An in vitro study on restoring bond strength of a GIC to saliva contaminated enamel under unrinse condition

Objectives. This study attempted to find a method of restoring the tensile bond strength of glass ionomer cement (GIC) to saliva contaminated enamel under unrinse condition. Methods. One hundred and thirty human non-carious permanent teeth were divided into two major groups. Either treatment with air drying, acetone, polyacrylic acid, maleic acid, tartaric acid, Scotchbond primer or no treatment at all was applied to both clean and saliva contaminated enamel surfaces prior to GIC placement. Samples were debonded in tension after 7 days of storage in water using a universal testing machine. Statistical analysis was performed using one-way ANOVA, Tukeyʹs studentized range test and Wilcoxonʹs rank sums test to determine the significance of the difference of tensile bond strengths within and between the two major groups. Results. Bond strength of GIC to clean enamel was 2.46±0.79 MPa while the bond strength of GIC to wet contaminated enamel was significantly reduced to 1.28±0.32 MPa (p<0.01). However, the bond strengths were restored when the contaminated enamel surfaces were air-dried (2.19±0.38 MPa) or applied with either maleic acid (2.80±0.63 MPa) or Scotchbond primer (2.13±0.65 MPa) before placing GIC over the enamels. Conclusions. Air drying, or application of maleic acid or Scotchbond primer to the contaminated enamel without rinsing prior to GIC placement can restore the tensile bond strength to a level similar to that of non-contaminated control.