Etching effect of 17% EDTA and a non-rinse conditioner (NRC) on primary enamel and dentin

To investigate the effect of a new non-rinse conditioner (NRC) and 17% EDTA as etchants on the micromorphology of primary tooth enamel and dentin, in comparison with 36% phosphoric acid (PA) when applied for 15 s and 7 s.

Enamel specimens obtained from 40 extracted primary second molars were used to create four groups (n=10) which received the following treatments on unground enamel surface: Group 1: 36% PA/15 s, Group 2: 36% PA/7 s, Group 3: NRC 20 s, Group 4: 17% EDTA/60 s. The same treatments were applied on flattened primary tooth dentin specimens (four groups/n=10). All treated surfaces were examined by SEM.

For enamel specimens, a Type II etching pattern was evident in Groups 1 and 3. In Group 2, an uneven Type II pattern was present with prism peripheries partially intact. A mixture of Type II and Type III etching patterns were observed in Group 4. Although all conditioners removed dentin smear to varying degrees, the overall performance of 17% EDTA was weaker than PA and NRC.