ABSTRACT
BACKGROUND:At present,the dental composite resin filling material composed of resin matrix monomer is the first choice material for the filling treatment of dental defects,but with the increase of its use time in the oral environment,the dental tissue will develop secondary caries and the filling material will wear and break.The main cause of these problems is the polymerization shrinkage of the filling material and its mismatch with the mechanical properties of the dental tissue. OBJECTIVE:To synthesize a new type of dental composite resin monomer by adding initiators with different components,to improve the traditional double bond conversion rate of the system and further improve the mechanical properties of the material. METHODS:A new composite resin matrix system was prepared by adding different initiators to the monomer of 3,3′,5,5′-tetramethoxybiphenyl-4,4′-diol epoxy acrylate resin.In group A,camphorquinone with a mass fraction of 1.1%was added.In group B,1-phenyl-1,2-propanedione with a mass fraction of 2.1%was added.In group C,a mixture of camphorquinone and 1-phenyl-1,2-propanedione(a mass ratio of the two was 1:1)with a mass fraction of 3.1%was added.The double bond conversion,polymerization shrinkage and mechanical properties of the samples were determined. RESULTS AND CONCLUSION:(1)The double bond conversion rate of groups B and C was higher than that of group A(P<0.05).The polymerization shrinkage of group B was higher than that of group A(P<0.05),while that of group C was lower than that of group A(P<0.05).(2)The flexural strength,elastic modulus and compressive strength of groups B and C were higher than those of group A(P<0.05,P<0.01).Vickers hardness of group B was higher than that of group A(P<0.05),and the Vickers hardness of group C was lower than that of group A(P<0.01).(3)These findings suggest that 1-phenyl-1,2-propanedione is an initiator with ideal performance.The combined application of 1-phenyl-1,2-propanedione and camphorquinone can effectively improve the double bond conversion rate of the resin matrix system and further improve the mechanical property of the resin.