Effect Of Veneer Repeated Firing On The Properties And Adaption Of Experimental Lithia Disilicate-based Glass-ceramic

It is known that tooth defect or dentition defect is a common disease of oral causedby caries disease, trauma, periodontal disease, seriously affecting people’s normalmasticator function and appearance beautiful, crown and bridge repair such defect or lackof more common way of repair. In clinically, the choice of the ceramic materials is varied.The popularity of ceramic restorations results from the properties of the ceramic materials,such as translucency, biocompatibility, and esthetics. Dental glass-ceramic combine theadvantages of glass and ceramic and also one of the hot areas of dental ceramic materials.Clinical promotion is limited because of high production cost. Experimental glass-ceramic is success developed in previous study. The aim of thisstudy was to investigate the mechanical property and microstructure of ELDC whichrepeated simulated layer or stain firing schedules; To compare the translucent of ELDCcore material through repeated firing; The effect of multiple firing on the marginal andinternal fit of ELDC single crowns and influence of veneer: core thickness ratio onfracture mode and strength of ELDC material, and provide experimental data for furtherclinical application.The whole studies were divided into four parts:Part one: To investigate the mechanical properties of flexural strength, Vickers andfracture toughness and microstructure of ELDC which simulated layer or stain firingschedules. It was showed that repeated firing had no influence on the mechanicalproperties and microstructure.Part two: To measure the color parameters after each firing cycle and calculatetranslucency parameter. One-way ANOVA was used to analyze the dates’(P＜0.05).Result shows that translucent of ELDC core material through repeated firing had nosignificant difference.Part three: To compare the marginal and internal fit of ELDC and IPS e.max crowns,evaluate the effect of repeated firing cycles on the adap tion, and statistically analyzed. Theadaption between ELDC and IPS e.max crowns had no significant difference. Andrepeated firing had no significant effect on the integrity adaption.Part four: The purpose of this part was to investigate the effect of veneer: core thickratio on the flexure strength and fracture mode of bilayered ELDC specimens. Resultsshowed that veneer：core thickness ratio could significantly influence the fracture mode.The flexural strength was stability for core: dentin thickness of1:1or higher.