Aim: This study aims to evaluate the impact of different pre-sintering coloring techniques and different sintering protocols on the translucency of monolithic zirconia with two thicknesses.
Materials and Method: Sixty disc-shaped samples (12 mm x 12 mm) of high translucent zirconia (BSM Aconia: Chengdu Besmile Biotechnology Co. China) were fabricated and divided into 2 groups (n=30) according to thickness; T1 (0.5mm), T2 (1mm). Before sintering, each group was subdivided into 3 subgroups (n=10) according to coloring techniques; T1C1 and T2C1 (immersion only for 15 secs in A1), T1C2 and T2C2 (application by brush twice in T01 then immersion in A1 for 15 sec), T1C3 and T2C3 (application by brush three times in T01 then immersion in A1 for 15 sec). Each subgroup was furtherly classified into 2 classes (n=5) according to sintering protocols; S (Standard), F (Fast). A spectrophotometer was used to measure translucency. A three-way ANOVA and Bonferroni's post-hoc tests were utilized for statistical analysis. The significant level was set at (P ≤ 0.05).
Results: T1 showed a higher mean value of TP (16.28) than T2 (10.25). C3 showed the highest mean value (14.2) followed by C2 (13.19) whereas; C1 showed the lowest mean value of TP (12.41). CL S recorded higher mean value of TP (13.51) than CL F (13.03).
Conclusions: For more natural appearance and translucent zirconia, it's preferable to reduce their thickness. Using brushing coloring technique with multiple applications significantly affected the translucency of zirconia. Standard sintering protocol ensures that zirconia restorations exhibit desired optical properties.