Panavia F 2.0 bonding to contaminated zirconia ceramic after different cleaning procedures.

OBJECTIVES

The purpose of this laboratory study was to evaluate the influence of different cleaning methods after saliva contamination and after using a silicone disclosing medium on the resin bond strength to zirconia ceramic. The hypothesis was that the resin-ceramic bond strength and its durability are related to the ceramic surface condition.

METHODS

Plexiglas tubes filled with composite resin were bonded to air-abraded zirconia ceramic disks using a phosphate monomer containing composite resin. Four surface cleaning methods were used after contaminating the ceramic surface: air abrasion with 50 mum Al(2)O(3) at 2.5 bar pressure for 15s, cleaning with 37% phosphoric acid for 60s once or for 30s twice, or cleaning in 96% isopropanol for 15s. The specimens of the control group were not cleaned after using the silicone disclosing medium. For each combination 16 specimens were bonded in an alignment apparatus. Subgroups of eight bonded specimens were tested for tensile bond strength (TBS) after storage for either 3 or 150 days combined with 37,500 thermal cycles. The statistical analyses were performed with the Kruskal-Wallis test, followed by multiple pair-wise comparisons using the Wilcoxon rank sum test.

RESULTS

The mean TBS ranged from 6.6 to 49.9 MPa after 3 days and from 0 to 19.8 MPa after 150 days. Air abrasion of the ceramic surface provided statistically significantly higher bond strengths than the other cleaning methods after 3 and 150 days. Alcohol cleaning of the ceramic did not provide durable bond strengths over time.

SIGNIFICANCE

Ceramic cleaning methods after try-in procedures have a significant influence on the resin-ceramic bond strength. Air abrasion of contaminated zirconia ceramic is the most effective.