Purpose: The aim of this study was to assess the accuracy of digital impressions for "all-on-four" implant rehabilitation.
Materials and methods: Patients edentulous in one or both jaws were randomly selected for this study. Complete arch immediately loaded prostheses supported by 4 implants (2 axial and 2 tilted) were placed. Five hours after implant placement, screw-retained full-arch temporary prostheses were positioned. After 4 months, a digital scan body was used to finalize definitive prosthesis. Radiographic assessments were obtained immediately after surgery and at each follow-up visit. Bone level measurements were reported at 6 and 12 months, and bone loss between upright and tilted implants was compared.
Results: Fourteen definitive cast metal frameworks prosthesis were delivered to the patients. No implant dropout occurred. All prosthesis were screwed onto the dental implants, and x-ray examinations revealed a bar-implant connection accuracy. The implant survival rate was 100% for all positioned implants. No statistically significant differences (P > 0.05) in crestal bone loss between tilted and upright implants were detected.
Conclusions: Digital impression creates an accurate physical model significantly improving efficiencies for the dental team and streamlining the workflow.