Effects of adhesive used as modeling liquid on the stability of the color and opacity of composites.

Objective This study evaluated the effects of adhesive type used as modeling liquid on the stability of the color and opacity of composites submitted to thermal cycling in staining solutions followed by a bleaching procedure. MethodsResultsThirty cylinder-shaped composite specimens (10 mm diameter x 1.5 mm thickness) were built using or not using (control) an adhesive (Adper Universal or Scotchbond Multipurpose) as the modeling liquid. After polishing procedures, the color and opacity were measured, and the specimens were submitted to 200 thermal cycles with 10 s of dwell time in baths of grape juice at 5 degrees C, water at 37 degrees C, and coffee at 55 degrees C. Changes in opacity and color caused by the staining solutions were measured. Then, the specimens were bleached with 35% hydrogen peroxide for 45 minutes followed by color/opacity measurements. Data were analyzed by ANOVA and Tukey's test (=0.05). The use of modeling liquids did not affect the initial color and opacity of composite. Reduced changes to color (E-00=3.44) and opacity (+2.67%) were observed for specimens modeled using Adper Universal. Bleaching procedures reduced the color (E-00=1.9-3.8) and opacity (-2.3 to 3.1%) alterations caused by staining solutions but were unable to restore the values observed at baseline. ConclusionClinical SignificanceThe use of universal adhesive as modeling liquid significantly reduced the color and opacity changes caused by staining solutions, and the bleaching procedure partially re-established the opacity and color of the composites. This study evaluates whether using adhesive systems for modeling a composite affects the color and opacity changes caused by staining solutions followed by a bleaching procedure. The findings suggest that the use of a universal adhesive as modeling liquid can reduce the alterations in optical properties caused by staining solutions, and the application of high-concentrated hydrogen peroxide over the composite reduce the color changes without fully recover the initial color.