Effect of Acidic pH on Surface Roughness of Current Esthetic Dental Materials.
Abstract: ABSTRACT Aim and Hypothesis The aim of this study was to compare the surface roughness changes of different CAD/CAM restorative dental materials after exposure to acidic pH by using a 3-D optical interferometer. After exposure to hydrochloric acid solution for 45 hours and 91 hours, it was hypothesized that Vita Enamic® and IPS Empress® CAD would have less surface roughness changes than ... read moreVITABLOCS® Mark II CAD. On the other hand, they would have more surface roughness changes than IPS e.max® CAD and BruxZir® Solid Zirconia. Materials and Methods Five groups of esthetic CAD/CAM block materials were selected: Leucite glass ceramic 'IPS Empress® CAD'; zirconia 'BruxZir® Solid Zirconia'; hybrid ceramic 'VITA Enamic®'; lithium disilicate glass ceramic'IPS e.max® CAD'; and feldspathic porcelain 'VITABLOCS® Mark II CAD'. Eighteen specimens were sectioned from CAD/CAM blocks into rectangular plates (2 mm thick) for each group. All specimens from each group were immersed in a petri dish filled with 20 ml of 5% hydrochloric acid (HCl) with a pH of two and placed into an incubator at 37 °C for 45 hours and 91 hours. The surface roughness average (Ra) of the specimens was measured using a 3-D optical interferometer before the storage period (baseline), after 45 hours, and after 91 hours of exposure to HCl. Results Regarding the comparison of surface roughness changes at different periods of evaluation (baseline, 45 hours, 91 hours), there were no statistically significant differences for IPS e.max® CAD (P = 0.063) or BruxZir® Solid Zirconia (P = 0.513). On the other hand, IPS Empress® CAD, VITABLOCS® Mark II CAD, and VITA Enamic® demonstrated statistically significant differences (P < 0.001). IPS Empress® CAD demonstrated statistically significant differences between all time points. VITABLOCS® Mark II CAD and VITA Enamic® showed statistically significant differences between baseline and 45 hours and between baseline and 91 hours, but not between 45 and 91 hours. For all tests that were statistically significant, there was greater surface roughness at the time point with longer duration of HCl exposure (e.g., for IPS Empress® CAD, there was greater surface roughness at 91 hours than at 45 hours, and greater surface roughness at 45 hours than at baseline). Regarding the comparison of materials in terms of change in surface roughness between baseline - 45 hours and baseline - 91 hours, the Kruskal-Wallis test indicated a statistically significant difference between the materials in both cases (P < 0.001). IPS e.max® CAD and BruxZir® Solid Zirconia exhibited the least surface roughness change among the five materials. For both baseline - 45 hours and baseline - 91 hours, the results of the post-hoc tests were the same: there were statistically significant differences between IPS e.max® CAD and all other material groups except BruxZir® Solid Zirconia, and there were statistically significant differences between BruxZir® Solid Zirconia and all other material groups except IPS e.max® CAD. No other post-hoc comparisons were statistically significant. Conclusion IPS Empress® CAD, VITABLOCS® Mark II CAD, and VITA Enamic® showed significant increases in surface roughness when they were exposed to simulated gastric acid for 45 and 91 hours. IPS e.max® CAD and BruxZir® Solid Zirconia showed no significant change in surface roughness after exposure to HCl for 45 hours and 91 hours.
Thesis (M.S.)--Tufts University, 2016.
Submitted to the Dept. of Other.
Advisor: Ala Ali.
Committee: Matthew Finkelman, Aikaterini Papathanasiou, Marcelo Suzuki, and Ruby Ghaffari.
Keyword: Dentistry.read less