Evaluation of Sella Turcica Variations in Lateral Cephalometric Radiographs and its Association with Malocclusion.

Objectives: Understanding the shape and size of the sella turcica may help predict future orthodontic treatment needs related to skeletal malocclusion. This study aims to assess different morphological types of the sella turcica in lateral cephalometric radiographs and its correlation with malocclusion, as well as the relationship between gender and linear measurements of sella turcica. Materials and Methods: The lateral cephalometric radiographs of 410 volunteers (111 men and 299 women) aged 8 to 30 years were evaluated. The patients were divided into three groups based on their skeletal growth patterns (cl I, II, and III). Then the anatomical shape and linear dimensions of sella turcica were assessed. Measurements were made using Adobe Photoshop Version: 20.0.0 software, and data analysis was performed by IBM SPSS Statistics version 25. Results: The following morphologies were observed: normal (37.8%), oblique anterior wall (9.3%), double contour of the floor (21.5%), sella turcica bridge (8.8%), irregularity (notching) in the posterior part of sella turcica (16.6%), and pyramidal shape of the dorsum sellae (6.1%). No statistically significant relationship was found between sella turcica variations and skeletal malocclusion. The correlation between female sex with the diameter (p=0.027) and depth values (p=0.035) of sella turcica was statistically significant. There was no statistically significant difference (p>0.05) in length based on gender. Conclusion: The most morphological type reported was normal sella turcica (37.8%). Anatomical variations of sella turcica had no association with malocclusion. The most considerable depth and diameter of sella turcica were found in women.

Dentin Thickness of the Danger Zone in the Mesial Roots of the Mandibular Molars: A Cone Beam Computed Tomography Analysis.

BACKGROUND: Mandibular first molars appear to be the most commonly tooth subjected to a root canal treatment, therefore a better understanding of the anatomy critical zones for resistance of this teeth may decrease the treatment's failure rate. So, this study was conducted to evaluate the dentin thickness of the danger zone in mesial roots of mandibular first molars using cone beam computed tomography in an Iranian population. METHODS: In this cross-sectional study, 210 Cone Beam Computed Tomography acquisition of the mandibular first molars were collected from a radiology center in Qazvin. The dentin thickness of the mesial roots (mesiobuccal and mesiolingual canals) was measured from the furcation to 5 mm below. The relationship between the dentin thickness in the danger zone and parameters, like age, gender, placement side, root length, the curvature of the canal, canal type, presence of middle mesial canal, and distance between the orifices of the mesial canals was investigated. Frequency, mean and standard deviation for variables were calculated, and data analysis was done by SPSS using simple and multiple linear regression and Pearson correlation coefficient. Also, two-sample t-test was used to compare mesiobuccal and mesiolingual on two sides. The significant level was also considered at (p < 0.05). RESULTS: The average minimum thickness of danger zone dentin was found to be 0.885 ± 0.259 mm in the mesiobuccal canal and 0.906 ± 0.206 mm in the mesiolingualcanal. Also, the minimum thickness of dentin in the mesiobuccal and mesiolingual canals in the range of 0 to 1 mm from the furcation was more than in other areas. There was no significant relationship between the minimum dentin thickness of the danger zone with gender, placement side, root length, canal type, and mesial canal entrance distance. But with increasing age, the thickness of dentin in the danger zone in the mesiolingualcanal increased significantly (p = 0.008). It was also observed that with the increase in the curvature of the canal, the thickness of the dentin in the danger zone in the mesiobuccal canal decreased (moderately curved (p = 0.008), severely curved (p = 0.046)). In addition, the thickness of the dentin in the mesiobuccal and mesiolingual canal was less in the samples with the middle mesial canal (p = 0.047, 0.044). CONCLUSIONS: Less dentin thickness in the danger zone in the mesial roots of mesiolingual mandibular first molars was seen in younger patients in mesiolingual canal, with a greater degree of canal curvature in the mesiobuccal canal and teeth with a middle mesial canal. Therefore, it is suggested that large taper instruments should be used with more precision to prevent complications.

Accuracy of Three Types of Apex Locators versus Digital Periapical Radiography for Working Length Determination in Maxillary Premolars: An In Vitro Study.

This study aimed to compare the accuracy of three types of apex locators versus digital radiography for working length (WL) determination. This experimental study was conducted on 58 extracted maxillary premolars. The teeth were decoronated, the access cavity was prepared, and WL was determined using a #15 K-file to serve as reference. The WL was then measured by Woodpex V, Woodpex III, and Root ZX apex locators in the presence of 0.9% saline, and also on a photostimulable phosphor plate (PSP) digital radiograph taken by the parallel technique. The values were compared with the actual WL using the paired t-test (alpha = 0.05). Digital radiography, Root ZX, Woodpex V, and Woodpex III determined the WL within ±0.5 mm from the actual value in 84.48%, 100%, 89.66%, and 87.93% of the cases, respectively. Woodpex V (p = 0.039), Woodpex III (p = 0.001), and Root ZX (p = 0.001) significantly over-estimated the WL. The WL measured on digital radiographs was not significantly different from the actual WL (p = 0.213). The position of the apical foramen (central/lateral) had no significant effect on the accuracy of WL determination by different techniques (p >0.05). Within the limitations of this in vitro study, all the tested modalities showed acceptable accuracy for WL determination in maxillary premolars.

Evaluation of dentin penetration of three different endodontic sealers in the presence and absence of the smear layer.

INTRODUCTION: A sealer's ability to effectively and stably penetrate the dentinal tubules is an essential factor for selecting an effective root canal obturation material. Evaluation of the sealers' penetration into the dentinal tubules provides valuable data in the endodontic treatment outcome.

Management of internal root resorption in the maxillary central incisor with fractured root using Biodentine.

Biodentine is desirable to successfully manage internal root resorption, and the MTA apical plug backfilled with thermoplasticized gutta-percha is suggested for the tooth with external apical root resorption.

The relationship between test anxiety and academic procrastination among the dental students.

BACKGROUND: Test anxiety is a major educational problem among students all around the world. The purpose of this study was to investigate the relationship between academic procrastination and test anxiety among the dental students of Qazvin University of Medical Sciences. MATERIALS AND METHODS: The present study was a descriptive-analytical study. The study sample consisted of 152 dental students; Solomon and Rothblum's procrastination scale and Friedman's test anxiety questionnaire were used to collect data. To analyze the data, descriptive and analytical statistics (analysis of variance, independent t-test, and Pearson's correlation) were used at a significance level of P < 0.05. RESULTS: The results of the present study showed that there is a significant relationship between procrastination and test anxiety and its components. The relationship between academic procrastination and gender was not significant, but a significant relationship was found between test anxiety and its dimensions with gender in terms of cognitive error and total test anxiety. No significant relationship was found between academic procrastination and test anxiety and their components with marital status, age, and grade point average. CONCLUSION: According to the findings of the present study, people with academic procrastination have more test anxiety and fear of humiliation, irrational and negative thoughts, and more stress.

Cone-Beam Computed Tomographic Evaluation of Artifact Effects of Three Different Sealers.

Introduction: Cone-beam computed tomography (CBCT) is one of the most important diagnostic tools in maxillofacial imaging. Nowadays different sealers are used in root canal therapy and some of them can create artifact in CBCT images. The aim of this study was to evaluate the effect of different sealers including AH-26, Diadent, and Anyseal in creation of artifact bands in the CBCT images based on voxel size. Methods and Materials: A total of 44 single rooted extracted teeth were selected. The canals were prepared by crown-down technique. All teeth were manually filed up to master apical file (MAF) size 45 and 1 mm shorter than the apical foramen. The teeth were divided into 4 equal groups. The canals were filled with gutta-percha and either of sealers AH-26, Diadent or Anyseal by lateral condensation technique. The control group were filled just with gutta-percha without any sealer. The CBCT images were taken in voxel sizes of 0.3 and 0.15. The Fisher exact and McNemar tests were used for statistical analysis. Results: Although, the control group had the lowest ratio of presence to absence of artifact, the ratio of presence to absence of artifact in voxel size of 0.3 and 0.15 mm were significantly lower in Anyseal than AH-26 (P=0.031, P=0.020) and Diadent (P=0.001, P=0.002). No significant difference was detected between two voxel sizes (P>0.05). Conclusion: In this in vitro study, all evaluated sealers induced artifacts in the CBCT images. Anyseal sealer had the lowest artifact in both evaluated voxel sizes.

In vitro Evaluation of the Accuracy of the Root Zx in the Presence of Naocl 2.5% and Chlorhexidine 0.2.

BACKGROUND: Establishing the working length at the apical constriction is considered ideal for root canal therapy. Because of the limitations of radiography and complicacy of the apex of the root, electronic measurement of canal length has become valuable for endodontic treatment. This study was designed to evaluation of the accuracy of the Root zx electronic apex locator in the presence of NaOCl 2.5% and chlorhexidine 0.2%. MATERIAL AND METHODS: Thirty extracted human premolars with complete root formation were enrolled. The actual length (AL) was assessed visually (under stereo microscope) and teeth mounted in the saline model. The electronic length (EL) measurements were recorded in the presence of NaOCl 2.5% and chlorhexidine 0.2% and the differences between the EL and AL were compared. RESULTS: By accepting the error of 0.5 and 1 mm, the accuracy of Root zx was 76.7% and 96.7% in the presence of chlorhexidine 0.2% and 90% and 100% in the presence of NaOCl 2.5%, respectively. No statistical differences was found between the measured groups (P=0.223). CONCLUSIONS: Our results confirmed that Root zx can accurately determine the apical constriction in presence of both NaOCl 2.5% and chlorhexidine 0.2%. Key words:Chlorhexidine, Sodium Hypochlorite, Root ZX.