RESEARCH AND EDUCATION Influence of resin-coating agents on the roughness and color of composite resins Fabio A. P. Rizzante, DDS, MSc, PhD, a Juliana S. F. Bombonatti, DDS, MSc, PhD, b Layla Vasconcelos, DDS, MSc, c Thiago S. Porto, DDS, MSc, PhD, d Sorin Teich, DMD, MBA, e and Rafael F. L. Mondelli, DDS, MSc, PhD f The pursuit of the perfect smile has made esthetic procedures essential in dental offices, and novel materials and techniques for increasing the reliability and efficiency of treatments are constantly being devel- oped. 1 Composite resin resto- rations reestablish esthetics and function in both the anterior and posterior area. 1-3 Color is one of the main reasons for restoration replace- ment, and color stability is a major element in the long-term success of esthetic restora- tions. 1,4,5 The surface quality of composite resins, as well as color stability, can be affected by filler particle size and composition, organic matrix composition, and crack for- mation and propagation over time. 1,3,6-8 The color of composite resins can change as a result of external stain or plaque accumulation, surface damage from material degradation and color pigment impregnation, and intrinsic physico- chemical reactions in the organic matrix. 1,4,5,9-12 Although it may not be possible to identify a single fac- tor as responsible for color changes because of the het- erogeneity of the composite resin structure, surface roughness is highly associated with color stability as a a Assistant Professor, Department of Comprehensive Care, Case Western Reserve University, School of Dental Medicine, Cleveland, Ohio. b Assistant Professor, Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo (USP), Bauru, Brazil. c Doctoral Candidate, Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo (USP), Bauru, Brazil. d Assistant Professor, Department of Comprehensive Care, Case Western Reserve University, School of Dental Medicine, Cleveland, Ohio. e Full Professor, Department of Comprehensive Care, Case Western Reserve University, School of Dental Medicine, Cleveland, Ohio. f Full Professor, Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo (USP), Bauru, Brazil. ABSTRACT Statement of problem. Resin-coating agents can be used to fill microstructural defects within composite resin restorations, which might result in a smoother surface. Nevertheless, data about the color stability and surface roughness of coated restorations are lacking. Purpose. The purpose of this in vitro study was to compare the surface roughness and color stability of restorations before and after application of different resin-coating agents. Material and methods. Forty specimens of composite resin (Filtek Z250) (diameter×height, 6×2 mm) were divided into 5 groups according to the surface treatments (n=8 per group): control (CTR), Fortify (FT), Lasting touch (LT), BisCover (BIS), and Fill Glaze (FG). The specimens were evaluated for surface roughness by using a profilometer with 3 readings for each specimen (separated by 300 mm) before immersion in a staining solution (coffee) and after 5 days immersed in coffee and for color stability (6E) by using a spectrophotometer before being immersed in coffee (initial reading) and after 6 hours, 12 hours, 1, 2, 3, 4, and 5 days. Results. Two-way ANOVA with repeated measures and the Tukey test showed that the CTR group showed the highest roughness values, similar to those of the FT and LT groups. The BIS and FG groups showed lower roughness than the other groups but similar results when compared with each other. All groups, except LT, showed increased roughness values after immersion in coffee solution, and the BIS group showed the lowest variation over time. Color alterations were found for all groups, with the CTR group showing the lowest 6E values when compared with the other groups except for the BIS group. No correlation was found between surface roughness and degree of color change (P=.401). Conclusions. The BisCover surface sealant showed the lowest surface roughness and the best color stability. Surface sealants can be used to fill microcracks and microgaps but should not be used as a substitute for polishing. (J Prosthet Dent 2019;-:---) THE JOURNAL OF PROSTHETIC DENTISTRY 1.e1