Objectives: Gingival retraction plays a decisive role during impression taking with regard to the reproduction of an infragingival finishing line. Only a moisture-free impression area can guarantee the precise reproduction of the abutment tooth and thus is a prerequisite for the exact marginal fit of the restoration. It was the aim of this study to analyze the influence of 3 different retraction procedures onto the sulcus-exudate-flow (SE) in-vivo. Materials and methods: Overall 335 prepared teeth (plaque index < 30%; probing depth £ 4mm) were distributed at random among 3 groups. The following retraction procedures were compared: A pure cotton cord (CC, Ultrapak, Ultradent), a cord impregnated with epinephrine chloride (EC, Surgident, Sigma Dental) and a chemical retraction technique (EX, Expasyl, Kerr, Saltec-Pierre Roland). SE was measured prior to gingiva retraction and immediately prior to impression taking after removal of the according retraction material by pressing an absorption cap onto the prepared tooth and its surrounding tissue for 2 seconds. The amount of fluid absorbed was gravimetrically determined. As the data obtained were not normally distributed, analysis was performed using non-parametric statistics (H- and U-test: p=0.05). Results: Median SE prior to gingiva retraction was determined as 10.4mg (CC), 11.1mg (EC) and 10.4mg (EX). After the retraction procedure and immediately before impression taking, SE was measured as 28.8 mg (CC), 2.55mg (EC) and 1.4mg (EX). The decrease in SE for EC and EX as well as the increase in SE in CC was significant (p<0.01). Conclusions: Within the limits of this study it can be concluded, that the selection of the retraction technique has a decisive impact on the reduction of sulcus exudate during impression taking. The data suggest, that pure cotton retraction cords are not favorable and should be avoided whenever possible.

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