The Effect of Coded Healing Abutments on Treatment Duration and Clinical Outcome: A Randomized Controlled Clinical Trial Comparing Encode and Conventional Impression Protocols

Purpose: To compare the Encode impression protocol (Biomet 3i) with the conventional impression protocol in terms of treatment duration, clinical accuracy, and outcome up to the first postplacement review of singleimplant crowns. Materials and Methods: A total of 45 implants were included in this study. The implants were randomly allocated to the Encode group (23 implants) or the conventional group (22 implants). At the time of surgery, all implants received two-piece Encode healing abutments. The implants were restored 3 months after insertion. In the conventional protocol, open-tray implant-level impressions were taken and the implants were restored with prefabricated abutments and porcelain-fused-to-metal (PFM) crowns. For the implants in the Encode group, closed-tray impressions of the healing abutments were taken. The generated casts were sent to the Biomet 3i scanning/milling center for custom abutment manufacturing on which PFM crowns were fabricated. Treatment duration (laboratory and clinical), clinical accuracy of occlusal and proximal contacts, and outcome (esthetics, patient satisfaction, and crown contour) were evaluated with the aid of a series of questionnaires. Results: The Encode protocol required significantly less laboratory time (18 minutes) than the conventional protocol for adjustment of the abutments. The impression pour time, time for the laboratory to return the crown, time for crown insertion at the final appointment, and total clinical time for crown insertion did not differ significantly between the two protocols. Likewise, clinical accuracy, esthetics, and patient satisfaction were similar for the two protocols. Conclusion: The two protocols were clinically comparable. The Encode protocol is advantageous in reducing the laboratory time before crown fabrication. Keywords: abutment, CAD/CAM, Encode, implant impressions, laboratory procedures