Light-cured glass ionomer cement as a bracket adhesive with different types of enamel conditioners

Eighty bovine incisors were ground on 320-grit silicone carbide paper and cleaned with fluoride-free prophylaxis paste. The enamel surface conditions were: 1. no conditioning; 2. salicylic acid (10%, 10s); 3. benzoic acid (10%, 10s); 4. air polishing with sodium hydrogen carbonate/Prophy-Jet; 5. Prophy-Jet, followed by polyacrylic acid (PAA, 10%, 10 s); 6. PAA, followed by saliva contamination; 7. PAA; 8. phosphoric acid (37%, 10 s). Fuji Ortho II LC (GC) was used as a bracket adhesive in groups 1 t0 7, and in group 8 Concise orthodontic (3M). Stainless steel lingual buttons were placed by hand. Polymerisation with visible light was carried out 20 s from mesial, distal, incisal and gingival. After 24 h storage in tap water at room temperature the shear bond strengths were tested in accordance with ISO specification TC 106/SC/WG16. Mean values of the groups were compared using Student's t-test. Group 7 (PAA) attained the highest mean shear strength (in comparison with control group): 28 MPa. This was both significantly different from the control group (Concise, 33 MPa) and highly significant in comparison with the other groups (< 16 MPa). The shear bond strength of Fuji Ortho II LC on PAA conditioned enamel indicates the clinical applicability of this material.