Assessing the Effects of Air Abrasion with Aluminum Oxide or Glass Beads to Zirconia on the Bond Strength of Cement

AIM

The purpose of this study was to evaluate the effects of air abrasion with aluminum oxide or glass beads to three types of zirconia containing various levels of cubic crystalline phases (3Y-TZP, Katana ML; 4Y-PSZ, Katana STML; and 5Y-PSZ, Katana UTML, Noritake) on the shear bond strength of resin cement.

MATERIALS AND METHODS

Thirty block specimens (8 × 8 × 3.5 mm) were milled out of each zirconia material and mounted in plastic pipe. Ten specimens of each of the zirconia materials were air-abraded using 50 μm aluminum oxide particles, ten specimens were abraded using 80 μm glass beads, and ten specimens served as a control and received no surface treatment. A zirconia primer was applied to the surface of the zirconia specimens. Composite disks were bonded using a resin cement and light-cured. The specimens were stored in 37°C distilled water for 24 hours and thermocycled for 2,500 cycles. The specimens were loaded in shear on a universal testing machine. Data were analyzed with one-way and two-way ANOVAs and Tukey's post hoc tests (α = 0.05).

RESULTS

A significant difference in shear bond strength was found based on the surface treatment (p < 0.001), but not on the type of zirconia (p = 0.132).

CONCLUSION

Air abrasion with glass beads or no surface treatment resulted in significantly lower bond strength of the resin cement to all three zirconia types compared to air abrasion with aluminum oxide.

CLINICAL SIGNIFICANCE

Although air abrasion with aluminum oxide may reportedly be more likely to weaken cubic-containing zirconia compared to air abrasion with glass beads, the use of aluminum oxide results in greater bond strength of the resin cement.

Surface Characterization and Cell Adhesion of Different Zirconia Treatments: An in vitro Study

AIM

The aim of this study was to characterize the surface of zirconia subjected to different treatments and evaluate its effect on cell adhesion and proliferation.

MATERIALS AND METHODS

A total of 80 zirconia disks were divided into four groups (n = 20) according to the surface treatments used: group I: as-sintered (AS), no surface treatment applied; group II: abrasion treatment applied using Rocatec (ROC; 3M ESPE) system with silica-coated alumina powder of grit size 110 μm; group III: erbium, chromium:yttrium, scandium, gallium, garnet (Er, Cr:YSGG) laser (LAS; BIOLASE) was used at a frequency of 20 Hz and output power of 3 W; and group IV: specimens were subjected to the selective infiltration etching (SIE) technique. Surface characterization was evaluated for the different groups (roughness, hardness, and morphology), and cell behavior (adhesion and proliferation) was tested (a = 0.05).

RESULTS

The ROC group reported a significant increase in surface roughness (2.201 ± 0.352) and Vickers hardness (1758 ± 16.6) compared with the other surface treatments. The SIE surface-treated group reported a significantly higher number of cells (64.5 ± 2.6 and 53.5 ± 2.2 respectively) compared with the other surface-treated groups.

CONCLUSION

The SIE is a promising surface treatment for zirconia that significantly enhances cell adhesion and osseointegration.

CLINICAL SIGNIFICANCE

The SIE treatment of zirconia implants may help in a faster and better osseointegration.