The purpose of this study was to compare the shear bond strength (SBS) of denture base resin (DBR) and dental materials produced by different methods and to investigate the effect of artificial gastric acid on bond strength. Heat-polymerized, subtractive (CAD/CAM-milled) and additive (3D printing) DBR-teeth combinations were investigated. 5 × 5 × 2 mm teeth, 10Ø, 2 mm high base samples were produced according to the manufacturer’s instructions. The teeth specimens were bonded with the same type of DBR and immersed in artificial gastric acid solution. They were stored in an incubation device at 37 °C for 96 h. The SBS test was performed on a universal testing machine. Statistical analysis of the results was performed using ANOVA and Games-Howell (α = 0.05). The mean SBS was highest in the 3D printed group (15.08 ± 4.25 MPa). This was followed by heat-polymerized (12.90 ± 3.00 MPa ), then CAD/CAM-milled group (6.57 ± 2.01 MPa ). The manufacturing method significantly affected the SBS (P < 0.001), but artificial gastric acid did not significantly change the SBS of any group (P = 0.488). The 3D printed group showed the highest bond strength. 3D printing method can be used safely in patients with gastroesophageal reflux disease (GERD).

This study aims to investigate the mechanical and optical properties of two different multilayer monolithic zirconia materials after the high-speed and repeated sintering process recommended by the manufacturers. In this study, specimens with a diameter of 12 mm and a thickness of 1 mm were fabricated using KATANA Zirconia YML (Kuraray Noritake) and IPS e.max ZirCAD Prime (Ivoclar Vivadent) multilayer zirconia. These specimens were processed with two different protocols to be used in the sintering process: high-speed and conventional sintering. Both protocols were repeated three times, after which the changes in the mechanical, microstructural and optical properties of the specimens were compared and analyzed. According to the biaxial flexural strength result, KATANA Zirconia YML (840.84 MPa) showed higher biaxial flexural strength compared to IPS e.max ZirCAD Prime (627.64 MPa) after repeated high-speed sintering. When the optical properties were analyzed, the translucency parameters of the IPS e.max ZirCAD Prime block were reliable in certain protocols. A comparison of mechanical and optical properties after repeated and high-speed sintering reveals that both materials offer advantages for different application requirements. The high biaxial flexural strength of KATANA Zirconia YML is more suitable for applications requiring strength. The homogeneous translucency of IPS e.max ZirCAD Prime is esthetically and optically safer for high-speed and repeated sintering processes.

Preclinical training is essential in dental education for developing psychomotor and clinical skills. Conventional phantom models are widely used, though they lack real-time tactile feedback. This study aimed to compare the effectiveness of conventional phantom training with that of advanced simulation-based systems in improving dental students’ tooth preparation skills. This randomized controlled trial included 40 s-year dental students (N = 40) with no prior experience in simulation. Participants were randomly assigned to either conventional phantom training or virtual reality (VR) based simulation. Both groups received 10 h of training. Pre- and post-tests involved preparing tooth 46 with a chamfer finish line. Performances were assessed using five criteria: parallelism, occlusal reduction, taper angle, finish line standardization, and presence of undercuts. Each was scored on a 0–10 scale by a blinded evaluator. Statistical analyses were performed using ANOVA with post hoc tests at a significance level of p < .05. Both groups showed improvement in post-test scores The simulation group’s post-test performance was found to be significantly higher than that of the other groups. Post hoc analysis confirmed that the simulation group outperformed both its own pre-test and the conventional group’s post-test results. Simulation-based training led to significantly higher outcomes in tooth preparation compared to conventional methods. The integration of digital simulation into dental education may enhance clinical readiness by providing individualized, repeatable, and measurable learning environments.

The durability of bonding between the denture base and reline materials plays a critical role in the long-term success of removable prostheses. This study aimed to compare the bond strength of denture base resins fabricated by heat-polymerization, CAD-CAM milling, and 3D printing techniques after thermocycling and different surface treatments. A total of 216 specimens (10 × 10 × 20 mm) were prepared from three base materials and subjected to surface treatment via no treatment (control), alumina air abrasion, or an Er/YAG laser. Two reline materials (hard and soft) were applied according to manufacturers’ instructions. All samples underwent 5000 thermal cycles and were tested using a tensile bond strength test. SEM analysis was performed to evaluate failure modes. The highest bond strength was observed in the milled resin group combined with alumina air abrasion and the hard reline material, reaching up to 12.41 MPa. Statistically significant effects were found for the material type, surface treatment, and reline material (p < 0.001). The results indicate that material properties, surface preparation, and reline type critically influence bond performance. Milled PMMA bases and hard relining agents, particularly when combined with air abrasion, offer superior bonding outcomes.

Aims: The crown implant ratio may pose a problem, especially when short implants are used. This condition is associated with marginal bone loss. Therefore, in this study, it was aimed to evaluate the stresses arising from the bone, implant and its parts and the restoration by finite element analysis (FEA), as a result of comparing a situation with ideal bone support and a similar situation with vertical bone loss. The null hypothesis is that the type of material and crown length chosen for implant-supported restorations will not make a difference in terms of stress on implants of different sizes. Methods: For this study, 8 mm implants were placed in the 44-46 region and a group with a 3-unit 12 mm length fixed prosthesis and a group with 12 mm implants and a 3-unit 8 mm length fixed restoration were designed. The data of the implant parts were obtained from a implant company (Bilimplant, İstanbul, Turkiye) and placed in the appropriate position within a bone data drawn in the Solidworks 2013 software (Solidworks Corp., USA). Appropriate multi-unit parts were then added and 3-unit restorations were designed with exocad. Necessary arrangements were made in the Geomagic Design X 2020 (3D systems, Morrisville, NC, USA) program, the restorations were given the characteristics of 2 different materials (lithium disilicate and zirconia). Applying a force of 200 N on the occlusal direction, the maximum principal stress values ​​​​occurring in the bone, implant, multi-unit, restoration and occlusal screw were recorded. Results: Principal stress (Pmax) values recorded on the implant for the 1st premolar were higher on the 12 mm implant (B1 and B2 groups) and lower on the 8 mm implant. For the implant applied to the 1st molar region, higher stress values were observed in the groups with 8 mm implants (A1 and A2 groups), while lower values were observed with 12 mm implants (B1 and B2 groups). Conclusion: As the crown/implant ratio increases in favour of the implant, the survival of the unit decreases. In addition, it is more appropriate to prefer rigid materials in implant restorations.

Aim: In multilayered zirconia blocks, the enamel layer consists of 5Y-TZP, whereas the transition and body layers consist of 3Y-TZP content. Zirconias, which have different compositions, can be sintered quickly and conventionally, but the effect of rapid sintering on light translucency is not fully known. The aim of this study was to investigate the effect of speed-sintering protocols on the light translucency of multilayered monolithic zirconia materials. Methodology: In this study, multilayered blocks underwent a speed sintering protocol: Katana Zirconia YML (Kuraray) and IPS e.max ZirCAD Prime (Ivoclar Vivadent). The samples were designed with a post-sintering diameter of 12 mm and thickness of 1 mm, and they were manufactured using a CAD/CAM milling machine (Onex Dental Coritec 350i). Samples obtained from the blocks were randomly divided into two groups and sintered in two different ways according to the sintering protocol (n=16). After sintering, L*, a*, b* values of all samples were measured with a spectrophotometer, and the measurements were recorded using black and white backgrounds. Translucency (TP) values were analyzed using a two-way analysis of variance (ANOVA) test to examine the effects of zirconia firing. Statistical analysis was performed using IBM SPSS. Results: The light translucency values of the ZirCAD Prime subgroup subjected to speed sintering were higher than those of the other groups. In the Katana YML group, no significant difference (p=0.161) was observed between the subgroups that sintered rapidly and conventionally. Conclusion: The differences in light translucency values may be attributed to variations in the amount and thickness of 5Y-TZP zirconia in the enamel layer. The light translucency of the Katana Zirconia YML block was not affected by the sintering protocol, demonstrating that this block can be safely speed-sintered. How to cite this article: Güntekin N, Kızılırmak B, Tunçdemir AR. Comparison of light transmission of multilayered zirconia materials produced using different sintering methods. Int Dent Res. 2024;14(S1):55-59 https://doi.org/10.5577/indentres.551