Influence of the Gingival Condition on the Performance of Different Gingival Displacement Methods—A Randomized Clinical Study

This randomized clinical study examined the influence of the gingival condition—healthy versus mild inflammation—on sulcus representation and possible gingival recession for two gingival displacement procedures prior to conventional impression making. The interventions double cord technique or a kaolin paste containing aluminum chloride were applied to 40 probands. The opposite quadrant served as intrapersonal reference (split-mouth design). Precision impressions were then made. Extraoral digitization of the plaster models resulting from the reference impression prior to gingival displacement, the intervention impression and control impressions were the basis for the computer-aided three-dimensional analysis. After six months, a mild artificial gingivitis was induced, and the contralateral quadrant (cross-over design) was examined for the intervention. The gingivitis deteriorated the sulcus representation for the double cord technique group but did not affect the paste technique group. The gingival condition had no influence on the marginal gingiva height changes. The minor extent of those changes, which were measured up to six months after intervention at the palatal study site, were not considered to be in the clinically relevant range for gingival recession. For healthy gingiva, the cord technique showed superior sulcus representation compared to the paste technique. This advantage was lost to a great extent under the conditions of mild gingivitis.