Effects of Acidic Media on the Mechanical and Optical Properties of Digitally Designed Restorative Materials

This investigation assessed how acidic environments affect the optical behavior, surface roughness, and hardness of a newly developed 3D-printed permanent resin compared with commonly used computer-aided design/computer-aided manufacturing restorative blocks.

The materials tested were lithium disilicate, a polymer-infiltrated ceramic network, a nanoceramic resin block, and a 3D-printed composite. Specimens were stored in hydrochloric acid and Coca-Cola, with distilled water as the control medium. Changes in color, translucency, roughness, and hardness were measured before and after immersion. Data were analyzed using R (v4.5) with a significance level of p < 0.05.

Lithium disilicate showed the greatest resistance to acidic conditions in both optical and mechanical properties. The polymer-infiltrated ceramic network and filler press and monomer infiltration materials showed intermediate stability under acidic challenges across all measured parameters. The 3D-printed resin was the least stable material. Gastric acid caused more pronounced deterioration than Coca-Cola, while water produced minimal changes.

Acidic exposure negatively affected the performance of all tested restorative materials. Lithium disilicate remained largely unaffected, whereas the 3D-printed permanent resin showed significant vulnerability. These findings emphasize that material choice is critical for patients prone to erosive challenges such as reflux or frequent soft drink intake.