Selected characteristics of an Ormocer and a conventional hybrid resin composite

摘要

Objectives. The objective of this in vitro study was to evaluate surface roughness, hardness and wear resistance of an Ormocer (Admira), polymerized by a plasma arc system. A secondary objective was to investigate two placement technique bulk or incremental layers. Methods. Blocks from Admira and Amelogen (a microhybrid composite) were prepared in cylinders, 3 mm in diameter, and 2 and 5 mm in thickness (bulk or incrementally placed) and polymerized by a plasma arc and a conventional light system. Surface roughness measurements were taken by a Surface Profilometer on the top of the specimens. Vickers hardness measurements, with a load of 600 mN were taken on the top and bottom of 2 mmand top, intermediate and bottom of 5 mm thickspecimens. For the wear test, specimes (8 mm in diameter and 2 mm in thickness) of Admira, Amelogen and amalgam were tested in a ball-on design, by circular movements of the antagonist (alumina ball; diameter 10 mm) under 10 N load. For the statistical evaluation of the results of surface roughness, microhardness and wear test; a paired samples t-test and Kruskal-Wallis analysis of variance test, were performed. Results. Admira showed highest hardness values in all polymerization types at the top surface and this was statistically significant (p < 0.05). These highest hardness values were obtained with conventional polymerization (81.84 +- 1.167 VHN). Meanwhile, the wear resistance of Admira was found to be higher than Amelogen (Wd_(admira) = 0.024 +- 0.00149 mm~3; Wd_(amelogen) = 0.032 +- 0.00075 mm~3). However, Admira demonstrated the highest surface roughness value compared to Amelogen, with plasma arc 5 s (0.65 +- 0.023 μm). Amelogen was found to have the lowest surface roughness value with conventional 40 s (0.45 +- 0.012 μm). Significance. The results indicated that Ormocer, which was developed by Ormocer technology, demonstrated higher microhardness and wear resistance when compared to a hybrid composite; however, the polishability of Ormocer needs further investigation. Also the selection of visible light activated composite resins exhibited higher surface microhardness values when polymerized with conventional rather than with plasma arc.