Experimental Study On The Effects Of Porcelain Etching Agents On The Bonding Performance Of Porcelain

With more and more intensive studies, bonding techniques today are widely used in every branches of dentistry. Now porcelain materials have been playing a decisive role in clinical procedures. The development of porcelain restorations has two important stages: the metalloporcelain restoration and all porcelain bonding restoration. All porcelain bonding restoration today are widely used in dentistry for its good esthetic character and biocompatibility of the porcelain materials. All these should owe to the constant introduction of new adhesion strategies and evolution of adhesive systems. We usually use composite resin adhesive for attaching porcelain restorations to teeth or repairing the fractured porcelain of a metalloporcelain restoration. Successful bonding between porcelains and resins is the key factor for the practice of all porcelain restorations.The reasonable and valid surface treatment techniques ofporcelain materials are element of first importance between porcelains and resins. There are some commonly methods of surface treatment, including roughening with bur, sandblasting, laser irradiation, etching and silane coupling agent treatment etc al, among which etching is the most effective factor. Etching can rough porcelain surface, improve the wetting of porcelain surface. Hydrofluoric acid (HF) etching combined with coupling agents can improve bond strength between porcelains and resins more effectively. The different concentrations of HF and different etching periods have obvious influence to porcelains and resins. In the study, we choose three concentrations of HF and some additioners to make out A, B, C types porcelain etching agents. The effects of concentrations of HF and different etching time, silane couping agents as well as their combinations on the bond strength between porcelain and resin were compared. Meantime, we use scanning electron microscopy (SEM) to observe microstructure of porcelain surface after HF etching for six periods to explore most suitable bonding concentration-time point .The main findings of this study are as follows:1. Porcelain etching agent can generate mechanical resistent structure to improve the bonding between porcelain and composite resin. The concentration and etching period of HF can significantly influence the bonding between porcelain and composite resin.2. The best mating points of three etching agents are 2.5%-150s, 6%-120s and 10%-30s. Type C etching agent (10% HF) can generate the highest bond strength at 30s. This etching agent can be used in clinic for all porcelain restoration surface treatment.