Zirconia surface infiltration with low-fusing glass: A surface treatment modality to enhance the bond strength between zirconia and veneering ceramic

BACKGROUND: The pursuit of esthetics and superior mechanical properties prompted the layering of Yttrium stabilized Zirconia with ceramic material. However, the bioinert nature of zirconia causes the chipping off of this ceramic layer. Selective infiltration etching (SIE) of zirconia provides good bond strength between zirconia and veneering ceramic. MATERIALS AND METHODS: One hundred and fifty zirconia specimens of dimensions 5 × 5 × 10 mm were divided into 5 groups. Group 1: Air abrasion with 30 μ Al(2)O(3) for 15 s with 0.4 bar pressure. Group 2: SIE and heat-induced maturation (HIM) as demonstrated by Abousheilb. Group 3: Sintered zirconia specimens were taken up for air abrasion followed by SIE/HIM. Group 4: Air abrasion and SIE performed on unsintered specimens followed by heat treatment at 1500°C. Group 5: Air abrasion performed on unsintered zirconia specimens followed by heat treatment at 1500°C followed by SIE/HIM. The samples were then layered with ceramic and subjected to shear bond strength (SBS) analysis. RESULTS: The mean and standard deviation were calculated for the data. The mean SBS among the groups was compared using ANOVA. The post hoc Bonferroni test was applied to compare between the groups. The mean SBS was highest for Group 5 (47.89 ± 6.53) followed by Group 2 (34.94 ± 3.04), Group 3 (32.56 ± 6.04), Group 1 (29.12 ± 7.37), and Group 4 (27.56 ± 7.54). ANOVA test showed statistically significant differences among the groups (F = 48.86, P = 0.00). CONCLUSION: SIE/HIM when combined with sandblasting with appropriate heat treatment demonstrated a significant increase in bond strength. This prolongs the longevity of the restoration, thereby meeting the clinical needs.