Effect of APF Treatment Of CAD/CAM Ceramics on Bond Strength

Hydrofluoric acid treatment is frequently used for the surface treatment of ceramic restoratives containing silica. However, hydrofluoric acid is extremely toxic and requires great care when used in chair-side situations. Acidulated phosphate fluoride (APF) solution is highly safe and widely used for caries prevention in both children and adults by application to the teeth. Use of a safer alternative to hydrofluoric acid is desirable, so this study aimed to investigate the effects of surface treatment with APF solution combined with heat treatment on bonding to CAD/CAM ceramics. Specimens of ceramics were distributed into five groups: Group A30, treated by 2% APF for 30 min; Group AH1, treated by APF with heat treatment (at 100⁰C for 1 min); Group AH5, treated by APF with heat treatment (at 100⁰C for 5min); Group HF, treated with 8% hydrofluoric acid, and Group CO, without etching treatment as a control. After treatment, specimens were bonded with dual-cured resin cement system. Tensile bond strength was measured after 24h. Mean bond strengths were as follows: Group CO, 11.03 MPa; Group A30, 12.96 MPa; Group AH1, 14.19 MPa; Group AH5, 17.15 MPa; and Group HF, 17.50 MPa. APF treatment combined with additional heat treatment offered effective bonding to CAD/CAM ceramics

Keywords: APF; Tensile bond strength; CAD/CAM ceramics