Clinical evaluation comparing the fit of all-ceramic crowns obtained from silicone and digital intraoral impressions.

Objectives: The aim of this study is to compare the fit of all-ceramic crowns fabricated from conventional silicone impressions with the fit of all-ceramic crowns fabricated from intraoral digital impressions.

Methods: Twenty patients with 26 posterior teeth with a prosthetic demand were selected for the study. Two crowns (Straumann-Zerion) were made for each preparation. One crown was fabricated from an intraoral digital impression system (IDI group; Cadent-iTero), and the other crown was fabricated from a conventional one-step silicone impression (CI group; Express Penta Putty and Body Light). To replicate the interface between the crown and the preparation, each crown was cemented on its corresponding clinical preparation with ultra-flow silicone (Express Ultra Light Body). Each crown was embedded in resin to stabilize the registered interface, cut in 2-mm-thick slices in a buco-lingual orientation. Internal misfit was measured in microns using stereomicroscopy with a magnification of ×40. Measurements were taken at different landmarks: margin, chamfer angle, axial, crest, and occlusal fosse. After checking for normality, data was analyzed using paired Student's t test (α = 0.05).

Results: Fit values were significantly affected by the impression technique (p = 0.000). Mean internal misfit and mean marginal misfit were 111.40 μm (SD = 54.04)/80.29 μm (SD = 26.24) for the crowns of the IDI group and 173.00 μm (SD = 92.65)/133.51 μm (SD = 48.78) for the CI group.

Conclusion: All-ceramic crowns fabricated from intraoral digital impressions with parallel confocal technology demonstrated a clinically acceptable internal and marginal fit as conventional impression.

Clinical Significance: Intraoral digital impressions as initial step to the digital workflow could further improve the marginal adaptation of all ceramic single crowns.

Trial Registration: http://www.isrctn.com/ISRCTN16111844.