[Marginal cleft and solubility]

Studies of extracted teeth showed that, when the width of the interval is increased by 0.1 mm, the depth of the interval enlarged an average of 0.067 mm. It would seem that, in terms of cement caries, the attachment cement loosens more quickly under the effect of carious processes. The loss of substance is less when the cement seams are below the gingival cuff. Laboratory tests of cement seams showed the loss of substance to be slight with zinc-oxide-phosphate cements. A distinct shrinkage was observed with carboxylate cements. The greatest amount of loss was reported with the EBA cement.