Coded Healing Abutment Impression Accuracy in Partially Edentulous Models: An In Vitro Study

Objectives To evaluate the accuracy of a coded healing abutment (CHA) across different impression workflows and partially edentulous configurations, using an impression coping (IC) as the comparator in the conventional workflow and an intraoral scan body (ISB) in the digital workflow. Methods In this in vitro study, eight posterior partially edentulous master models representing different defect configurations (U6, U67, U46, U47, B6, B67, B46, and B47) were fabricated and digitized as reference datasets. For each master model, conventional impressions were made 10 times each with ICs and CHAs, and digital impressions were obtained 10 times each with ISBs and CHAs using Primescan, iTero Lumina, Aoralscan Elite, and Trios 5. Trueness and precision were calculated as root mean square deviations of the virtual analogue surfaces. Trueness and precision were analysed using Gamma regression models with Holm adjustment, applying a generalized linear model and a generalized linear mixed-effects model, respectively. Results Under the conventional workflow, CHA showed trueness comparable to that of IC in all configurations except U6, where it was significantly better, and showed significantly higher precision in most configurations. Under the digital workflow, CHA generally showed trueness and precision comparable to those of ISB across the tested scanners and defect configurations. Significantly better trueness was observed only in selected configurations, including U6 and B46 with Aoralscan Elite, U67 with iTero Lumina, and U6 with Trios 5. Significantly better precision was also limited to selected configurations, most frequently with Primescan and iTero Lumina. Conclusions Within the limitations of this in vitro study, CHA showed trueness and precision broadly comparable to those of ICs and ISBs across multiple partially edentulous configurations, with superior performance in selected conditions. Clinical significance CHA may serve as a feasible alternative impression component in both conventional and digital workflows under the tested in vitro conditions.