Objectives: This in vitro study aimed to compare the volumes of unfilled areas in oval-shaped root canals filled with five different obturation techniques after minimally invasive root canal shaping using cone beam computed tomography (CBCT). Materials and Methods: 50 extracted mandibular premolars with oval-shaped root canals were used. Root canals were instrumented with K3 files (Kerr, USA) to size #30.04. Then, the samples were randomly distributed into five groups and obturated with different techniques; single cone technique with AH plus (Group A), single cone technique with BIO-C® SEALER (Group B), modified lateral condensation technique with AH Plus using 0.04 GP (Group C), conventional lateral condensation technique with AH Plus (Group D) and continuous warm compaction with AH plus (Group E). All teeth were scanned using CBCT before and after obturation. Volume of voids was calculated in each third of the root canal using 3D Doctors software. Kruskal-Wallis and post hoc Dunn tests were used for statistics (p<0.05). Results: Group E showed the least mean volume percentage of voids, whereas Group A showed the highest mean volume percentage of voids in the coronal third, the middle third and overall. However, in the middle and apical thirds, there was no statistically significant difference between the groups regarding the mean volume percentage of voids (p>0.05). Conclusion: The obturation technique effected the quality of obturation minimally in the middle and apical thirds of oval-shaped root canals. The single cone techniques had a higher percentage volume of voids than the continuous wave compaction technique.

Objectives: Various artifacts can be encountered when examining Cone-beam computed tomography(CBCT) images. In recent years, no descriptive study has been conducted on CBCT artifacts in the literature. The aim of this study is to identify artifacts in CBCT images with different imaging fields (FOV) taken on the same device, to determine their frequency, and also to reveal artifacts that are little known in the literature. Materials and Methods: In the study, CBCT images of the Faculty of Dentistry between the years 2012-2021 were scanned retrospectively and a total of 359 Cone Beam Computed Tomography images with 50x55, 100x55, 100x90, 130x55, 130x90, 230x170, 230x270 imaging fields (FOV) in the database, which met the exclusion and inclusion criteria, were analyzed by three oral and maxillofacial radiology research assistants and the types of artifacts seen on these images were determined. The incidence of the identified artifact types in the specified imaging areas was evaluated. Results: When looking at all images, the most common errors, regardless of FOV, were inevitable artifacts. Aliasing and motion artifacts were seen at higher rates on CBCT images with a larger field of view. In addition, the ring artifact was encountered in CBCT images with high imaging fields such as 130x90, 230x170 and 230x270. Conclusion: To know the incidence and causes of artifacts in images; it will prevent the patient, the environment and the practitioner from receiving x-rays (radiation) unnecessarily, mixing these errors with different pathological conditions and repetition of the image.

Objectives: Many patients with metallic objects in the head and neck region may require magnetic resonance imaging (MRI). The aim of this study was to assess the artifacts produced by different dental crown materials on ultrashort echo time (UTE) MRI. Materials and Methods: Cobalt-chromium (Co-Cr) and zirconia (Zr) crown and fixed bridges were included and embedded in agar gel. UTE sequence by 1.5T MRI was performed and the artifact area produced by these materials, were measured within the region of interest (ROI). Mean artifact areas were recorded. Results: Mean artifact area produced by Co-Cr and Zr was 140.055 mm2 and 102.349 mm2, respectively. Zr material produced less artifacts than metal restoration. It was stated that the amount of artifact increased as the number of elements increased. Conclusions: Co-Cr metal restorations have stronger effect than Zr material on UTE MRI. UTE sequence is useful in evaluating susceptibility artifacts from different materials. Knowing the amount of artifact produced by different materials will help to produce new materials that cause less artifact formation or to improve the properties of existing materials.