Accuracy of Single-Step versus 2-Step Double-Mix Impression Technique

Abstract

Objective. To investigate the accuracy of dies obtained from single-step and 2-step double-mix impressions. Material and Methods. Impressions (n = 10) of a stainless steel die simulating a complete crown preparation were performed using a polyether (Impregum Soft Heavy and Light body) and a vinyl polysiloxane (Perfectim Blue Velvet and Flexi-Velvet) in two consistencies, in one or two (without relief) steps. Accuracy of the stone dies was accessed at a measuring microscope, using a metallic crown with perfect fit to the reference crown preparation. Data were submitted to 2-way ANOVA and Tukey test (α = 0.05). Results. The single-step technique resulted in slightly larger dies, while the 2-step technique without relief produced significantly smaller dies, when compared to the original stainless steel die. Stone dies obtained from 2-step polyether impressions were significantly smaller when compared to dies obtained from 2-step vinyl polysiloxane impressions (Impregum 2-step: −290.94 ± 71.64 μm; Perfectim 2-step: −201.86 ± 28.58 μm). No significant differences were observed in dies obtained from either polyether or vinyl polysiloxane with the single-step technique (Impregum single-step: 63.52 ± 16.60 μm; Perfectim single-step: 79.40 ± 14.11 μm). Conclusion. Higher discrepancies were detected for the 2-step impression technique without relief for the investigated materials.

Dimensional Stability and Accuracy of Silicone – Based Impression Materials Using Different Impression Techniques – A Literature Review

“…The measurements of all distances of the plaster models show altered dimensions with significant negative linear changes (contraction) compared to the standard (control) model, cast in a stainless steel. The plaster models obtained from the tested addition silicones were dimensionally more precise than the tested [29] PE, PVS N=10 Double-phase 1-step 1 h Measurements using laser scanner with 3D superimpositional software faria (2007) [18] AL, PS, PE, CS, PVS N=5 [7] PVS N=15 Mono-phase; Doublephase 1-step, 2-step; novel 2-step injection 1 h Measurements were made with a scanner 2 mm franco (2011) [10] PE, PVS N=10 Double-phase 1-step, 2-step 2 h Microscopic measurement of models 2 mm Kumar (2011) [11] PE, CS, PVS N=12 Mono-phase; Double-phase 2-step 8,…”

“…The 2-step double phase technique is performed first by filling up the tray with the putty impression material and record the abutment. The second step continues after setting (hardening) of the impression and its extraction from the mouth where low viscosity material is afterwards applied on the first impression and is again returned into the mouth for correctional impression [7][8][9][10].…”

Evaluation of the impression area precision depending on the impression technique

“…Część publikacji wskazuje na metodę jednoczasową dwuwarstwową jako dokładniejszą od dwuczasowej (10)(11)(12). Odmiennego zdania są Nissan i wsp.…”

“…Analogiczne wyniki uzyskali naukowcy (10,11) pobierania wycisków. W opozycji do powyż-szych ustaleń stoją wyniki Nissana i wsp.…”

Performance of dental impression materials: Benchmarking of materials and techniques by three-dimensional analysis

“…Image analysis of tooth contours allows for free-form shape analysis of the more complex geometries of prepared teeth 20,21) . Distance measurements of arches and abutments are also used for the analysis of factors other than the impression material itself: impression technique [22][23][24][25][26][27] , impression tray 28,29) , material volume [30][31][32] , or the effect of using a surfactant prior to pouring an impression 33) . Even when 3D digital data are used, the following analysis is often reduced to two-dimensional (2D) distance measurements 4,34) .…”