ORIGINAL ARTICLE Shear bond, wettability and AFM evaluations on CO 2 laser-irradiated CAD/CAM ceramic surfaces Ahmed El Gamal 1 & Etienne Medioni 1 & Jean Paul Rocca 1 & Carlo Fornaini 1 & Omid H. Muhammad 1 & Nathalie Brulat-Bouchard 2 Received: 4 July 2016 /Accepted: 8 February 2017 # Springer-Verlag London 2017 Abstract The purpose of this study is to determine the CO 2 laser irradiation in comparison with sandblasting (Sb), hydrofluoric acid (Hf) and silane coupling agent (Si) on shear bond strength (SBS), roughness (Rg) and wettability (Wt) of resin cement to CAD/CAM ceramics. Sixty (CAD/CAM) ce- ramic discs were prepared and distributed into six different groups: group A, control lithium disilicate (Li); group B, control zirconia (Zr); group C, Li: CO 2 /HF/Si; group D, Li: HF/Si; group E, Zr: CO 2 /Sb/Si; group F, Zr: Sb/Si. Result showed significant difference between irradiated and non-irradiated in terms of shear bond strength for zirconia ceramics ( p value = 0.014). Moreover, partial surface wettability for irradiated and non-irradiated ce- ramics. Irradiated surface demonstrated more rough surface in lithium disilicate than zirconia ceramics. CO 2 irradiation could increase shear bond strength, surface roughness and wettability for both CAD/CAM ceramics. Keywords CO 2 laser . CAD/CAM ceramics . Shear bond strength . Roughness . Wettability Introduction All-ceramic materials are an increasingly popular alternative to metal ceramic restorations due to their excellent aesthetics, chem- ical stability and biocompatibility [1]. However, ceramic restora- tions are very brittle and have limited flexural strength, so adhesive cementation also increases the risks of fracture [2–5] and debonding [6, 7]. CAD/CAM dental ceramics are classified as either zirconia-based or lithium disilicate-based [8] which have to be roughened to achieve successful chemical bonding and micromechanical interlocking with the resin cement [9, 10]. For both types of ceramics, different surface treatment methods are proposed to provide roughness and promote micromechanical retention [11]. Studies have shown that hydrofluoric acid (HF) and then applied silane coupling agent enhanced the roughness of a ceramic surface for lithium disilicate [12–14]. It is recom- mended to use the silane for glasses and porcelains which are able to form a siloxane network with the silica, which helps improve bonding between resin cement and ceramic surfaces [ 15], but this treatment is not appropriate to zirconia-based ceramics. Some authors assert that sandblasting is a useful method to increase surface roughness and successfully improve the bonding strength of zirconia-based ceramics [16]. Chen et al. [17] assert that sandblasting should be avoided in lithium disilicate due to the possibility of volume loss and changes in morphology of ceramics. Laser irradiation is proposed as a promising method for ce- ramic surface treatment. Many types of laser have been tested, including CO 2 (carbon dioxide) and Er:YAG (erbium-doped yttrium aluminium garnet) lasers [18]. Some studies have report- ed that laser irradiation with CO 2 laser increases the bond strength of resin cement to zirconia ceramics [19, 20], whereas others demonstrated that sandblasting was more efficient than Er: YAG laser to increase the bonding of resin cement to zirconia ceramics [ 21, 22]. The aim of this study was to determine the effect of CO 2 laser compared to (1) sandblasting and silane coupling agent on shear bond strength of resin cement to a zirconia ceramic base and (2) * Ahmed El Gamal aelgamal@unice.fr 1 Micoralis EA 7354 Laboratory, University Côte d’Azur, Nice, France 2 Mines ParisTech, Centre de Mise en Forme des Matériaux (CEMEF), CNRS-UMR 7635, Sophia Antipolis, France Lasers Med Sci DOI 10.1007/s10103-017-2171-4