dental materials 26 ( 2 0 1 0 ) 306–319 available at www.sciencedirect.com journal homepage: www.intl.elsevierhealth.com/journals/dema Surface deterioration of dental materials after simulated toothbrushing in relation to brushing time and load S.D. Heintze a,* , M. Forjanic a , K. Ohmiti b , V. Rousson b a R&D, In Vitro Research, Ivoclar Vivadent AG, Bendererstrasse 2, FL-9494 Schaan, Liechtenstein b Statistical Unit, Institute for Social and Preventive Medicine, University of Lausanne, Switzerland article info Article history: Received 29 September 2008 Accepted 24 November 2009 Keywords: Toothbrushing Surface roughness Surface gloss Load Time abstract Objectives. (1) To evaluate the changes in surface roughness and gloss after simulated tooth- brushing of 9 composite materials and 2 ceramic materials in relation to brushing time and load in vitro; (2) to assess the relationship between surface gloss and surface roughness. Methods. Eight flat specimens of composite materials (microfilled: Adoro, Filtek Supreme, Heliomolar; microhybrid: Four Seasons, Tetric EvoCeram; hybrid: Compoglass F, Targis, Tetric Ceram; macrohybrid: Grandio), two ceramic materials (IPS d.SIGN and IPS Empress pol- ished) were fabricated according to the manufacturer’s instructions and optimally polished with up to 4000 grit SiC. The specimens were subjected to a toothbrushing (TB) simulation device (Willytec) with rotating movements, toothpaste slurry and at three different loads (100 g/250 g/350 g). At hourly intervals from 1 h to 10 h TB, mean surface roughness Ra was measured with an optical sensor and the surface gloss (Gl) with a glossmeter. Statistical analysis was performed for log-transformed Ra data applying two-way ANOVA to evaluate the interaction between load and material and load and brushing time. Results. There was a significant interaction between material and load as well as between load and brushing time (p < 0.0001). The microhybrid and hybrid materials demonstrated more surface deterioration with higher loads, whereas with the microfilled resins Heliomo- lar and Adoro it was vice versa. For ceramic materials, no or little deterioration was observed over time and independent of the load. The ceramic materials and 3 of the composite mate- rials (roughness) showed no further deterioration after 5 h of toothbrushing. Mean surface gloss was the parameter which discriminated best between the materials, followed by mean surface roughness Ra. There was a strong correlation between surface gloss and surface roughness for all the materials except the ceramics. The evaluation of the deterioration curves of individual specimens revealed a more or less synchronous course suspecting hint- ing specific external conditions and not showing the true variability in relation to the tested material. ∗ Corresponding author. Tel.: +423 235 3570; fax: +423 233 1279. E-mail address: siegward.heintze@ivoclarvivadent.com (S.D. Heintze). 0109-5641/$ – see front matter © 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.dental.2009.11.152