Comparison Between the Conventional and Electronic Smoking Effects on Periodontal Health-A Cross-Sectional Study.

Objectives: To compare the adverse effect of e-cigarettes and conventional cigarette smoking on periodontal health. Materials and Methods: Sixty participants were split into two groups of 30 each (Group A-traditional cigarettes and Group B-e-cigarette smokers). Socio-demographic data, smoking, and oral health status were gathered using a self-administered questionnaire. Gingival index (GI), Russell's periodontal index, and clinical attachment loss (CAL) were recorded in patients of both the groups. Results: The mean GI (1.79), periodontal index (5.92), and CAL (3.44) were higher in patients using traditional cigarettes than e-cigarettes. The questionnaire revealed that patients using traditional cigarettes had bleeding gums (32.22%), pus in the gums (39.22%), extracted teeth due to mobility (59.65%), discolored tooth (89.66%), and tongue (71.76%), which was more than e-cigarette smokers. Conclusion: E-cigarette smokers have similar adverse effects on the periodontal tissues but are less as compared to normal cigarette smokers.

Comparative Efficacy of Non-Invasive Therapies in Temporomandibular Joint Dysfunction: A Systematic Review.

Temporomandibular disorder (TMD) is a multifaceted disorder impacting the temporomandibular joint (TMJ), causing substantial discomfort and functional limitations. This systematic review aims to comprehensively assess the effectiveness of non-invasive treatment modalities for TMJ dysfunction, prioritizing a definitive protocol to ensure patient safety and enhance quality of life. Employing the PRISMA guidelines, we meticulously analyzed 20 studies from a pool of 1,417 articles sourced from databases such as PubMed, Google Scholar, ScienceDirect, and Medline. These studies underscore the multifarious nature of TMD and the varied responses to treatments such as physical therapy, laser therapy, ultrasound and electrical stimulation, splint therapy, injections, and arthrocentesis. Notably, the review highlights the paramount importance of precise diagnosis, often through surface electromyography, followed by a tailored treatment approach integrating manual therapy, counseling, and splint therapy. The systematic analysis revealed that while certain treatments such as transcutaneous electrical nerve stimulation and low-level laser therapy showed limited efficacy, combination therapies, especially those involving manual therapy, counseling, and splint therapy, demonstrated substantial improvement in reducing pain, depression, and anxiety. The findings advocate for a non-invasive, patient-centric approach, emphasizing education and symptom management before considering more invasive procedures such as injections and arthrocentesis. The review identifies the need for more comprehensive, longitudinal studies to establish a standardized, evidence-based treatment protocol for TMJ dysfunction, aiming to improve patient outcomes holistically.

Salivary levels of inflammatory and anti-inflammatory biomarkers in periodontitis patients with and without acute myocardial infarction: implications for cardiovascular risk assessment.

Background: Periodontitis is initiated by a dysbiotic activity and furthermore leads to a chronic inflammatory response. The presence of pro-inflammatory markers plays an important role in the inflammatory load. Macrophage inflammatory protein-1 alpha (MIP-1α) and C-reactive protein (CRP) are pro- inflammatory biomarkers that quantify clinical and subclinical inflammation in cardiac ischemia in cardiac inflammation and disease. Adiponectin is an anti-inflammatory marker associated with good health. The susceptibility of periodontitis patients to cardiovascular events needs to be evaluated. Objective: This study aims to assess the levels of biomarkers in periodontitis patients with and without acute myocardial infarction (AMI) compared to controls. Material and methods: Pro-inflammatory and anti-inflammatory analytes were examined by collecting unstimulated saliva from three groups (n = 20/each): healthy individuals, individuals with stage III periodontitis, and post-myocardial infarction patients with stage III periodontitis. The samples were collected within 48 h of AMI. Results: Adiponectin levels were significantly lower in patients with periodontitis with and without AMI compared to controls, while CRP and MIP-1α were significantly higher in patients with periodontitis with and without AMI compared to controls. The highest titers for MIP-1α and CRP were detected among patients with periodontitis with and AMI. Conclusion: Our study provides possible evidence of the association between periodontitis and salivary analytes that occur in tandem with cardiovascular disease. The lower levels of Adiponectin and higher levels of CRP and MIP-1α in patients with periodontitis indicate that this condition is a potential risk factor for cardiovascular disease. The findings emphasize the importance of early detection and intervention for periodontitis patients to prevent cardiovascular events.

The response of salivary proinflammatory biomarkers to tooth extraction in individuals with type II diabetes mellitus.

PURPOSE: This study investigated the levels of salivary proinflammatory cytokines in the saliva of patients living with type II diabetes mellitus (DM) compared to those in healthy individuals three times: before tooth extraction and at 2 hours and 2 days after tooth extraction. METHODS: The study included 27 participants. Among them, 20 (n = 20; 74%) had type II DM, and seven (n = 7; 26%) were healthy control subjects. Saliva samples were collected at three time intervals: before tooth extraction and 2 hours and 2 days after tooth extraction. The salivary biomarkers were investigated using a Luminex multiplex assay. These salivary biomarkers included tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), interleukin 1-beta (IL-1ß), and interferon-gamma (IFN-γ). RESULTS: At baseline, patients with type II DM had significantly lower levels of IL-1ß (P = 0.016). Moreover, 2 hours after extraction, patients with type II DM had significantly lower levels of IL-1ß and TNF-α than did healthy control subjects (P = 0.046 and P = 0.020, respectively). In addition, 2 days after tooth extraction, the DM group had significantly greater IL-6 levels (P = 0.010) than the control group. CONCLUSIONS: In patients with type II DM, salivary proinflammatory biomarker levels are generally comparable or lower than those in healthy control subjects. Proinflammatory cytokines manifest differently in patients with type II DM after tooth extraction than in normal healthy individuals. There is generally a delayed early response of salivary proinflammatory markers in patients living with type II DM who undergo tooth extraction.

Knowledge of Dental Students and Practitioners About Medication-Related Osteonecrosis of the Jaw in the Central Region of Saudi Arabia.

BACKGROUND: Bisphosphonates (BPs) are often used in treating benign and malignant disorders. Medication-related osteonecrosis of the jaw (MRONJ) is a significant problem that arises from the long-term use of BPs. OBJECTIVE: In this study, we assessed the knowledge of students and dentists about MRONJ in the central region of Saudi Arabia. METHODS: A cross-sectional study was conducted to collect information from dental students and practitioners from the central region of Saudi Arabia. A valid, reliable, and structured questionnaire was used to gather data using a non-probability convenient sampling technique. IBM SPSS Statistics for Windows, Version 22.0 (Released 2013; IBM Corp., Armonk, New York, United States) was used to analyse the data. The descriptive data were expressed as frequencies and percentages to evaluate the association between dentists and students concerning overall knowledge related to osteonecrosis of the jaw, and a chi-squared test was applied. RESULTS: In total, 250 individuals completed the questionnaire. The general knowledge of antiresorptive/antiangiogenic medications showed that most dentists (87.5%) and students (68.4%) knew about BP medications. A general lack of understanding about the therapeutic uses of antiangiogenic and antiresorptive medications was demonstrated by the participants. A significant proportion of dentists (58.8%) and students (50.9%) were not convinced that invasive dental procedures can be safely performed on patients receiving intravenous BP therapy. A significant proportion of the participants in the sample were unclear of the principal diseases that antiresorptive and antiangiogenic medications target. A mere 22% of respondents were aware of the accurate definition of medications-related MRONJ. CONCLUSION: There is insufficient knowledge about MRONJ among students and practitioners. Therefore, these findings suggest increased emphasis should be placed on educating dentists and students about this condition to ensure patients receive the best possible care.

P63 and Ki-67 expression in radicular cyst.

Objectives: The aim of the current study was to identify the expression of P63 and its relation to odontogenic epithelial cell proliferation, severity of the inflammatory infiltrate and size of radicular cysts (RCs). Methods: In this retrospective cross-sectional study, 30 cases of paraffin-embedded RCs were randomly selected from the archive. P63 and Ki-67 expression was assessed by immunohistochemistry. Results: Epithelial P63 expression was absent in four (13.3%), weak in 10 (33.3%), and moderate in 16 (53.3%) cases. In the connective tissue wall of RC, P63 expression was absent in two (6.7%) cases, weak in 24 (80.0%) cases, and moderate in four (13.3%) cases. Ki-67 was found to be weakly expressed in 12 (40.0%) cases, moderately expressed in 13 (43.3%), and strongly expressed in five (16.7%) cases. No correlation was found between Ki-67 expression in odontogenic epithelium and P63 expression in the odontogenic epithelium (rho = 0.110, p = .563) or fibrous capsule (rho = 0.160, p = .399). Nevertheless, we found a positive correlation between Ki-67 expression in the odontogenic epithelium and the size of the RC (rho = 0.450, p = .013). The inflammatory infiltrate was negatively correlated with P63 expression in the odontogenic epithelium (rho = -0.428, p = .018), and with the size of cysts (rho = -0.728, p < .001). Conclusions: There is a high expression of P63 throughout the odontogenic epithelium and connective tissue capsule of the RC. P63 expression in the odontogenic epithelium is negatively correlated with the degree of the inflammatory infiltrate but not with epithelial cell proliferation or the size of the cyst.

Molecular pathogenicity of 1-nonadecene and L-lactic acid, unique metabolites in radicular cysts and periapical granulomas.

Recently, 1-nonadecene and L-lactic acid were identified as unique metabolites in radicular cysts and periapical granuloma, respectively. However, the biological roles of these metabolites were unknown. Therefore, we aimed to investigate the inflammatory and mesenchymal-epithelial transition (MET) effects of 1-nonadecene, and the inflammatory and collagen precipitation effects of L-lactic acid on both periodontal ligament fibroblasts (PdLFs) and peripheral blood mononuclear cells (PBMCs). PdLFs and PBMCs were treated with 1-nonadecene and L-lactic acid. Cytokines' expression was measured using quantitative real-time polymerase chain reaction (qRT-PCR). E-cadherin, N-cadherin, and macrophage polarization markers were measured using flow cytometry. The collagen, matrix metalloproteinase (MMP)-1, and released cytokines were measured using collagen assay, western blot, and Luminex assay, respectively. In PdLFs, 1-nonadecene enhances inflammation through the upregulation of some inflammatory cytokines including IL-1ß, IL-6, IL-12A, monocyte chemoattractant protein (MCP)-1, and platelet-derived growth factor (PDGF) α. 1-Nonadecene also induced MET through the upregulation of E-cadherin and the downregulation of N-cadherin in PdLFs. 1-Nonadecene polarized macrophages to a pro-inflammatory phenotype and suppressed their cytokines' release. L-lactic acid exerted a differential impact on the inflammation and proliferation markers. Intriguingly, L-lactic acid induced fibrosis-like effects by enhancing collagen synthesis, while inhibiting MMP-1 release in PdLFs. These results provide a deeper understanding of 1-nonadecene and L-lactic acid's roles in modulating the microenvironment of the periapical area. Consequently, further clinical investigation can be employed for target therapy.

The performance of inferior alveolar nerve block technique among undergraduate students.

AIMS: This study aimed at evaluating the ability to feel bone touch, positive aspirations, and frequency of the success rate during the direct inferior alveolar nerve block (IANB) among dental students. METHODS: This prospective cross-sectional study involved 203 cases of IANB injections for patients requiring extraction of mandibular posterior teeth who visited student dental clinics at Ajman University, Fujairah Campus. Students' performance of direct IANB including ability to perceive bone touch, frequency of positive aspirations, and success rate were reported. RESULTS: Students reported feeling bone contact in 148 (72.9%), 43 (21.2%), and 12 (5.9%) of the first, second, and third attempts during the IANB, respectively. Positive aspiration was found in 46 (22.7%) of the injections. The success was in 195 (96.1%) of the total injections. Spearman's correlation coefficient indicated that there was no significant correlation between the success rate and the result of aspiration (rho = .054, p = .440). Additionally, there was no correlation between attempts to touch the bone and the outcome of the aspiration (rho = -.091, p = .198) or success rate (rho = -.083, p = .240). CONCLUSION: There is a relatively high success rate of direct IANB technique among dental students. This confirms the inclusion of this technique in the curriculum. Furthermore, the high rate of positive aspiration reflects the awareness and competency of dental students with the aspiration technique. In turn, this will reduce the failure of anaesthesia and the subsequent systemic complications.

The Prevalence of EBV and KSHV in Odontogenic Lesions.

OBJECTIVES: Odontogenic lesions evolve as a result of altered dental development. This study aimed to evaluate the prevalence and the coinfection of Epstein-Barr virus (EBV) and Kaposi sarcoma-associated herpesvirus (KSHV) in radicular cysts, dentigerous cysts, odontogenic keratocysts, and ameloblastomas. METHODS: Polymerase chain reaction (PCR) was used to analyse 66 cases of odontogenic lesions for the presence of EBV-DNA and KSHV-DNA. These lesions were 15 radicular cysts, 16 dentigerous cysts, 18 odontogenic keratocysts, and 17 ameloblastomas. RESULTS: EBV-DNA was detected in 24 (36.4%) of the studied samples as follows: 6 samples (40.0%) of radicular cysts, 4 (25.0%) of dentigerous cysts, 10 (55.6 %) of odontogenic keratocysts, and 4 (23.5%) of ameloblastomas (P = .168). KSHV-DNA was found in 16 (24.2%) of the studied samples as follows: 1 sample (6.7%) of radicular cysts, 6 (37.5%) of dentigerous cysts, 8 (44.4 %) of odontogenic keratocysts, and 1 (5.9%) of ameloblastomas (P = .001). Additionally, EBV and KSHV were positively correlated in all studied samples (P = .002). CONCLUSIONS: Both EBV and KSHV are found in odontogenic cysts and ameloblastomas. KSHV and EBV are more prevalent in odontogenic keratocysts than in other studied odontogenic lesions. Further, there is a high prevalence of EBV and KSHV coinfection in odontogenic cysts and ameloblastomas.

Analysis of the Volumetric Asymmetry of the Mandibular Condyles Using CBCT.

OBJECTIVES: The aim of this study was to analyse volumetric asymmetries between the right and left condyles in relation to age, gender, and dental status. MATERIALS AND METHODS: A retrospective analysis of 150 cone beam computed tomography (CBCT) scans was conducted. A single investigator performed the volumetric analysis of the CBCT scans using Vesalius 3D software. The volumetric data were analysed in relation to the gender, age, and dental status. RESULTS: The mean right condylar volume was significantly higher (P < .01) than the left condylar volume. Right and left condylar volumes were significantly higher (P < .01) in male study participants when compared to female study participants. There was no significant difference (P = .47) in the volumetric asymmetry between the male and female study participants. The volumetric asymmetry was significantly higher (P < .01) in the older age groups when compared to the younger age groups. The volumetric asymmetry was significantly higher (P < .01) in the partially and completely edentulous patients when compared to the dentate study participants. The condylar volume on the side having a partially edentulous area was significantly lower than the condylar volume of the contralateral dentate side (P < .001). CONCLUSIONS: The volumetric asymmetry between the right and left condyle significantly increases with age and edentulousness. The result of the study encourages the clinicians to perform volumetric evaluation of the condyles in cases of radiographically evident condylar asymmetries to obtain a more accurate diagnosis.

The pattern of mandibular third molar impaction and its relationship with the development of distal caries in adjacent second molars among Emiratis: a retrospective study.

OBJECTIVES: The purpose of this study was to investigate the pattern of mandibular third molar (MTM) impaction and associated carious lesions in adjacent mandibular second molars (MSMs) in a sample of Emirati individuals. METHODS: This retrospective study assessed 2000 orthopantomograms of Emirati patients who visited the Specialized Fujairah Dental Center between 2015 and 2020. The depth, ramus relation and angulation of the impacted MTMs were assessed according to the Pell and Gregory classification and Winter's classification. In addition, carious lesions in adjacent MSMs associated with the evaluated parameters were identified. RESULTS: A total of 461 (23.05%) of the patients had at least one impacted MTM. The mean age of the study population was 26.24 years. Mesioangular, level B, and class II impactions were the most common, at 47.37% (χ2 = 382.134; p < 0.001), 45.48% (χ2 = 56.889; p < 0.001), and 74.05% (χ2 = 513.099; p < 0.001), respectively. There was a higher percentage of level C impaction among females than among males (χ2 = 19.178; p < 0.001). A total of 126 impacted teeth (18.36%) had associated carious lesions. These carious lesions were predominantly found in teeth with mesioangular impactions (χ2 = 59.430; p < 0.001), level A and B impactions (χ2 = 23.301; p < 0.001), and class II and I impactions (χ2 = 17.918; p = 0.006). CONCLUSIONS: It is imperative to raise awareness of soft tissue mesioangular-impacted MTMs, as they are the most frequently associated with the development of carious lesions in adjacent MSMs. Approximately one quarter of evaluated Emiratis had at least one impacted MTM, with the most prevalent pattern being class II, level B, and mesioangular impactions. Furthermore, surgical removal is expected to be more challenging for females than for males.

Morphological and Chemical Analysis of Different Types of Calcium Silicate-Based Cements.

Objectives: Particle size and shape can influence the properties of materials. However, to improve the physicochemical and biological properties of mineral trioxide aggregate (MTA), silicate-based hydraulic cements were introduced. This study aimed to evaluate and compare the major constituents and crystalline structures along with the surface morphology of different types of calcium silicate-based cement (CSC). Materials and Methods: Six different types of CSC (white Portland cement, white ProRoot MTA, white MTA Angelus, Biodentine, and Endosequence, both putty and paste) were used in this study. Five samples of each material were analyzed in both uncured and cured cement using scanning electron microscopy/energy-dispersive X-ray (SEM/EDX), X-ray diffraction (XRD), and Fourier transform-infrared spectroscopy (FTIR). Results: SEM analysis showed that the surfaces of all materials consisted of particle sizes ranging from 0.194 µm to approximately 51.82 µm. The basic elements found in both uncured and cured cement of all tested materials using EDX were carbon, calcium, silicon, and oxygen. A difference was observed in the presence or absence of magnesium, aluminum, bismuth, zirconium, and tantalum. XRD showed that all tested materials were composed mainly of tricalcium silicate and dicalcium silicate, which are the main components of Portland cement. FTIR analysis showed aromatic rings, phosphine PH, alkyl halides, and alcohol O-H groups in all tested materials but at different wavenumbers. Conclusions: The different types of CSCs tested in this study were primarily modified types of Portland cement with the addition of radiopacifiers. ProRoot MTA and MTA Angelus contained bismuth oxide, Biodentine contains zirconium oxide, whereas Endosequence root repair materials (both putty and paste) contained zirconium oxide and tantalum oxide. Endosequence root repair materials showed smaller particle sizes than the other groups. White PC had the most irregular and large particle sizes. CSC had a smaller particle size, except for MTA Angelus. Clinical Relevance. The composition of CSC has a direct influence on the properties of these cements, which may affect the clinical outcome of the treatment.

The correlated expression of COX-2 and keratin 15 in radicular cysts.

Background: The expression of cyclooxygenase-2 (COX-2) and Keratin-15 (K15) in radicular cysts (RCs) is poorly understood. Identifying the expression of these two markers may modify the current treatment of RC. The objective of this study was to evaluate the expression of COX-2 and its relationship to K15 expression in the odontogenic epithelial cells of the RC. Material and Methods: A total of 18 RCs were immunohistochemically analyzed for COX-2 and K15 expression. The cellular inflammatory reaction in the cyst wall was also assessed by measuring the percentage of inflammatory cells to the total number of cells. Results: COX-2 expression in the odontogenic epithelium of RC was absent in 11.1 % (n=2), mild in 27.8 % (n=5), moderate in 22.2% (n=4) and strong in 38.9% (n=7). Meanwhile, K15 expression was absent in 27.8% (n=5), mild in 16.7% (n=3), moderate in 44.4% (n=8), and strong in 11.1% (n=2) of the cases. The inflammatory infiltrate was mild in 2 cases (11.1%), moderate in 6 cases (33.3%), and high in 10 cases (55.6%). Spearman's correlation test revealed significant correlation (rho= .533; p= .023) between COX-2 and K15 expression in the odontogenic epithelium of RC. However, no correlation was noted between inflammation and expression of COX-2 (rho= 0.248, p=.321) or K15 (rho= -0.162, p= .520). Conclusions: There is high and correlated expression of COX-2 and K15 in the odontogenic epithelium of RC. COX-2 could therefore be involved in epithelial cell differentiation of the cyst. Additionally, the expression of K15 in RC may be an indicator of epithelial cell differentiation. Key words:Cyclooxygenase, COX-2, Keratin-15, K15, Radicular cyst.

Prevalence of unculturable bacteria in the periapical abscess: A systematic review and meta-analysis.

OBJECTIVE: To assess the prevalence of unculturable bacteria in periapical abscess, radicular cyst, and periapical granuloma. METHODS: PubMed, Scopus, Science Direct, and Ovid databases were systematically searched from January 1990 to May 2020. All the included studies were cross-sectional design. The risk of bias was assessed using Joanna Briggs Institute check-list. Heterogeneity was described using meta-regression and mixed-effects model for lesion, country, and sequence technique moderators. Funnel plot and unweighted Egger's regression test were used to estimate the publication bias. Microbiome data on diversity, abundance, and frequency of unculturable bacteria in the periapical lesions were reviewed, analysed, and the principal component analysis (PCA) was performed. RESULTS: A total of 13 studies out of 14,780, were selected for the final analysis. These studies focused on the prevalence of unculturable bacteria in periapical abscesses and related lesions. Approximately 13% (95% CI: 7-23%) of the cumulative number of bacteria derived from periapical abscesses was unculturable. Country moderator significantly (P = 0.05) affects the diversity summary proportion. While the pooled frequency of unculturable bacteria was 8%; 95% CI: 5, 14%, the estimate of the pooled abundance of unculturable bacteria was 5%; 95% CI: 2, 12% with a significant (P = 0.05) country moderator that affects the abundance summary proportion. Of the 62 unculturable bacteria, 35 were subjected to PCA and Peptostreptococcus sp. oral clone CK035 was the most abundant species in periapical abscesses. Hybridization techniques were found to be the most reliable molecular methods in detecting the abundance and frequency of unculturable bacteria. CONCLUSION: The significant prevalence of unculturable bacteria in the periapical abscess, suggests that they are likely to play, a yet unknown, critical role in the pathogenesis and progression of the disease. Further research remains to be done to confirm their specific contributions in the virulence and disease progression.

Immunomodulatory Expression of Cathelicidins Peptides in Pulp Inflammation and Regeneration: An Update.

The role of inflammatory mediators in dental pulp is unique. The local environment of pulp responds to any changes in the physiology that are highly fundamental, like odontoblast cell differentiation and other secretory activity. The aim of this review is to assess the role of cathelicidins based on their capacity to heal wounds, their immunomodulatory potential, and their ability to stimulate cytokine production and stimulate immune-inflammatory response in pulp and periapex. Accessible electronic databases were searched to find studies reporting the role of cathelicidins in pulpal inflammation and regeneration published between September 2010 and September 2020. The search was performed using the following databases: Medline, Scopus, Web of Science, SciELO and PubMed. The electronic search was performed using the combination of keywords "cathelicidins" and "dental pulp inflammation". On the basis of previous studies, it can be inferred that LL-37 plays an important role in odontoblastic cell differentiation and stimulation of antimicrobial peptides. Furthermore, based on these outcomes, it can be concluded that LL-37 plays an important role in reparative dentin formation and provides signaling for defense by activating the innate immune system.

Human cytomegalovirus is present in the odontogenic epithelium of ameloblastoma.

Background: The factor behind the activation of the remnant odontogenic tissues and development of odontogenic cysts and tumors is poorly understood.This study aimed to investigate the presence of human cytomegalovirus (HCMV) in dentigerous cyst (DC), odontogenic keratocyst (OKC), and ameloblastoma (AB). Methods: The study included 41 samples, which distributed into DC (n=13), OKC (n=12), and AB (n=16). Conventional PCR assay and IHC analysis were used to detect the HCMV-DNA and HCMV glycoprotein B (HCMV-gB) respectively. Results: HCMV-DNA was detected in 10 samples (62.5%) of AB, four samples (30.8%) of DC, and three samples (25 %) of OKC respectively (χ2 test = 1.195, p= 0.247). Meanwhile, HCMV-gB was found in 12 (75%) of AB, in 2 (15.4%) of DC, and absent in OKC (0.0%) (χ2 test = 4.122, p= 0.042). Conclusions: The high prevalence of HCMV inside the odontogenic epithelium of AB could indicate a possible role of the virus in the oncogenesis and/or oncomodulation of the AB. Additionally, we recommend the IHC for the detection of HCMV in the odontogenic tumors like AB.

p63 Expression and its Relation to Epithelial Cells Proliferation in Dentigerous Cyst, Odontogenic Keratocyst, and Ameloblastoma.

The current controversy about the classification of odontogenic keratocyst reflects the shortage in the understanding of the odontogenic cysts and tumors. The aim of the present study was to investigate p63 immunoexpression and its relation to the proliferation of the epithelial lining in dentigerous cyst (DC), odontogenic keratocyst (OKC), and follicular type of ameloblastoma (AB). The study involved 36 samples, which are DC (n = 12), OKC (n = 9), and AB (n = 15). p63 protein expression was evaluated by immunohistochemistry. The results on Ki-67 expression were obtained from our previous studies and correlated with p63 expressions. p63 was expressed differently in the studied lesions with various distribution in different study samples. Statistical analysis using Kruskal-Wallis test showed a significant difference in the expression of p63 protein among DC, OKC, and AB (p = 0.048). Subsequently, Mann-Whitney U test revealed the expression of p63 protein was significantly higher in OKC than DC (p = 0.018). Interestingly, Spearman's correlation analysis showed a positive correlation between the expression of p63 and Ki-67 in the odontogenic epithelium of DC (σ = 0.757, P = 0.004) and OKC (σ = 0.741, P = 0.022). While no such a positive correlation was found between the two studied markers in AB group (σ = 0.006, P = 0.983). In conclusion, the present results indicated various expression and correlation of p63 with the proliferation of odontogenic epithelial cells in DC, OKC, and AB. This diversity could reflect a different role and pathways of ΔNp63 in odontogenic tumor than that in odontogenic cyst. These together will help in better understanding the pathogenesis and biological behavior of odontogenic cysts and tumors.

Expression of keratin 15 in dentigerous cyst, odontogenic keratocyst and ameloblastoma.

The etiology and pathogenesis of odontogenic lesions are poorly understood. Keratin 15 (K15) is a type I cytoskeletal protein that provides structural support to the cells and has been considered to be a stem cell marker. The aim of the present study was to evaluate the expression of K15 in the epithelial lining of dentigerous cysts (DCs), odontogenic keratocysts (OKCs) and ameloblastomas (ABs). The study included 41 samples of DCs (n=13), OKCs (n=12), and AB tissues (n=16). K15 protein expression was evaluated via immunohistochemistry and data were statistically analyzed using a Kruskal-Wallis test. K15 was expressed in the majority of the studied lesions with various distributions in the different study samples. The Kruskal-Wallis test revealed non-significant differences in the expression of K15 among the three odontogenic lesions (P=0.380). The present study confirmed the high expression of K15 in the different epithelial layers of DC, OKC and AB. This type of expression excludes the reliability of regarding K15 as a stem cell marker in DC, OKC and AB. However, K15 may reflect the abnormal differentiation of pathological epithelial cells in these lesions.

Odontogenic epithelial proliferation is correlated with COX-2 expression in dentigerous cyst and ameloblastoma.

Investigation of cyclooxygenase (COX)-2 in dentigerous cyst and ameloblastoma may help to improve understanding of the nature and behavior of odontogenic cysts and tumors, and in addition may eventually represent a definitive target for a pharmacological approach in the management of these lesions. The aim of this study was to evaluate COX-2 expression and its correlation with the proliferation of odontogenic epithelium in these lesions. Dentigerous cysts (n=16) and ameloblastomas (n=17) were evaluated. Detection of Ki-67 and COX-2 protein expression was conducted by immunohistochemistry. Data were statistically analyzed using Mann-Whitney U test and Spearman's rank correlation coefficient. No significant differences were found in the expression of Ki-67 and COX-2 between dentigerous cysts and ameloblastomas (P>0.05). A significant positive correlation (P=0.018) and highly significant positive correlation (P=0.004) were found between Ki-67 and COX-2 expression in the odontogenic epithelium of dentigerous cyst and ameloblastoma, respectively. COX-2 was expressed in the odontogenic epithelium of dentigerous cyst and ameloblastoma. It may contribute to local extension of these lesions by increasing the proliferation of their odontogenic epithelial cells.