Contour is a dispersed phase alloy that features a firm pack with smooth carving.
Contour helps avoid chipping and flaking of marginal ridges.
You maybe removing the matrix band too soon. Not condensing the alloy adequately. 3.The matrix band may have indentations in its surface caused by the amalgam condenser which will drag on the amalgam possibly causing it to break off. The matrix band could have been bent during the insertion of the interproximal wedge causing it to drag on the amalgam during removal. An easy way to solve the above problem is to cut the matrix band either buccal or lingual to the contact area and pull the band through the contact from the side that was not cut.