Experimental Study Of Two Dentin Adhesives With Microtensile Strength And Durability

Purpose:Compare shanghai Nano center and 3M corresponding products with evaluation of microtensile bond strength(?TBS)and bonding durability between self-etch and etch-and-rinse adhesives.Methods:1.60 human premolars extracted for orthodontic reasons were collected for the experiment.The specimens were divided ramdomly into 2 groups and 4 sub groups(n=15),according to whether thermal cycling and types of resin cements rendered.2.Four resin cements respectively are Shanghai Nano center's self-etch adhesive(44)and etch-and-rinse adhesive(45),Easy one(EO)and Single bond2(SB).All specimens were subjected to microtensile bond strength test(?TBS)by a microtensile tester machine.3.Four resin cements after thermal cycling respectively are Shanghai Nano center's self-etch adhesive(T44)and etch-and-rinse adhesive(T45),Easy one(TEO)and Single bond2(TSB).All specimens were subjected to 5 C and 55 C on distilled water,each stays 5sec as a cycle,thermal cycle for 5000 times.Test the microtensile bond strength(?TBS).4.stereoscopic microscope images and scanning electron microscopy image of the debonding areas were used to evaluate the fracture mode.Results:1.Before thermal cycling,?TBS rate was increased from EO(26.03±2.24)Mpa to SB(35.07±3.25)Mpa.The difference of ?TBS test between 44 and EO was statiscally significant,the same with 45 and SB.2.After thermal cycling,the result of ?TBS rate,TSB was the highest,followed by T45 and TEO.Whether thermal cycling or not,The difference of ?TBS test between T44 and TEO was statiscally significant,the same with T45 and TSB.3.The bonding strength of the same adhesive was declining after thermal cycles.4.Mixed failures were the major fracture failure patterns in all groups.Conclusions:1.Comparing Nano center and 3m product,self-etch adhesive shows higher microtensile bonding strength and better durability,etch-and-rinse adhesives showed opposite result.2.Both ?TBS rate and durability showed lower in After thermal cycling in all adhesives.3.The major failure mode was mixed failures,showed relevance between microtensile bond strength and failure mode.