Effects of various beverages on hardness, roughness, and solubility of esthetic restorative materials

Restorative materials may either be exposed intermittently or continuously to chemical agents found in beverages, which may lead to biodegradation.

This study was aimed to evaluate effects of various beverages on microhardness, surface roughness, and solubility of esthetic restorative materials.

Materials used were conventional glass ionomer, resin-modified glass ionomer, compomer, and composite resin. Microhardness of the restorative materials was measured using Vickers microhardness tester. Surface roughness was measured using surface profilometery. Solubility was measured using an electronic balance.

In general, low pH beverages adversely affected the properties of the tested materials. Microhardness of tested materials was significantly decreased after immersion in the various beverages, whereas surface roughness and solubility were increased with the exception of natural milk. Natural milk and water did not affect the tested materials as Mirinda orange or mango juice did. Microhardness, roughness, and solubility of the tested materials in water were comparable with those of natural milk. After the immersion period, the conventional glass ionomer showed the roughest surface and exhibited the highest solubility, whereas composite resin was the smoothest surface and the lowest solubility. There was a negative correlation between surface roughness and microhardness, as well as between solubility and microhardness. There was a positive correlation between surface roughness and solubility.

Low pH beverages were the most aggressive media for glass ionomers and compomer, by contrast, composite resin was relatively less affected. Water and natural milk appeared relatively benign towards the tested materials.