Improvement Of GG Bonding Porcelain And The Studies On The Clinical Performance Of GG Porcelain

The low adhesion between titanium is mainly because the formation ofoxide film in the titanium surface. Surface modification is always used to reducethe production of TiO₂and increase the chemical combination between Ti andporcelain. The purpose of this study was to enhance the combination ofTi-porcelain through adding Sn with reducing state into bonding porcelain. Thispaper discussed the sintering parameters of the improved bonding porcelain, thereason of the increased Ti-porcelain bonding force, the effect of the color changof the improved GG bonding porcelain on the mask compatibility of GG opaqueporcelain, and the corrosion ability of the improved bonding porcelain. Alsoexperiments were carried out to determine the wear resistance and the marginalfit of the GG porcelain.Results:1. Using the thermodynamic formula to determine the percentage range ofSnX added in glass powder was about6%-11%in mass fraction. The lightmicroscopy results of the GG bonding porcelain powder showed that the powder particles were mainly at10μm. This result was consistent with the SuperPorcelain Ti-22particle size analysis results. The XRD results showed that thetypical SnX phase was found in the improved GG bonding porcelain. The threepoint bending strength results showed that the improved GG bonding porcelaincould siginificantly improve the Ti-porcelain bonding strength. The SEM resultsof debonded interfaces of the8%SnX group demonstrated that compared toother groups larger porcelain remains were observed, and the EDS showed thatthere was the highest content of silicon and oxygen particles residue. The aboveresults comfirmed that the appropriate the mass percentage of SnX added intothe glass powder was8%.The XRD results showed that there was a typicalcrystalline phase-Ti3Sn on the debonded surface, which indicated a chemicalcombination between titanium substrate and the bonding porcelain was occurred.The SEM of the sagittal section of the specimes showed the boundaries betweenTi and porcelain were not clear in the8%SnX group. Line scan analysisi foundthat Sn elements wae enriched on the interface. It was unable to identify changeby eyes on the mask compatibility of GG opaque porcelain before and after theuse of the improved bonding porcelain2. The three point bending strength results showed that the SnX with reducingstate into bonding porcelain can improve the corrosion resistance of specimens.Ti-porcelain bond strength did not change significantly in acidic saliva. But thebonding strength decreased with the increase of acid concentration and fluorideion, while after7days there were no significant changes in values of bondingstrength. The SEM results showed that porcelain residues reduced on thedebonded interface due to the erosion of the fluoride ions in acidic saliva. Andthe titanium substrate became loose and honeycomb-like. The XRD analysesshowed that hydrogen and fluorine were observed on the debonded surface. At the same time, TiH₂phase was observed on the debonded surface afterimmersion in acidic fluoride saliva, which confirmed that the weak combinationbetween Ti and porcelain is due to the brittle TiH₂formation. The bondingstrength of Ti-porcelain decreased with the increase of acid and fluoride ionconcentration and static pressure, while there were no significant changes invalues of bonding strength after14days.The SEM results showed thatimmersing in the same acidic artificial saliva ceramic residues reduced ondebonded surface as the increase of static pressure. And titanium substratebecame loose, honeycomb-like. The XRD results were similar to the previousexperiment.3. The amount of volume loss of the GG body porcelain was mostclose tonatural teeth in this experiment on experimental porcelain materials. The frictioncoefficient curve results showed that the larger friction of the GG body porcelainwas conductive to masticatory function play.4. In the two experimental groups, we found significant differences inmarginal fit between the substrate crown and fused porcelain crown. There wereno siginificant differences on marginal fit of crowns when porcelain fused. Thedifferences of the sintering parameters did not affect the marginal fit. Theincrease of the sintering times had no significant effect on marginal fit.The improved GG bonding porcelain could prevent the formation of TiO₂,and produce the chemical combination. Compared to Superporcelain Ti-22, thebonding strength of the improved GG bonding porcelain was increased by20%.It was contributed to reduce the failure rate of of the titanium ceramicrestorations and expand the clinical applications of Ti-porcelain restorations.