Objective: The purpose of this study is to evaluate the accuracy of different putty-wash impression techniques.

Methods: A stainless steel die was produced to simulate the maxillary arch. Three tapering cylindrical preparations were made, one at the anterior midline and two at the molar areas. 30 impressions were made of C-silicone (Alphasil, Omicron Dental, Germany) with metal tray and divided into 3 groups of 10 impressions each.

Group 1: Putty-wash one step technique.

Group 2: Putty-wash two step technique without relief.

Group 3: Putty-wash two step technique with spacer.

Accuracy of techniques was assessed by measuring interabutments (A,B), crossarch (C,D) and occlusogingival (E,F,G) distances on stone dies with 3D contact measuring device (Tesa MS 6101 3D, Swiss)(see figure). Data were analyzed with Kruskal-Wallis and Mann-Whitney tests.

Results: Mean and standart deviatons are shown on table. Kruskal-Wallis test showed statistically significant differences amongst three techniques in vertical direction (p<0.05), but not in horizontal direction (p>0.05). Mann-Whitney showed that the dimensional deformation of the putty-wash two step technique without relief was significantly smaller than the other two techniques.

Conclusion: Within the parameter of this study it was observed that putty-wash two step techniques showed the most accurate result in occlusiogingival dimension.

	1.group		2.group		3.group
Distances	Mean(SD)		Mean(SD)		Mean(SD)
A	-0.07	(±0.5819)	-0.1001	(±0.0305)	0.085	(±0.07568)
B	0.014	(±0.5729)	-0.03	(±0.037)	0.1641	(±0.07705)
C	-0.1025	(±0.6732)	-0.2211	(±0.09617)	-0.08	(±0.06489)
D	0.024	(±0.09613)	0.1226	(±0.09899)	-0.02	(±0.06705)
E	0.22384	(±0.06342)	-130200	(±0.018)	-0.3042	(±0.0145)
F	-0.07	(±0.05554)	0.015	(±0.0075)	0.023	(±0.019)
G	0.1637	(±0.05838)	0.1017	(±0.019)	0.1111	(±0.0455)