Crown adjustment and chairside efficiency of single‐unit restorations fabricated from immediate and staged impressions using a digital workflow for posterior implants

Abstract

PurposeThis is a clinical study to compare immediate and staged impression methods in a complete digital workflow for single‐unit implants in the posterior area.Materials and MethodsSixty patients requiring single‐unit implant crowns were enrolled. Forty patients were assigned to the test group, immediate digital impression after implant surgery with crown delivery 4 months later. The remaining 20 patients were assigned to the control group, staged digital impressions 4 months after implant surgery, and crown delivery 1 month later. Both workflows involved free‐model CAD‐CAM crown fabrications. The crowns were scanned before and after clinical adjustment using an intraoral scanner (TRIOS Color; 3Shape). Two 3D digital models were trimmed and superimposed to evaluate the dimensional changes using Geomagic Control software. Chairside times for the entire workflow were recorded. Kruskal–Wallis was performed to compare crown adjustments between two groups, while One‐way ANOVA was used to compare chairside time durations between the test and control groups.ResultsAll crowns were delivered without refabrication. The average maximum occlusion adjustment of crowns was −353.2 ± 207.1 μm in the test group and −212.7 ± 150.5 μm in the control group (p = 0.02). The average area of occlusal adjustment, measured as an area of deviation larger than 100 μm, was 14.8 ± 15.3 and 8.4 ± 8.1 mm2 in the test and control groups, respectively (p = 0.056). There were no significant differences in the mesial and distal contact adjustment amounts, or the maximum deviations of the proximal area, between the two groups. The mean chair‐side time was 50.25 ± 13.48 and 51.20 ± 5.34 min in the test and control groups, respectively (p = 0.763).ConclusionsThe immediate impression method in the digital workflow for single‐unit implants required more occlusal adjustments of crowns but showed similar chairside times compared to the staged impression method.