In Vitro Study On The Effect Of Bonding Property Between The Ceramic Inlays And The Teeth After Treated By Different Lasers

With the development of bonding technology and the increasingly aesthetics demandingby the patients, the ceramic inlay/onlay is widely applied in the restoration of the teethlesions. The bonding strength between the surface of the teeth and inlay/onlay is one of thekey factors of the deciduous of the restorations, which will affect the durability of theinlay/onlay, prevent the microleakage and secondary caries on the margin of the inlay/onlay.In the past few years, one of the favorite topics concerned by the dentists is how to improvethe bonding property and increase the durability of the inlay/onlay.The rapid development of the laser technology provides a new idea to solve theseproblems. The surfaces of the teeth and inlay/onlay will be roughen enough to increase thebonding area and improve the bonding strength. But the studies on this method were rarelyreported. In these research works, three different types of lasers were applied to pretreat thesurfaces of the teeth and the inlay/onlay, and the bonding strength and property of therestorations were evaluated. The results will provide a certain theoretical foundation for the choices of bonding methods in the clinical work.In these research works, the fitting surfaces of the extracted human teeth and inlay/onlaywere pretreated by810nm and980nm wavelength diode laser, water laser and acid etching.The effects of bonding property between the dentin and the inlay/onlay were evaluated bythe SEM and shear strength tests, and the effects of the adaptation between the teeth andinlay/onlay were investigated by the microleakage test.The results of these research works indicate as the following:1. Different sizes of micropore can be found on the surfaces of ceramic inlay/onlay treatedby hydrofluoric acid and810nm diode laser by SEM, which would benefit to the resinbonding; there were also significant changes on the dentin treated by water laser and810nmdiode laser.The results of SEM analysis showed that the dentin surface had been roughensignificantly and the dentin tubule was opened.2. The results of artificial simulated aging test showed that: the shear bond strengthsbetween the dentin and inlay/onlay in the groups of phosphoric acid,water laser,810nm and980nm wavelength diode laser and control group were1.19±0.93MPa、6.64±3.72MPa、2.33±1.16MPa、2.01±1.97MPa、1.03±0.64MP respectively.There was siginificantdifference between the water laser group and the other groups. It can be concerned that thebonding strength between the fitting surfaces of ceramic inlay/onlay and the teeth wasimproved significantly after treated by water laser.3. The results of microleakage between the ceramic inlay/onlay and teeth after the dentintreated by different etching were that: control group is0.92±0.25mm,phosphoric acid is0.66±0.34mm,810nm wavelength diode laser is0.94±0.17mm,980nm wavelength diodelaser is0.82±0.21mm, water laser is1.01±0.26mm.Only the water laser group hadstatistically significant higher microleakage than the phosphoric group(P <0.05);There wasno significant statistical difference between other groups(P>0.05).On the gap width,nostatistical differences were found(P>0.05).