Glutaraldehyde-methacrylate dentine adhesive: the relationship between cavity site and marginal contraction gaps

Previous studies have shown that dentine adhesives reduce or eliminate contraction gaps in composite restorations. This study examined the relationship between cavity site and contraction gaps when two dentine adhesives were used in combination with two composites. One hundred and fifty-two cavities, each measuring 2.0 mm diameter and 1.5 mm depth, were prepared on side surfaces of extracted teeth, with each surface classified into three levels: upper, middle and lower. The dentine adhesives and composites were randomly assigned to the cavities. Four pre-determined, diametrical measurements of contraction gaps were made for each restored cavity using a Nikon Measurescope. Measurements yielded overall mean contraction gaps of 0.229, 0.262, and 0.260 for upper, middle and lower levels on the crown; the differences between means were not statistically significant. Type of dentine adhesives and composites influenced the size of contraction gaps rather than cavity site.