Nine prophylactic polishing pastes: impact on discoloration, gloss, and surface properties of a CAD/CAM resin composite.

To investigate discoloration reduction and changes of surface properties of a CAD/CAM resin composite after 14 days´ storage in red wine and polishing with nine different prophylactic polishing pastes (PPPs). Rectangular discs (N = 172) were fabricated and polished (P4000) using GC Cerasmart (GC Europe) to investigate different polishing protocols with 1-4 related descending PPPs (22 in total): Cleanic/CLE-Kerr, CleanJoy/CLJ-Voco, Clean Polish/Super Polish/SPO-Kerr, Clinpro Prophy Paste/CPP-3M, Détartrine/DET-Septodont, Nupro/NUP-Dentsply Sirona, Prophy Paste CCS/CCS-Directa, Proxyt/PXT-Ivoclar Vivadent, and Zircate/ZIR Prophy Paste-Dentsply Sirona. Surface properties (roughness values (RV)/Ra, Rz, Rv, surface free energy (SFE), surface gloss (G), and discoloration (ΔE)) were analyzed before and after storage and additional polishing. Data were examined using Kolmogorov-Smirnov test, three-way ANOVA followed by Tukey-B post hoc, Mann-Whitney U, and Kruskal-Wallis H tests (α < 0.05). Regarding RV, CLE, followed by CCS, and CPP showed the highest values; the lowest presented SPO and DET (p < 0.001). No impact of PPP was observed on ΔE values (p = 0.160). The lowest SFE presented DET, followed by SPO; highest showed CCS followed by NUP and CPP (p < 0.001). Within G, lowest values were observed for CLE and NUP, followed by CCS, ZIP, and CLJ (p < 0.001); the highest presented SPO (p < 0.001). Polishing showed generally a positive impact on SFE values (p < 0.001-p = 0.007), except ZIP (p = 0.322) and CLE (p = 0.083). G increased and RV decreased after polishing (p < 0.001), except SPO, with no significant change for G (p = 0.786). Polishing with PPPs improves the surface properties and is generally recommended. The choice of PPP has a minor role in removing discolorations. Multi-step systems should be carried out conscientiously. The proper selection of PPP is essential for the clinical outcome of surface properties of prosthetic restorations. Not every polishing paste leads to the same final surface quality.