Sarrett 274 The Journal of Adhesive Dentistry
XP BOND in Self-curing Mode used for Luting Porcelain Restorations. Part A: Microtensile Test Ornella Raffaelli a /Maria Crysanti Cagidiaco b /Cecilia Goracci c /Marco Ferrari d Purpose: To assess the bond strength to dentin of an experimental adhesive and the proprietary resin cement used in different curing modes to lute ceramic disks of different thicknesses. Materials and Methods: Empress II disks (Ivoclar-Vivadent) were luted to dentin using XP BOND (<strong>Dentsply</strong> [XP]) in combination with the proprietary self-curing activator (SCA) and cement Calibra (<strong>Dentsply</strong> [C]). Curing of the adhesive was induced either by mixing with the activator (activator, groups 3 to 6) or by light irradiation for 20 s (group 2). The cement was either light cured for 40 s through the ceramic onlay (groups 1 to 5) or cured chemically (groups 6 and 7). Groups 2 and 4 were compared with group 1, in which Prime & Bond NT (<strong>Dentsply</strong> DeTrey) was tested as control. In groups 3 and 6, 2-mm-thick onlays were luted with XP+SCA, and the cement was light cured for 40 s or let autocure for 5 min, respectively. These groups were compared with group 7, in which Syntac (Ivoclar Vivadent) was applied with C and, in order to reproduce the handling procedures of group 6 (although contrary to manufacturer’s instructions), no light irradiation was provided for the adhesive or the cement. The influence of onlay thickness (2, 3, 4 mm) on the bond strength developed by XP+SCA/C was assessed by comparing groups 3, 4, 5. In these groups, C was light cured for 40 s through the onlay. Microtensile beams were obtained from the luted teeth. Results: Bond strengths not including pretest failures (in parentheses: value including pretest failures as 0 MPa) were 21.0 (17.5) MPa in group 1, 24.9 (21.2) MPa in group 2, 23.7 (21.3) MPa in group 3, 29.9 (26.7) MPa in group 4, 30.3 (24.6) MPa in group 5, 28.6 (24.6) MPa in group 6, and 17.1 (9.2) MPa in group 7. Statistically significant differences were found between groups 1 and 4, groups 3 and 5, and groups 6 and 7. Conclusion: The bonding potential of XP BOND used with the activator or light cured in combination with Calibra in self- or dual-curing mode outperformed that of a control adhesive-cement system. The bond strength of XP+ SCA + Calibra was not negatively affected by the onlay thickness. J Adhes Dent 2007; 9: 275-278. Submitted for publication: 15.12.06; accepted for publication: 5.1.07. a PhD Student, Department of Dental Materials and Prosthodontics, University of Siena, Siena, Italy. b Clinical Professor of Dentistry, Department of Dental Materials and Prosthodontics, University of Siena, Siena, Italy. c Assistant Professor and Chair, Department of Endodontics, University of Siena, Siena, Italy. d Professor and Chair, Department of Dental Materials and Prosthodontics, University of Siena, Siena, Italy. Paper presented at Satellite Symposium on Dental Adhesives, Dublin, September 13th, 2006. Reprint requests: Prof. Marco Ferrari, Research Center for Dental Health, 19 Piazza Attias, 57120 Livorno, Italy. Tel: +39-586-892-283, Fax: +39-586-898-305. e-mail: ferrarimar@unisi.it Many new bonding systems are introduced every year on the market. Some of them are primer-adhesive solutions in combination with a prior phosphoric acid treatment, others avoid the total-etch step and offer self-etching or selfadhesive bonding solutions. 3,5,7-10 However, practitioners would like to use the same bonding systems for all clinical applications, although most simplified bonding solutions are not necessarily indicated for luting indirect restorations, limiting their clinical indications to direct restorations. Recently, XP BOND (<strong>Dentsply</strong> DeTrey; Konstanz, Germany), using tert-butanol for the first time as solvent in dentistry, was proposed as a one-bottle universal adhesive, also in combination with a new self-curing activator (SCA). When luting a porcelain restoration, differences in thickness may reduce the light penetration, resulting in a reduced polymerization rate of the luting material. 1,2,4 To avoid an incomplete cure of the resin cement adhesive interface, the self-curing activator can be used. Consequently, the aims of this study were to evaluate (1) the procedure for adhesively luting ceramic to dentin and, specifically, when light is applied, to cure either the adhesive before or after applying the cement, (2) the influence of ceramic thickness when the adhesive is not separately light cured but mixed with a self-curing activator (SCA), (3) the influence of SCA on the bonding efficacy when no light is used. The null hypothesis tested is that differences in porcelain thickness and curing mode do not affect the bond strength values. Vol 9, Supplement 2, 2007 275