An evaluation on microleakage and gap width of different dentin bonding agents in high copper amalgam restorations

Statement of Problem: A lot of efforts have been made to create a complete adaptation between tooth and amalgam restorations. The aim of this study was to evaluate microleakage and interfacial micromorphology of amalgam restorations lined with dentin adhesives, namely One Coat Bond, Syntac, Excite and Copalite,as liners. 144 intact human canine teeth were selected. Then class V cavities, with enamel and dentinal margins, were prepared on each of them. Cavities were lined with different dentin bonding systems (Syntac, One Coat Bond and Excite) according to the manufacturer's instructions and restored with Oralloy and Cinalloy, non gamma 2 spherical amalgams and Aristaloy a non gamma 2 Admixed alloy. Copalite was used in the group, served as controls. After thirty days storage in synthetic saliva at 37°c, the specimens were thermocycled in saliva (4000 cycles). The degree of microleakage was assessed by means of basic fushin dye penetration and recorded. The gap width was evaluated with Scanning Electron Microscope. Pearson and %2 tests were used to analyze the results. None of the systems, tested in this study, eliminated microleakage completely, Pearson's correlation coefficient showed a positive correlation between gap and microleakage (P<0/05).Statistical significant differences were revealed among the liners regarding gap and microleakage (P<0.05).One Coat Bond and Syntac appeared to leak less than other groups. The gap width by One Coat Bond and Syntac were respectively 0.35 and 0.3 urn in dentine, 0.2 and 0.1 in enamel. Excite and copalite gap width in dentine and enamel were 1,3-1.36 urn and 0.3-0.6, respectively. The type of amalgam did not have any effect in the degree of microleakage and gap width (P>0/05). One Coat Bond and Syntac, comparing to Excite and Copalite, showed less microleakage and gap width.