dental materials 25 ( 2 0 0 9 ) 750–759 available at www.sciencedirect.com journal homepage: www.intl.elsevierhealth.com/journals/dema Nanohybrid vs. fine hybrid composite in Class II cavities: Clinical results and margin analysis after four years Norbert Krämer a , Christian Reinelt b , Gert Richter c , Anselm Petschelt d , Roland Frankenberger d,* a Department of Pediatric Dentistry, University Medical Center Carl Gustav Carus, Technical University Dresden, Germany b Private Practice, Nuremberg, Germany c Department of Prosthetic Dentistry, University Medical Center Carl Gustav Carus, Technical University Dresden, Germany d Dental Clinic 1 - Operative Dentistry and Periodontology, University Medical Center Erlangen, University of Erlangen-Nuremberg, Glückstrasse 11, D-91054 Erlangen, Germany article info Article history: Received 2 July 2008 Received in revised form 20 November 2008 Accepted 17 December 2008 Keywords: Resin composites Nanofiller Marginal integrity Etch and rinse abstract Objectives. This controlled prospective split-mouth study evaluated the clinical behavior of two different resin composites in extended Class II cavities over a period of four years. Methods. Thirty patients received 68 direct resin composite restorations (Grandio bonded with Solobond M: n = 36, Tetric Ceram bonded with Syntac: n = 32) by one dentist in a private practice. All restorations were replacement fillings, 24 cavities (35%) revealed no enamel at the bottom of the proximal box, in 33 cavities (48%) the proximal enamel width was less than 0.5 mm. The restorations were examined according to modified USPHS criteria at baseline, and after six months, one, two, and four years. At each recall, impressions were taken for replica preparation. Replicas of 44 select subjects were assessed for marginal quality under a stereo light microscope (SLM) at 130× and 22 replicas were assessed under a scanning electron microscope (SEM) at 200×. Results. Both recall rate and survival rate were 100% after four years of clinical service. No significant difference was found between the restorative materials (p > 0.05; Mann–Whitney U-test). Hypersensitivities were significantly reduced over time (p < 0.05; Friedman test). A significant deterioration over time was found for the criteria marginal integrity (66% bravo after four years), tooth integrity (15% bravo), filling integrity (73% bravo) and proximal contact (p <0.05; Friedman test). SLM and SEM analysis of restoration margins revealed differences in the amount of perfect margins, in favor of Tetric Ceram (p < 0.05). Significances. Both materials performed satisfactorily over the four-year observation period. Due to the extension of the restorations, wear was clearly visible after four years of clinical service with 50% bravo ratings. © 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. 1. Introduction Both anterior and posterior restorations are today predom- inantly made by use of resin composites [1–4]. Successful * Corresponding author. Tel.: +49 9131 8533693 fax: +49 9131 8533603. E-mail address: frankbg@dent.uni-erlangen.de (R. Frankenberger). adhesion to tooth hard tissues is a fundamental prereq- uisite for pit and fissure sealings, direct resin composites, and bonded ceramics [5–9]. However, without successful adhesion, gap formation and finally recurrent caries have a 0109-5641/$ – see front matter © 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.dental.2008.12.003