Introduction:
Effective preparation of the shoulder margin in abutment teeth for crowns and bridges is the key factor determining the seal and durability of such restorations.

Aim of the study:
To assess the flow of impression material into the gingival sulcus, taking into account the impression material used and the impression-taking technique.

Material and methods:
Eight impression materials were tested and six impression techniques were examined. The standard for the study was a model of the mandible and prepared teeth 43 and 46. A simulation was made of gingival sulci 200 µm in width in the region of the abutment teeth. The study material comprised 250 impressions.

Results:
The greatest material flow in the gingival sulcus was achieved with the two-step two-phase technique without cutting-out a layer of impression material in the cervical area. A twostep two-phase method produced a greater flow of impression material into the gingival sulcus than single-step techniques. Material flow in the gingival sulcus was weaker when impressions were taken with customized trays compared with standard trays.

Conclusions:
1. The deepest flow in the gingival sulcus was achieved with Silagum using a twostep two-phase technique with cut-out interdental spaces. 2. Impression material achieves greater flow in the gingival sulcus when two-step twophase techniques are used than with one-step one-phase techniques. 3. Impression material applied in standard trays ensured deeper flow in the gingival sulcus than impressions taken in custom-made trays.