Persistence of Endodontic Methacrylate-Based Cement Residues on Dentin Adhesive Surface Treated with Different Chemical Removal Protocols MILTON CARLOS KUGA, 1 * MARCUS VINICIUS REIS SO ´ , 2 EDSON ALVES DE CAMPOS, 1 GISELE FARIA, 1 KA ´ TIA CRISTINA KEINE, 1 ANDREA ABI RACHED DANTAS, 1 AND NORBERTO BATISTA FARIA- JUNIOR 1 1 Department of Restorative Dentistry, Araraquara Dental School, UNESP—University of Estadual Paulista, Araraquara, Sao Paulo, Brazil 2 Department of Endodontics, Rio Grande do Sul Federal University, Rio Grande do Sul, Brazil KEY WORDS cleaning; endodontics; methacrylate cement; microscopy; scanning electron microscopy ABSTRACT The aim of this study was to evaluate the persistence of methacrylate-based cement residues on the dentin, after dentin surface cleaning with ethanol or acetone, with or with- out previous application of a dentin adhesive. Forty bovine crown fragments were obtained and the dentin surface was washed with 1.0 mL of 2.5% sodium hypochlorite (NaOCl), followed by 0.1 mL of 17% ethylenediaminetetraacetic acid application for 3 min, and final irrigation with 2.5% NaOCl. The specimens were air dried and resin-based cement was rubbed onto the dentine surface with a microbrush applicator. In 20 specimens, previously to cement, a dentin adhesive was applied in all surfaces. After 15 min, the surface was scrubbed with a cotton pellet and moistened with ethanol or acetone, compounding the following groups: G1—99.5% ethanol and G2—acetone, with- out previous use of dentin adhesive; G3—99.5% ethanol and G4—acetone, with previous use of dentin adhesive. The dentin surface was scrubbed until the cement residues could not be visually detected. Sections were then processed for scanning electron microscopy and evaluated at 5003 magnification and scores were attributed to each image according to the area covered by residual sealer, and data were subjected to Kruskal–Wallis at 5% significance. The lower residue presence was observed in G3 (P 5 0.005). All surface presented cement residues when acetone was used as cleaning solution (P 5 0.0005). The cleaning solutions were unable to completely remove the cement residues from both surfaces. The ethanol used after previous application of the dentin ad- hesive promoted the lower presence of residues. Microsc. Res. Tech. 75:1432–1436, 2012. V V C 2012 Wiley Periodicals, Inc. INTRODUCTION Polymethacrylate-based cement with silane-coated inorganic particles is frequently used in restorative dentistry. The advance in adhesive system technology encourages the use of a methacrylate-resin-based com- posite as material associated to gutta-percha in root canal obturation (Bitter et al., 2004; Costa et al., 2010; Schwartz and Fransman 2005; Zmener and Pameijer, 2010). The Epiphany (Pentron Clinical Technologies, Wall- ingford, CT) was the first methacrylate-based cement used in endodontics. This cement is basically composed of resins (Bis-GMA, urethane dimethacrylate [UDMA], PEGDMA, EBADMA), fillers (barium sulfate, bismuth oxychloride, calcium hydroxide, silica, silane-treated bariumboraluminosilicate glass), coloring pigments, dual-cured initiators (cumene hydroperoxide, thiosin- amine, champhorquinone), and stabilizers (butylated hydroxytoluene [2,6-di-tert-butyl-4-methylephenol]) (Karapınar-KazandaG ˘ et al., 2011). The Epiphany, first generation, had a core material (Resilon), a dual-curing resin-based sealer (Epiphany), and a self-etching primer (Resende et al., 2009; Shipper et al., 2004). In second generation, namely Epiphany self-etch (SE), the system has only two components: Epiphany self-adhesive cement (Epiphany SE; Parkell, Farmington, NY) and Resilon. Acid resin monomers that are originally found in SE primers have been incorporated into the self-adhesive resin-based sealers, reducing the application time and the possibility of errors during adhesive procedures (Babb et al., 2009; Kim et al., 2010). The system has possible capability to create a ‘‘monoblock’’ between the dentin wall and the root canal obturation, increasing the obturation her- metic sealing (Kim et al., 2010; Tay and Pashley, 2007). After finishing root canal obturation, methacrylate- based cement residues which remain into the pulp chamber dentin should be removed, to prevent a possi- ble negative influence on the longevity of esthetic resto- rations. Hydrophilic methacrylate resin-based resin composite particles can absorb water and elute *Correspondence to: Milton Carlos Kuga, Department of Restorative Dentistry, Araraquara Dental School, UNESP—University of Estadual Paulista, Araraquara, Rua Humaita ´, 1680. CEP: 14801-903 Araraquara, Sao Paulo, Brazil. E-mail: kuga@foar.unesp.br Received 4 April 2012; accepted in revised form 13 May 2012 DOI 10.1002/jemt.22086 Published online 20 June 2012 in Wiley Online Library (wileyonlinelibrary.com). V V C 2012 WILEY PERIODICALS, INC. MICROSCOPY RESEARCH AND TECHNIQUE 75:1432–1436 (2012)