Introducing a new auto edge detection technique capable of revealing cervical root resorption in CBCT scans with pronounced metallic artifacts.

Cervical resorption is a serious threat to the longevity of the teeth. In this study, the Canny edge-detection algorithm was applied on CBCT images to compare the accuracy of original and Canny views for diagnosing cervical resorption in endodontically treated teeth. Intracanal metallic posts were inserted in 60 extracted teeth being randomly divided into three groups: control, 0.5 mm, and 1 mm cervical resorption. CBCT scans of the teeth were presented to three observers in both original and Canny formats with the accuracy being determined by receiver operating characteristic (ROC) analysis. The DeLong test was used for paired comparisons with the significance level set at 0.05. The highest accuracy belonged to Canny images in 1 mm resorption, followed by Canny images in 0.5 mm resorption, original images in 1 mm resorption, and original images in 0.5 mm resorption, respectively. The Canny images were significantly more accurate in the diagnosis of 0.5 mm (p < 0.001) and 1 mm (p = 0.009) resorption. Application of the Canny edge-detection algorithm could be suggested as a new technique for facilitating the diagnosis of cervical resorption in teeth that are negatively affected by metallic artifacts.

Assessment of mucin and alpha-amylase levels in gingival crevicular fluid of chronic periodontitis patients.

BACKGROUND: Chronic periodontitis is the most common form of periodontitis. Several immune and inflammatory factors responsible for periodontal destruction have been found in gingival crevicular fluid (GCF). The current study was conducted to determine the correlation between mucin and alpha-amylase protein values in GCF with chronic periodontitis. METHOD: Forty-five patients with moderate-to-severe chronic periodontitis were selected. Samples of GCF were taken from a specific part of a single root tooth and placed in a closed test tube containing phosphate-buffered saline (PBS) (pH = 7). Sampling was done again after one month. Pre- and post-treatment samples were analyzed for measuring the levels of mucin and alpha-amylase proteins. RESULTS: Paired t test results for these two variables showed that the difference between mucin and alpha-amylase levels before and after treatment is significant. CONCLUSION: The level of both mucin and alpha-amylase in GCF in patients with chronic periodontitis was higher than that of patients who have recovered successfully; and evaluating the values of these two markers could be used to determine the activity of the periodontal disease.

Fractal analysis of the trabecular bone pattern in the presence/absence of metal artifact-producing objects: Comparison of cone-beam computed tomography with panoramic and periapical radiography.

OBJECTIVES: The effect of metallic objects on the fractal dimension (FD), bone area fraction (BAF) and gray scale values (GSVs) of cone-beam CT (CBCT) images was assessed. Also, FD, BAF and GSV were compared among CBCT, digital periapical and panoramic radiographies. METHODS: Digital periapical and panoramic radiographs were acquired from six blocks of bovine rib. Additionally, different arrangements of titanium implants and intracanal metallic posts were created in the bone blocks and CBCT scans were taken from the different implant-root arrangements. The three radiographical modalities were compared by analysis of variance. Pairwise comparisons between the modalities were performed by the Tukey test (significance level set at 0.05). RESULTS: Different root-implant arrangements in the CBCT images revealed no significant differences in the FD (p = 0.920), BAF and GSV values (p = 0.623). FD differed significantly among the three modalities (p < 0.001). Significant differences were found between CBCT and each of the periapical and panoramic techniques (p < 0.001), while no remarkable differences were observed in the FD of the periapical and panoramic images (p = 0.294). BAF and GSV showed significantly different results among the three radiographical techniques (p < 0.001). The difference was remarkable between CBCT and periapical (p < 0.001), CBCT and panoramic (p < 0.001) and periapical and panoramic (p = 0.008). CONCLUSION: Presence of titanium implants and intracanal posts does not produce different results in the fractal analysis (FA) of the CBCT images. The trabecular bone pattern is best assessed by FA of the periapical radiographs followed by the panoramic and CBCT techniques, respectively.

Effect of slice inclination and object position within the field of view on the measurement accuracy of potential implant sites on cone-beam computed tomography.

PURPOSE: The purpose of this study was to evaluate the accuracy of linear measurements in the horizontal and vertical dimensions based on object position and slice inclination in cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: Ten dry sheep hemi-mandibles, each with 4 sites (incisor, canine, premolar, and molar), were evaluated when either centrally or peripherally positioned within the field of view (FOV) with the image slices subjected to either oblique or orthogonal inclinations. Four types of images were created of each region: central/cross-sectional, central/coronal, peripheral/cross-sectional, and peripheral/coronal. The horizontal and vertical dimensions were measured for each region of each image type. Direct measurements of each region were obtained using a digital caliper in both horizontal and vertical dimensions. CBCT and direct measurements were compared using the Bland-Altman plot method. P values <0.05 were considered to indicate statistical significance. RESULTS: The buccolingual dimension of the incisor and premolar areas and the height of the incisor, canine, and molar areas showed statistically significant differences on the peripheral/coronal images compared to the direct measurements (P<0.05). Molar area height in the central/coronal slices also differed significantly from the direct measurements (P<0.05). Cross-sectional images of either the central or peripheral position had no marked difference from the gold-standard values, indicating sufficient accuracy. CONCLUSION: Peripheral object positioning within the FOV in combination with applying an orthogonal inclination to the slices resulted in significant inaccuracies in the horizontal and vertical measurements. The most undesirable effect was observed in the molar area and the vertical dimension.

Detection of peri-implant bone defects using cone-beam computed tomography and digital periapical radiography with parallel and oblique projection.

PURPOSE: To compare the diagnostic accuracy of cone-beam computed tomography (CBCT) with that of parallel (PPA) and oblique projected periapical (OPA) radiography for the detection of different types of peri-implant bone defects. MATERIALS AND METHODS: Forty implants inserted into bovine rib blocks were used. Thirty had standardized bone defects (10 each of angular, fenestration, and dehiscence defects), and 10 were defect-free controls. CBCT, PPA, and OPA images of the samples were acquired. The images were evaluated twice by each of 2 blinded observers regarding the presence or absence and the type of the defects. The area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were determined for each radiographic technique. The 3 modalities were compared using the Fisher exact and chi-square tests, with P<0.05 considered as statistical significance. RESULTS: High inter-examiner reliability was observed for the 3 techniques. Angular defects were detected with high sensitivity and specificity by all 3 modalities. CBCT and OPA showed similar AUC and sensitivity in the detection of fenestration defects. In the identification of dehiscence defects, CBCT showed the highest sensitivity, followed by OPA and PPA, respectively. CBCT and OPA had a significantly greater ability than PPA to detect fenestration and dehiscence defects (P<0.05). CONCLUSION: The application of OPA radiography in addition to routine PPA imaging as a radiographic follow-up method for dental implantation greatly enhances the visualization of fenestration and dehiscence defects. CBCT properly depicted all defect types studied, but it involves a relatively high dose of radiation and cost.

Designing and assessing fixed dental prostheses 2 multimedia-based education in dentistry students.

Background: Above all methods effective learning results from decent training, acquired in the proper environment and encouraging creative methods. Computer-assisted training by educational software is considered a fundamental measure to improve medical and dentistry education systems. This study aims to design and assess fixed dental prostheses via 2 multimedia instructional contents at the Guilan dentistry school. Methods: This is a descriptive and cross-sectional study. First off, the instructional content was analyzed. The software used to produce multimedia was the iSpring suite Ver.7.0. After designing the instructional multimedia, this software was loaded by LMS. Sixty-nine dentistry students in the 5th semester at Guilan Dentistry School were selected via convenience sampling. At the end of the course, a structured questionnaire containing 26 items were handed to the students to evaluate the instructional multimedia quality. Results: Mean ±SD age was 24.68±3.24 years, 43 were women (62.4%) and 26 were men (37.6%) -the majority of 76.8% used the internet at home. A portion of 33.3% were inclined to use multimedia and the internet with in-person training. About 60% declared that multimedia quality as being good. Conclusion: the instructional multimedia designs which are compatible with lesson objectives and audiovisual facilities can have a great effect on the student's satisfaction. Preparing instructional multimedia makes the instructional content easily accessible for students to be able to review it several times at the proper opportunity and if presented through LMS they would be able to study the lesson subject wherever and whenever accessing the internet.