A double-blind randomized within-subject study to evaluate clinical applicability of four digital workflows for the fabrication of posterior single implant crown

Objective: To compare efficiency and clinical efficacy of posterior single implant crowns (PSIC) fabricated using four digital workflows.Materials and Methods: Twenty-two patients with one missing first molar were included. Each patient received four screw-retained implant crowns fabricated through four different workflows including a fully digital workflow with immediate digital impression (Group i-IOS), a fully digital workflow with digital impression after implant osseointegration (Group d-IOS), a model-based hybrid workflow using immediate analogue impression (Group i-AI), and a model-based hybrid workflow with conventional analogue impression after implant osseointegration (Group d-AI). The crown delivery sequence was randomized and blinded. The efficiency for each workflow and clinical outcome of each crown were recorded.Results: The average clinical working time in fully digital workflows (i-IOS 46.90 min, d-IOS 45.66 min) was significantly lower than that in the hybrid workflows (i-AI 54.59 min, d-AI 55.96 min; p < .001). Significantly more laboratory time was spent in hybrid workflows (i-AI 839.60 min, d-AI 811.73 min) as compared to fully digital workflows (i-IOS 606.25 min, d-IOS 607.83 min, p < .01). No significant differences in the chairside time at delivery were found. More crowns in Group i-AI (15%) needed additional laboratory interventions than in the other groups (p = .029).Conclusion: Digital impression and model-free fully digital workflow improved prosthetic efficiency in the fabrication of PSIC. With the limitation that the results were only applicable to the implant system used and the digital technologies applied, findings suggested that workflows integrating immediate impression with implant surgery procedure was clinically applicable for restoration of PSIC.