Evaluation of cavity adaptation of low-shrinkage composite resin

Keizo Tanno, DDS,a Noriko Hiraishi, DDS, PhD,a Masayuki Otsuki, DDS, PhD,a and Junji Tagami, DDS, PhDa,b

aCariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, and bGlobal Center of Excellence (GCOE) Program; International Research Center for Molecular Science in Tooth and Bone Diseases, Tokyo Medical and Dental University, Tokyo, Japan

Purpose: The purpose of this in vitro study was to evaluate cavity adaptation of a low-shrinkage composite resin lining with or without a flowable composite resin.
Materials and Methods: One-mm-deep dentin and 2-mm-deep enamel-dentin cylindrical class I cavities were prepared and restored with a self-etch adhesive and either of a low-shrinkage composite or a conventional composite resin (1-mm-deep and 2-mm-deep cavities) and with or without a flowable composite (2-mm-deep cavity). Samples were crosscut and evaluated for gap formation using a digital microscope.
Results: Slight gap formations were observed at resin-cavity interface in all groups. There was no statistical difference of the gap formation among experimental groups.
Conclusion: Cavity adaptation of a low-shrinkage composite resin was comparable to that of a conventional composite resin. Intermediate layer of a flowable composite did not improve the adaptation at resin-cavity interface.(Asian Pac J Dent 2011; 11: 27-33.)

Key Words: composite resin, gap formation, low shrinkage