Journal of Dental Research, Vol 65, 1319-1321, Copyright © 1986 by International & American Associations for Dental Research Online Journals
Effect of cavity depth and application technique on marginal adaptation of resins in dentin cavities
E. K. Hansen
Department of Technology, Royal Dental College, Copenhagen, Denmark.
The wall-to-wall polymerization contraction of two restorative resins was
investigated in butt-joint dentin cavities prepared in extracted human
teeth. The cavity diameter was 4 mm, and the cavity depth ranged between
0.5 and 3.0 mm. The width of the maximum marginal contraction gap was
measured, using a light microscope, approximately 0.1 mm below the original
free surfaces of the fillings. It was found that increasing the cavity
depth from 0.5 to 3.0 mm did not influence the marginal contraction gap
close to the free surfaces of the fillings. It was also found that a
two-phase application technique, where the surface of the first layer was
placed parallel to the free surface of the cavity, did not reduce the
marginal contraction gap, while a two-phase technique with oblique layers
resulted in approximately a 25% reduction.
