dental materials xxx ( 2 0 0 6 ) xxx–xxx available at www.sciencedirect.com journal homepage: www.intl.elsevierhealth.com/journals/dema Adhesive systems and secondary caries formation: Assessment of dentin bond strength, caries lesions depth and fluoride release Alessandra R. Peris a , Fabio H.O. Mitsui a , Maristela M. Lobo b , Ana K.B. Bedran-russo c , Giselle M. Marchi b,* a Department of Restorative Dentistry, Amazon State University-UEA, Manaus, Amazonas, Brazil b Department of Restorative Dentistry, School of Dentistry of Piracicaba-UNICAMP, Piracicaba, Sao Paulo, Brazil c Department of Restorative Dentistry, University of Illinois, Chicago, College of Dentistry, 801 South Paulina, Room 337, 60612 Chicago, IL, USA article info Article history: Received 31 March 2005 Received in revised form 29 November 2005 Accepted 10 January 2006 Keywords: Fluoride releasing materials Microtensile bond strength In vitro secondary caries Depth of caries formation abstract Objectives. The present study evaluated the microtensile bond strength and caries formation on adhesive/dentin interfaces before and after dynamic chemical formation of secondary caries. Methods. Restorations were prepared on the dentin surface of 80 bovine incisors using four adhesive systems: two fluoride-free (Single Bond and Clearfil SE Bond) and two fluoride containing (Optibond Solo Plus and Clearfil Protect Bond). The restored teeth were then sectioned into multiple slabs that were further trimmed at the bonded interface to a cross- sectional area of 1 mm 2 . Half of the slabs were subjected to secondary caries formation using a pH cycling model (treated groups); while the other half was used as the control group (no pH cycling). The specimens designated for bond strength evaluation were subjected to microtensile bond strength test (TBS). Caries lesions formation was assesses by polarized light microscopy at different depths from the adhesive–dentin bonded interface. The fluoride ion concentration was evaluated using the de/remineralization solutions (De/Re). Results. No differences in TBS were observed among the adhesive systems in both the control and treated conditions. Secondary caries significantly reduced the values of TBS for all adhesives (p < 0.05). Optibond Solo Plus presented the lowest caries formation at 5 m depth. Fluoride concentrations present in the De/Re were less than 0.03ppm, regardless of the adhesive system tested. Significance. Bond strength values significantly decreased after in vitro secondary caries for- mation. Fluoride present in adhesive systems is not capable of inhibiting secondary caries or maintaining bond strength values following caries formation. © 2006 Published by Elsevier Ltd on behalf of Academy of Dental Materials. All rights reserved. 1. Introduction Recent developments in adhesive systems have resulted in a greater application of these agents on daily dental practice. ∗ Corresponding author at: Piracicaba School of Dentistry, Unicamp Av. Limeira, 901, Bairro Arei˜ ao, P.O. Box 52, Piracicaba, SP 13414-903, Brazil. Tel.: +55 19 3412 5200/5337; fax: +55 19 3412 5218. E-mail address: gimarchi@fop.unicamp.br (G.M. Marchi). Contemporary adhesives systems present satisfactory bond- ing to enamel and dentin [1]. However, replacement of the restorations due to secondary caries formation is still a major problem and of great concern in dentistry [2]. 0109-5641/$ – see front matter © 2006 Published by Elsevier Ltd on behalf of Academy of Dental Materials. All rights reserved. doi:10.1016/j.dental.2006.02.001 DENTAL-927; No. of Pages 9