The Effect Of Different Curing Methods On Accuracy And Physical Properties Of Denture Base Resin

Objective To evaluate the effect of different curing methods on accuracy and physical properties of denture base resin and the effect of different investing methods on the surface roughness of denture base resin. Methods The study is to compare the difference of denture base resin cured by traditional heat polymerization in water bath, low temperature polymerization for 12 hours and for 24 hours in water bath. The dimensional accuracy between the posterior border of upper, complete denture and standardized cast at five different positions by travelling measuring method. Specimens sized 50mm×6mm×4mmare made for impact strength test. Specimens with 64mm×10mm×2. 5mm are made for measuring flexural strength and flexural modulus. Surface roughness is measured on 1Omm×10mm×2. 5mm specimens with Talysurf-4 profilometer. Results The posterior border gaps between the upper complete denture and standardized cast range from 195μm-280μm, 120μm-198μm and 65μm-144μm,respectively cured by three methods. The gaps at B, D are lower than those of A, C, E. Impact strength and flexural strength of specimens cured by traditional heat-cured method in water bath is lower than that of low temperature polymerization for 12 hours and 24 hours (P<0.01). Flexural modulus of specimens cured by low temperature polymerization for 12 hours and 24 hours in water bath is lower than that of traditional heat-cured method (P<0. 01). The surface roughness of specimens invested for three times is lower than that of invested twice (P<0. 01). Conclusions The dimensional accuracy of upper complete denture cured by low temperature polymerization methods in water bath is higher than that of traditional heat-cured method. The adaptation between the resin denture and cast is increased. Physical properties of specimens made by lower temperature in water bath are higher than those of traditional method. The surface roughness of denture base invested for three times is lower than that of invested twice. Dentureprocessed by this method can get smoother and more sheeney surface.Postgraduate Chen Chunxia (Prosthodontics)Directed by Li Ningyi Wang Xue Sun Guilan...