Investigating the Morphology of the Nasolacrimal Canal in Cone Beam Computed Tomography Images and Its Relationship with Age and Gender.

INTRODUCTION: Nasal and paranasal anatomical structures are closely related to the nasolacrimal canal (NLC). As a result of this anatomical relationship, several studies have reported that nasal and paranasal sinus pathologies often play a major role in the etiology of nasolacrimal duct obstruction. The purpose of this study was to investigate the anteroposterior diameter, transverse diameter, length and angle of the bony NLC with nasal floor on the right and left by using cone beam computed tomography (CBCT) and to explore the influence of gender and age on the above-mentioned parameters. METHODS: The current study was conducted by examining the archive of primary CBCT images of patients who were referred for medical imaging to a private maxillofacial radiology clinic in Ahvaz, Iran, in 2020. In axial images, anteroposterior diameter and transverse diameter of the canal in the level of infraorbital were measured. In sagittal images, the length of the NLC was evaluated from the most proximal to the most distal part. Also, to examine the canal pathway, the angle between the canal and the floor of the nasal cavity was measured. Finally, all patient data, including age, gender and canal dimensions, diameter and path, was collected in the information form and referred to the statistics consultant for analysis. RESULTS: In the present study we included information of primary CBCT images of 126 patients who had been referred to a private maxillofacial radiology in Ahvaz, Iran, in 2020. Participants' average age was 28.22±8.13 years for women and 31.54±8.12 years for men, and a small age difference between sexes was seen. The average angle of the right canal with nasal floor was 108.29±7.96º for men and 113.70±7.57º for women, with a significant statistical difference by gender being observed. The mean values of the right channel length were 10.47±2.56 mm for women and 12.54±2.40 mm for men, and the difference between them was statistically significant. The mean values of the left canal length were 109.30±8.67 mm for women and 114.52±9.01 mm for men, and the difference between them was also statistically significant. CONCLUSION: This study provides useful information on the morphometric properties of the bony nasal canal. Careful anatomical knowledge about the morphology of the bony nasal canal may help physicians to plan the treatment options. As the present study raises some concerns related to the age and gender differences in nasopalatine canal morphology that may affect patients' diagnosis and treatment, dentists are recommended to use CBCT images as well as additional techniques with this regard.

Associations between the severity of nasal septal deviation and nasopharynx volume in different ages and sexes: a cone-beam computed tomography study.

BACKGROUND: Nasal septum deviation (NSD) can cause serious anatomical and clinical complications. It can change the breathing pattern and thus alter the anatomy of the airway structures. Despite its importance, the association between NSD with the nasopharynx volume (NPV) has not been assessed before. Therefore, we aimed to investigate it for the first time. METHODS: Archival CBCTs of 202 patients older than 17 years and without any history of trauma or pathology of the nasopharynx and without any orthodontic/orthognathic treatments were evaluated (129 women, 73 men, mean age: 36.24 ± 14.61 years). All included CBCTs must have been taken with a 12 × 8 field of view and fully covered the nasopharynx areas. The extent of NSD (°) and NPV (mm3) were measured. NSDs were categorized as mild (NSD ˂ 9°), moderate (9 ≤ NSD ≤ 15°), and severe (NSD ˃ 15°). Associations between sex, age, NSD, and nasopharynx volume were assessed using independent-samples t test, chi-square, one-way ANOVA, Tamhane post hoc test, Pearson and point-biserial correlation coefficients, and multiple linear regressions (α = 0.05). RESULTS: Mean NSDs were 11.27 ± 4.69° (range 1-19.5), 11.58 ± 4.63°, and 10.70 ± 4.76° in the sample, females, and males, respectively (P > 0.05). Of females, 27.9%, 40.3%, and 31.8% had mild, moderate, and severe NSDs. These were 35.6%, 39.7%, and 24.7% in males (P > 0.05). Mean NPVs were 4.88 ± 1.49, 4.80 ± 1.43, and 5.04 ± 1.60 mm3 in the sample, females, and males, respectively (P > 0.05). Mean NPVs were 6.41 ± 1.21, 4.87 ± 0.73, and 3.30 ± 0.65 mm3 in mild, moderate, and severe NSD groups (all P values = 0.000). Mean ages were 27.06 ± 6.49, 29.80 ± 9.64, and 54.73 ± 8.45 years in mild, moderate, and severe NSD groups (severe group being older than the other two groups, P = 0.000). NSD was strongly, negatively correlated with NPV (R = - 0.793, P = 0.000). Sex was not correlated with NPV or NSD (P ≥ 0.189). Age was negatively and positively correlated with NPV and NSD, respectively (P = 0.000). Modeling NSD (ß = -0.776, P = 0.000) as a predictor for NPV rendered age effect insignificant (P > 0.05). CONCLUSIONS: It was found, for the first time, that the more deviated the nasal septum, the smaller the nasopharynx volume. Aging might increase NSD and through it, reduce the nasopharynx volume. Sex might not affect NSD or NPV.

Anatomy of the Posterior Superior Alveolar Artery: a Cone-Beam Computed Tomographic Study.

Introduction: Posterior superior alveolar artery (PSAA) is a major part of the circulation of the sinus floor. This study aimed to analyze the anatomy of PSAA in an Iranian population for the first time. Methods: This study was performed on coronal CBCT slices of 400 hemimaxillae (1598 slices through premolar and molar areas), to evaluate the PSAA's prevalence, diameter, and its vertical distances from the sinus floor and the alveolar ridge. Potential associations between anatomical properties with age, gender, and maxilla sides were assessed statistically (α = 0.05, 0.0125). Results: The PSAA was detected in 73.2% of all slices (58.5%, 79.6%, 71.5%, and 83.0%, in P1-M2 areas, respectively). The mean PSAA diameter was 0.83 ± 0.33 mm (95% CI 0.81-0.85; 0.96, 0.85, 0.80, and 0.74 mm, in P1-M2 areas, respectively). Canals > 2 mm in diameter were seen only in M1 (0.4%) and M2 (0.9%) areas. Conclusions: PSAA diameters were smaller in this population than all others, with very few large canals available. Although the average diameter increased in the anterior regions, large canals were not present in these regions. Males tended to have larger PSAAs. Age might not change canal parameters. Gender might affect canal diameter. Right/left sides are similar.

Evaluation of Resistin Levels in Saliva of Patients with Chronic Periodontitis and Healthy Subjects.

OBJECTIVE: To evaluate resistin levels in the saliva of patients with chronic periodontitis, and healthy subjects. METHODS: Thirty-four subjects aged between 25 and 50 years were included and divided into healthy group (n = 19) and chronic periodontitis group (n = 15). The saliva levels of resistin were assessed by enzyme-linked immunosorbent assay. Comparisons of resistin levels between the two groups were made with the Mann-Whitney Test. RESULTS: The chronic periodontitis group showed significantly higher resistin levels than the control group (P = 0.001). CONCLUSION: The level of resistin in saliva might help to determine the inflammatory status of periodontal diseases.

Effect of Field of View and Resolution in Detection of Horizontal Root Fractures in CBCT images: An In Vitro Study.

Introduction: New cone-beam computed tomography (CBCT) devices are capable of imaging with different resolutions and field of views (FOVs), in which higher resolutions and FOVs impose a higher dose to the patient. This study was an attempt to investigate the detection accuracy from different FOVs and resolutions in detection of horizontal root fractures. Methods and Materials: Through this experimental study, in five different field of views (FOV) and resolutions (voxel size) of New Tom VGi CBCT (Italy) system was used to scan fifty teeth with horizontal root fractures in half of them. The images were evaluated by four observers (two maxillofacial radiologists and two general dentists) who recorded the presence or absence of horizontal root fractures. The data were analyzed by SPSS 22 software and MacNemar and kappa test were used to compare results with reality. Results: The highest sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy (AZ) were attributed to 8×8 FOV and high resolutions (0.125 mm voxel size) but the difference between sensitivity, specificity, PPV and NPV was not significant. Kappa values for inter-observer agreement between radiologists and general dentists and also intra-observer agreement were in excellent ranges. The highest Kappa in both cases was attributed to 8×8 FOV and high resolutions. Conclusion: There was no significant difference to diagnose of horizontal root fracture between two observer groups and for all of the FOVs and voxel sizes.

Gonad Shielding during Pelvic Radiography: A Systematic Review and Meta-analysis.

BACKGROUND: Gonad shielding has been extensively advocated during pelvic radiography at or below reproductive ages. The popular practice of gonad shielding is placement of a lead shield in the midline of the pelvis. The aim of this study was to address the prevalence of gonad shielding and find out whether the current practice of gonad shielding can be considered as an effective method to reduce radiation exposure in patients undergoing pelvic radiography. METHODS: National and international electronic databases, including PubMed, MEDLIN, EMBASE, and Google-Scholar, were searched up to January 2016. The database searches were supplemented with manual searches of reference lists. Two authors independently assessed the eligibility of all studies and extracted data. RESULTS: The searches yielded a total of 243 publications. After assessing each identified study against specific inclusion exclusion criteria, 18 studies were deemed as relevant for this review. The total prevalence rate of gonad shielding was estimated at 58% (95% CI: 40 to 74%). It was estimated that only 34% (95% CI: 25 to 44%) of the radiographs had correct positioning of the shield. Also, incorrect positioning of the shield was statistically significantly higher in females than males (85% vs. 52 %; P-value < 0.001). CONCLUSIONS: Our study demonstrates that the current practice of gonad shielding during female pelvic radiography should be no longer considered as an effective method to reduce radiation exposure. Training the best qualified radiographers is the key to accurate positioning of the shield in male subjects.

Primary Malignant Melanoma of the Oral Cavity Around Dental Implants: Report of an Unusual Case.

INTRODUCTION: Primary oral melanoma is an uncommon malignant tumor that originates from the proliferation of melanocytes. CASE PRESENTATION: A 78-year-old man presented with a pigmented lesion around the maxillary anterior implant prosthesis. The lesion was excised and diagnosed as a melanoma. Biopsy showed a malignant pigmented neoplasm that included proliferation of dysplastic melanocytes into the superficial layers of the submucosa. Initial testing, including a positron emission tomography scan, showed no metastasis; however, after 7 months, the patient developed a cervical lymphadenopathy. A neck dissection was performed and indicated that there was metastasis of the primary melanoma. After surgery, the patient received chemotherapy. CONCLUSIONS: Histologic examination of the excised lesion revealed the presence of a malignant melanoma in association with a junctional nevus of the oral mucosa. The patient was referred to the oral and maxillofacial department for further evaluation.

Comparison of BCG artifact removal methods for evoked responses in simultaneous EEG-fMRI.

Simultaneous recording of electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) has gained attention due to the complimentary properties of the two imaging modalities. Their combined recording enables the study of brain function while taking advantage of the high temporal resolution of EEG and high spatial resolution of fMRI. However EEG data recorded inside the MR scanner is significantly contaminated by two main sources of artifacts: MR gradient artifacts and ballistocardiogram (BCG) artifacts. Most existing removal approaches for these artifacts fall into two main categories: average artifact subtraction (AAS) and optimal basis selection (OBS). While these techniques can improve the data quality significantly, highly effective removal of artifacts - particularly the BCG artifact - from the data is still lacking. Here, we compared two of the most commonly used algorithms for BCG artifact removal (OBS and AAS) based on the estimated signal-to-noise ratio (SNR) of auditory and visual evoked responses recorded during fMRI acquisition. We also further compared optimization of OBS for groups, and at the individual subject and run level. The results suggest that performance of the OBS algorithm can be significantly improved by choosing the optimum number of principal components. Furthermore, optimizing the number of principal components at the individual participant and run level results in significant improvements in the SNR of evoked responses compared to group optimization.