| The post-core-crown system is mainly applied in restoration of the residual crown or root, in which the post plays an important role. In the past, the metal post was mostly applied in this procedure. However, it caused the root fracture at every turn, for the elastic module of the metal post is far larger than that of dentin. At present, the post of fibre reinforced composite (FRC) is applied in clinical procedure gradually, which can prevent the root from fracturing, for its elastic module is approximate to that of dentin. But the FRC post is prefabricated, it can not be shaped individually to fit the different figure of root canal, and can not meet the clinical needs of modifying crown direction flexibly. So, it is necessary to develop a kind of FRC post which possesses plasticity and can be shaped individually. At abroad,only a kind of fibre post named Everstick is developed by StickTeck company in Finland,which can meet the above needs.However,there is no studies on this kind of fibre post at home.In this research, a kind of plastic FRC post was developed with the light cure technology, fibre reinforced technology and interpenetrating polymer network (IPN) technology, and was evalued elementarily on some properties including mechanics performances, biological safety and adhesive abilities. This research laid an experimental foundation to introduce this kind of post to the clinical applications.In this research, the Strategy and Procedure is studied from part to entirety and from process to properties. Firstly, we discussed the influence of different compose on the properties of composites, according to the basal mechanical properties of material matrix. At the same time, the synthesis process and formula is groped. Then the biology security of material was primary evaluated. At last, the adhesion which is closed contacted with clinic application was studied.The content and method are as follows:1. Preparation and formula of interpenetrating polymer network (IPN) of polymer were studied. The Bis-GMA and PMMA which is common material in oral cavity resin were used as matrix. Bis-GMA and PMMA were mixed with different ratio, then react in certain condition to form IPN polymer. The best ratio to form IPN polymer were confirmed according to the mechanical properties and Tg.2. The influence of glass fiber content on mechanical properties of fiber reinforced composites (FRC) was studied. Then the effect rules on mechanical properties were discussed.3. The influence of light initiation system on curing properties of fiber reinforced composite was studied. According to the mechanical properties and conversion of resin, the components content of light initiation system were confirmed. 4. The influence of the light time on mechanical properties of fiber reinforced composites was studied. According to the mechanical properties, the light time of curing resin composites were confirmed.5. Dental plastical IPN posts polymer composites were synthesized, according to the above formula and process. The mechanical properties of IPN posts were studied.6. The biological safety of the post made by self-fabricated dental plastical IPN posts polymer composites was evalued by MTT test, hemolysis test in vitro, oral mucous membrane irritation test, acute general toxicity test.7. The micro push-out test was applied to evalue the adhesive abilities between the post made by self-fabricated dental plastical IPN posts polymer composites and dentin with three kinds dentin adhesive agent, which was compared with that of EverStick, and microscopy was applied to observe the structure of the fracture section.8. The micro push-out test was applied to evalue the adhesive abilities betwwen the post made by self-fabricated dental plastical IPN posts polymer composites and three kinds of resin core materials, which was compared with that of EverStick, and microscopy was applied to observe the structure of the fracture section.The results are as follows:1. In certain condition, Bis-GMA and MMA can form the better IPN structure. The structure and properties is best when the MMA content is 20%.2. When the glass fiber content is about 73.8%, the properties of IPN composites reached best.3. The best ratios of CQ and EDB in light initiation system are 0.5 wt% and 1.0 wt% respectively.4. According to the mechanical properties and clinic manipulation, the best light curing time is 60S.5. Dental IPN posts polymer composites are plastical and easy to clinic manipulation. In addition, the bend strength is 647.05MPa, and the bend modulus is 33.03GPa, which closed to the mechanical properties of dental essence.6. The post made by self-fabricated dental plastical IPN posts polymer composites was avirulent to cells, was considered to bring no hemolysis phenomena and be no influences on function of cruor, for the hemolytic rates of samples is 1.76%, have no mucous membrane irritations, could not induce acute general toxicities.7. There was no significant diference on adhesive effects to dentin between the post made by self-fabricated dental plastical IPN posts polymer composites and EverStick. There was no significant diference on adhesive effects among utilizing GC Fuji PLUS, Panavia F and 3M ESPE RelyXtm Unicem.8. Clearfil APX could adhere to the post made by self-fabricated dental plastical IPN posts polymer composites better than 3M ESPE Filtektm Z250 or Dentsply Definite Core.Conclusions: The new pattern FRC post can be fabricated with the light cure technology, fibre reinforced technology and interpenetrating polymer network (IPN) technology. It possesses good mechanics performances and plasticity, and can be shaped individually and meet the clinical needs of modifying crown direction flexibly. There is no significant diference between self-fabricated FRC post and EverStick. In this research, the technics and components buildup is at the experimental level, and need more improved.
|
PDF Full Text Request