OBJECTIVES The goal of this study was to determine the sealing ability of MTA, Biodentine, and Fuji IX as root-end materials after ultrasonic retrograde preparation using a dye penetration method. MATERIALS AND METHODS Seventy permanent anterior teeth were used in this study. Root canals were prepared using rotary endodontic files, and obturated using the lateral condensation technique. The resection of the root apices was performed perpendicularly to the long axis, and 3 mm deep retrocavities were made by ultrasonic tips. The samples were randomly divided into three experimental groups (N=20) and two control groups (N=5). The root-end cavities were filled with mineral-trioxide aggregate (Rootdent MTA, TehnoDent, Russia) in Group 1, Biodentine (Septodont, Saint Maur des Fossés, France) in Group 2 and Fuji IX GP (GC Corporation, Tokyo, Japan) in Group 3. The retrocavities of the positive control group were left unfilled, while retrocavities in the negative control group were sealed using a flowable composite material. The samples were made transparent, and dye penetration was assessed under a stereomicroscope (x10). The data were analyzed with the Kruskal-Wallis test and the Mann-Whitney U-test. RESULTS The Biodentine group had a lower mean leakage value than the MTA and Fuji IX groups, and the difference was statistically significant (P<0.01). No statistical difference in apical microleakage was found between the MTA and Fuji IX groups (P>0.05). CONCLUSION Within the limitations of this study, it was concluded that Biodentine provides better sealing ability as a root-end material than MTA and Fuji IX. There was no statistically significant difference between the sealing ability of MTA and Fuji IX as root-end materials.

Aim: The aim of this study was to compare time of preparation and canal aberrations in a simulated root canals after using three different rotary systems: Endostar E5, Endostar E3 and T One File Gold. Materials and Methods: A total of 90 endodontic training blocks were used in this study and divided into three groups consisting of 30 each (n = 30). Blocks processing was performed by thirty dentists without any prior experience in rotary instrumentation techniques. In the first group blocks were prepared using Endostar E5, in second one with Endostar E3 and in third one with T One File Gold system. The preparation time was measured. The postoperative image of each block was taken by stereomicroscope and canal aberrations (ledge and instrument fracture) was recorded. Statistical analysis was done by SPSS software. Results: Instrumentation with T One File Gold system is significantly faster compared to instrumentation with Endostar E5 and Endostar E3 systems (p <0.05). There are no statistically significant differences in the type and number of procedural errors between Endostar E5, Endostar E3 and T One File Gold systems when the operators have no previous experience in rotary instrumentation techniques. Conclusion: Under the conditions of this study, the incidence of examined canal aberrations were similar for all tested systems. The preparation time was significantly shorter with single file system.

Objective: The present study aims to investigate the influence of presence and shape of cervical lesions on biomechanical behavior of mandibular first premolar, subjected to two types of occlusal loading using three-dimensional (3D) finite element method (FEM). Materials and Methods: 3D models of the mandibular premolar are created from a micro computed tomography X-ray image: model of sound mandibular premolar, model with the wedge-shaped cervical lesion (V lesion), and model with saucer-shaped cervical lesion (U lesion). By FEM, straining of the tooth tissues under functional and nonfunctional occlusal loading of 200 (N) is analyzed. For the analysis, the following software was used: CTAn program 1.10 and ANSYS Workbench (version 14.0). The results are presented in von Mises stress. Results: Values of calculated stress in all tooth structures are higher under nonfunctional occlusal loading, while the functional loading is resulted in homogeneous stress distribution. Nonfunctional load in the cervical area of sound tooth model as well as in the sub-superficial layer of the enamel resulted with a significant stress (over 50 [MPa]). The highest stress concentration on models with lesions is noticed on the apex of the V-shaped lesion, while stress in saucer U lesion is significantly lower and distributed over wider area. Conclusion: The type of the occlusal teeth loading has the biggest influence on cervical stress intensity. Geometric shape of the existing lesion is very important in the distribution of internal stress. Compared to the U-shaped lesions, V-shaped lesions show significantly higher stress concentrations under load. Exposure to stress would lead to its progression.