Microleakage Between Tooth Canal Dentin And Three Cements For Bonding Fiber Post Under Dynamic Loading

The posts made by the fiber reinforcement material have been widely restored the coronal defection of endodontically treated teeth. Resin luting cements to Fiber-reinforced posts to strengthen the resistence form and the retention form.At present,resin cements had various brands, they have different effective hard to evaluate.At same time oral evironment were complicated,such as the occlusal chewing forces,the repetitive expansion and contraction stresses due to temerature changes,saliva.These factor may infuence the effect of bonding .At present,there were many research about temerature changes and saliva influence the bonding strengthen of the fiber post. Therefore the research about the chewing forces influence the bonding strengthen of the fiber post was relatively few.Thus,the study of the degradation mechanisms of dentin adhesive,it is necessary to imitate these oral chewing factors in vitro.Objects:The purpose of this in-vitro study is to compare the microleakage between tooth canal dentin and three cements for bonding fiber post under dynamic loading and to prospect three cements long-term effect.Method: A total of 30 extracted human mandibular first premolars were randomly divided into 3 groups.Three cements (C3M ESPE RelyX Luting,Super-bond C&B, 3M ESPE RelyX Unicem )were used respectively to bond fiber posts of 1.4 mm in diameter after the root canal was prepared with usual methods. The cores were made with the same resin. All the teeth were mounted in resin blocks. Loads were applied on the samples at 135 degrees and tested with fatigue test machine, which were immersed in a 0.5% basic fuchsin solution. After 10000 cycling the specimens were cut into two sections longitudinally, and then observed with stereomicroscope, and Kruskal- Waillis H test was used to analyze the results.Results: Under dynamic loading, the microleakage was observed in all the three cements for bonding tooth canal dentin.B group (Super-bond C&B) showed the least microleakage compared with the other.Three groups mean rank were respectively 7.1,22.5,15.5.The rank of A and B groups,B and C groups,A and C groups were significantly different among them ( P < 0.05 ). The statistic were respectively 37.82,11.19,7.87.Conclusion:1.There was microleakage between endodontically treated teeth canal dentin and the two composite cements under dynamic loading. Super-bond C&B showed the least microleakage compared with the other.2.Bonding to fiber-reinforced posts,Luting agent can decrease the coronal microleakage. Super-bond C&B resin cement provides bettersealing ability than RelyX Unicem luting agent·...