.org/10.5577/10.5577/intdentres.2021.vol11.suppl1.47 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Dental follicle cell differentiation towards periodontal ligament-like tissue in a self-assembly three-dimensional organoid model

Periodontitis remains an unsolved oral disease, prevalent worldwide and resulting in tooth loss due to dysfunction of the periodontal ligament (PDL), a tissue connecting the tooth root with the alveolar bone. A scaffold-free three-dimensional (3D) organoid model for in vitro tenogenesis/ligamentogeneis has already been described. As PDL tissue naturally arises from the dental follicle, the aim of this study was to investigate the ligamentogenic differentiation potential of dental follicle cells (DFCs) in vitro by employing this 3D model. Human primary DFCs were compared, in both two- and three-dimensions, to a previously published PDL- hTERT cell line. The 3D organoids were evaluated by haematoxylin and eosin, 4′,6-diamidino-2-phenylindole and F-actin staining combined with detailed histomorphometric analyses of cell-row structure, angular deviation and cell density. Furthermore, the expression of 48 tendon/ligament- and multilineage-related genes was evaluated using quantitative polymerase chain reaction, followed by immunofluorescent analyses of collagen 1 and 3. The results showed that both cell types were successful in the formation of scaffold-free 3D organoids. DFC organoids were comparable to PDL-hTERT in terms of cell density; however, DFCs exhibited superior organoid morphology, cell-row organisation (p < 0.0001) and angular deviation (p < 0.0001). Interestingly, in 2 dimensions as well as in 3D, DFCs showed significantly higher levels of several ligament- related genes compared to the PDL-hTERT cell line. In conclusion, DFCs exhibited great potential to form PDL-like 3D organoids in vitro suggesting that this strategy can be further developed for functional PDL engineering.

Overview of Radiological Studies on Visualization of Gubernaculum Tracts of Permanent Teeth

The eruption pathway from the dental follicle to the gingiva for permanent teeth is known as the gubernaculum tract (GT), a physiologic structure thought to play a role in tooth eruption. Cone beam computed tomography and multi-detector computed tomography have recently been used to visualize the GT, with the results indicating that this structure might be related to the normal eruption of teeth. By contrast, curved and/or constricted GTs may lead to abnormal tooth eruption. In addition, complex odontomas have been reported from within the GT or dental sac of unerupted permanent teeth. If an odontoma occurs within the GT, the tooth will not erupt normally. Moreover, the imaging characteristics of the GT from the top of the odontogenic mass to the alveolar crest are extremely useful for making a differential pathological diagnosis and for differentiating between odontogenic and non-odontogenic masses. Therefore, radiological studies on the GT have been attracting increasing attention. Given this background, the present review aims to clarify the imaging characteristics and review recent studies on the GT considering the importance of the research.

Function of Dental Follicle Progenitor/Stem Cells and Their Potential in Regenerative Medicine: From Mechanisms to Applications

Dental follicle progenitor/stem cells (DFPCs) are a group of dental mesenchyme stem cells that lie in the dental follicle and play a critical role in tooth development and maintaining function. Originating from neural crest, DFPCs harbor a multipotential differentiation capacity. More importantly, they have superiorities, including the easy accessibility and abundant sources, active self-renewal ability and noncontroversial sources compared with other stem cells, making them an attractive candidate in the field of tissue engineering. Recent advances highlight the excellent properties of DFPCs in regeneration of orofacial tissues, including alveolar bone repair, periodontium regeneration and bio-root complex formation. Furthermore, they play a unique role in maintaining a favorable microenvironment for stem cells, immunomodulation and nervous related tissue regeneration. This review is intended to summarize the current knowledge of DFPCs, including their stem cell properties, physiological functions and clinical application potential. A deep understanding of DFPCs can thus inspire novel perspectives in regenerative medicine in the future.

Monitoring enlarged dental follicles: case report and literature review of an unusual presentation of a unicystic ameloblastoma

An ameloblastoma is a benign, yet locally aggressive odontogenic tumour. The vast majority (80%) of ameloblastomas arise in the mandible, and unicystic ameloblastomas are commonly found in relation to an unerupted lower third molar. We present the case of a 39-year-old patient with an incidental finding of an enlarged dental follicle around an unerupted lower third molar that progressed to an extensive unicystic ameloblastoma. This ameloblastoma was decompressed and marsupialized before enucleation to reduce the risk of pathological fracture due to the extensive size of the tumour. CPD/Clinical Relevance: The case is relevant to general dental practitioners when considering monitoring dental follicles of unerupted teeth because the enlarged dental follicle described progressed to an extensive odontogenic tumour.