The Effect of Different Surface Treatments on The Bond Strength of Zirconia

Objectives: The purpose of the study was to evaluate the influence of various surface treatment methods on the resin bond durability of zirconia. Methods: Hundred KATANA Zirconia STML (n=20) specimens were sectioned and sintered in an induction furnace (CEREC SpeedFire, Dentsply Sirona, Germany). Specimen surfaces were ground finished with 800 grit silicon carbide abrasive with cooling water and cleaned in an alcohol bath ultrasonically before cementation for 5 min, and thoroughly washed again with running distilled water. Specimens in Group 1 had no surface treatment, Group 2 was air-abraded with 50 μm aluminum oxide, Group 3 was air abraded with glass bead particles, Group 4 specimens were immersed in Zircos E etching solution for 2 h and Group 5 specimens were immersed in 48% Hydrofluoric acid solution heated at 25oC for 30 min. Cylindrical composite resin specimens (2.1 mm in diameter, 3 mm in height) were bonded to the zirconia samples with self-adhesive resin cement Panavia V5 (PV5, after application of ceramic primer) following manufacturers’ instructions. A load of 1000 g was applied to the composite cylinders during bonding in an alignment apparatus, then light cured for 80 s. Each main group was divided into two subgroups (n = 10/each). Half of the samples were tested for SBS after 48 h in distilled water at 37o C (100-percent humidity), 10 then subjected to 10,000 thermo cycles and the other half were tested after 10,000 thermo cycles. Shear bond strength was determined using a universal testing machine at a crosshead speed of 0.5 mm/m expressed in MPa. The fractured surfaces of specimens were inspected with a stereo microscope and classified as adhesive, cohesive, or mixed failures. One-way ANOVA test and paired t- test was applied for statistical analysis. Results: All four surface treatment methods tested were significantly different from each other and with the control group (no surface treatment). Mean shear bond strength values for group1 8.316(SD 1.953), group 2 14.976(SD 3.189), group 3 9.286(SD 0.985), group 4 4.831(SD 0.468), and group 5 14.796(SD 0.829). The mean shear bond strength values for all the groups decreased significantly after thermocycling. Conclusions: According to the results of this in vitro study, air abrasion and heated hydrofluoric acid proved to be better methods for surface treatment of zirconia as compared to other methods. Newly launched zirconia etching solution containing hydrofluoric acid (HF), hydrochloric acid (HCl), sulfuric acid (H2SO4), nitric acid (HNO3), and phosphoric acid (H3PO4) performed poorly as surface treatment agents in increasing the bond strength of zirconia

Comparative evaluation of the influence of immediate versus delayed loading protocols of dental implants: A radiographic and clinical study

Aim: Immediate loading protocol, in recent times, has gained popularity as it has not only shortened the treatment time but also resulted in enhanced patient satisfaction. The aim of this study was to evaluate and compare the effectiveness of immediate implant loading protocol over conventional implant loading protocol with respect to peri-implant bone loss. Materials and Methods: Twenty patients selected for this study were divided into two groups. In Group I patients, implants were immediately loaded, whereas in Group II, they were loaded with conventional loading protocol. Peri-implant bone loss was measured and compared using intraoral periapical radiographs with the grid at the time of implant loading, 1, 3, and 6 months after implant loading. Results: Change in radiographic bone loss in both the groups was found to be statistically significant when baseline was compared to 1, 3, and 6 months, but the difference in the bone loss between Group I and II was not found to be statistically significant. Conclusion: No statistically significant difference was observed in the crestal bone loss on comparison of immediate loading to delayed loading protocol. Clinical Significance: After achieving good primary stability, immediate-loaded implants can be used for the benefit of the patients as it reduces the period of edentulism