Abstract
The physical and chemical properties, toxicity, fitness to the model and relining procedure of light curing type new soft denture lining materials(NewS and NewH), consisting of vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene copolymer(2-4-6FL)and 2, 2, 3, 3, tetrafluoropropyl α-fluoroacrylate(4FFA)were compared with those of commercial soft denture lining materials.The mixture of 2-4-6FL and 4FFA was kept in a dough state until irradiation.The new lining materials after curing showed the following properties:The amount of residual monomer was less than 0.01wt%.Water sorption after immersion for 8 weeks was 0.60mg/cm2(NewH)and 1.08mg/cm2(NewS), and less than that obtained in the commercial soft denture liners of a monomer/polyer curing type.Solubility in water after 8 weeks was very low(0.10mg/cm2).At a water contact angle of 92 degrees, the material had a water-repellent nature.Oil sorption after 3 weeks was the lowest;0.03mg/cm2(NewH)and 0.09mg/cm2(NewS).Hardness(JIS A)of 30(NewS)and 44(NewH)revealed them to be soft enough and they had a viscoelastic property.They had good adhesiveness to usual acrylic denture base material.Fitness of the materials cured by inttermittent irradiation was better than that obtained in the conventional heat-curing acrylic resin.This suggested that they would be applicable not only for indirect relining but also for direct relining.Cytotoxicity was the lowest among the materials tested.The new materials had many properties suitable as a soft denture lining material, and should be worth applying to practical use.
