Preparation Of Photo-curing 3D Printing Dental Resin And The Study On Its Antibacterial Properties

The light curing DLP printing technology can print small sample with high precision and play a key role in the digital production of dental products.At present,3D printed product generally have the problem of poor mechanical properties.Moreover,Dental products used in oral cavity tend to grow bacteria membranes and endanger the health of patients.In order to solve the problems above,this paper first developed a light-curable 3D printing resin that can be used in oral cavity,and then added nano inorganic filler to the resin matrix to reinforce the resin.Finally,the antimicrobial function of the resin was realized by adding silver loaded nano inorganic filler.In this project,Urethane dimethacrylate(UDMA)and Triethylene glycol dimethacrylate(TEGDMA),which have better fluidity in dental resin,were selected as the main components of printing material;4,6-trimethylbenzoyl-diphenylphosphine oxide(TPO)were selected as a photoinitiator which could match the wavelength of DLP printer(405nm).By studying the ratio of the two component resins and the photoinitiator,the formula most suitable for the DLP type printer was selected.The results showed that when the content of UDMA was more than 70%,the viscosity of the resin increased significantly,which may not suitable for DLP printing.The resin have a higher flexural properties and lower shrinkage rates with increasing UDMA content.When the content of TPO was up to 1%,the curing rate of the resin could be basically reached a relative high level.Printability analysis of resin found that the energy required for curing at a thickness of 0.1 mm was about 11mJ/cm~2 and that the details of the printed sample could be basically restored printing with this parameter.The halloysite nanotube(HNT)was silane-modified to obtain mHNT,which was then added to the prepared resin formulation.The study found that the addition of mHNT to more than 10%of the resin fluid has serious shear thinning effect.When the content of mHNT less less than 10%,the resin had no obvious effect on the curing properties,shrinkage and water absorption rate.The flexural property reaches the maximum when the content of mHNT increase to 5%,the flexural strength increased by 20%,and the flexural modulus increased by 30%.The Vickers hardness of the composite resin is obviously improved when the mHNT content is above 5%.The Vickers hardness increases by 30%at5%and 70%at 10%.The halloysite nanotube was loaded with silver nitrate and sintered to obtain Ag-HNT,which was then added to the prepared resin formulation.The content of Ag-HNT below 3%will slightly prolong the curing time of the resin.Ag-HNT has good dispersion in the resin,and the bending property of the resin is enhanced with the increase of content.Resin with the content of less than 3%Ag-HNT has sustained antibacterial ability for at least seven days,and the silver ion concentration of the leaching solution is kept in a certain range.Ag-HNT composite resin with content below 3%has no obvious toxicity on L929 cells,and does not have hemolysis,which indicated good biocompatibility.