| Objective：In recent years, the all-ceramic crown increasing applicate in prosthesis.Butbacause the metal post-core color problems will affect the aesthetic effect ofall-ceramic crowns and some metals have the problem of affecting bio-safety andMRI imaging results, its application is restricted;The fiber post due to poor fractureresistance does not apply to repair the abutments of large tooth structure defects andlarger bite force. The zirconia post both aesthetic effects, mechanical strength,but alsohas a bio-security, attention in clinical applications.But because the zirconia ceramicssurface does not contain the silicon, and it can’t be acid corrosion, so the bondstrength with resin luting cement is poor. The purpose of this study is to investigatedthe effect of different surface treatment methods on zirconia post to enhance the bondstrength of zirconia post and resin luting agent.Methods：1.Teeth collection: The collection of forty-five mandibular premolars of theStomatological Hospital Affiliated to Nanchang University between March1,2011-April1, freshly extracted due to orthodontic reasons (informed consent ofpatients).The inclusion criteria: simple root canal, no wedge–shaped defects,caries-free, no cracks, no absorption, more direct root morphology and root canalmorphology is basically the same. All extracted teeth with0.1%thymoldisinfection,stored in3℃freezer.2. The teeth of prepared according to post space and zirconia posts wererandomly divided into three groups(n=15). Group A treat as: airborn sandblasting+silane coupling agent treatment; group B:airborn sandblasting+30%silicone coating+silane coupling agent treatment; group C: airborn sandblasting+mesoporous silicacoating+silane coupling agent treatment.3. Use resin luting agent bonding the zirconia post of finished surface treatmentinto the teeth which have prepared post space. Medical hard issue cutting machine cross cut each specimen into2mm height of slices. The height was used verniercaliper for height measurement, control error in within0.01mm.4.Thermal cycling treatment: All specimens were immersed in artificial saliva at37℃for24h, then thermocycled for500cycles at5℃and55℃, each temperaturestayed30s,interval10s.5. Push-out test: The specimens fixed on the universal testing machine byprecision lathes mechanics, adjust the load head direction perpendicular to the postcross-section, control the loading speed of0.5mm/min, record the maximumspecimens damaging load, calculate each specimen zirconia post in the bonded areaof truncated, shear strength=maximum failure load/bonding area.6. Each of group took out five specimens before push-out test, sprayed goldplated film and observed the microstructure of zirconia post/resin luting cementinterface under a Scanning electron microscopy (Scanning electron microscope, SEM)1000times and3000times.7. Stered microscope observed the specimen fractures in bond failure mode.Results：1.Group A(airborn sandblasting+silane coupling agent processing) as a controlgroup, the rest of the group B(airborn sandblasting+30%silicone coating+silanecoupling agent) and group C(airborn sandblasting+mesoporous silica coating+silane coupling agent) as the experimental group. The bond strength of control groupis less than the experimental group. There were statistically significant differencesconcerning the bond strength results between control group and experimental group(P<0.05).There were also statistically significant differences in experimental groups(P<0.05), and there were significant statistical differences between group A and groupC(P=0.000).2.The thickness of resin luting cement will affect the bond strength. The bondstrength will decrease when the thickness is thicker.3.Scanning electron microscopy (SEM) indicate that the zirconia post afterairborn sandblasting treatment, the surface appear some cracks,clearly the boundariesinterface between the zirconia post and resin luting cement; the crack reduce in group B,the bonding interface can still be identified; group C basically no crack found,zirconia post/resin luting cement bonding interface happened fully merged.Conclusion：1. Airborn sandblasting will lead to appear cracks on the surface of zirconia post,the cracks will become stress concentration points,which will influence the bondstrength of zirconia/resin luting cement.2.30%silicone coating can improve the bond strength of zirconia post/resinluting cement.3. Mesoporous silica coating treatment can large extent improve bondingstrength of zirconia post/resin luting cement, the effect is better and more long time. |
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