Abstract: Objective: To investigate the marginal microleakage of the new self-adhesive flow resin Constic and other three cavity filling materials in the in vitro experiments of permanent molars, and to provide the references for the selection of clinical Ⅴ -type cavity filling materials. Methods: A total of 40 fresh and extrated teeth including 20 premolars and 20 third molars were collected,and the V-type cavities were prepared on the buccal surface; the teeth were randomly divided into 4 groups(n=10),and the cavities were filled by self-adhesive flow resin Constic(Constic group),self-adhesive flow resin Dyad Flow(Dyad Flow group),flow resin Filtek Z350XT(Filtek Z350XT group) and Z350XT nano-resin(Z350 group).Five teeth were selected from each group and received cold and heat cycles for 100 times,and another five simples were used for 500 times.After thermal test,all teeth were stained with 0.1% Rhodamine-B solution. The microleakage was observed under confocal laser scanning microscope,the microleakage degree was evaluated,and the depth of microleakage was detected. Results: The marginal microleakage in different degrees was found in the materials in various groups.There was no significant difference in the microleak degree of the same meterial after 100 times and 500 times of cold and heat cycles(P>0.05).Compared with Constic group, the microleakage depths in the side of mouth and the side of gum in Dyad Flow group, Filtek Z350XT group and Z350XT group were increased(P<0.05);the microleakage depths in the side of mouth and the side of gum in Dyad Flow group and Filtek Z350XT group were lower than those in Z350XT group (P<0.05). Conclusion: Constic has low microleakage and high edge tightness and is more effective than Dyad Flow,Filtek Z350XT and Z350XT.

Key words: self-adhesive flowa resin, microleakage, self-etch adhesive, confocal laser scanning microscope