A Clinical Comparative Study of 3-Dimensional Accuracy between Digital and Conventional Implant Impression Techniques

Area of Science:

• Dental technology
• Prosthodontics
• Digital dentistry

Background:

• Accurate dental impressions are crucial for fabricating well-fitting implant restorations.
• Conventional impression techniques (pick-up and transfer) have established accuracy, but digital intraoral scanners (IOS) offer potential advantages.
• Evaluating the clinical accuracy of IOS for implant impressions is essential for widespread adoption.

Purpose of the Study:

• To compare the accuracy of a digital implant impression technique using a TRIOS 3Shape IOS against conventional pick-up and transfer methods.
• To assess linear displacement, interimplant distances, and angular displacements in clinical settings.

Main Methods:

• Thirty-six patients with two implants each underwent impression procedures using conventional (pick-up, transfer) and digital (TRIOS 3Shape IOS) techniques.
• Reference models were created and impressions were made using dental stone for conventional methods.
• Digital scan files were captured using the IOS and converted to STL format.
• A coordinate-measuring machine (CMM) and CATIA 3D software were used to measure and compare deviations between techniques.

Main Results:

• The digital impression group showed statistically significant differences in all measured variables compared to the pick-up group (p < 0.001).
• Significant differences were found between the transfer and digital groups for angular displacement (p < 0.001), distance (p = 0.01), and linear displacement (p = 0.03).
• No significant differences were observed between the pick-up and transfer conventional impression techniques across all measured variables.

Conclusions:

• The digital implant impression technique exhibited the lowest accuracy among the evaluated methods.
• Observed distance and angulation errors with the digital technique may be too substantial for fabricating accurately fitting restorations.
• The pick-up technique was the most accurate, with the transfer technique showing comparable accuracy.