In Vivo Esthetic Appearance of the Full-anatomic Zirconia Crowns Made by Gel-deposition and Dry-milling Approaches

Objectives: The aim of this clinical evaluation was to compare the esthetic effect and color-matching behaviors of full-anatomic zirconia crowns, which were manufactured by two different methods, three dimensional gel deposition or CAD/CAM dry milling of partially sintered blocks respectively.
Methods: Twenty patients with one premolar undergone root canal treatment were recruited into this prospective, single blind, randomized self-control clinical evaluation. A pair of full-anatomic zirconia crowns were fabricated by a precision 3D additive gel deposition approach (self-glazed zirconia made by Erran Tech, China) or by CAD/CAM method (Zenostar zirconia made by Wieland, Germany) for the same premolar with the identical shape and the same shade selection from the Vita shade guide of each patient. The color difference ΔE of two full-anatomic zirconia crowns were measured respectively compared to the adjacent natural tooth. A visual analog Scale (VAS) was used to assess the satisfaction degree of patient. A more preferable crown was selected and was bonded on the prepared premolar. The following-up clinical observations were carried on and assessed through the standard of United States Public Health Service (USPHS).
Results: The average color difference ΔE of the gel-deposition’s crowns and dry-milling’s crowns were 2.14±1.18 NBS and 4.19±2.02 NBS (P<0.05). The visual analog scale score was higher in the gel-deposition’s crowns than in dry-milling’s crowns(P<0.05).
Conclusions: The full-anatomic zirconia crowns fabricated by a precision additive 3D gel deposition approach displayed less color difference and excellent esthetic appearance in the aspect of color and translucency gradient.