Evaluation of Surface Characteristics and Cytotoxicity of Dental Composites

The purpose of this study was to evaluate the surface and in vitro cytotoxicity on human dysplastic oral keratinocytes (DOK) of four commercial resins-based dental composites commonly used in prosthodontics dental therapies: two indirect composites for crown and bridges—SR Adoro (IvoclarVivadent GmbH) and Solidex (Shofu Dental GmbH); and two dual-curing luting resin cements—RelyxUnicem (3M ESPE Dental Products) and Variolink Esthetic DC (IvoclarVivadentGmbH). A complex assessment of surface characteristics of the four materials was conducted before and after the exposure to artificial saliva through various analyses, such as Scanning Electron Microscopy, Atomic Force Microscopy and Cross Polarized Light Microscopy (PLM). The results showed that DOK viability was not severely affected by exposure to any of these materials; however, Variolink expressed higher values but still above the toxicity level of the rest of the composites. The analysis of the surface structure between initial and artificial saliva exposed specimens returned a compact aspect in both categories and although Variolink and Relyx were subjected to increased roughness after saliva exposure, no damage of the internal compactness was recorded, demonstrating a fair behavior of the luting cements in contact with the saliva.