Análise de diferentes protocolos para polimento de cerâmicas vítreas na translucidez, contraste e opalescência

Abstract

Polishing protocols aim to create a smooth and glossy surface, enhancing the optical properties of restorative materials. The objective of this study was to analyze the influence of different manual polishing protocols and glaze application on the parameters of translucency, contrast, and opalescence of a zirconia-reinforced lithium silicate ceramic, with or without an additional firing. A total of one hundred and twenty standardized samples were fabricated and divided into five experimental groups according to the surface treatment performed: Glaze (GL), Exa-Cerapol (EX), Ceramisté (CM), PK5 Ceram (PK), and Optragloss Ceram (OG). Each group was further subdivided based on the presence (CDQ) or absence (CD) of prior firing. The specimens underwent a roughening process and were subsequently polished according to their respective group. Color parameters were measured using a spectrophotometer (Vita Easyshade Advance 4.0; VITA Zahnfabrik). Statistical analysis was performed using the non-parametric Aligned Rank Transform (ART) test, and post hoc interaction comparisons were carried out using the pairwise method in the emmeans package. The software used was R (version 4.4.1). The values obtained for translucency indicated that the CD ceramic was the most affected, especially by the PK, EX, and OG protocols. Opalescence was also significantly affected, being reduced by the glaze and increased by manual polishing methods, with different behaviors observed between CD and CDQ ceramics. Contrast analysis did not reveal significant differences between groups. It is concluded that the different polishing protocols distinctly affect the optical properties of zirconia-reinforced lithium silicate (ZLS) ceramics, with and without firing. Manual polishing was able to enhance translucency and opalescence — key characteristics for restorations in areas of high esthetic demand. Glaze application, on the other hand, proved effective in preserving the original optical properties and may be recommended in cases where color stability is a priority.