The radiological and histological investigation of the dental follicle of asymptomatic impacted mandibular third molars

Analysis of mast cells in dental follicle and dentigerous cyst: A histopathological study

Introduction

Mast cells are large granular cells that arise from multipotent CD 34+ precursors in the bone marrow normally distributed throughout the connective tissues. Following activation of immunologic or nonimmunologic stimuli, mast cells release secretory granules which give the characteristic metachromatic appearance with toluidine blue stain. Release of numerous mediators on degranulation of mast cells plays an important role in the pathogenesis of odontogenic cysts.

Context

Odontogenic cysts, such as dentigerous cysts, arise due to the accumulation of fluid between the crown of an unerupted tooth and the reduced enamel epithelium. Dental follicles, which surround developing teeth, can also undergo cystic transformation. Mast cells activity might contribute to cyst expansion and bone resorption, highlighting their potential role in cystic pathology.

Aims

To study the presence of mast cells in the dental follicle and dentigerous cyst. To quantify the mast cells in the abovementioned subjects. To study the pattern of distribution of mast cell distribution in different zones of the study groups.

Settings and Design

This was histopathological study conducted at the Department of Oral Pathology and Microbiology, Vydehi College of Dental Sciences and Research Centre, Bengaluru, between 2012 and 2015.

Methods and Material

Our study was conducted in the Department of Oral Pathology and Microbiology at Vydehi College of Dental Sciences and Research Centre in the year 2012 to 2015. Histopathologically analyzed 30 cases each of dental follicle, and dentigerous cysts were taken and 4-5 micron sections were stained with toluidine blue. Counting of mast cells was done in three different zones which included subepithelial, intermediate, and deep zone. The results were tabulated and statistically analyzed.

Statistical Analysis Used

Kruskal-Wallis Chi-squared test.

Results

Both dental follicles and dentigerous cysts showed the presence of mast cells, and highest numbers of mast cells were seen in subepithelial zone followed by intermediate and deep zones. There was statistically significant relation in the number of mast cells in dentigerous cysts and dental follicle along subepithelial and intermediate zone with a P value of <0.05. In our study, we also found increased mast cell count in inflamed cases of dental follicle and dentigerous cyst compared with noninflamed cases with a P value of <0.01.

Conclusions

It is well known that mast cells play a role in the initiation of inflammation, and this inflammatory process may be associated with pericoronal follicle enlargement, a process that could result in cystic transformation of the follicle. Hence, regular radiographic follow-up is necessary especially for teeth with a maximum dental follicle width of 2-3 mm.

Conditioned Medium Derived From Human Dental Follicle Mesenchymal Stem Cells Alleviates Macrophage Proinflammatory Responses Through MAPK-ERK-EGR1 Axis

The regulation of macrophage polarization by mesenchymal stem cells (MSCs) is a prominent area of research but faces challenges due to limited MSC sources and incomplete understanding of underlying mechanisms. We sought to identify an accessible MSC source and investigate how MSCs regulate macrophage polarization using high-throughput sequencing. We isolated dental follicle MSCs from discarded human third molar dental follicles and cocultured them with THP-1-derived macrophages in the conditioned medium. Transcriptome sequencing identified differentially expressed genes (DEGs) in macrophages, integrating with multiomics database analysis to uncover polarization mechanisms. Our findings demonstrated successful MSC extraction from dental follicles, with the conditioned medium suppressing proinflammatory macrophage functions and influencing macrophage subtyping. MSCs, through paracrine signaling, activated the mitogen-activated protein kinase (MAPK) pathway, leading to extracellular regulated protein kinases (ERK)1/2 phosphorylation and upregulation of early growth response 1 (EGR1) protein. Elevated EGR1 levels inhibited inflammatory gene expression, inhibiting the pro-inflammatory immunoregulatory function of macrophages in inflammatory states. This study provides an efficient method for in vitro macrophage polarization identification. It offers insights into MSC-regulated polarization mechanisms, with potential clinical implications for anti-inflammatory therapy and immune regulation.

Immunohistochemical Analysis of Dentigerous Cysts and Odontogenic Keratocysts Associated with Impacted Third Molars-A Systematic Review

OBJECTIVE

This systematic review investigates the diagnostic, prognostic, and therapeutic implications of immunohistochemical markers in dentigerous cysts (DCs) and odontogenic keratocysts (OKCs) associated with impacted third molars.

MATERIALS AND METHODS

A comprehensive search strategy was employed across major databases including MEDLINE/PubMed, EMBASE, and Web of Science, from the inception of the databases to March 2024. Keywords and Medical Subject Heading (MeSH) terms such as "dentigerous cysts", "odontogenic keratocysts", "immunohistochemistry", "Ki-67", and "p53" were used. The PRISMA 2020 guidelines were followed to ensure methodological rigor. Inclusion criteria encompassed studies on humans and animals providing definitive diagnoses or specific signs and symptoms related to DCs and OKCs, with results on protein expression derived from immunohistochemistry, immune antibody, proteomics, or protein expression methods.

RESULTS

Of the 159 studies initially identified, 138 met the inclusion criteria. Our analysis highlighted significantly higher expressions of Ki-67 (22.1% ± 4.7 vs. 10.5% ± 3.2, p < 0.001), p53 (15.3% ± 3.6 vs. 5.2% ± 1.9, p < 0.001), and Bcl-2 (18.4% ± 3.2 vs. 8.7% ± 2.4, p < 0.001) in OKCs compared to DCs, indicating a higher proliferative index, increased cellular stress, and enhanced anti-apoptotic mechanisms in OKCs. Additionally, PCNA levels were higher in OKCs (25.6% ± 4.5 vs. 12.3% ± 3.1, p < 0.001). Genetic mutations, particularly in the PTCH1 gene, were frequently observed in OKCs, underscoring their aggressive behavior and potential malignancy.

CONCLUSIONS

The findings emphasize the significant role of immunohistochemical markers in distinguishing between DCs and OKCs, with elevated levels of Ki-67, p53, Bcl-2, and PCNA in OKCs suggesting a higher potential for growth and recurrence. Genetic insights, including PTCH1 mutations, further support the need for personalized treatment approaches. These markers enhance diagnostic accuracy and inform targeted therapeutic strategies, potentially transforming patient management in oral and maxillofacial surgery.

Role of αENaC in root resorption of adjacent teeth due to entirely impacted mandibular third molars

BACKGROUND

Entirely impacted mandibular third molar (EIM3M) concerns the pathological external root resorption (ERR) of the adjacent mandibular second molar (M2M) and formation of granulation tissue between two molars. The study aimed to clarify the effect of αENaC, a mechano-sensitive molecule, to explore the mechanical mechanism in this scenario.

METHODS

The force EIM3M exerted on M2M was proved by finite element analysis. αENaC expressions were tested by real-time polymerase chain reaction (PCR), immunoblotting and immunofluorescence. Inflammatory and epithelial-mesenchymal transition (EMT)-related molecules expressions were also detected by real-time PCR. The correlation was analyzed by Spearman's correlation analysis, and receiver-operator characteristic (ROC) curve was further exhibited.

RESULTS

The force was concentrated in the ERR area. αENaC was upregulated, positively correlated with ERR degree and localized to the fibroblasts in ERR granulation tissues. Moreover, αENaC was respectively and positively associated with elevated TNF-α and N-cadherin in ERR granulation tissues. More importantly, ROC analysis verified αENaC as a novel indication of the incidence of this disease.

CONCLUSIONS

Our finding revealed the force from EIM3M causing ERR of M2M, and elucidated the expression and localization of αENaC and its positive correlation with inflammation, EMT and disease severity, suggesting a novel indication in this disease.

Dentists' perception of third molar surgery in the Kingdom of Saudi Arabia: A cross sectional pilot study

Background/purpose

Concerns about the indications for the surgical removal of third molars have not yet reached a decisive agreement. The aim of the study was to evaluate the perception and practice of Saudi' dentists when encountering third molars clinical situations including diagnosis, treatment, and postsurgical care.

Materials and methods

A cross-sectional survey was conducted and approved by the ethics research committee at Prince Sattam Bin Abdulaziz (PSAU). The survey comprised of four sets of questions with multiple-choice answers including the participants' details and type of practice (private or government), clinical awareness and attitude regarding lower third molars surgery, and the confidence level of dentists when performing third molars extraction. The survey was published online with a timeframe of three months to respond.

Results

196 participants responded to the designated survey (55 dental interns and 141 general dental practitioners (GPs)). Most responses (80.1%) were from Riyadh province (central region). There was a significant difference between GPs and interns in terms of impacted third molars with associated cystic lesions, bony impactions, and diffuse pain (P < 0.05). Male dentists tend to prescribe antibiotics more than female dentists (P = 0.001) and GPs more than interns (P = 0.027). The results also indicated that male dentists were more confident than females when performing third molar extraction. Generally, female dentists preferred to have further training on such surgery (P < 0.05).

Conclusion

Continuing professional development programs both during dental internship and general practice are recommended to improve the required skills of third molar extraction.