Purpose: To evaluate the influence of enamel condition and etching strategy on bond strength of a universal adhesive
in primary teeth.
Materials and Methods: Thirty-six primary molars were randomly assigned to six groups (n = 6) according to the
enamel condition (sound [S] and demineralized [DEM]/cariogenic challenge by pH cycling prior to restorative procedures)
and adhesive system (Scotchbond Universal Adhesive [SBU]) used in either etch-and-rinse (ER) or selfetching
(SE) mode, with Clearfil SE Bond as the self-etching control. The adhesives were applied to flat enamel
surfaces and composite cylinders (0.72 mm2) were built up. After 24-h storage in water, specimens were subjected
to the microshear test. Bond strength (MPa) data were analyzed using two-way ANOVA and Tukey’s post-hoc tests
(α = 0.05).
Results: Significant differences were found considering the factors adhesive system (p = 0.003) and enamel condition
(p = 0.001). Demineralized enamel negatively affected the bond strength, with μSBS values approximately
50% lower than those obtained for sound enamel. SBU performed better in etch-and-rinse mode, and the bond
strength found for SBU applied in self-etching mode was similar to that of CSE.
Conclusions: Enamel etching with phosphoric acid improves the bond strength of a universal adhesive system to
primary enamel. Demineralized primary enamel results in lower bond strength.