Salivary DNA Methylation as an Epigenetic Biomarker for Head and Neck Cancer. Part I: A Diagnostic Accuracy Meta-Analysis.

DNA hypermethylation is an important epigenetic mechanism for gene expression inactivation in head and neck cancer (HNC). Saliva has emerged as a novel liquid biopsy representing a potential source of biomarkers. We performed a comprehensive meta-analysis to evaluate the overall diagnostic accuracy of salivary DNA methylation for detecting HNC. PubMed EMBASE, Web of Science, LILACS, and the Cochrane Library were searched. Study quality was assessed by the Quality Assessment for Studies of Diagnostic Accuracy-2, and sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (dOR), and their corresponding 95% confidence intervals (CIs) were calculated using a bivariate random-effect meta-analysis model. Meta-regression and subgroup analyses were performed to assess heterogeneity. Eighty-four study units from 18 articles with 8368 subjects were included. The pooled sensitivity and specificity of salivary DNA methylation were 0.39 and 0.87, respectively, while PLR and NLR were 3.68 and 0.63, respectively. The overall area under the curve (AUC) was 0.81 and the dOR was 8.34. The combination of methylated genes showed higher diagnostic accuracy (AUC, 0.92 and dOR, 36.97) than individual gene analysis (AUC, 0.77 and dOR, 6.02). These findings provide evidence regarding the potential clinical application of salivary DNA methylation for HNC diagnosis.

Detection of the Accessory Mental Foramina on Human Mandibles Using Cone-beam Computed Tomography: A Systematic Review and Meta-analysis.

INTRODUCTION: This study aimed to perform a systematic review and meta-analysis on accessory mental foramen (AMF) research using cone-beam computed tomographic (CBCT) imaging. METHODS: A systematic review was performed in PubMed, Embase, Thomas Reuter's Web of Science, Scopus, and ScienceDirect databases according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement. Articles focusing on AMF prevalence and location using CBCT imaging were selected without language restrictions. Studies reporting pooled results only or presenting any pathology in the area surrounding the mental foramen (MF) were excluded. A meta-analysis using random effects was performed. RESULTS: The present meta-analysis included a total of 46 articles involving 21,761 subjects. The overall pooled AMF prevalence was 7.87% (95% confidence interval [CI], 6.69-9.24) in subjects and 4.75% (95% CI, 3.79-5.95) in hemimandibles (n = 31,158). AMF presence was most commonly unilateral, reaching 90.15% (95% CI, 82.98-94.49). AMFs were significantly more frequent in right hemimandibles (χ2 = 5.20, P < .05) and were most commonly located posterior and inferior to the MF. However, AMFs superior to the MF were also observed in 47.43% (95% CI, 38.45-56.58) of cases. The studies conducted over the last 3 years showed significantly higher AMF prevalence levels (χ2 = 5.12, P < .05). CONCLUSIONS: Our meta-analysis demonstrates that AMF prevalence is considerable and should not be underestimated. AMFs are most frequently located in right hemimandibles. The presence of AMFs superior to the MF is frequent. Around 3% of people present superior AMFs. This fact puts those patients at greater risk for injury when performing periapical surgery in this area.

Anatomical characteristics and visibility of mental foramen and accessory mental foramen: Panoramic radiography vs. cone beam CT.

BACKGROUND: The mental foramen (MF) is a small foramen located in the anterolateral region of the mandible through which the mental nerve and vessels emerge. The knowledge on the anatomic characteristics and variations of MF is very important in surgical procedures involving that area. The aim of this study was two-fold: firstly, to analyze the anatomic characteristics of MF and the presence of accessory mental foramen (AMF) using CBCT and, secondly, to compare the capability of CBCT and PAN in terms of MF and AMF visualization, as well as influencing factors. MATERIAL AND METHODS: A sample of 344 CBCT scans was analyzed for presence and characteristics (i.e. diameter, area, shape, exit angle) of MF and AMF. Subsequently, corresponding PANs were analyzed to ascertain whether MF and AMF were visible. RESULTS: Out of the 344 patients, 344 (100%) MFs and 45 (13%) AMFs were observed on CBCT. Regarding gender, MF diameter and area, MF-MIB and MF-MSB distances, and exit angle were all significantly higher in males. Also, statistically significant differences were found in terms of age and dental status. Statistically significant differences in MF long and short diameters and MF area were found with respect to AMF presence (p=.021, p=.008, p=.021). Only 83.87% of the MFs and 45.83% of the AMFs identified on CBCT were also visible on PANs. MF diameter, shape, exit angle, and age had a significant influence on MF visualization on PAN (B=.43, p=.005; B=-.55, p=.020; B=.20, p=.008; B=.61, p=.005). CONCLUSIONS: PAN is not an adequate technique to properly identify MF and AMF. Diameter, shape, exit angle, and age are all factors influencing MF visualization on PAN images. For surgery involving the MF anatomical region, a preoperative radiological study with CBCT is of crucial importance to avoid complications.