Influence of additives on the properties of Bis-GMA/Bis-GMA analog comonomers and corresponding copolymers.
OBJECTIVE
The purpose of this study was to evaluate the effect of two additives: propionaldehyde (aldehyde) and 2,3-butanedione (diketone) on the properties of Bis-GMA diluted with TEGDMA and the synthesized Bis-GMA analogs, propoxylated Bis-GMA (CH(3)Bis-GMA) and propoxylated fluorinated Bis-GMA (CF(3)Bis-GMA).


METHODS
Nine experimental comonomers were prepared combining Bis-GMA and TEGDMA, CH(3)Bis-GMA, CF(3)Bis-GMA, with aldehyde (32mol%) and diketone (32mol%). Photopolymerization was effected by using Camphorquinone (0.2wt%) and N,N-dimethyl-p-toluidine (0.2wt%). Experimental comonomer viscosity (Brookfield viscometer), polymerization shrinkage (gravimetrically), degree of conversion (FT-IR) and contact angles (contact angle goniometer) were determined. Comonomer and copolymer T(g)s (DSC and Fox equation) were also evaluated. Data were analyzed by one-way ANOVA and Tukey test (alpha=0.05).


RESULTS
Bis-GMA/CH(3)Bis-GMA and Bis-GMA/CF(3)Bis-GMA with additives exhibited lower viscosities (p<0.01). Inclusion of additives into the comonomer systems did not produce significant increase in polymerization shrinkage (p>0.05). A significant increase in degree of conversion was shown for Bis-GMA/TEGDMA and Bis-GMA/CH(3)Bis-GMA with additives (p<0.01). Additives reduced contact angle and comonomer T(g) values, whereas the corresponding copolymers with additives showed an increase in T(g).


CONCLUSIONS
Use of novel comonomer systems with the addition of aldehyde and diketone functional groups would improve dental resin composite properties.
Prakki
Anuradha
A
Department of Operative Dentistry, Endodontics and Dental Materials, University of São Paulo, Bauru, São Paulo, Brazil.
Tallury
Padmavathy
P
Mondelli
Rafael Francisco Lia
RF
Kalachandra
Sid
S
D000447:Aldehydes / Q000494:pharmacology*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D003931:Diacetyl / Q000494:pharmacology*; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D014783:Viscosity / Q000187:drug effects
D000447:Aldehydes; D011109:Polymethacrylic Acids; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C005556:propionaldehyde; D003931:Diacetyl