Abstract
Objectives. The potential of a recently marketed resin-based composite (RBC), namely X-tra fil (shade A3), which claims to be amenable to curing to a depth of 4 mm was investigated.
Methods. Disc-shaped specimens (11 mm diameter, 2 mm thickness) of Filtek (TM) Z250, Admira. and X-tra fil were tested in bi-axial flexure to determine the strength. Water sorption, water solubility and Vickers hardness measurements were determined following short-term (0.1, 0.5, 1, 4, 24 and 48 h) and medium-term (1, 4, 12 and 26 weeks) water immersion on discshaped specimens (11 mm diameter, I mm thickness). The top (t) 0-1 mm depth and bottom (b) 3-4mm depth of X-tra fil were tested for water sorption, water solubility and Vickers hardness measurements. In addition an analysis of pulpal cell cytotoxicity at 1, 2, 3, 7 and 14 days was also performed on the RBCs.
Results. No significant differences in the bi-axial flexure strength or top to bottom hardness ratios were evident between the materials examined. However, the water sorption and water solubility values obtained for Filtek (TM) Z250 (12.3 +/- 11.8 and 2.7 +/- 1.6 mu g/mm(3) respectively) and Admira (16.0 +/- 1.5 and 4.3 +/- 0.2 mu g/mm(3), respectively) were increased compared with X-tra fil (t) (SA 0.7 and 0.8 +/- 0.2 mu g/mm(3), respectively) and X-tra fil (b) (6.8 +/- 0.6 and 2.4 +/- 1.1 mu g/mm(3), respectively) but within the ISO specification standard of <= 40 and <= 7.5 mu g/mm(3), respectively No statistically significant differences were identified on cell viability between the RBCs used in the current study
Significance. The manufacturer claims that the recently marketed material X-tra fil could be cured to a depth of 4 mm appear to be vindicated and the performance in terms of flexure strength, water uptake and biocompatibility are comparable with conventional RBCs. (C) 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.