Effect of hydrofluoric acid etching on bond strength of composite luting agent to lithium disilicate ceramic material

Taro Nagai, DDS,(a) and Yoshikazu Kawamoto, DDS, PhD(a,b)

(a)Department of Crown and Bridge Prosthodontics, and (b)Division of Advanced Dental Treatment, Dental Research Center, Nihon University School of Dentistry, Tokyo, Japan

Purpose: The purpose of the current study was to evaluate the effect of surface preparation on bond strength of a composite luting agent joined to a heat-pressed ceramic material.
Materials and Methods: Two sizes of disk specimens were made from a lithium disilicate-based ceramics (IPS Empress 2) and their surfaces were separately prepared with three methods: etching with phosphoric acid (PE), etching with hydrofluoric acid (HF), and air-borne particle abrasion with alumina (AA). Each group was further divided into two sub-groups: bonding with the Panavia F material (PF), and silane treatment followed by bonding with the Panavia F material. Shear testing was performed both before and after 20,000 thermocycles.
Results: Bond strength varied from 14.2 MPa to 46.6 MPa for the pre-thermocycling groups, whereas post-thermocycling bond strength ranged from 0.3 MPa to 37.5 MPa.
Conclusion: Hydrofluoric acid etching effectively enhanced bond strength of the Panavia luting agent to the ceramic material, regardless of the application of silane primer. (Int Chin J Dent 2004; 4: 100-106.)
Clinical Significance: Hydrofluoric acid etching roughened the IPS Empress 2 ceramic surface. The etched surface was suitable for adhesive bonding with the Panavia F composite luting agent.
Key Words: bonding, ceramics, composite, hydrofluoric acid, lithium disilicate.