Post-etching cleaning and resin/ceramic bonding: microtensile bond strength and EDX analysis

The aim of this study was to evaluate the microtensile bond strength of a resin composite bonded to two heat-pressed ceramics after performing different post-etching cleaning techniques.

Resin composite specimens were bonded to IPS Empress Esthetic (EE) and IPS Empress 2 (E2) heat-pressed ceramic disks after etching with 10% HF, surface cleaning, silanization and application of an unfilled hydrophobic resin. Resin composite specimens were fabricated using 4-mm (height) Tygon tubes of 0.8 mm diameter and bonded according to the post-etching cleaning technique employed (n = 30): no cleaning (NC); air-water spray for 30 s (AWS); 37% phosphoric acid etching for 30 s (PA); ultrasonic bath in distilled water for 5 min (UB); PA + UB (PAUB); application of a self-etching silane/bonding system Clearfil Silane Kit (CSK). The resin composite specimens were subjected to tensile tension at a crosshead speed of 0.5 mm/min. SEM observation and EDX analysis were performed for each group to determine elemental distribution in the samples.

Two-way ANOVA with random effect showed statistically differences between subgroups for E2, in which E2NC only showed bond strength significantly lower than E2AWS and E2BU, as indicated by Student's t-test and a contrast method. For EE, subgroups EENC and EECSK groups showed statistically significant differences between each other and among the other post-etching cleaning technique groups (p < 0.05).

Air-water spray may be used as a post-etching cleaning technique for both ceramics. The presence of residues did not significantly reduce the bond strength of resin composite to IPS Empress 2 ceramic.