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Tooth eruption as a crucial part in tooth development and regeneration is accompanied by ongoing osteogenesis and osteoclast activity. The dental follicle (DF) surrounding the developing tooth harbors dental follicle stem cells (DFSCs) which play a crucial role in maintaining bone remodeling. However, the mechanisms through which they regulate the balance between osteogenesis and osteoclast activity during tooth eruption remain poorly understood. Notably, extracellular vesicles (EVs) in bone homeostasis are considered essential. Our study revealed that the DFSCs could modulate tooth eruption by inhibiting osteoclast differentiation via EVs. Further investigation showed that EVs from DFSCs could inhibit osteoclast differentiation through the ANXA1-PPARγ-CEBPα pathway. Animal experiments indicated that EVs from DFSCs and the cargo ANXA1 affected tooth eruption. In summary, this study suggests the critical role of the dental follicle in tooth eruption through EVs, which may provide therapeutic targets for abnormal tooth eruption and effective approaches for the eruption of regenerated teeth. DFSCs regulate tooth eruption by releasing extracellular vesicles. During tooth eruption, dental follicle stem cells inhibit osteoclast differentiation by releasing extracellular vesicles containing ANXA1 and its mediated PPARγ-CEBPα pathway, thereby preventing premature tooth eruption. The elucidation of this mechanism is crucial for understanding and treating abnormal tooth eruption diseases and the eruption process of tooth regeneration. (Image created with BioRender.com, with permission). [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate whether epigenetic markers are expressed in the dental follicles surrounding ectopically erupting teeth. Twenty‐one dental follicles were collected in 20 adolescent children through surgical exposure of ectopic teeth. The epigenetic modifications of DNA methylation and histone acetylation were evaluated by immunohistochemistry. The results showed cells positive for DNA‐methyltransferase 1 (DNMT1), DNA methyltransferase 3 beta (DNMT3B), ten‐eleven translocation‐2 (TET2), acetyl‐histone H3 (AcH3), acetyl‐histone H4 (AcH4), 5‐methylcytosine (5mC), and 5‐hydroxymethylcytosine (5hmC) were present in all the samples. The levels of epigenetic markers representing active chromatin (5hmC, AcH3, AcH4, and TET2) were statistically significantly higher than those of markers representing inactive chromatin (5mC, DNMT3B, DNMT1). In conclusion, follicles in ectopic teeth display major epigenetic modifications. In the follicles, epigenetic markers associated with the activation of bone‐related genes are more abundant than markers associated with the inactivation of bone‐related genes. [ABSTRACT FROM AUTHOR]

Primary failure of eruption (PFE) is a rare disorder that is characterized by the inability of a molar tooth/teeth to erupt to the occlusal plane or to normally react to orthodontic force. This condition is related to hereditary factors and has been extensively researched over many years. However, the etiological mechanisms of pathogenesis are still not fully understood. Evidence from studies on PFE cases has shown that PFE patients may carry parathyroid hormone 1 receptor (PTH1R) gene mutations, and genetic detection can be used to diagnose PFE at an early stage. PTH1R variants can lead to altered protein structure, impaired protein function, and abnormal biological activities of the cells, which may ultimately impact the behavior of teeth, as observed in PFE. Dental follicle cells play a critical role in tooth eruption and root development and are regulated by parathyroid hormone-related peptide (PTHrP)–PTH1R signaling in their differentiation and other activities. PTHrP–PTH1R signaling also regulates the activity of osteoblasts, osteoclasts and odontoclasts during tooth development and eruption. When interference occurs in the PTHrP–PTH1R signaling pathway, the normal function of dental follicles and bone remodeling are impaired. This review provides an overview of PTH1R variants and their correlation with PFE, and highlights that a disruption of PTHrP–PTH1R signaling impairs the normal process of tooth development and eruption, thus providing insight into the underlying mechanisms related to PTH1R and its role in driving PFE. [ABSTRACT FROM AUTHOR]

Tooth eruption as a crucial part in tooth development and regeneration is accompanied by ongoing osteogenesis and osteoclast activity. The dental follicle (DF) surrounding the developing tooth harbors dental follicle stem cells (DFSCs) which play a crucial role in maintaining bone remodeling. However, the mechanisms through which they regulate the balance between osteogenesis and osteoclast activity during tooth eruption remain poorly understood. Notably, extracellular vesicles (EVs) in bone homeostasis are considered essential. Our study revealed that the DFSCs could modulate tooth eruption by inhibiting osteoclast differentiation via EVs. Further investigation showed that EVs from DFSCs could inhibit osteoclast differentiation through the ANXA1-PPARγ-CEBPα pathway. Animal experiments indicated that EVs from DFSCs and the cargo ANXA1 affected tooth eruption. In summary, this study suggests the critical role of the dental follicle in tooth eruption through EVs, which may provide therapeutic targets for abnormal tooth eruption and effective approaches for the eruption of regenerated teeth.

Fibroblast growth factor (FGF) signalling plays a crucial role in the morphogenesis of multiple tissues including teeth. While the role of the signal has been studied in tooth crown development, little is known about root development. Of several FGF ligands involved in hard tissue formation, we suggest that FGF18 regulates the development of murine tooth roots. We implanted FGF18‐soaked heparin beads into the lower first molar tooth buds at postnatal day 6 (P6), followed by transplantation under the kidney capsule. After 3 weeks, FGF18 significantly facilitated root elongation and periodontal tissue formation compared to the control. In situ hybridisation showed that Fgf18 transcripts were initially localised in the dental pulp along Hertwig's epithelial root sheath at P6 and P10 and subsequently in the dental follicle cells at P14. Fgf receptors were expressed in various dental tissues during these stages. In vitro analysis using the dental pulp stem cells revealed that FGF18 inhibited cell proliferation and decreased expression levels of osteogenic markers, Runx2, Alpl and Sp7. Consistently, after 1 week of kidney capsule transplantation, FGF18 application did not induce the expression of Sp7 and Bsp, but upregulated Periostin in the apical region of dental mesenchyme in the grafted molar. These findings suggest that FGF18 facilitates molar root development by regulating the calcification of periodontal tissues. [ABSTRACT FROM AUTHOR]

Two studies were conducted to evaluate the effects of the follicular wave on ovarian function and fertility in dairy heifers and lactating cows. In study 1, the estrous cycle of the selected Holstein heifers was initially synchronized using two intra-muscular prostaglandin F2a (PGF2a) administrations 11 days apart. Heifers in group FFW (n = 14) received an intra-muscular 500 µg PGF2a administration on day 7 after detecting standing estrus, while Heifers in group SFW (n = 14) were administered PGF2a 13 days after detecting standing estrus. The pregnancy rates of FFW (n = 98) and SFW (n = 100) heifers were also determined 35-37 days after artificial insemination (AI). In Study 2, healthy Holstein lactating cows (n = 28) were randomly assigned to either the FFW (n = 14) or SFW (n = 14) groups. The estrous cycles of the cows were presynchronized using two intra-muscular administrations of PGF2a given 14 days apart. Then, the emergences of the follicular waves were induced using an Ovsynch protocol. The pregnancy rate of FFW (n = 99) versus SFW (n = 98) cows was also determined 35-37 days after AI. The ovulatory follicle and corpus luteum (CL) resulting from the ovulatory follicle of FFW were larger than those of the dominant follicle and the CL of SFW in dairy heifers and lactating cows. However, the pregnancy rate did not differ between the FFW and SFW groups in heifers and lactating cows 35-37 days after AI. In conclusion, although the characteristics of the ovulatory follicles in FFW versus SFW animals differed, the follicular wave in dairy heifers or lactating cows did not affect fertility. [ABSTRACT FROM AUTHOR]

This study aimed to study the effect of oreganum on forced molting in laying Japanese quails to improve the physiological performance and restore the reproductive capacity of females. A total of 120 female Japanese quails (Coturnix coturnix Japonica) aged 18 weeks were divided randomly into six groups: group A - pre-molting from weeks 18 to 19; group B - supplemented with oregostim at a dose of 0.3 mL\1000 mL; group C (molting from weeks 20 to 22) - fed a restricted diet; group D - fed a limited diet with oregostim at the same dose and post-molting from week 23 to week 37; group E - fed a basal diet; and group F - fed a basal diet and treated by oregostim. The results showed that the molting group caused a significant reduction in the weight of body and ovary in group C and group D, while the weights were restored in group E and group F relative to other groups. Besides, there was a significant decrease of WBCs and RBCs count in group C and group D with a significant elevation in group E and group F compared with group A and group B. The percentage of egg production and large follicle number in group C and group D decreased significantly compared with group A and group B, while they restored to normal values in group E and group F compared with group A and group B and showed a significant increase as compared with group C and group D, respectively. We concluded from this study that oregostim does not have adverse effects on the molting period. Thus, the standard diet supplemented with oregostim was considered as a better molting technique. [ABSTRACT FROM AUTHOR]

Abstract Aim This study was performed to histologically evaluate peri-coronal tissues of partially impacted and erupted third molars that did not exhibit pathologic peri-coronal radiolucency. Materials and methods Healthy patients with erupted or partially erupted (with part or all of the dental crown present in the oral cavity) mandibular third molars (classified as IA and IIA according to the Pell and Gregory classification) and vertically positioned (according to the Winter classification or erupted third molars) associated with peri coronal radiolucency of equal to or less than 2.5 mm. Associated with third molar surgery, tissue sampling from the distal area was performed, which was subjected to an anatomopathological examination to determine the histological nature. Results One hundred teeth (100 patients) were selected, and 100 specimens were analyzed. 53% of the sample were included in the non-pathological group and 47% showed pathological changes (fibrotic tissue (n 15), periodontal cyst-like (n 9), squamous epithelial metaplasia (4 cases), islands of odontogenic epithelial residues organized micro-cyst with keratocystic/ameloblastic appearance (4 cases), granulation tissue (n 8), giant cell tumour (n 4) and lobular capillary hemangioma (n 4)). Pathological changes did not have differences in incidence between the gender (p value = 0.85) and did not show any correlation with age, (p value = 0,96). Conclusions These findings suggest that radiographic appearance may not be a reliable indicator of the absence of disease within a dental follicle. Therefore, clinicians should pay attention to or follow up on even peri-coronal radiolucency of less than 2.5 mm.

Background: Dentigerous cysts are among the most prevalent odontogenic cysts associated with impacted teeth, particularly impacted third molars. Understanding the clinicopathological correlation between impacted teeth and factors contributing to cyst formation is essential. Aim: This study aimed to investigate the clinicopathological correlation between impacted teeth and the factors associated with dentigerous cyst formation. Materials and Methods: The study analyzed a total of 30 cases, which were categorized into two subgroups: 16 cases of dental follicles and 14 cases of dentigerous cysts. Retrospective data were collected from the departmental archive, and demographic data along with clinical parameters were correlated. In addition, the Ki-67 index was assessed through immunohistochemical analysis for both study groups. Results: A clinical correlation between impacted teeth along with Ki-67 index in both dental follicles and dentigerous cysts was observed. Conclusion: Based on the findings, it is hypothesized that prophylactic extraction of impacted third molars should be mandatory, irrespective of their symptomatic or asymptomatic status. [ABSTRACT FROM AUTHOR]

Statement of the Problem: Gubernacular canal (GC) is a canal that extends from the follicle of unerupted permanent teeth to the alveolar bone crest filled with remnants of the dental lamina. This canal is thought to guide tooth eruption and be related to some pathologic conditions.Purposes: This study aimed to determine the presence of GC and its anatomical characteristics in teeth, which failed to erupt normally on cone beam computed tomography (CBCT) images.Materials and Method: This cross-sectional study evaluated CBCT images of 77 impacted permanent and supernumerary teeth obtained from 29 females and 21 males. The frequency of GC detection, its location in relation to the crown and root, the anatomical surface of the tooth from which the canal has originated, and the adjacent cortical table to which the canal opens, along with the length of the GC were studied.Results: GC was observed in 53.2% of teeth. The anatomical tooth aspect of origin was occlusal/ incisal in 41.5% and crown in 82.9% of teeth. Moreover, 51.2% of GCs opened in palatal/lingual cortex and 63.4% of canals were not located along the tooth long axis. Finally, GC was detected in 85.7% of teeth undergoing the crown formation stage.Conclusion: Although GC was introduced as an eruption pathway, this canal is also present in impacted teeth. This means that presence of this canal does not promise the normal eruption of tooth and the anatomical characteristics of GC may influence the eruption process.

The over-accumulation of ROS during prolonged in vitro expansion could negatively affect the properties of stem cells. This leads to a reduced capacity for self-renewal and a lower potential for multiple differentiation, ultimately hindering their applicability in regenerative medicine. Herein, we fabricated platinum nanoparticles (PtNPs) as a potential biocompatible antioxidant to efficiently eliminate the ROS accumulation in human dental follicle stem cells (hDFSCs) during in vitro expansion, thereby enhancing hDFSCs proliferation and osteogenic differentiation. Transcriptome analysis revealed that PI3K/AKT signaling pathway was activated in PtNPs-treated hDFSCs. Transplantation of PtNPs-treated rDFSCs could facilitate new bone formation compared to transplantation of PBS or un-treated rDFSCs, leading to efficient regeneration of bone tissue in rat mandibular bone defect models. In conclusion, PtNPs offered a novel antioxidative strategy to improve stem cell properties and stem-cells-based alveolar bone regeneration.

Background: Dentigerous cysts are among the most prevalent odontogenic cysts associated with impacted teeth, particularly impacted third molars. Understanding the clinicopathological correlation between impacted teeth and factors contributing to cyst formation is essential. Aim: This study aimed to investigate the clinicopathological correlation between impacted teeth and the factors associated with dentigerous cyst formation. Materials and Methods: The study analyzed a total of 30 cases, which were categorized into two subgroups: 16 cases of dental follicles and 14 cases of dentigerous cysts. Retrospective data were collected from the departmental archive, and demographic data along with clinical parameters were correlated. In addition, the Ki-67 index was assessed through immunohistochemical analysis for both study groups. Results: A clinical correlation between impacted teeth along with Ki-67 index in both dental follicles and dentigerous cysts was observed. Conclusion: Based on the findings, it is hypothesized that prophylactic extraction of impacted third molars should be mandatory, irrespective of their symptomatic or asymptomatic status.

Abstract Objectives The indication for removal of asymptomatic fully impacted third molars is still controversial. In this study, radiological and histological investigation of the dental follicle of asymptomatic impacted mandibular third molars was performed, aiming to provide a reference for clinical prophylactic extraction of these teeth. Methods Patients with impacted mandibular third molars were included and the maximum width of the dental follicle around the crown was measured in horizontal, sagittal and coronal sections by cone beam computed tomography. The dental follicles were stained with haematoxylin-eosin, analysed by a pathologist and classified as normal, inflammatory or cystic. A Chi-squared test was used to analyse the association of the incidence of inflammation and cysts with the clinical variables of the impacted mandibular third molars. Results Thirty-seven samples were normal dental follicles; 52 samples showed inflammatory infiltration with an incidence of 57.14%; 2 samples with a maximum dental follicle width of 2–3 mm were diagnosed as odontogenic cysts, and the incidence was 2.20%. There was no significant difference in the incidence of inflammatory and cystic dental follicles between males and females, or between different age groups (P > 0.05). With an increase of the maximum width of the dental follicle, there was a rise in the incidence and degree of infiltration of chronic nonspecific inflammation. Conclusion Asymptomatic impacted mandibular third molars tend to be extracted, especially for teeth with a 2–3 mm maximum width of the dental follicle on radiological examination.

Aim: This study was performed to histologically evaluate peri-coronal tissues of partially impacted and erupted third molars that did not exhibit pathologic peri-coronal radiolucency. Materials and methods: Healthy patients with erupted or partially erupted (with part or all of the dental crown present in the oral cavity) mandibular third molars (classified as IA and IIA according to the Pell and Gregory classification) and vertically positioned (according to the Winter classification or erupted third molars) associated with peri coronal radiolucency of equal to or less than 2.5 mm. Associated with third molar surgery, tissue sampling from the distal area was performed, which was subjected to an anatomopathological examination to determine the histological nature. Results: One hundred teeth (100 patients) were selected, and 100 specimens were analyzed. 53% of the sample were included in the non-pathological group and 47% showed pathological changes (fibrotic tissue (n 15), periodontal cyst-like (n 9), squamous epithelial metaplasia (4 cases), islands of odontogenic epithelial residues organized micro-cyst with keratocystic/ameloblastic appearance (4 cases), granulation tissue (n 8), giant cell tumour (n 4) and lobular capillary hemangioma (n 4)). Pathological changes did not have differences in incidence between the gender (p value = 0.85) and did not show any correlation with age, (p value = 0,96). Conclusions: These findings suggest that radiographic appearance may not be a reliable indicator of the absence of disease within a dental follicle. Therefore, clinicians should pay attention to or follow up on even peri-coronal radiolucency of less than 2.5 mm. [ABSTRACT FROM AUTHOR]

Impacted third molar extractions are one of the most common oral surgical procedures. In cases where a pathological condition is observed, it is relatively easy to decide on surgery. However, cystic changes can be observed in follicular tissues even in cases where pathological changes are not observed on radiography. The present study aimed to evaluate the histopathologic changes in dental follicles associated with radiographically normal impacted lower third molar. One hundred and one dental follicles were obtained after third molar surgeries. The patients with follicular width of less than 2.5 mm in the panoramic radiographs were included in the study. The relationships between pathological changes in follicular tissues and angular position of impacted teeth, age and gender were statistically examined. Cystic changes were observed in 65 (64.3%) of 101 follicles examined. The relationship between cystic changes and the angular position of impacted lower third molars was statistically significant (p < 0.05). Cystic changes were observed in 13 (43.3%) of 30 mesioangular teeth, 24 (80%) of 30 vertical teeth, 19 (65.5%) of 29 horizontal teeth, and 9 (75%) of 12 distoangular teeth. About 60% of cystic changes and 64.06% of inflammation occurred in patients between the ages of 20 and 30. Cystic changes can be observed in the follicular tissues of impacted lower third molars that are radiographically normal. There is a probability of histopathological changes, especially in patients over the age of 20 years and in the impacted lower third molars in the vertical position. [ABSTRACT FROM AUTHOR]

The period that includes the first thousand days of life of an infant is considered of vital importance for the development of organs and tissues, for this reason periodic controls should be performed to rule out or confirm possible pathologies in time. One of the most recurrent pathologies in the cavity of infants is the eruption cyst, which is made up of soft tissue of a purplish-bluish color resulting from a separation of the dental follicle from the crown of an erupting tooth whose diagnosis could be confused with other pathologies. Its pigment depends on the amount of blood in the cyst when the dental crown fails to break the gingival mucosa. The objective is focused on analyzing the characteristics of eruption cyst in infants by histological examinations and radiographic interpretations, through a literature review between the years 2014-2022. As a result, it was obtained that the treatment of preference for the eruption cyst should be determined for each case with an adequate diagnosis both in its clinical and radiographic findings and should be managed correctly to reduce the complications of the developing tooth and the health of the infant. [ABSTRACT FROM AUTHOR]

Root apical complex, including Hertwig's epithelial root sheath, apical papilla, and dental follicle (DF), is the germinal center of root development, wherein the DF constantly develops into periodontal tissue. However, whether DF development is regulated by the adjacent apical papilla remains largely unknown. In this study, we employed a transwell coculture system and found that stem cells from the apical papilla (SCAPs) inhibit the differentiation and maintain the stemness of dental follicle stem cells (DFSCs). Meanwhile, partial SCAP differentiation markers were upregulated after DFSC coculture. High-throughput RNA sequencing revealed that the Hedgehog (Hh) pathway was significantly downregulated in DFSCs cocultured with SCAPs. Upregulation or downregulation of the Hh pathway can respectively activate or inhibit the multidirectional differentiation of DFSCs. Osteoglycin (OGN) (previously known as mimecan) is highly expressed in the dental papilla, similarly to Hh pathway factors. By secreting OGN, SCAP regulated the stemness and multidirectional differentiation of DFSCs via the OGN-Hh pathway. Finally, Ogn –/– mice were established using the CRISPR/Cas9 system. We found that the root length growth rate was accelerated during root development from PN0 to PN30 in Ogn –/– mice. Moreover, the hard tissues (including dentin and cementum) of the root in Ogn –/– mice were thicker than those in wild-type mice. These phenotypes were likely due to Hh pathway activation and the increased cell proliferation and differentiation in both the apical papilla and DF. The current work elucidates the molecular regulation of early periodontal tissue development, providing a theoretical basis for future research on tooth root biology and periodontal tissue regeneration. [ABSTRACT FROM AUTHOR]

Statement of the Problem: Gubernacular canal (GC) is a canal that extends from the follicle of unerupted permanent teeth to the alveolar bone crest filled with remnants of the dental lamina. This canal is thought to guide tooth eruption and be related to some pathologic conditions. Purposes: This study aimed to determine the presence of GC and its anatomical characteristics in teeth, which failed to erupt normally on cone beam computed tomography (CBCT) images. Materials and Method: This cross-sectional study evaluated CBCT images of 77 impacted permanent and supernumerary teeth obtained from 29 females and 21 males. The frequency of GC detection, its location in relation to the crown and root, the anatomical surface of the tooth from which the canal has originated, and the adjacent cortical table to which the canal opens, along with the length of the GC were studied. Results: GC was observed in 53.2% of teeth. The anatomical tooth aspect of origin was occlusal/ incisal in 41.5% and crown in 82.9% of teeth. Moreover, 51.2% of GCs opened in palatal/lingual cortex and 63.4% of canals were not located along the tooth long axis. Finally, GC was detected in 85.7% of teeth undergoing the crown formation stage. Conclusion: Although GC was introduced as an eruption pathway, this canal is also present in impacted teeth. This means that presence of this canal does not promise the normal eruption of tooth and the anatomical characteristics of GC may influence the eruption process. [ABSTRACT FROM AUTHOR]

Poor fiber orientation and mismatched bone–ligament interface fusion have plagued the regeneration of periodontal defects by cell‐based scaffolds. A 3D bioprinted biomimetic periodontal module is designed with high architectural integrity using a methacrylate gelatin/decellularized extracellular matrix (GelMA/dECM) cell‐laden bioink. The module presents favorable mechanical properties and orientation guidance by high‐precision topographical cues and provides a biochemical environment conducive to regulating encapsulated cell behavior. The dECM features robust immunomodulatory activity, reducing the release of proinflammatory factors by M1 macrophages and decreasing local inflammation in Sprague Dawley rats. In a clinically relevant critical‐size periodontal defect model, the bioprinted module significantly enhances the regeneration of hybrid periodontal tissues in beagles, especially the anchoring structures of the bone–ligament interface, well‐aligned periodontal fibers, and highly mineralized alveolar bone. This demonstrates the effectiveness and feasibility of 3D bioprinting combined with a dental follicle‐specific dECM bioink for periodontium regeneration, providing new avenues for future clinical practice. [ABSTRACT FROM AUTHOR]

Background: Although researchers have been exploring therapeutic strategies of treating serious periodontal tissue loss, including the application of stem cells, tissue regeneration of the periodontal complex involving cementum, periodontium, and alveolar bone has hardly been achieved. Aiming at tackling the problem of severely damaged periodontal complex, it is worth trying to make advantages of Hertwig's epithelial root sheath (HERS) cells to tissue regeneration mimicking the physiological developmental process with their ability of cementum, bone, and periodontium formation. Methods: HERS cells and dental follicle cells (DFCs) were acquired from Sprague Dawley rats' molar germs and identified by immunofluorescence. Alizarin red assay, ALP staining, AKP test, real‐time quantitative polymerase chain reaction (RT‐qPCR) and Western blot were conducted to confirm the osteogenic potential, epithelial‐mesenchymal transition (EMT) character of harvested HERS cells and epithelial‐mesenchymal interaction (EMI) with DFCs. An animal model of periodontal defect was constructed to testify the tissue regeneration ability in vivo. Micro‐CT and histological examinations were interpreted to unveil the tissue repair outcomes. Results: HERS cells expressed strong epithelial cell markers CK14 and E‐cadherin. The in vitro experiments overall showed the concretely enhanced osteogenic differentiation ability in either HERS group or HERS+DFC group. Meanwhile, the in vivo conduction of rat mandibular periodontal repair experiment showed regenerative effectiveness of periodontal complex structure in both HERS and HERS+DFC group in situ, testified by Micro‐CT and histological analysis. Conclusions: HERS cells show potential for periodontal tissue regeneration which suggests the future possibilities of being considered as one of the cell choices for severely damaged periodontal tissue repair. [ABSTRACT FROM AUTHOR]

Objectives: The indication for removal of asymptomatic fully impacted third molars is still controversial. In this study, radiological and histological investigation of the dental follicle of asymptomatic impacted mandibular third molars was performed, aiming to provide a reference for clinical prophylactic extraction of these teeth. Methods: Patients with impacted mandibular third molars were included and the maximum width of the dental follicle around the crown was measured in horizontal, sagittal and coronal sections by cone beam computed tomography. The dental follicles were stained with haematoxylin-eosin, analysed by a pathologist and classified as normal, inflammatory or cystic. A Chi-squared test was used to analyse the association of the incidence of inflammation and cysts with the clinical variables of the impacted mandibular third molars. Results: Thirty-seven samples were normal dental follicles; 52 samples showed inflammatory infiltration with an incidence of 57.14%; 2 samples with a maximum dental follicle width of 2–3 mm were diagnosed as odontogenic cysts, and the incidence was 2.20%. There was no significant difference in the incidence of inflammatory and cystic dental follicles between males and females, or between different age groups (P > 0.05). With an increase of the maximum width of the dental follicle, there was a rise in the incidence and degree of infiltration of chronic nonspecific inflammation. Conclusion: Asymptomatic impacted mandibular third molars tend to be extracted, especially for teeth with a 2–3 mm maximum width of the dental follicle on radiological examination. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to develop liposomes loaded with (-)- epigallocatechin gallate (EGCG) by using the Quality by Design (QbD) approach. Methods: The risk assessment tools (Ishikawa diagram and Risk Estimation Matrix) highlighted three formulation factors, namely phospholipid concentration, phospholipid to cholesterol molar ratio and EGCG concentration that are likely to influence the critical quality attributes (CQAs) of the EGCG containing liposomes and thus were studied through a D-optimal experimental design. Results: The results revealed that all three formulation factors presented a great influence on liposomes CQAs. High concentrations of EGCG and cholesterol were observed to increase the encapsulation of EGCG into liposomes at low values of the phospholipid concentration. On the other hand, high concentrations of EGCG increased liposomal size and zeta potential values. The optimal formulation featured an entrapped drug concentration of 221.9 µg/ml, corresponding to an encapsulation efficiency of 69.2%, while the liposomal size was 175.2 nm. The release profile illustrated a prolonged release of EGCG from the optimal formulation on a period of 72 h, with a total percentage released of 56%. The in vitro studies performed on dental follicle (DF) mesenchymal stem cells and periodontal ligament (PDL) mesenchymal stem cells showed that EGCG exert its antioxidant effect on DF but not on PDL. Conclusion: The application of the QbD concept in the development of EGCG loaded liposomes improved the understanding of the manufacturing process as well as the influence of the formulation factors on the quality attributes of liposomes. [ABSTRACT FROM AUTHOR]

Central odontogenic fibroma (COF) is an extremely rare benign odontogenic tumor, which is associated with an unerupted tooth in one‐third of the cases. Hyperplastic dental follicle (HDF) is an odontogenic hamartomatous lesion associated with delayed or tooth eruption failure in young patients. Dentigerous cyst (DC) is an epithelial‐lined developmental cyst surrounding the crown of an unerupted or impacted tooth. Here, we present a case of 13‐year‐old boy with pericoronal radiolucency around impacted right maxillary canine tooth, which detected during routine dental examination on panoramic radiograph. The size of radiolucency was varied between 5 and 10 mm and was asymmetrical. Lesion was underwent biopsy with suspicion to a dentigerous cyst. On microscopic examination, the lesion was composed of a cellular fibrous connective tissue with odontogenic epithelium in the form of strands or nests throughout the lesion and calcifications in the form of basophilic cementum‐like material and dentinoid. Due to its nonspecific histological features, we encountered a diagnostic dilemma. In this case report, we discuss the clinical and radiologic features of COF, DC, and HDF. We preferred COF for this lesion. By combining surgical and orthodontic treatments, the impacted tooth was directed to its correct position in the maxilla. This case report highlights the importance of clinicopathological correlation in the diagnosis of pericoronal radiolucencies. [ABSTRACT FROM AUTHOR]

Rationale: Multiple Calcifying Hyperplastic Dental Follicle (MCHDF) is an extremely rare condition and is characterised by multiple impacted permanent teeth, with enlarged dental follicles, containing calcifications. Cone-beam computed tomography (CBCT) is the ideal exam for the identification of this condition. Patient Concerns: The present study seeks to compare the behaviour of MCHDF in imaging exams of three clinical cases with their MCHDF imaging diagnoses, in which a change about tooth eruption was observed. Diagnosis: CBCT proved to be an important diagnostic tool for MCHDF, as it is able to identify these small calcifications, as well as measure the size of the follicle. Treatment Outcomes and Take-Away Lessons: With a consistent imaging diagnosis, less invasive treatments become a viable option for this condition, since functional and aesthetic involvement is common in these patients, who often tend to be quite young. [ABSTRACT FROM AUTHOR]

Dental follicles are involved in odontogenesis, periodontogenesis, and tooth eruption. Dental follicles are unique structures, considering that their remnants can persist within the jawbones after odontogenesis throughout life if the tooth does not erupt. Pathological changes may occur in these tissues as individuals age. The changes range from benign to life threatening. Thus, the assessment of age‐related changes in dental follicles associated with unerupted teeth is of paramount importance. In this review, we summarize the physiological roles and changes in dental follicles in odontogenesis, tooth eruption, and aging, in addition to the pathological changes associated with these structures. We encourage investigators to consider this peculiar tissue as a unique model and explore its potential to clarify its importance from the viewpoints of developmental biology, tissue physiology, and pathology. Key Findings: Dental follicle has important roles in odontogenesis, periodontogenesis, and tooth eruption. When tooth eruption is impaired, remnants of dental follicle can permanently persist in the jaws.Oral pathologists tend to refer to the tissue associated with unerupted teeth as "dental follicles". This term should be interpreted with caution, considering that these are remnants of the dental follicle.As individuals age, dental follicles associated with unerupted teeth undergo morphological and molecular changes. Notably, odontogenic cysts and tumors can originate from dental follicles associated with unerupted teeth.Herein, we integrated information on dental follicles from development to aging, and pathological changes. [ABSTRACT FROM AUTHOR]

Dentigerous cysts, also known as follicular cysts, are among the most common developmental cysts of the gnathic bones. The majority of cases are clinically asymptomatic and discovered incidentally on panographic radiographs during routine dental care. The cyst appears as a radiolucency, classically unilocular, associated with the crown of an unerupted or impacted tooth. Usually diagnosed in the 2nd–3rd decade, third molars of the mandible are the most commonly affected teeth. Histologically, dentigerous cysts demonstrate a fibrous or fibromyxoid connective tissue wall lined by squamous epithelium, classically lacking rete ridges. Inflammation may introduce histologic changes, however. The differential diagnosis includes hyperplastic dental follicle, periapical or radicular cyst, unicystic ameloblastoma, odontogenic keratocyst, and other odontogenic cysts and tumors. While the findings are generally classic and pose no diagnostic dilemma, the diagnosis is best made in the context of the appropriate clinical and radiographic setting. Submitted tissue with a lack of history, to include a detailed relationship with the affected tooth, may result in misdiagnosis and subsequent confusion for the clinician. So, despite its simple features, dentigerous cysts are not uncommonly mischaracterized. Therefore a review of a classic case of dentigerous cyst is presented. [ABSTRACT FROM AUTHOR]

In mammals, high concentrations of gonadotropins are necessary early in life to reach a full‐sized pool of ovarian follicles at the age of puberty. This case report describes the reproductive status of a 28‐month‐old, 9.1 kg, crossbred bitch (Bitch 1) which had been treated neonatally with 18.8 deslorelin acetate subcutaneously for contraceptive purposes. The female had just passed pubertal oestrus when hormones were measured and then spayed. The ovaries were histologically assessed. Two crossbred bitches were used for comparisons. Bitch 1's anti‐Müllerian hormone (AMH) and progesterone serum concentrations were 0.35 and 16.7 ng/ml, respectively. The total number of ovarian follicles and proportions were normal and the number of primary and antral follicles was increased. These findings might suggest an enhanced recruitment of the follicle pool to the growing population which could be related to the relatively low AMH concentrations. [ABSTRACT FROM AUTHOR]

The periodontium is essential for supporting the functionality of the tooth, composed of diversity of mineralized and non-mineralized tissues such as the cementum, the periodontal ligament (PDL) and the alveolar bone. The periodontium is developmentally derived from the dental follicle (DF), a fibrous tissue surrounding the developing tooth bud. We previously showed through in vivo lineage-tracing experiments that DF contains mesenchymal progenitor cells expressing parathyroid hormone-related protein (PTHrP), which give rise to cells forming the periodontal attachment apparatus in a manner regulated by autocrine signaling through the PTH/PTHrP receptor. However, the developmental relationships between PTHrP+ DF cells and diverse cell populations constituting the periodontium remain undefined. Here, we performed single-cell RNA-sequencing (scRNA-seq) analyses of cells in the periodontium by integrating the two datasets, i.e. PTHrP-mCherry+ DF cells at P6 and 2.3kb Col1a1 promoter-driven GFP+ periodontal cells at P25 that include descendants of PTHrP+ DF cells, cementoblasts, osteoblasts and periodontal ligament cells. This integrative scRNA-seq analysis revealed heterogeneity of cells of the periodontium and their cell type-specific markers, as well as their relationships with DF cells. Most importantly, our analysis identified a cementoblast-specific metagene that discriminate cementoblasts from alveolar bone osteoblasts, including Pthlh (encoding PTHrP) and Tubb3. RNA velocity analysis indicated that cementoblasts were directly derived from PTHrP+ DF cells in the early developmental stage and did not interconvert with other cell types. Further, CellPhoneDB cell-cell communication analysis indicated that PTHrP derived from cementoblasts acts on diversity of cells in the periodontium in an autocrine and paracrine manner. Collectively, our findings provide insights into the lineage hierarchy and intercellular interactions of cells in the periodontium at a single-cell level, aiding to understand cellular and molecular basis of periodontal tissue formation.

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 followups 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. [ABSTRACT FROM AUTHOR]

Aging is not a matter of choice; it is our fate. The “time-dependent functional decline that affects most living organisms” is coupled with several alterations in cellular processes, such as cell senescence, epigenetic alterations, genomic instability, stem cell exhaustion, among others. Age-related morphological changes in dental follicles have been investigated for decades, mainly motivated by the fact that cysts and tumors may arise in association with unerupted and/or impacted teeth. The more we understand the physiology of dental follicles, the more we are able to contextualize biological events that can be associated with the occurrence of odontogenic lesions, whose incidence increases with age. Thus, our objective was to assess age-related changes in metabolic pathways of dental follicles associated with unerupted/impacted mandibular third molars from young and adult individuals. For this purpose, a convenience sample of formalin-fixed paraffin-embedded (FFPE) dental follicles from young (26 y.o., n = 7) individuals was selected. Samples were analyzed by high-performance liquid chromatography-mass spectrometry (HPLC-MS)-based untargeted metabolomics. Multivariate and univariate analyses were conducted, and the prediction of altered pathways was performed by mummichog and Gene Set Enrichment Analysis (GSEA) approaches. Dental follicles from young and older individuals showed differences in pathways related to C21-steroid hormone biosynthesis, bile acid biosynthesis, galactose metabolism, androgen and estrogen biosynthesis, starch and sucrose metabolism, and lipoate metabolism. We conclude that metabolic pathways differences related to aging were observed between dental follicles from young and adult individuals. Our findings support that similar to other human tissues, dental follicles associated with unerupted tooth show alterations at a metabolic level with aging, which can pave the way for further studies on oral pathology, oral biology, and physiology.

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. [ABSTRACT FROM AUTHOR]

Tooth eruption is closely linked to the normal development of dentition and proper establishment of occlusion. Disturbances in tooth eruption may affect oral physiological functions, facial contour and aesthetics; it is therefore important to understand the eruption process. This process is a complex biological event involving dynamic changes at the tissue and cellular levels. It is guided by anatomical structures as well as biological and molecular factors that result in the movement of the tooth to its final functional position in the oral cavity. Evidence increasingly suggests that stem cells contribute to tooth development and eruption. Multiple stem cell populations have been discovered in teeth and in their supporting tissues, such as dental follicle precursor cells, orofacial bone--/bone marrow--derived mesenchymal stem cells, periodontal ligament stem cells, stem cells from the apical papilla and dental pulp stem cells. These stem cells exhibit distinct differentiation capacities and are closely linked to alveolar bone remodelling, periodontium development and root formation during the eruption process. The present review summarises the current knowledge of the characteristics and functions of orofacial stem cells in tooth eruption, with a particular focus on recent discoveries concerning their lineage allocation and regulatory mechanisms. [ABSTRACT FROM AUTHOR]

The dental follicle (DF) is the tissue that surrounds the crown of the developing tooth. In X-ray, images it appears as a radiolucent area. The removal of an impacted mandibular third molar is a common procedure in oral surgery. The radiographic evidence of pathology, commonly defined as a pericoronal radiolucency measuring at least mm 2.5 mm in any dimension, is accepted for the extraction of impacted mandibular third molars. Mesioangular impactions are usually more closely placed to the inferior alveolar canal, and the use of cone beam computer tomography (CBCT) before the removal of impacted mandibular third molars has been reported to be appropriate in these cases. The aim of this study was to evaluate the microscopic features of radiographically normal DFs associated with mesioangular impacted mandibular third molars examined through CBCT. Thirteen mesioangular impacted third molars from ten patients (5 males and 5 females, mean age ± SD: 15.1 ± 1.66) with a maximum width of the DF <2.5 mm, as digitally established by CBCT, were included in this study. All the DFs associated with the removed third molars were examined histologically through the analysis of different variables. The mean (±SD) and range of the maximum width of the DFs were 1.35 (±0.47) mm and 0.71–2.21 mm, respectively. Nine (69.23%) DFs showed odontogenic remnants, five (38.46%) showed focal squamous metaplasia and eight (61.53%) mild mesenchymal myxoid degeneration. The maximum width of the DF failed to show any significant correlation with all the histological variables considered in this study. Aware of the limited number of patients included in this study, the histo-radiographic correlation in our case series confirm data in the literature, according to which normal pericoronal imaging may be associated with DF tissue changes/variations that in turn are potentially associated with the development of pathologies including odontogenic cysts and tumors. Whether these changes/variations are enough to make prophylactic germectomy of impacted third molars the standard by themselves remains to be established. However, they require accurate correlations with the radiographic data for the appropriate histologic assessment of a DF. [ABSTRACT FROM AUTHOR]

The dental follicle is part of the tooth germ, and isolated stem cells from this tissue (dental follicle cells; DFCs) are considered, for example, for regenerative medicine and immunotherapies. However somatic stem cells can also improve pharmaceutical research. Cell proliferation is limited by the induction of senescence, which, while reducing the therapeutic potential of DFCs for cell therapy, can also be used to study aging processes at the cellular level that can be used to test anti-aging pharmaceuticals. Unfortunately, very little is known about cellular senescence in DFCs. This review presents current knowledge about cellular senescence in DFCs. [ABSTRACT FROM AUTHOR]

Background: FHIT (Fragile histidine triad) a member of tumor suppressor family, has been extensively studied in many solid tumors including head and neck squamous cell carcinoma. Among all head and neck cyst and tumors odontogenic lesions account approximately 3%-9%. The molecular pathogenesis of these lesions is less explored. Defects in cell cycle regulators and tumor suppressor genes could result in the development of odontogenic cyst and tumors. Hence, we aimed to determine the significant role of a tumor suppressor gene FHIT in most commonly occurring odontogenic lesions mainly ameloblastoma, odontogenic keratocyst and dentigerous cyst. Subjects and Methods: Immunohistochemical analysis of FHIT was done in ameloblastoma, odontogenic keratocyst, dentigerous cyst and dental follicle. Interpretation of the stained slides were done using standard scoring criteria by two pathologist. The results were subjected for statistical analysis. Results: Expression of FHIT varied among the groups, with highest negative expression in ameloblastoma 44.4% followed by odontogenic keratocyst 14% and 100%positive expression was seen in dentigerous cyst. The expression levels between the groups were statistically insignificant. Conclusion: The varied expression or negative expression of FHIT could be considered as an indicator for aggressive behavior and transformation of preneoplastic/cystic epithelium.

Background and purpose: Keratocystic odontogenic tumor tends to recur and behave more aggressively than follicular cysts and dental follicles. Eosinophils are multifunctional leukocytes, but their role in oral lesions is controversial. Current study aimed at assessing the density of eosinophils in aggressive odontogenic lesions. Materials and methods: In this descriptive-analytical cross-sectional study, paraffin blocks were obtained from Babol Dental School archives including 16 cases of keratocyst,19 follicular cyst, and 12 dental follicle and their demographic characteristics were extracted. The overall density of eosinophils and density of eosinophils in adjacent areas and away from odontogenic epithelium were examined in slides stained with Congo red in 10 microscopic fields (40x). Results: Eosinophil density was 0.08±0.3 in dental follicles, 1.7±2.1 in follicular cysts, and 6.14±5.6 in keratocystic odontogenic tumors. The eosinophil density in areas adjacent to odontogenic epithelium in keratocyst and follicular cysts was greater than that in areas away from odontogenic epithelium (P>0.001). Conclusion: Based on current study, eosinophils appear to influence the pathogenesis of follicular cysts and keratocystic odontogenic tumors. Their increased density in keratocysts, especially in the vicinity of odontogenic epithelium, is effective in its aggressive behavior.

Inflammatory cytokines such as interleukin-1α (IL-1α) are increased in teeth with periapical lesions. Primary teeth with periapical lesions have a propensity for accelerated eruption of the successors. In this study, we asked whether increased levels of IL-1α in the dental follicle (DF) occurring as the result of periapical lesions promote tooth eruption, possibly due to enhanced osteoclastic remodeling of DF cells (DFCs). To this end, we studied the effect and possible mechanism of IL-1α on osteogenic differentiation, osteoclastogenic activity, and matrix remodeling of DFCs. Results demonstrated that DFCs cultured with IL-1α exhibited reduced osteogenic capacity, higher osteoclastogenic activity, and stronger invasive ability. Phosphorylation of JNK and p38 was upregulated, and pretreatment with SB203580 and SP600125 reversed the effect of IL-1α on DFCs. Neonatal rats subjected to subcutaneous injection of an IL-1 receptor antagonist exhibited a reduced number in activated osteoclasts, increased expression of alkaline phosphatase and osteopontin, and delayed tooth eruption. These data support our hypothesis that increased IL-1α cytokine levels as they occur during periodontal and periapical inflammation cause osteoclastic remodeling of the alveolar socket as a requirement for tooth eruption and thus may indirectly promote the vertical eruption of teeth toward the occlusal plane. [ABSTRACT FROM AUTHOR]

Dental follicle cells (DFCs) are progenitor cells for mineralizing cells such as alveolar osteoblasts, but little is known about the mechanisms of the differentiation. Interestingly, different cell lines sometimes have different potentials to differentiate into mineralizing cells. In this study, we compared two different DFC lines, with one cell line (DFC_B) showing a high alkaline phosphatase (ALP) activity in long-term cultures with standard medium and a reliable mineralizing potential. However, the other cell line DFC_A shows low ALP activity in standard medium and almost no mineralization. Known osteogenic markers such as RUNX2 were similarly expressed in both cell lines. However, the proosteogenic signaling pathway of the bone morphogenetic protein (BMP) is induced in DFC_B, and the parathyroid hormone-related protein (PTHrP), which is involved in tooth root development, was also expressed more strongly. Previous studies have shown that the secreted PTHrP negatively regulate the transition from pre-osteoblastic progenitors to osteoblasts, but we showed that an inhibition of PTHrP gene expression reduced the ALP activity and the BMP-signaling pathway. In addition, endogenously expressed PTHrP is located in the cell nucleus. In contrast, supplementation of PTHrP or an inhibitor for the PTHrP receptor did not affect the ALP activity of DFC_B. In conclusion, our data suggest that a high endogenous expression of PTHrP in DFCs supports the induction of osteogenic differentiation via an intracrine mode. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells may be used for the treatment of sepsis. Dental follicle stem cells (DFSCs) are easily accessible but have not been studied in vivo or in clinical trials in sepsis models. We aim to elucidate DFSC effects on host immunological functions in a rat cecal ligation and perforation (CLP) sepsis model. Adult male rats were categorized into group 1 (sham procedure SP), group 2 (SP + 1 × 106 DFSCs administered 0 h after SP), group 3 (CLP + saline), group 4 (CLP + 1 × 106 DFSCs administered 0 h after CLP), and group 5 (CLP + 1 × 106 DFSCs administered 4 h after CLP). Green fluorescent protein–labeled cells were used for imaging. Histopathological examination of ileal tissues was performed. A significant increase in the percentage of CD4+/CD25+/Foxp3+ Treg cells in groups 4 and 5 occurred compared with that in group 3. No significant changes in CD3+/CD4+ helper T-cells and CD3+/CD8+ cytotoxic T-cells were observed. Treatment with DFSCs at 4 h significantly decreased the level of TNF-α compared with that in group 3. No significant changes in IL-10 levels and lymphocyte proliferation suppression were observed. During histopathological examination, no high scoring (Chiu scores: 3 or 4) rats were observed in the curative treatment group (group 5). Treatment with DFSC after 4 h of sepsis induction downregulates tissue inflammatory responses by decreasing TNF-α levels and increasing Treg cell ratio. This also has a protective effect on intestinal tissues during sepsis. [ABSTRACT FROM AUTHOR]

Introduction: Third molars (TMs) are the most frequently impacted teeth due to the frequent lack of space in the dental arch resulting in their malposition or inability to erupt. Partially erupted TMs that cause recurrent inflammatory conditions must be removed. The aim of this study was to assess TM position on panoramic radiographs. Materials and methods: We evaluated 200 panoramic radiographs of patients 18-72 years of age. Teeth were assessed in terms of the presence of dental follicle, cervix/root ratio and root development stage. Maxillary TMs were assessed using the Archer and Pell and Gregory classifications, whereas the mandibular ones according to Pell and Gregory, Winter, IAN and Pederson classifications. Results: 622 TMs were assessed. In the maxilla, the most common type was A-positioned, vertically angulated TM with completely formed root/roots. In the mandible, the most common type was A1-positioned, mesioangular TM with completely formed root/roots and without enlarged follicle. According to Pederson's index, 59.44% TMs were moderately difficult to extract. Most roots were in contact with inferior alveolar nerve. Conclusions: The use of the classifications mentioned above is helpful in assessment of the surgery difficulty level. In the long term this allows to increase the predictability of the procedure and minimize the intra- and post-operative complications. [ABSTRACT FROM AUTHOR]

Several studies have indicated that dietary silicon (Si) is beneficial for bone homeostasis and skeletal health. Furthermore, Si-containing bioactive glass biomaterials have positive effects on bone regeneration when used for repair of bone defects. Si has been demonstrated to stimulate osteoblast differentiation and bone mineralisation in vitro. However, the mechanisms underlying these effects of Si are not well understood. The aim of the present study was to investigate the effects of soluble Si on osteogenic differentiation and connexin 43 (CX43) gap junction communication in cultured pluripotent cells from human dental follicles (hDFC). Neutral Red uptake assay demonstrated that 25 μg/ml of Si significantly stimulated hDFC cell proliferation. Dosages of Si above 100 μg/ml decreased cell proliferation. Alizarin Red staining showed that osteogenic induction medium (OIM) by itself and in combination with Si (25 μg/ml) significantly increased mineralisation in hDFC cultures, although Si alone had no such effect. The expression of osteoblast-related markers in hDFC was analysed with RT-qPCR. OSX, RUNX2, BMP2, ALP, OCN, BSP and CX43 genes were expressed in hDFC cultured for 1, 7, 14 and 21 days. Expression levels of BMP-2 and BSP were significantly upregulated by OIM and Si (25 μg/ml) and were also induced by Si alone. Notably, the expression levels of OCN and CX43 on Day 21 were significantly increased only in the Si group. Flow cytometric measurements revealed that Si (50 μg/ml) significantly increased CX43 protein expression and gap junction communication in hDFC. Next-generation sequencing (NGS) and bioinformatics processing were used for the identification of differentially regulated genes and pathways. The influence of OIM over the cell differentiation profile was more prominent than the influence of Si alone. However, Si in combination with OIM increased the magnitude of expression (up or down) of the differentially regulated genes. The gene for cartilage oligomeric matrix protein (COMP) was the most significantly upregulated. Genes for the regulator of G protein signalling 4 (RGS4), regulator of G protein signalling 2 (RGS2), and matrix metalloproteinases (MMPs) 1, 8, and 10 were also strongly upregulated. Our findings reveal that soluble Si stimulates Cx43 gap junction communication in hDFC and induces gene expression patterns associated with osteogenic differentiation. Taken together, the results support the conclusion that Si is beneficial for bone health. [ABSTRACT FROM AUTHOR]

Ki67 expressions are the most widely used markers to show the pathologic proliferation and early-stage tumoral alterations in vital tissues. This study aimed to compare the expressions of Ki67 protein between smokers' and nonsmokers' pericoronal follicles of asymptomatic impacted lower third molars (ILTMs), thirty-seven specimens of DFs associated with impacted mandibular third molars fully covered by mucosa or bone were surgically removed from 37 patients. The patients were divided into 2 age groups. 19 of thirty-seven DFs were between (18-24) years (Group 1) and 18 were (< 24) years (Group 2). Ki-67 immunostaining was evaluated in the epithelial component of the all DFs, independent-samples t-test analyses were conducted with SPSS 10.0 with statistical significance set at a P-value equal to 5%. There were statistically significant differences in the mean values of KI-67 (%) expression between the non-smokers group and the smokers group regardless of the patient's age group The values of KI-67 (%) expression in the non-smokers group were smaller than in the smokers group, in both the( 18-24) age group and the( 24 >) year age group. Separately in the research sample. this study showed that DFs of smokers have higher Ki67 expressions than nonsmokers follicles. [ABSTRACT FROM AUTHOR]

Lesions arising from odontogenic tissues of the jaws vary from very common to very rare. Some, such as radicular cysts, form a routine part of the diagnostic workload for histopathologists who report specimens from the head and neck, but many other lesions are rarely seen and can cause significant diagnostic difficulty for the non-specialist. These issues are compounded by the vagaries of dental disease (and terminology used by dentists and oral surgeons) and issues in the interpretation of radiographic images, which can be crucial to making a correct diagnosis. In this review article, we will discuss a number of areas of diagnostic difficulty, largely based on the authors experience in receiving tertiary referrals. This will focus on practical advice to help avoid the pitfalls in the diagnosis of odontogenic lesions. [ABSTRACT FROM AUTHOR]

Ameloblastoma is a benign odontogenic tumor in the jaw bone and can become malignant. Ameloblastoma covers 9-11% of all cases of odontogenic tumors present. The incidence of malignant ameloblastoma reaches 1.79 per 10 million people per year. Generally, as much as 80% of cases of ameloblastoma occur in the mandibular region with a posterior predilection. Ameloblastoma lesions are very progressive, invasive, and infiltrate the bone in the medullary spaces and cortical bone. In general, patients with ameloblastoma perform operative measures such as enucleation and curettage in the bone, even marginal or segmental resection can also be performed. However, after the operative procedure it causes a defect in the jaw bone. This condition, if not done regeneratively can cause effects such as speech disorders, masticatory disorders and deformity in the jawbone. The combination of dental follicle stem cells is planted in a nanocomposite fibrous scaffold to optimize the regeneration of osteogenic cells. Dental follicle stem cells and Nanocomposite fibrous scaffold have the ability as angiogenesis and osteoinductive. To analyze the potential combination of dental follicle stem cells and Nanocomposite fibrous scaffold to regenerate postoperative ameloblastoma bone defects. The use of dental follicle stem cell has the osteoinductive ability by increasing the expression of RunX2, Coll1, and ALP markers which play a role in inducing osteoblast formation. The use of Nanocomposite fibrous scaffold can release VEGF, FGF2, and BMP2 which are useful in stimulating vascularization and bone regeneration. The combination of dental follicle stem cells and nanocomposite fibrous scaffold can increase proliferation, differentiation and osteogenic stimulation of stem cells. The combination of dental follicle stem cells and nanocomposite fibrous scaffold has the potential to regenerate postoperative ameloblastoma bone defects. [ABSTRACT FROM AUTHOR]

Collagen signaling is critical for proper bone and tooth formation. Discoidin domain receptor 2 (DDR2) is a collagen-activated tyrosine kinase receptor shown to be essential for skeletal development. Patients with loss of function mutations in DDR2 develop spondylo-meta-epiphyseal dysplasia (SMED), a rare, autosomal recessive disorder characterized by short stature, short limbs, and craniofacial anomalies. A similar phenotype was observed in Ddr2-deficient mice, which exhibit dwarfism and defective bone formation in the axial, appendicular, and cranial skeletons. However, it is not known if Ddr2 has a role in tooth formation. We first defined the expression pattern of Ddr2 during tooth formation using Ddr2-LacZ knock-in mice. Ddr2 expression was detected in the dental follicle/sac and dental papilla mesenchyme of developing teeth and in odontoblasts and the periodontal ligament (PDL) of adults. No LacZ staining was detected in wild-type littermates. This Ddr2 expression pattern suggests a potential role in the tooth and surrounding periodontium. To uncover the function of Ddr2, we used Ddr2slie/slie mice, which contain a spontaneous 150-kb deletion in the Ddr2 locus to produce an effective null. In comparison with wild-type littermates, Ddr2slie/slie mice displayed disproportional tooth size (decreased root/crown ratio), delayed tooth root development, widened PDL space, and interradicular alveolar bone defects. Ddr2slie/slie mice also had abnormal collagen content associated with upregulation of periostin levels within the PDL. The delayed root formation and periodontal abnormalities may be related to defects in RUNX2-dependent differentiation of odontoblasts and osteoblasts; RUNX2-S319-P was reduced in PDLs from Ddr2slie/slie mice, and deletion of Ddr2 in primary cell cultures from dental pulp and PDL inhibited differentiation of cells to odontoblasts or osteoblasts, respectively. Together, our studies demonstrate odontoblast- and PDL-specific expression of Ddr2 in mature and immature teeth, as well as indicate that DDR2 signaling is important for normal tooth formation and maintenance of the surrounding periodontium. [ABSTRACT FROM AUTHOR]