Gr Esfahani Zadeh, N Akhavan Saless, M Noor Bakhsh, Mh Salari, D Ghalebaaghi,
Volume 3, Issue 2 (4-2018)
Abstract
Background and Aim: Due to the importance of the bond strength between zirconia core (ZC) and porcelain veneer (PV) as well as the paradox about the functionality of sandblasting on the solidity between those layers, this research aimed to evaluate the effect of sandblasting on the shear bond strength (SBS) between ZC and PV.
Materials and Methods: After preparing 20 zirconia discs (7 mm × 3 mm) in this experimental study, they were randomly divided into two groups of case and control. In the case group, sandblasting with 120-μm aluminum oxide particles (Al2O3) was performed under 3.5-bar pressure at 10 mm distance from the zirconia surface for 15 seconds. Next, all the samples were cleaned with ultrasonic and 96% isopropyl alcohol for 3 minutes as well as steam cleaning for 10 seconds. Then, the samples were veneered with porcelain (3 mm × 5 mm). SBS was assessed using a universal testing machine. After data collection, the mean and standard deviation (SD) were calculated and analyzed using T-test.
Results: The SBS between ZC and PV was 62.56±8.35 MPa in the case group (after sandblasting) and 94.62±7.69 MPa in the control group. The SBS showed a significant statistical difference between the two groups (P=0.001).
Conclusion: The result of this research indicated that sandblasting reduces the SBS between ZC and PV. Considering the limitations and the methodology of the study, the hypothesis regarding the positive impact of sandblasting on SBS was not proven.
Vamsee Priya Golla, Satyanarayana Raju Mantena, Rama Krishna Alla, Vineeth Guduri, Suresh Sajjan Mc, Bheemalingeswara Rao D, Deepika Kandukuri,
Volume 10, Issue 1 (3-2025)
Abstract
Background and Aim: Several studies have investigated the effect of addition of fillers on mechanical strength of denture base materials. This study aimed to evaluate the mechanical properties of heat-cure denture base materials incorporated with different concentrations of zirconia nanotubes (ZNTs).
Materials and Methods: In this in vitro study, 90 specimens were fabricated from each denture base resin material (Trevlon and DPI) and divided into three groups (n=30) based on the mechanical properties to be tested (flexural strength, impact strength, and surface hardness). Thirty specimens in each group were further subdivided into 5 subgroups (n=6) based on the weight percentage (wt%) of ZNTs (0.0wt%, 0.5wt%, 1.0wt%, 2.0wt%, and 5.0wt%). The specimens were subjected to flexural strength, impact strength, and surface hardness testing using a universal testing machine, IZOD impact testing machine, and Vickers hardness tester, respectively. One-way ANOVA and post-hoc tests were used for statistical analyses (alpha=0.05).
Results: The maximum flexural strength was observed following the inclusion of 2.0wt% and 1.0wt% ZNTs in Trevlon and DPI, respectively. The maximum impact strength was obtained with the addition of 1.0wt% ZNTs to both Trevlon and DPI. The surface hardness of Trevlon and DPI increased significantly with an increase in the concentration of ZNTs (P=0.005). Flexural strength (P=0.000) and surface hardness (P=0.005) were significantly different among various concentrations of Trevlon and DPI, but the impact strength (P=0.013) was significantly different only in DPI.
Conclusion: The optimal concentration of ZNTs to obtain enhanced mechanical properties of denture base resins was found to be 1.0wt%.
