Comparison Of The Bonding Strength Of Four Kinds Of Autopolymerizing Acrylic Resin To A Heat-polymerized Denture Base Resin

To compare the property of clinical commonly used auto polymerizing acrylic resin (polymethyl -methacrylate,PMMA) , as a part (component)of series research. In this study,we tested the bond strength of four Auto polymer PMMA and one Heat-cured PMMA, the data were carried on analysis and comparison. then we discussed the internal relation between bond strength and material property, to provide theoretical support for the optimizing of the combined application of Auto polymer PMMA and Heat-cured PMMA, to improve the quality of restoration and provide instruction for the clinical selection of Auto polymer PMMA material, and to complete the experimental results of this series research.Four auto polymer PMMA materials were used in this study,respectively is: Shanghai dental produced PMMA(Shanghai dental,simple type) ? Heraeus produced PMMA–Meliodent (Heraeus,fibre type)?Nisshin produced PMMA-Nature(Nisshin, fibre type)?Tokuyama produced PMMA-REBASEⅡ(TOKUYAMA, Hard-lining type)(the same Auto polymer PMMA materials as previous experiment uesd) meanwhile, wechose Hera- eus MELIODENT denture base resin (Heat-cured)as 1 Heat-cured PMMA material in this study. Using standard stainless steel mold,we manufactured the bond samples of 4 Auto polymer PMMA and 1 Heat-cured PMMA, And then we tested the bond-stretch strength of the four samples,observed the modality of the fracture surface via Asana microscope, the samples were carried on one-way ANOVA using SPSS17.0 (Chinesization) statistical software.There were no significant differences in bonding property between Heraeus Auto polymer PMMA and Shanghai dental Auto polymer PMMA(P=0.989), but significant differences could be found between the two above and Nisshin Auto polymer PMMA?Tokuyama Auto polymer PMMA(P<0.05)?The bond property comparative order of the 4 Auto polymer PMMA materials mentioned above were : Heraeus≈Shanghai dental> Nisshin>TOKUYAMA. Observed the modality of the fracture surface of the samples via Asana microscope, results show that interface fractures between the two materials were the main fracture modality(90%) in Heraeus Auto polymer PMMA and Shanghai dental Auto polymer PMMA experimental group, and there were 100%interface fractures in Nisshin Auto polymer PMMA experimental group. But there were 40% cohesion destruction in Tokuyama Auto polymer PMMA experimental group,coming from Tokuyama Auto polymer PMMA hard-lining material,the rest were interface fractures.Based on the experimental results above ,we concluded that Heraeus Auto polymer PMMA and Shanghai dental Auto polymer PMMA material had high bond strength and mostly had interface fractures in the bond destroy modality, so we considered both of them had good bond property. We preferred this two materials in the fracture of removable partial denture and complete denture base?artificial tooth break off?fall off and so on. In the hard-lining needed cases of complete denture or partial denture, if the patients'oral mucosa were not allergic to Auto polymer PMMA materials definitely,and there were no special request to the pungent smell of monomeric and exothermic process ,we could use this two materials,either. the bond strength of TOKUYAMA Auto polymer PMMA hard-lining material was poor, and existed cohesion destruction. its bond property was not ideal,although it was exclusive-using material for hard lining. In the hard-lining needed cases of complete denture or partial denture, if the patients'oral mucosa were sensitive and intolerable to the pungent smell of monomeric and exothermic process ,we could consider to use TOKUYAMA Auto polymer PMMA hard-lining material.