Background and Aim:
Accuracy in impression making is a critical factor in the success of fixed dental prostheses, particularly in anterior edentulous spaces that vary in length. A precise impression ensures proper fit and function of the final restoration and helps prevent complications such as marginal gaps, gingival inflammation, or treatment failure. The aim of this study was to compare the accuracy of one-step and two-step impression techniques in anterior edentulous spaces of different lengths (short and long).

Materials and Methods:
In this in-vitro study, two dentate models were designed, each simulating an anterior edentulous space—one with a long span and the other with a short span. For each impression technique (one-step and two-step), 10 impressions were made. All impressions were scanned using an intraoral scanner, and digital analysis was performed using Exocad software to assess dimensional accuracy. Data were analyzed using independent t-tests in Stata software to compare the deviation of each technique from the reference model.

Results:
In the long edentulous span, the one-step technique showed a statistically significant deviation from the original model (P<0.05), while the two-step technique demonstrated higher accuracy. Conversely, in the short edentulous span, the two-step technique showed a significant deviation (P<0.001), whereas the one-step technique achieved better conformity with the reference model.

Conclusion:
The accuracy of impression techniques is influenced by the length of the edentulous space. The two-step technique performs more accurately in long edentulous spans, whereas the one-step technique yields better results in shorter spans. Selecting the appropriate impression technique based on the clinical condition can enhance prosthesis fit and overall treatment success.