Evaluation of the Shear Bond Strength of Two Adhesive Systems in Enamel and Dentin of Temporary Teeth.

Objectives: Demonstrate through in vitro shear tests, if there are statistically significant differences for the adhesive resistance between etch-and-rinse and self-etching adhesive systems in enamel and dentin of deciduous teeth.
Methods: 104 enamel and dentin samples obtained from the coronal portion of temporal teeth, cut in a distal-mesio direction, were divided into 4 groups, according to the adhesive treatment to be performed and according to the dental substrate: (1) Enamel treated with two-step etch-and-rinse adhesive system, fifth generation (Single Bond 2, 3M-ESPE), (2) Enamel treated with two-step self-etching adhesive system, sixth generation (Clearfil SE Bond, Kuraray), (3) Dentin treated with Single Bond 2, 3M-ESPE, (4) Dentin treated with Clearfil SE Bond, Kuraray. In each group the adhesive system was applied following the manufacturer's instructions. Then, using an "Ultradent Adhesion Guide", a composite resin cylinder (Herculite Précis, Kerr) was applied incrementally in 2 layers not larger than 2 mm each, polymerizing 40 seconds each increment. Finally shear strength tests are performed on the test machine (Shear Bond Tester, Bisco). The obtained data were processed with the statistic t student test (p <0.05).
Results: A significantly higher difference was obtained for the etch-and-rinse adhesive Single Bond 2 in enamel; while, in dentin, a significantly higher difference was obtained for the self-etching adhesive Clearfil SE Bond.
Conclusions: There is a statistically significant difference in the adhesive resistance between etch-and-rinse and self-etching adhesive systems in enamel and dentin of temporary teeth. After the tests, it is evident that Single Bond 2 has a significantly higher primary enamel adhesive strength than Clearfil SE Bond. Whereas, in primary dentin, the results indicate a significantly higher adhesive resistance for Clearfil SE Bond.