Evaluation of the morphology of accessory canals of the canalis sinuosus via cone-beam computed tomography.

PURPOSE: This study aims to assess the presence of accessory canal (AC) associated with canalis sinuous (CS), describing their frequency, lateralization, location, direction, and measurements in cone beam computed tomography (CBCT). METHODS: Axial, coronal, sagittal, and cross-sectional reconstructions were analyzed in 248 CBCT images and the presence of CS, the presence of AC associated with CS, the lateralization, localization, and direction course of AC associated with CS was evaluated. CS diameter, AC diameter, the distance between the nasal cavity floor and CS (M1), CS and the buccal cortical bone (M2), and CS and the alveolar ridge (M3) were measured. RESULTS: CS was detected in all CBCT scans as bilaterally. The prevalence of AC associated with CS was 35.5%. There was a significant difference between dental status anthe d presence of AC associated with CS. There was a significant difference between gender, dental status, and lateralization of AC associated with CS. While M1 was greater in male patients than females, M3 was greater in female patients. M2 and M3 were greater in younger patients. CONCLUSION: Clinicians performing surgical procedures should keep in mind that anatomical variations of the vascular nerve bundle may be seen. M1, M2, and M3 measurements can be affected by gender, age, and dental status.

Comparison of the asymmetry index determined on digital panoramic radiographic images and on posteroanterior cephalometric images: a retrospective cross-sectional study.

OBJECTIVE: The purpose of this study was to compare the asymmetry index determined on digital panoramic radiographic (PR) images and posteroanterior cephalometric (PACR) images. METHODS: This study included 100 patients whose PR and PACR images were registered in a database. Condylar height, ramus height, and condylar height plus ramus height measurements were measured bilaterally. Condylar asymmetry, ramus asymmetry, and total asymmetry were evaluated. RESULTS: There was a statistically significant difference between the right and left side for all measurements when evaluated on the PR and also on the PACR images (p < 0.01). When calculating the asymmetry index, the resulting condylar asymmetry and ramus asymmetry values did not show significant differences between PR and PACR images. On the other hand, only the presence of total asymmetry showed a statistically significant difference between techniques (p = 0.013). CONCLUSION: Asymmetry indices can be reliably obtained from both PR and PACR images.

Effects of Occlusal Scheme on All-on-Four Abutments, Screws, and Prostheses: A Three-Dimensional Finite Element Study.

An ideal occlusal scheme plays an important role in a good prognosis of All-on-Four applications, as it does for other implant therapies, because of the potential impact of occlusal loads on implant prosthetic components. The aim of the present 3D finite element analysis (FEA) study was to investigate the stresses on abutments, screws, and prostheses that are generated by occlusal loads via different occlusal schemes in the All-on-Four concept. 3D models of the maxilla, mandible, implants, implant substructures, and prostheses were designed according to the All-on-Four concept. Forces were applied from the occlusal contact points formed in maximum intercuspation and eccentric movements in canine guidance occlusion (CGO), group function occlusion (GFO), and lingualized occlusion (LO). The von Mises stress values for abutment and screws and deformation values for prostheses were obtained, and results were evaluated comparatively. It was observed that the stresses on screws and abutments were more evenly distributed in GFO. Maximum deformation values for prosthesis were observed in the CFO model for lateral movement both in the maxilla and mandible. Within the limits of the present study, GFO may be suggested to reduce stresses on screws, abutments, and prostheses in the All-on-Four concept.