| Objective:Implant denture teeth known as third vice humans, lack of dental restorations in recent years research and application focus. Currently used in the clinic for titanium metal implant, its structure and composition of the alveolar bone and teeth far, despite a large number of surface modification, but there is no ideal method for modifying clinical application. Therefore, the search has been planted bioactive implant restoration research focus. Zirconia (Z1O2) ceramic has good biocompatibility and mechanical and physical properties, is the best, one of the greatest hardness of the wear resistance of ceramic material present, in recent years, as a growing number of implant study. Nano-hydroxyapatite (n-HA) structure and chemical composition of the teeth and bone tissue is very similar, with excellent bone tissue formation induced biological activity and biocompatibility, is widely used in the repair of bone defects. Nano-hydroxyapatite as titanium implant surface modification of materials has been to improve the focus of implant osseointegration, but there is no breakthrough. Zirconia matrix, application of nano-hydroxyapatite surface modification is a worthy cause concern, in order to improve the biological activity of the implant study provides a new way. In this study zirconia ceramic matrix, nano-hydroxyapatite ceramic coating material as its binding, choose a different sintering temperature, by detecting the level of its bond shear strength, screening the best sintering temperature, for further study provides the basis and foundation.Methods:Experiment one preparation of nano-hydroxyapatite paste:sol/gel technology, polyvinyl alcohol powder and nano-hydroxyapatite powder mass fraction of 1:4 blend into the beaker, slowly adding the mass fraction of 10% acetic acid solution, stirred with a magnetic stirrer for 5 hours until the powder was completely dissolved and gelled to prepare nano-hydroxyapatite slurry.Experiment two specimen Preparation and sintering bonding:homemade mold fixed zirconia body surface, layered nano-hydroxyapatite slurry evenly filled within 20 paraffin oil painting die, 80? constant temperature drying for 10 minutes, remove mold, were randomly divided into four groups, respectively, into the zirconia crystal furnace, sintering temperatures of 1300?,1400?, 1500?,1550?, sintering to the specified temperature after 4 hours incubation, with the furnace cooling. After removing with a vernier caliper (accuracy 0.02 mm) was measured after sintering surface area of the bond between the two materials.Experiment three shear experiment:four groups will make a good specimen in turn fixed to the universal dynamometer to measure the shear strength and shear strength is calculated for each group of specimens. Four experiments interfacial fracture observation:Application stereomicroscope (deleted) observed fracture and fracture type interface shear test specimens after each group.Results:1. By sol/gel technology, application of acetic acid and polyvinyl alcohol gel nano-hydroxyapatite tune Bancheng state, nano-hydroxyapatite and zirconia body can form a good initial adhesion.2.1300? nano-hydroxyapatite and zirconium dioxide shear strength (4.04±1.19) N/mm2, 1400? nano-hydroxyapatite and zirconium dioxide shear strength (6.60±0.95)N/mm2,1500? nano-hydroxyapatite and zirconium dioxide shear strength (16.511±1.93)N/mm2,1550? nano-hydroxyapatite and zirconium dioxide shear strength (80.47±19.31)N/mm2. In four specimens, the higher the temperature, the greater the shear strength,1550? group the highest shear strength. Pairwise comparison of the differences between the shear strength of the four groups was significant, including 1550? group and the other three groups, P<0.01.3. The adhesive surface fracture type specimen vast majority of interfacial fracture, and 1550? group also mixed cohesive fracture and breakage, cohesive fracture occurs at the nanometer hydroxyapatite ceramics.Conclusions:1. By sol/gel technology, polyvinyl acetate and nano-hydroxyapatite modulated into a gel state, the nano-hydroxyapatite can be more firmly bound to the surface of the zirconia body.2. The shear force test results show that between 1300? to 1550?, with the increase of sintering temperature, shear strength increasing,1550? sintered zirconium dioxide and nano-hydroxyapatite under anti-shear strength of 80.47±19.31MPa, significantly higher than the other groups (P<0.01), shows that the air as sintering atmosphere began to heat up at room temperature, heating rate of 3??4?/min, slowly warming to 1550?, heat 4h after cooling to room temperature with the furnace open, zirconia sintering process under this prepared for nano-hydroxyapatite ceramic coating the substrate with the highest shear strength.3. The adhesive surface fracture type specimen vast majority of interfacial fracture, and 1550? group mixed fracture phenomenon also occurred, indicating that 1550? nano-hydroxyapatite and zirconia sintering addition to good adhesion outside the strength, but also has a high compressive strength and hardness.4. The results show that the use of sol/gel technology, applications pressureless sintering method, according to the sintering process, the temperature of 1550 degrees, nano-hydroxyapatite and zirconia matrix can form a good bond, to the performance of the coating requirements, it is feasible to use a method for preparing a green zirconia implants n-HA coating is a technique worthy of further study. |
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