International Journal of Paediatric Dentistry 2002; 12: 265–270 © 2002 BSPD and IAPD 265 Blackwell Science, Ltd Sealing ability of a single bond adhesive in primary teeth. An in vivo study A. A. EL-HOUSSEINY & N. FARSI Pediatric Dentistry Division, Faculty of Dentistry, KAAU, PO Box 80209, Jeddah 21589, Saudi Arabia Summary. Aim. To compare the ability of a single bond adhesive to its preceding mul- tiple step dentin bonding agent in reducing microleakage around class V composite resin in primary teeth. Material and methods. Twelve children, between 9 and 11 years old, with non-carious primary canines indicated for extraction for orthodontic purposes, were selected for this study. Each child had facial surfaces of his or her upper and/or lower canines prepared for class V cavities. One canine was randomly selected for restoration using the Scotch- bond Multi Purpose Plus System (group I) and its antimere for the Single Bond adhesive (group II). Thirty cavities were restored by Z-100 composite. Materials were handled according to the instructions of the manufacturer. All teeth were extracted one month later, immersed in 2% basic fuchsin then sectioned to evaluate dye penetration. Results. No statistically significant difference was found in the degree of microleakage between the two materials. Conclusions. Neither of the two adhesive systems was able to completely prevent leak- age of class V restorations. Additional preventive measures should be implemented whenever using composite resin restorations in children. Introduction In recent years, the popularity of aesthetic restorations has increased. Composite resin is the most aesthetic restorative material currently available for restoring anterior teeth. It provides acceptable aesthetics and has relatively good handling properties. Nevertheless, problems still exist in terms of polymerization shrinkage and subsequent inadequate adhesion to cavity walls which leads to microleakage [1]. Composite resin restorations have been documented to have a high failure rate in primary teeth [2–4]. This could be due to lack of cooperation in the children leading to inadequate tooth isolation and a higher incidence of marginal leakage. An important area of research focuses on new methods for producing better dentinal bonding agents. When using these dentinal bonding systems, the problem of microleakage, postoperative sensitiv- ity and inadequate adhesion of composite resins have been improved in the permanent dentition [5]. However, several in vitro studies indicated that a problem still exists with dentinal bonding systems when used in primary teeth [6,7]. In the early 1990s, the fourth generation of dentin adhesives was introduced. Most of these systems, which are based on ‘total etch’ techniques in com- bination with improved formulations of primers and resins, have been advocated as a safe and effective method to achieve significant improvement in adhe- sion to dentin [8,9]. Because the three-step bonding systems are per- ceived by some dentists as being too complicated and time consuming, especially with children, many manufacturers have attempted to simplify the systems Correspondence: Dr N. Farsi, Pediatric Dentistry Division, Faculty of Dentistry, KAAU, PO Box 80209, Jeddah 21589, Saudi Arabia. E-mail: N_Farsi@yahoo.com