Marginal adaptation of a low-shrinkage silorane-based composite: A SEM-analysis

Introduction – Shrinkage during polymerization of resin-based composite materials may lead to gap formation and hamper the marginal adaptation of the restorations. To reduce the problem of polymerization shrinkage, a new composite material (FiltekTM Silorane, 3M-ESPE, Germany), with a reduced shrinkage, has been marketed. Objective – To investigate whether reduced polymerization shrinkage improves the marginal adaptation of composite restorations. Material and methods – A total of 156 scanning electron microscopy (SEM) pictures (78 baseline, 78 follow-up) of the occlusal part of Class II restorations in molars were included in the study. The restorations originated from a randomised clinical trial, conducted in 20072009 which compared the clinical performance of a low-shrinkage composite material (FiltekTM Silorane) with that of a methacrylate-based composite material (Ceram•XTMmono). Eponcasts of the restorations were used for SEM pictures at x 16 magnification. Pictures from baseline and follow-up (398 days, SD 29 days) were randomised and the examiner was blinded to the material and the age of the restoration. Stereological measurements were used to calculate the length and the width of the marginal discrepancies. Results – No statistically significant difference in gap formation and chipping was found between the two materials. Conclusion – The results of the present study do not support the hypothesis that reduced polymerization shrinkage improves the marginal adaptation. SEM-study of a lowshrinkage composite abstract Marginal adaptation of a low-shrinkage silorane-based composite: A SEM-analysis