title: In vitro biocompatibility of oxirane/polyol dental composites with promising physical properties.
abstract: OBJECTIVE
  Visible light cure oxirane/polyol resins of Cyracure UVR-6105 with pTHF-250 has been previously shown useful for development of dental composites. This oxirane/polyol (4016) in combination with other oxiranes were formulated into composites (4016E, 4016G and 4016GB) containing 72.9-74.9% quartz filler. The main objective of the study was to evaluate some of the physical properties and the biocompatibility of the composites.
  
  
  RESULTS
  PhotoDSC analysis of composites demonstrated twice the enthalphy values of Z100 (31J/g). Composites 4016E and 4016G showed compressive strengths similar to Z100 (337+/-35Mpa), P>0.05. Discs of composite 4016E, containing Epon 825 oxirane (E), and composite 4016G containing Araldite GY 281 oxirane (G) were non-cytotoxic (-) while the composite 4016GB, containing G and Ebecryl 1830 (B), was mildly (+) cytotoxic to L929 cells in the agar diffusion assay. Seven-day extracts of 4016GB composite were cytotoxic while extracts of 4016E and 4016G were less cytotoxic to L929 cells in the MTT assay. Extracts were obtained from 7 day incubations of composite (3 cm(2) surface area/ml) in acetone or ethanol/saline (1:20) at 37 degrees C. All composite extracts were non-mutagenic to Ames strains TA100, TA98, TA97a and TA1535. The overall results with composite 4016GB suggest that leachable components were cytotoxic but non-mutagenic. With the exception of oxirane components, G and E, the oxirane Cyracure UVR-6105 and other components were non-mutagenic. From cytotoxicity studies, the photoinitiator, Sarcat CD 1012, was the most cytotoxic (TC(50)=14 microM) component. Components G (TC(50)=17 microM), E (TC(50)=50 microM) and B (TC(50)=151 microM) were significantly (p < 0.05) more cytotoxic than Cyracure UVR-6105 (1488 microM) and the polyol, pTHF-250 (TC(50)=6072 microM).
  
  
  CONCLUSIONS
  Favorable results obtained with composites 4016G and 4016E indicates that suitable oxirane/polyol formulations can be designed and optimized for development of dental composites with acceptable mechanical properties and biocompatibility. However, leachable analysis of extracts obtained from longer incubation periods is needed before final conclusions could be drawn about the leachability of oxirane components.
authors.affiliation: Department of Oral Biology, School of Dentistry, University of Missouri, 650 East 25th Street, Kansas City, MO 64108-2784, USA. eickj@umck.edu
authors.forename: J D
authors.initials: JD
authors.lastname: Eick
authors.forename: E L
authors.initials: EL
authors.lastname: Kostoryz
authors.forename: S M
authors.initials: SM
authors.lastname: Rozzi
authors.forename: D W
authors.initials: DW
authors.lastname: Jacobs
authors.forename: J D
authors.initials: JD
authors.lastname: Oxman
authors.forename: C C
authors.initials: CC
authors.lastname: Chappelow
authors.forename: A G
authors.initials: AG
authors.lastname: Glaros
authors.forename: D M
authors.initials: DM
authors.lastname: Yourtee
mesh_terms: D000818:Animals; D019540:Area Under Curve; D001672:Biocompatible Materials / Q000737:chemistry* / Q000633:toxicity*; D002470:Cell Survival / Q000187:drug effects; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003188:Composite Resins / Q000737:chemistry* / Q000633:toxicity*; D004587:Electrophoresis, Agar Gel; D004853:Epoxy Resins / Q000633:toxicity; D005027:Ethylene Oxide / Q000633:toxicity*; D007739:L Cells / Q000187:drug effects; D007928:Lethal Dose 50; D008422:Materials Testing; D051379:Mice; D009152:Mutagenicity Tests; D011108:Polymers / Q000633:toxicity; D012995:Solubility
chemical_list: D001672:Biocompatible Materials; D003188:Composite Resins; D004853:Epoxy Resins; D011108:Polymers; C024617:polyol; D005027:Ethylene Oxide