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.
Department of Operative Dentistry, University of Athens, Thivon 2, 115 27, Goudi, Athens, Greece. afrodite1@otenet.gr
A
A
Kakaboura
C
C
Rahiotis
S
S
Zinelis
Y A
YA
Al-Dhamadi
N
N
Silikas
D C
DC
Watts
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