Flextural bond strength and electron microscopic observation of repaired high copper amalgam

ABSTRACT

The aim of this study is to compare the flextural bond strength values of nonrepaired, mercury repaired and Amalgambond [a 4-META based resin] repaired high copper amalgam alloys. Four amalgam alloys were investigated [Dispersalloy, Contour, Sybralloy and Tytin]. The flextural bond strength was determined by using a three point bending test on an Instron testing machine at a crosshead speed of 0.5mm/mn. Scanning electron microscopic examinations between x l00 and x2500 revealed a cohesive pattern of failure for the nonrepaired specimens, a dominating adhesive failure for the mercury repaired specimens and a combined adhesive-cohesive type of failure for the Amalgambond-repaired specimens. An ANOVA test and a Duncan's multiple range test at P<.05 indicated a statistically significant difference between the bond strength of the non-repaired Contour specimens and the other three alloys. It also revealed no statistically significant difference between all the mercury-repaired specimens, and no statistically significant difference between all the Amalgambond repaired specimens. However, a significant difference existed between the mercury-repaired and the Amalgambond-repaired amalgams. The bond strength of the mercury-repaired amalgams was almost half that of the non-repaired ones, whereas the bond strength of the Amalgambond-repaired amalgams was again nearly half of the mercury repaired ones for the four types of alloys tested