In vitro characterization of two laboratory-processed resin composites.
OBJECTIVE
To compare various characteristics of two new-generation laboratory-processed resin composites (BelleGlass HP/SDS-Kerr and Sinfony/3M-ESPE). The properties evaluated were degree of C=C conversion, microhardness, roughness, biaxial flexural strength and polymerization shrinkage-strain.


METHODS
All specimens were subjected to a first and a second polymerization cycle according to the manufacturers' instructions. The degree of C=C conversion (DC) was recorded on rectangular (3 x 2 x 0.5mm(3)) specimens (n=3) by FT-IR micromultiple internal reflectance spectroscopy immediately after each of the two polymerization cycles. Twenty cylindrical specimens (10 x 2mm(2)) of each material were prepared for surface microhardness (n=10, VHN, 200 g load, 20s) and surface roughness (n=10, Ra) measurements. The biaxial flexural strength and stiffness were determined on disk-shaped (n=8, 15 x 0.7 mm(2)) specimens loaded to fracture at 1 mm/min crosshead speed. The polymerization shrinkage-strain was calculated with the bonded-disk method. All values were statistically analyzed by Student's unpaired t-test (p<0.05).


RESULTS
The second polymerization cycle significantly increased the degree of C=C conversion for both materials (p<0.05). BelleGlass HP exhibited significantly higher degree of C=C conversion, surface microhardness, surface roughness, biaxial flexural strength and stiffness values compared to Sinfony (p<0.05).


CONCLUSIONS
Several differences exist between the materials although both products are recommended for the same clinical applications.
Kakaboura
A
A
Department of Operative Dentistry, University of Athens, Thivon 2, 115 27, Goudi, Athens, Greece. afrodite1@otenet.gr
Rahiotis
C
C
Zinelis
S
S
Al-Dhamadi
Y A
YA
Silikas
N
N
Watts
D C
DC
D003188:Composite Resins / Q000737:chemistry*; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D004548:Elasticity; D006244:Hardness; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D018583:Pliability; D011108:Polymers / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
D003188:Composite Resins; D008689:Methacrylates; D011108:Polymers; C477352:Sinfony composite resin; C110370:belleGlass