Effect of a novel sintering protocol on the translucency of multilayered monolithic zirconia crowns (An Invitro study)

ABSTRACT
Aim: to evaluate the effect of a novel speed sintering protocol on the translucency of monolithic zirconia crowns.
Materials and Methods: 20 Monolithic Zirconia crowns fabricated from CEREC MTL zirconia were divided into 2 groups (10 per group); Group (I) Crowns sintered with conventional sintering protocol (control) Group (II) Crowns sintered with speed sintering protocol (intervention). Translucency was evaluated and measured quantitatively by comparing the reflectance of light through testing the specimen over a backing with high reflectance (white background) to that of low reflectance or absorbance (black background). Translucency parameter (TP) was calculated using specific equation to give the color difference's degree expressed in ∆𝐸 units. The total color difference according to L*, a*, b* coordinates is calculated.
Results: The mean ∆𝐸 for Group I was 6.19 ± 0.55 and for Group II was 5.69 ± 0.61 without significant difference in the translucency between both groups. Unpaired Student's t-test performed for the color coordinates ΔL, Δa and Δb showed a significant difference in Δb, but no significant difference in ΔL and Δa.
Conclusion: It was concluded that speed sintering protocol is an acceptable alternative to conventional sintering for chairside use of monolithic zirconia.