Laboratory Evaluation of Dental Amalgam Alloys.

摘要

Five newly developed high-copper amalgam alloys were evaluated to determine their suitability for use in military dentistry. Measured property values were compared to those of eight conventional alloys which presently enjoy wide usage in the U.S. Uniformed Federal Services dental clinics. Setting expansion or contraction was characteristic feature of the amalgamates. Ten of 13 alloys exhibited contraction and 3 expansion. Early (15-minute) tensile strengths of ternary high-copper materials were higher than those of either a dispersed phase product or the conventional alloys. Early tensile strengths ranged from 340 psi for one conventional material to 1,200 psi for an indium-containing high-copper alloy. Ranges of mean tensile and compressive strengths at 24-hours were relatively narrow. Static creep (deformation under constant load) of the high-copper alloys was low (0.21 - 0.71%). The high-copper alloys evaluated merit consideration for procurement and routine use in military dentistry. However, use of these products will not guarantee superior dental treatment. Numerous manipulative variables are important in determining the character of the finished amalgam restoration. Also, the importance of good cavity preparation cannot be overstated.