Evaluation of Surface Roughness of Ceramic and Resin Composite Material Used for Conservative Indirect Restorations, after Repolishing by Intraoral Means

PurposeTo evaluate and compare the mean surface roughness (Ra) of one ceramic and one resin composite material used for indirect restorations, after grinding and repolishing by intraoral means. Materials and MethodsThe materials used were the lithium disilicate glass ceramic IPS e.max Press (EMP) and the indirect resin composite restoration system Gradia (GR). Twelve specimen disks were prepared from each material according to the manufacturer of each material. Five initial measurements of the Ra (Ra-1) were made on each specimen as a referral basis, and the specimens were ground with a fine (red) diamond bur. The specimens were repolished using (a) Komet Dialite Polishing Kit for EMP and (b) Enhance Finishing and Polishing System and Prisma Gloss Polishing Paste for GR. Five final Ra (Ra-2) measurements were performed on each specimen. All measurements were made using a laser profilometer. Scanning electron microscopy (SEM) was also used to visualize the initial surface morphology and the morphological changes on the specimens' surface after repolishing. ResultsA highly significant difference was found between Ra-1EMP and Ra-2EMP (p < 0.001), between Ra-1GR and Ra-2GR (p < 0.001), as well as between Ra-2EMP and Ra-2GR (p < 0.001), when compared in pairs. A highly significant difference (p < 0.001) was also found between Ra-EMP and Ra-GR, with Ra-GR being higher than Ra-EMP. The Ra-GR values were higher than the Ra-EMP values at all times. SEM revealed that both EMP and GR repolished surfaces presented with irregularities; however, in GR specimens major voids and craters were present. ConclusionsEMP was found to perform better when polished by intraoral means compared with GR. Both materials exhibited Ra-2 above the critical threshold for increased plaque accumulation and periodontal inflammation. If enamel-to-enamel roughness found in occlusal contact areas is considered as baseline, both materials were clinically acceptable after repolishing.