Effects of elevated extrinsic-stain firing temperatures on the optical, surface, and mechanical properties of lithium disilicate ceramics.

Authors

Matheus Morcela de Souza, Cássia Cunha de Lima, José Vitor Quinelli Mazaro, Natália Almeida Bastos Bitencourt, Letícia Moretti, Sandy Gabrielle Giorgetti Pereira, Débora Novais da Silva, Ana Carolina da Conceição Sanches, Marcella Santos Januzzi, André Luíz de Melo Moreno, Marcelo Coelho Goiato, Daniela Micheline Dos Santos

Published in

Journal of clinical and experimental dentistry. Volume 18. Issue 9. Pages e1087-e1094. Epub Aug 28, 2026.

Abstract

This study evaluated the effect of different firing temperatures of extrinsic staining, including temperatures higher than those recommended by the manufacturer, on the optical properties, surface roughness, and microhardness of lithium disilicate ceramics.
IPS e.max CAD blocks (Ivoclar) were sectioned and allocated into six groups (n=10) according to surface treatment: glaze only or glaze plus extrinsic staining, fired at 710°C, 770°C, or 820°C. A2 shade pigment paste (Ivoclar) was applied and fired according to manufacturer recommendations, followed by glazing at the same temperature. Color stability (ΔE00), translucency parameter (TP), and contrast ratio (CR) were assessed with a UV-visible spectrophotometer, surface roughness (Ra) was measured using contact profilometry and Vickers microhardness (MH) was obtained using a microdurometer. Data were analyzed with Shapiro-Wilk, Friedman or ANOVA, and Wilcoxon tests, with α=0.05.
For optical properties, firing at 770°C resulted in the lowest ΔE00 values, while 820°C yielded the highest TP values. CR differences before and after crystallization were significant in all groups except those fired at 820°C. Glazing significantly reduced surface roughness in all groups (p<0.001), with lower Ra values at 770°C and 820°C, independent of staining. Increased microhardness after stain+glaze was observed at 770°C.
Firing at 770°C improved color stability and surface smoothness, while increased microhardness was observed when extrinsic stain and glaze were combined at this temperature. Firing temperature significantly influenced the optical properties and surface roughness of extrinsically stained lithium disilicate ceramics, with 770°C providing the most favorable balance between color stability and surface smoothness.

PMID:
42894686
Bibliographic data and abstract were imported from PubMed on 19 Oct 2026.

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