# The Effect of Erosion on Optical Properties and Surface Texture of Stained Lithium Disilicate Restorations

## TL;DR

This study found that stained lithium disilicate dental restorations exposed to simulated gastric acid showed significant changes in color and surface roughness, with one staining method being more resistant.

## Contribution

The study introduces a comparison of two staining methods for lithium disilicate ceramics under acidic conditions, revealing differences in acid resistance.

## Key findings

- Acid exposure significantly altered the color of both stained groups, with IPS Ivocolor showing greater changes.
- Surface roughness increased significantly in the IPS Ivocolor group after acid immersion.
- Translucency remained unchanged in both groups despite acid exposure.

## Abstract

To evaluate the surface topography, color stability, and translucency of stained lithium disilicate ceramics after immersion in simulated gastric acid.

Twenty specimens were prepared from Amber Mill: HASS lithium disilicate ceramic blocks and divided into two groups (n = 10). One group was stained and glazed using IPS Ivocolor Essence (Ivoclar Vivadent, Liechtenstein) and the other with GC Initial IQ lustre paste (GC, Japan). Specimens were immersed in 5 mL of 0.113% hydrochloric acid for 96 h at 37°C. morphological changes were evaluated using scanning electron microscopy (SEM), surface roughness was measured with a contact profilometer, and color and translucency were assessed using a spectrophotometer before and after acid immersion.

Acid exposure significantly affected the color of both groups (p-value < 0.001), with greater changes observed in the IPS Ivocolor group. Surface roughness parameters (Ra, Rq,  and Rz) also increased significantly in this group following immersion. Translucency parameters remained unchanged in both groups.

Simulated gastric acid adversely affected the color and surface integrity of lithium disilicate ceramics stained with IPS Ivocolor more than those treated with GC Initial Spectrum. The latter demonstrated greater resistance to acidic conditions and may offer better long-term performance in patients at risk of intrinsic acid exposure.