Effect of Prophylactic Pastes on Surface Roughness and Gloss of Esthetic Dental Restorative Materials

Objective: To evaluate the average surface roughness (Ra) and gloss (GU) of four different commonly used ceramics, four resin composites and human enamel after application of four different types of prophylactic pastes. Material and methods: A total of two hundred and forty specimens, composed of four types of ceramics and four types of resin composites were prepared to test the hypothesis. Twenty specimens were assigned to the first two ceramic groups: Lithium disilicate (LiSi2), and Feldspathic ceramic (FP). The third ceramic group, Zirconia (Zi) included one-hundred and twenty specimens divided into two groups of sixty specimens each (IPS e.max ZirCAD MT A2, and MT Multi A2). All ceramic specimens were sectioned into 2 mm thick slices (12x14mm) and each material was sintered and glazed according to the manufacturer’s instructions. For the LiSi2 and FP ceramics, a spray glaze was used, while for the Zi group, three glaze techniques were used as follows: spray glaze, paste/liquid glaze, and stain followed by paste/liquid glaze. All samples were finished and polished gradually down to 1,200 grit size and ultrasonically cleaned and dried twice (before and after glazing). A total of eighty specimens of four types of resin composites were prepared to test the hypothesis. The first three groups (n=20): Nano-hybrid (NH), Nano-fill (NF), and Supra- nanofill (SN) were cured under Mylar strips using a broad-spectrum LED curing light into disk shape specimens (2x14mm diameter). The fourth group, microhybrid (MH) included a total of twenty millable resin composite Tetric CAD, which were prepared by sectioning the CAD/CAM block into 2-mm-thick slices (12x14 mm). All specimens were then finished and polished gradually down to 1,200-grit size and ultrasonically cleaned and dried. Four intact human teeth were served as a control group. Baseline surface gloss was measured with a glossmeter from 3 spots on each specimen. Additionally, baseline surface roughness (Ra) was measured with a profilometer from 3 spots on each specimen. Five specimens from each group were randomly assigned to one of the four groups of the following prophylactic polishing pastes: Proxyt coarse (PC) and Proxyt fine (PF), Nupro coarse (NC) and Nupro fine (NF). Results: Nupro coarse had the highest reduction of surface gloss and increase in surface roughness in most of the materials with statistical significance (p \u3c0.05) compared to the other prophylactic pastes. Proxyt Fine had the least effect on gloss and roughness on all materials with statistical significance (p\u3c0.05) compared to the other prophylactic pastes groups