Zirconium oxide ceramic has excellent mechanical and mechanical properties, good biocompatibility, stable properties, good aesthetic effects and other metal and The advantages that ceramics cannot possess at the same time have attracted the attention of scholars in the dental field and have been widely used in clinical dental crown restoration, implant and abutment restoration, etc. However, its long-term repair effect is not as good as that of metal restorations, and the main clinical problem is poor retention. This is mainly because zirconia is an inert material with very little silicate and glass phase on the surface, so its bonding effect with teeth is poor. In order to solve this problem, many scholars have done a lot of research, mainly starting from changing the surface properties of zirconia ceramics, increasing surface roughness, and developing better adhesives.
1 .Change surface properties
1.1Glaze
Glazing is a method of applying glaze (a low-melting ceramic) to the surface of zirconia ceramics. The surface of zirconia ceramics after glazing is a feldspathic ceramic material, which can be treated with hydrofluoric acid or silane coupling agent. Studies have shown that glazing combined with hydrofluoric acid and silane coupling to treat the surface of zirconia can greatly improve the bonding effect between zirconia and adhesives. There are also reports in the literature that after glazing, the bonding strength between the hydrofluoric acid treatment group and the sandblasting group for yttria-stabilized tetragonal zirconium dioxide and resin adhesives is equivalent.
Since this is a recently proposed new technology, there are few studies on the impact of hydrofluoric acid treatment on the bonding effect after glazing the zirconia ceramic surface.
1.2< span style="margin: 0px; padding: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); font-family: arial, helvetica, sans-serif;">Silicon coating< /span>
Silicon coating, i.e. oxidation The zirconium surface is covered with silicon, allowing the zirconium oxide ceramic to react with the adhesive to form chemical bonds. Silicon coating treatment can increase the hydrophilicity of the zirconia ceramic surface and increase its bonding durability. Methods for preparing silicon coating onto the surface of zirconia include chemical friction, sol-Gel method and plasma spraying method. Among them, the sol-gel method is more economical, simple to operate and has better bonding effect than the other two types of technologies. Stronger advantages.
1.3< span style="margin: 0px; padding: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); font-family: arial, helvetica, sans-serif;">High pressure spray coupling agent
High-pressure spray coupling agent is under the action of pressure The zirconium-ceramic coupling agent is dispersed into fine droplets and evenly dispersed on the ceramic surface. However, different zirconium-ceramic coupling agents have different compositions and physical and chemical properties, which will affect the bonding strength of zirconium dioxide. Wang Chen et al. Applying high-pressure spraying technology to prosthodontics for the first time, he studied Cleafil Ceramic Primer and Z-PrimePlus two zirconium porcelain coupling agents on the surface morphology of zirconium dioxide and the bonding strength with resin adhesives The results show that the surface roughness of zirconium dioxide obtained by high-pressure spraying is significantly higher than that of low-pressure spraying. Cleafil Ceramic PrimerZirconium-ceramic coupling agent treatment has the highest shear resistance. However, there are few studies on this technology, and the bond durability performance is still unclear. No relevant reports
2.Increase surface roughness
2.1< span style="margin: 0px; padding: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); font-family: arial, helvetica, sans-serif;">hydrofluoric acid or Silane coupling agent treatment
Hydrofluoric acid can dissolve glass phase, destroying the silicon-oxygen bond, forming micro-grooves and pores on the surface of silicate ceramics, forming a honeycomb structure, which is conducive to forming a strong mechanical fit with the adhesive. However, zirconium dioxide is a non-silicate ceramic, and hydrofluoric acid cannot be used to form such a strong bond. Hydrofluoric acid etching alone is not suitable for surface treatment of zirconium oxide ceramics. However, composites of zirconia with other materials can be treated with hydrofluoric acid, such as zirconia-reinforced lithium silicate ceramics (ZLS), it has glass phase silicon-oxygen bonds on its surface, and treatment with hydrofluoric acid can make the surface Becomes rougher, which is conducive to the formation of micromechanical retention force. This is a combination of surface modification and surface roughness increasing methods. Silane coupling agents are similar to hydrofluoric acid and are often used as surface treatment agents for silicate ceramic materials. Zirconia ceramics are non-polar surfaces that lack Si-OH groups and cannot form chemical bonds with traditional silane coupling agents, so Poor adhesion.
However, studies have shown that silane coupling agent combined with sandblasting treatment can improve the bonding strength between zirconia and resin, which is also a combination of surface modification and surface roughness increasing methods.
2.2< span style="margin: 0px; padding: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); font-family: arial, helvetica, sans-serif;">Sandblast
Sandblasting can remove the stain layer on the surface of zirconium dioxide ceramics, making the surface rough and increasing the bonding area , increase the bonding force. Many studies have shown that sandblasting can significantly improve the bonding strength and bonding durability between ceramics and resin. However, some scholars believe that the surface roughness caused by sandblasting is related to the bonding strength and bonding durability. There is no positive correlation with the properties. Experiments by Zhang Hong and others also show that sandblasting has limited improvement in bonding strength and has no effect on bonding durability. However, there are also many documents showing that sandblasting can cause damage to the ceramic surface and affect the bonding strength. The bonding effect will be damaged and the physical properties of zirconium dioxide ceramics will be damaged. On the whole, the advantages of sandblasting outweigh the disadvantages, and it is one of the more certain surface treatment methods in clinical practice.
2.3Thermal acid etching
Thermal acid etching technology is a new technology that has been applied to the surface treatment of zirconium dioxide in recent years. Its mode of action is similar to the effect of hydrofluoric acid on silicate ceramics to a certain extent. By improving the bonding strength between zirconia and tooth enamel, it achieves stable bonding durability between zirconia ceramics and resin adhesives without significant impact on the compression and flexural strength of zirconia. Studies by Lu Pin and others have shown that the bonding strength after hot acid etching is much higher than that after sandblasting, and the durability is better. However, whether this technology will affect other physical properties of zirconia ceramics needs further study.
2.4< span style="margin: 0px; padding: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); font-family: arial, helvetica, sans-serif;">Laser etching
Laser etching is when the laser beam When the material surface is irradiated, after the material absorbs the transmitted photoelectric energy or photothermal energy, it will be compressed, melted, evaporated or burned, forming pits, thereby increasing the bonding effect. Studies have shown that after laser etching the surface of zirconia ceramics, its roughness and shear bonding strength increase. However, there are few studies on whether it affects the mechanical properties, aging resistance and fatigue resistance of zirconia. The lasers currently being studied include Nd:YAGlaser, Er:YAG laser, fiber laser and water laser.
2.5< span style="margin: 0px; padding: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); font-family: arial, helvetica, sans-serif;">Selectively permeable acid Eclipse
Selective penetration acid etching is The gap between the zirconium oxide particles is increased at high temperature, and the molten glass is penetrated into the particles, and then etched with hydrofluoric acid to form a strong mechanical retention force. Casucci and other studies have found that compared with the zirconia surface treated by sandblasting and hydrofluoric acid, selective penetration acid etching treatment can increase the roughness of the zirconia ceramic surface. Many studies have shown that zirconia ceramics after selective penetration acid etching can obtain strong bonding force with adhesives.
2.6< span style="margin: 0px; padding: 0px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); font-family: arial, helvetica, sans-serif;">Electrolytic etching
Electrolytic etching (EDM) The desired shape is created by eroding the material through electrical sparks in an electrolyte solution. In the past, because zirconium dioxide was a poor conductor, it could not be processed with EDM. In 2010, EDM technology was applied to zirconium dioxide surface treatment after Kucukturk and Cogun improved their equipment. Based on the research of Kucukturk and Cogun, Rona et al. further improved the EDM device. The results showed that after the improved EDM device treated the zirconium dioxide surface, the roughness was rougher than the surface obtained by sandblasting and chemical friction silicon coating. And a stronger bonding force can be obtained with the dual-curing resin adhesive Panavia F2.0, and this technology has no impact on the mechanical properties of zirconium dioxide.
