Preparation Of The Amphipathic Dental Adhesive And Its Reinforcement By Silica Nanoparticles

Dental adhesive plays an important rola in oral restoration and has a huge market potential in China along with its social economy development.Unfrotunately,China domestic market of these materials was dominated by foreign brands for a long time.So it‘s really necessary not only for improving peoples‘living standard but also for the economic benefits to develop the advanced adhesives with independent intellectual property rights.There have developed a system of adhesion theory during the past years of study.Recent reachers devoted adhesives into the?All in One?systems,which meant the adhesive with only one mixed conpontent in one bottle and could be used with only one step.This kind of adhesive asks for higher requests:Firstly,the adhesive should be amphipathic and of great flowability to permeate into the dentine structure.Secondly,the adhesive should well fulfill the dentinal dubules and with small polymerization shrinkage to avoid the risk of microleakage.This work aimed at the preparation of a one-component dental adhesive and studying the effect of the nano SiO₂ filler,with various particle sizes and surface modifications,on the dental adhesive were studied.?1?Preparation of the one-component dental adhesive.A dental adhesive system using a mixture of Bis-GMA,TEGDMA and HEMA as the resin matrix,CQ/DMAEMA as the initiator and acetone as the solvent served as a model.Properties of experimental dental adhesives with various Bis-GMA/TEGDMA ratios and HEMA contents were tested.The results showed that the properties maximized when the ratio of GMA/TEGDMA was 3:2.The bond strength of the adhesives to the restoration resin,compressive strength of the cured adhesives and the degree of conversion were 33.9 MPa,295.1 MPa and 60.3%,respectively.Meanwhile,although HEMA did negative effects on some properties of adhesive,it improved the bond strength between resin and dentine because of its perfect infiltration to the hydrophilic dentine.?2?Adding the nano SiO₂ into the adhesive.The SiO₂ particles were used as the model filler to study the filler reinforcement of the adhesives.The effect of the particle size on the properties of the experimental adhesive was investigated by incorporation of the 93.2 nm and 18.4 nm APTES modified SiO₂ into the adhesive.Then the effect of surface modification of SiO₂ on the properties of the experimental adhesive was investigated by incorporating various modified SiO₂?18 nm?into it.The result showed that both increased its degree of the conversion.Besides,he properties of the adhesive were improved less by incorporation of the bigger SiO₂ particles than that by the smaller ones.Adhesive with 10%SiO₂?18.4nm?showed a bond strength of 35.7 MPa to the restoration resin and a compressive strength of 317.9 MPa after cured.Also,it was proved that incorporation of the SiO₂ modified with APTES,MPS or 4-META resulted in various properties,which could be arranged as 4-META@SiO₂>MPS@SiO₂>APTES@SiO₂.The adhesive with 5%4-META@SiO₂showed the highest bond strength of 13.6 MPa between resin and dentine,while the adhesive with 5%unmodified SiO₂ showed 8.79 MPa only.In conclusion,this paper worked on the effects of the components and the nano SiO₂ fillers with various size and modification.The properties of several adhesives prepared in the experiment were comparable to the commercial ones.This work has definite guiding sense to design and production of the advanced adhesives.