Purpose: To establish an effective bonding for zirconia, the aim of this study was to evaluate the influence of air-borne particle abrasion, Piranha acid etching and hot acid etching pre-treatments on bond strength of zirconia with self-adhesive resin cements (Panavia SA, TheraCem) and conventional adhesive resin cement (Panavia F2.0). Also, the effect of Silano-Pen treatment on the bond strength of zirconia to resin cements was evaluated.
Materials and Methods: Eighteen zirconia blocks were cut, sintered and divided into three groups (n=6): air-borne particle abrasion, Piranha acid etching (3H2SO4:1H2O2), and hot acid etching (1HNO3:1HF). From each group, the bonding surfaces of three zirconia blocks were treated with Silano-Pen. Each zirconia block was bonded to its corresponding composite block utilizing either Panavia SA, TheraCem or Panavia F2.0. Each ceramic ̸ resin ̸ composite assembly was sectioned perpendicular to the bonding interface to obtain microbars of 1 mm2 thickness. A total of 180 microbars were subjected to 10000 thermal cycles between 5°C and 55°C with dowel time of 30 seconds. Each microbar was subjected to tensile force until de-bonding. The data was statistically analyzed.
Results: The hot acid showed the highest µTBS (21.96±5.86 MPa) followed by air-borne particle abrasion (16.40±6.23 MPa) and the lowest was Piranha (15.04±7.12 MPa). With Panavia SA, there was significant difference (p=.035) between µTBS with Silano-Pen in air-borne particle abrasion and Piranha groups, also there was significant difference (p=.004) between Piranha and hot acid groups. With TheraCem, there was significant difference (p=.008) between µTBS with Silano-Pen in air-borne particle abrasion and Piranha groups, also there was significant difference (p=.003) between air-borne particle abrasion and hot acid groups. The interaction between cement and Silano-Pen was insignificant (p=.067).
Conclusions: Pre-treatment method and type of adhesive resin cement influences the effectiveness of bonding of zirconia. The hot acid etching recorded the highest bond strength, whereas the lowest was recorded with Piranha etching. Silano-Pen treatment after hot acid etching improved the bonding of zirconia to adhesive resin cement. The self-adhesive MDP-containing resin cement (Panavia SA) enhanced the effectiveness of the bond strength with zirconia.