To achieve a precise passive fit of an implant prosthesis, it is important to reproduce three dimensional relationship of implants and abutments by an accurate impression procedure. Aim: The accuracy of closed and non-splinted open tray abutment level impression techniques for the All-On-Four implant protocol was compared. Methods and Material: Four implants were inserted into an acrylic edentulous maxillary reference model in accordance with the All-On-Four technique. Two straight transmucosal abutments were used for two straight anterior implants, and two 30° angled transmucosal abutments were used for two distal positioned posterior implants. With the use of polyether impression material, closed (n = 10) and unsplinted open tray (n = 10) impressions were made. The casts made from closed and unsplinted open tray groups as well as the reference acrylic model were measured linearly and angularly using a coordinate measuring machine. Statistical analysis used: The difference in inter-implant distance in the X-axis and Y-axis between the reference, Group A, and Group B was analysed using the Kruskal-Wallis test. The implant angulation to the horizontal plane in the z-axis of the two groups was compared using the Mann Whitney U test. Results: The linear and rotational differences between the casts made from the closed and unsplinted open tray and those made from the reference acrylic model did not differ significantly. Conclusions: When a suitable multi-unit abutment is utilised to correct the implant angulation, either non- splint open or closed tray impressions can be made, within the scope of our study's constraints.