Investigation of flexural strength and cytotoxicity of acrylic resin copolymers by using different polymerization methods.
OBJECTIVE
The aim of this study was to appraise the some mechanical properties of polymethyl methacrylate based denture base resin polymerized by copolymerization mechanism, and to investigate the cytotoxic effect of these copolymer resins.


METHODS
2-hydroxyethyl methacrylate (HEMA) and isobutyl methacrylate (IBMA) were added to monomers of conventional heat polymerized and injection-molded poly methyl methacrylate (PMMA) resin contents of 2%, 3%, and 5% by volume and polymerization was carried out. Three-point bending test was performed to detect flexural strength and the elasticity modulus of the resins. To determine the statistical differences between the study groups, the Kruskall-Wallis test was performed. Then pairwise comparisons were performed between significant groups by Mann-Whitney U test. Agar-overlay test was performed to determine cytotoxic effect of copolymer resins. Chemical analysis was determined by FTIR spectrum.


RESULTS
Synthesis of the copolymer was approved by FTIR spectroscopy. Within the conventional heat-polymerized group maximum transverse strength had been seen in the HEMA 2% concentration; however, when the concentration ratio increased, the strength decreased. In the injection-molded group, maximum transverse strength had been seen in the IBMA 2% concentration; also as the concentration ratio increased, the strength decreased. Only IBMA showed no cytotoxic effect at low concentrations when both two polymerization methods applied while HEMA showed cytotoxic effect in the injection-molded resins.


CONCLUSIONS
Within the limitations of this study, it may be concluded that IBMA and HEMA may be used in low concentration and at high temperature to obtain non-cytotoxic and durable copolymer structure.
Department of Prosthodontics, Faculty of Dentistry, Bülent Ecevit University, Zonguldak, Turkey.
Onur
0000-0002-8018-6946
O
Sahin
Department of Prosthodontics, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey.
Ali Kemal
AK
Ozdemir
Department of Prosthodontics, Dentaforum Dental Clinic, Kayseri, Turkey.
Mehmet
M
Turgut
Department of Chemistry, Tunceli University, Tunceli, Turkey.
Ali
A
Boztug
Department of Microbiology Faculty of Medical, Cumhuriyet University, Sivas, Turkey.
Zeynep
Z
Sumer
2-Hydroxyethyl methacrylate; Acrylic resin; Copolymer; Cytotoxicity; Flexural strength; Isobutyl methacrylate