Experimental Study Of The Bonding Interface Between Different Base Material And Veneering Porcelain

Objective: with the elecrtron probe, observe the changes of chemical elementsbetween the different base material and the veneering porcelain. Analyse the patternand strength of chemical combination between the different base material and theveneering porcelain.Materials and methods: use the maxillary lateral incisor as a model,manufacture Ni-Cr alloy, zirconia, the Au-Pd alloy,press casting ceramic,Co-Cr alloy,mixed Au-Pd alloy base crown separately，and recorded as1、2、3、4、5、6group inturn. Mixed Au-Pd alloy group was added13ratios recycling old metal to the freshprecious alloy. According to the recommended procedures by manufacture, firingopaque and body porcelain on the six different base crown separately. And the thicknessof ceramic layer is controlled in2mm on the labial side. The six experimental samplesare embedded in the length4cm, width3cm and height2cm, polyether rubber moldfilled with epoxy and left stand overnight until the epoxy is solidified. Cut along thelongitudinal axis of the experimental sample with the low speed diamond saw.Grind,polish and ultrasonic clean the cut surface. The zirconia sample and press castingporcelain sample were sprayed with gold in vacuum. Then observe the interface withelectron microscopy, and analyse the situation of the elements exchange and transferwith the line scan and point scan of electron probe in the interfacial depth of about10μm.Results: Group1: Al、Si、Ni、Cr、O are detected in the Ni-Cr base crown. Al、Si penetrate into crown in the range of2μm，and meanwhile Ni Cr penetrate intoveneering porcelain in the range of2μm。Group2: Al and Si are detected in the zirconia base crown in the range of2μm,and reduce gradually from interface to deep base crown. Group3: Al、Na and Si are detected in the Au-Pd base crown in the range of1μmGroup4: There is no obvious bonding layer under the electron microscope, andthe entire crown is seamless. The bonding interface of veneering porcelain and presscasting ceramic base crown is not found.Group5:C、Si、Cr、Co are detected in the Co-Cr base crown. Si penetrated into thebase crown the range of2μm, and decrease gradually from interface to deep base crown.Cr and Co penetrated into the veneering porcelain about2μm and decreasedgradually from the interface to the veneering porcelain.Group6:Al K Fe Sn Pt Au are detected in the side of mixed Au-Pd alloy basecrown. Pt penetrated into the veneering porcelain about1μm。Conclusion: Element transfer appears between the Ni-Cr alloy, zirconia, theAu-Pd alloy,Co-Cr alloy, mixed Au-Pd alloy base crown and veneering porcelain, andthe extent of element transfer weakens until it disappears with the increase of depth.This phenomenon proves that there is chemical combination between the5kind of basecrown and the veneering porcelain during the process of firing.The interface of presscasting porcelain cronw and veneeing porcelain didn’t be found. This result illustratethat the composition between press casting crown and veneering porcelain is same.