Surface and Compatibility Topography of Restorative Materials after Artificial Aging

Objectives: Aim of the present study was to evaluate the effect of two different finishing procedures on Ceram-X (TM, Dentsply) restorative material. Particularly, the consequence of artificial aging (UV-irradiation) on this resin-composite material was investigated determining also its outcome on cell behavior.

Methods: 36 specimens (10 mm x 2 mm) of restorative material were prepared using a light emitting diode curing unit and randomly assigned to 3 groups: 1. samples were left undisturbed after the removal of a Mylar strip (control); 2. samples were polished with diamond finishing burs, followed by diamond discs;3. samples were finished using tungsten carbide burs, followed by diamond discs. Surface morphology as well as roughness profile (Ra) of native and artificially aged materials were assessed with Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Cell compatibility (using MTT viability test and SEM) was also evaluated. Data were subjected to one way analysis of variance and Student-Neuman-Keuls test.

Results: no significant differences in Ra values were observed in group 2 (0.97µm ±0.17) in comparison with group 3 (0.84µm ±0.16) . Conversely, significant differences (p<0.05) were detected for both group 2 and 3 in comparison with group 1 (0.55µm ±0.15). After artificial aging, a decrease of Ra was observed for all the materials (group1:0.43µm ±0.12; group 2: 0.81µm ±0.1; group 3: 0.79µm ±0.16). MTT viability test revealed good interactions with the biological environment for all tested groups, either before and after artificial aging.

Conclusion: The observed behavior can be partly related to the fact that different Ra may affect protein absorption and, consequently, cell adhesion and proliferation. UV artificial aging of the tested specimens shows changes in the surface profiles independently on finishing and polishing procedure, without affecting its compatibility, thus showing that even if the material mechanical properties change its long-term biocompatibility is not affected