Masking capacity of a polycrystalline ceramic with microstructural gradation

• Grant number: 24/20152-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: December 31, 2025
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Camila da Silva Rodrigues
• Grantee: Fatima Letícia dos Santos Batista
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil

Abstract

Zirconia-based ceramics with microstructure gradation have been developed to combine high mechanical strength with a translucency gradient that mimics the appearance of natural teeth. However, color selection still represents a significant challenge in clinical practice, especially when it comes to darkened substrates. Thus, this study will investigate the effectiveness of a zirconia with a microstructure gradient in different thicknesses on the masking capability of darkened substrates when different colors of resin cement are used. Rectangular slices will be cut from a disc of a zirconia with a microstructure gradient (Zr Line 3D Multi, Besser Digital - color A1). The specimens will be prepared in different thicknesses: 0.5 mm, 1.0 mm, and 1.2 mm. The translucency of the ceramic specimens will be measured using a spectrophotometer and the CIEDE2000 equation (TP00). Composite resin substrates in colors A1, A3, and C4 will be fabricated, and the ceramic specimens will be cemented onto them using light-curing resin cement in either translucent or A1 colors. Color readings (Lab* parameters) will be taken with a spectrophotometer at three points on each specimen: over the most opaque part, over the transition zone, and over the most translucent zone. The color difference (¿E00) will be calculated using the CIEDE2000 equation. The masking capability will be determined by calculating ¿E00 between the reference set (zirconia, resin cement, and substrate in color A1) for each thickness and the sets cemented on darkened substrates (A3 or C4) with different cements (translucent or A1). In addition to statistical analysis, perceptibility thresholds will be used to assess the clinical significance of the results."