RESUMO
<p><b>OBJECTIVE</b>To evaluate the microtensile bond strength (µTBS) of five dentin adhesives and their respective fracture modes.</p><p><b>METHODS</b>The flat dentine surfaces of 75 primary teeth were randomly divided into five groups,which was treated with FL-BondII(group A), Clearfil Protect Bond(group B), Clearfil SE Bond(group C), Adper(TM) Easy One(group D), and Single Bond 2(group E) respectively. The µTBS was determined with microtensile tester and the fracture mode was observed by scanning electron microscope(SEM).</p><p><b>RESULTS</b>The mean µTBS for group A,B,C,D and E was (28.3 ± 2.2), (32.4 ± 2.5), (38.3 ± 2.8), (32.9 ± 3.4) and (23.2 ± 1.9) MPa respectively. There was significant difference between group C and group A,E (P < 0.01), and no significant difference between group C and group B,D. There was no significant difference between group A and group E (P > 0.05). The SEM indicated that there was no significant difference in the fracture mode.</p><p><b>CONCLUSIONS</b>The bonding property of Clearfil Protect Bond is equivalent to Clearfil SE Bond and Adper(TM) Easy One, superior to Single Bond 2 and more suitable for primary dentin bonding .</p>