Relation between Condyle Horizontal Angle and Intercondylar Angle with Disc Displacement in Patients with Temporomandibular Joint Disorders: An MRI Evaluation.

Background: Internal derangement (ID) is the most common cause of temporomandibular disorders (TMDs) and extensively affects the articular disc function. The anterior disc displacement is among the most important findings in ID. Knowledge about the etiology of this condition is imperative, and the role of structural parameters in the development of TMDs has not been well evaluated. Objectives: This study aimed to assess the relationship between condylar angulation and intercondylar angle with anterior disc displacement in patients with TMD using magnetic resonance imaging (MRI). Materials and Methods: This case-control study evaluated 31 temporomandibular joints with internal derangement and 57 normal joints. The data retrieved from MRI included disc position in the open mouth (normal, anterior disc displacement with a reduction (DDWR) and without reduction (DDWOR), and posterior displacement (PD)), horizontal condylar angle categorized as normal (10 to 30° angle) and abnormal (<10° and >30°), and intercondylar angle. Chi-square test, T-test, and Fisher's exact were done to assess the relationship between horizontal condylar angle and intercondylar angle in patients with TMDs with DDWR and DDWOR compared with the control group. Results: Patients with DDWR and DDWOR had higher odds of abnormal horizontal condylar angle, particularly >30° angle, which was a significant correlation (odds ratio of 0.19 and 8.3, respectively). The intercondylar angle in the patients with disc displacement was significantly smaller compared to the control group. Conclusion: Disc displacement was correlated with abnormal horizontal angle (particularly < 30) and smaller intercondylar angle compared with the control group.

Effect of metal artifact removal modes on the accuracy of linear measurement around titanium implants by applying different voltages: an original article.

BACKGROUND: This study aims to evaluate the effects of the artifact removal algorithm on linear measurements of the buccal cortical plate by altering the voltage. METHODS: Ten titanium fixtures were inserted at the site of central, lateral, canine, premolars and molars of dry human mandibles. Vertical height of buccal plate was measured using a digital caliper as a gold standard. Mandibles were scanned with 54 and 58 kVp. Other parameters were constant. Images were reconstructed with none, low, medium and high artifact removal modes. Two Oromaxillofacial radiologists evaluated and measured the buccal plate height using Romexis software. Statistical package for the social sciences (SPSS) version 24 was used for data analysis. RESULTS: In medium and high modes, the difference between 54 and 58 kVp was significant (p < 0.001). No significance was noted by using low ARM (artifact removal mode) at the 54 kVp and 58 kVp. CONCLUSION: Using artifact removal in low voltage decreases the accuracy of linear measurement and buccal crest visibility. By using high voltage, artifact removal would have no significant effect on accuracy of linear measurements.