Composite Bonding to Stainless Steel Crowns Using a New Universal Bonding and Single-Bottle Systems

Aim. The aim of this study is to evaluate the shear bond strength of nanocomposite to stainless steel crowns using a new universal bonding system. Material and Methods. Eighty (80) stainless steel crowns (SSCs) were divided into four groups (20 each). Packable nanocomposite was bonded to the lingual surface of the crowns in the following methods: Group A without adhesive (control group), Group B using a new universal adhesive system (Scotchbond Universal Adhesive, 3M ESPE, Seefeld, Germany), and Group C and Group D using two different brands of single-bottle adhesive systems. Shear bond strengths were calculated and the types of failure also were recorded. Results. The shear strength of Group B was significantly greater than that of other groups. No significant differences were found between the shear bond strengths of Groups C and D. The control group had significantly lower shear bond strength ( ) to composite than the groups that utilized bonding agents. Conclusion. Composites bonding to stainless steel crowns using the new universal bonding agent (Scotchbond Universal Adhesive, 3M ESPE, Seefeld, Germany) show significantly greater shear bond strengths and fewer adhesive failures when compared to traditional single-bottle systems. 1. Introduction Stainless steel crowns (SSCs) are most commonly used for full coverage restoration of posterior primary teeth [1–3]. Given the nature of primary enamel, the need for a full coverage restoration in children is all the more important [4]. For children who presented with large, multisurface carious lesions of the primary teeth, the American Academy of Pediatric Dentistry recommended the full coverage of crowns using SSCs [5]. Despite their high success rate, this proven restoration often fails to meet the esthetic demands of patients and their parents [3, 6]. Esthetic SSCs are composite or porcelain coatings that are chemically or mechanically attached to a metal coping which allows for a tradeoff between their respective strengths and weaknesses [6]. Esthetic SSCs have several shortcomings relative to traditional SSC restorations such as requiring a greater reduction of tooth structure during preparation [7], inability to crimp the crown [8], and repair of fractured coatings sometimes requiring complete replacement [9]. The shape of an esthetic SSC cannot be altered, because this would change the rigid metal coping structure beneath the somewhat brittle composite, leading to the possibility of future fracture of the composite [10]. Although there is documentation of the repair of fractured esthetic crowns