Effects of Cleaning Protocols on Resin Bond Strength to Saliva-Contaminated Monolithic Zirconia

TL;DR

This study found that using Ivoclean after sandblasting provides the strongest bond between resin cement and saliva-contaminated zirconia.

Contribution

The study introduces a novel cleaning protocol combining sandblasting and Ivoclean for improved resin bonding to zirconia.

Findings

Sandblasting followed by Ivoclean produced the highest shear bond strength (9.3 MPa).

Ivoclean alone and sandblasting alone also showed significantly higher bond strength than other methods.

Air-water spray, pumice, and isopropyl alcohol were less effective in restoring bond strength.

Abstract

Considering the significant weakening of the bonding of resin cements to saliva-contaminated zirconia restorations, this study aimed to investigate the effect of various surface treatment methods on the bonding of self-adhesive resin cement to zirconia after various cleansing methods.

A total of 105 monolithic zirconia specimens were cut from pre-sintered blocks using a water-cooled precision diamond saw. Specimens were kept in the artificial saliva except for the control group. The specimens were then cleaned using one of the following methods: 1. Air-water spray, 2. Isopropyl Alcohol, 3. Pumice, 4. Universal cleaning agent (Ivoclean), 5. Sandblasting, 6. Sandblasting + Ivoclean. Specimens were bonded to self-adhesive resin cement. Specimens were thermocycled for 5,000 cycles after cementation and tested in shear mode (1 mm/min). Images were obtained using a stereomicroscope, scanning electron microscope, and energy-dispersive spectroscopy. Data were analyzed using ANOVA, and multiple comparisons were performed with the Duncan test (α = 0.05).

The mean shear bond strength values were as follows in descending order: Sandblasting + Ivoclean (9.3 MPa) > sandblasting (8.59 MPa) > Ivoclean (7.21 MPa) > Pumice (4.82 MPa) > Air-water spray (4.15 MPa) > Control (3.65 MPa) > Isopropyl alcohol (3.04 MPa). Significant difference was observed between sandblasting and Ivoclean groups, and between sandblasting and sandblasting + Ivoclean groups (P < 0.05). A significant difference was also found between the Ivoclean and sandblasting + Ivoclean groups. The groups treated with sandblasting + Ivoclean, sandblasting, and Ivoclean showed a significant difference compared to all other surface treatment groups. There was no significant difference in shear bond strength among the control, air-water, alcohol, and pumice groups (P > 0.05). Sandblasting, Ivoclean, and Ivo-clean after sandblasting applications were found to deliver significantly higher (P < 0.05) adhesion compared with air-water, pumice, and alcohol applications.

Subsequent applications of Ivoclean after sandblasting established a stronger bond between self-adhesive resin cement and monolithic zirconia than other cleaning methods tested.

Following airborne particle abrasion, intaglio surfaces of zirconia restorations should best be cleaned using Ivoclean.

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