| Objectives:To evaluate the closure of the fixed screw holes of implant denture after using of four different Light-cured composite resins(LCRs);To observe the effects of organosilane and thermocycling on the microleakage. Methods:Eighty hollow semi-cylinders were fabricated with titanic alloy.The upper half of specimens were sintered with porcelain.Internal surfaces were sandblasted and etched.All specimens were divided into two groups respectively:one group was treated with organosilane and another not treated. After specimens bonding with four kinds of LCRs, They thermocycled or not.Then the specimens were installed into leakage apparatus.After 21 days,we draw leakage samples out from the apparatus.At last the microleakage were measured with GOD-POD methods. Results:There were significant differences in the degree of microleakage between the four kinds of LCRs(P<0.01). Statistical analysis revealed that organosilane would affect the amount of microleakage(P<0.01).There were also significant differences on microleakage between did and did not thermocycle(P<0.01).Analyzed interaction among the three interfered factors:bonding materials(A factor), organosilane disposal(B factor) and thermocycling disposal(C factor).We found that only B and C have the interaction(P<0.01).Their trend of action showed:when organosilane was disposed,whether thermocycling or not had tiny effect on microleakage (P>0.05).but when organosilane was absent, whether thermocycling or not had significant effect on microleakage (P<0.01). Conclusions:The results suggested that bonding materials were the important factor on affecting microleakage.And the microleakage could reduce if specimen interfaces were treated with organosilane.The tolerance of specimens under thermocycling was very poor.Thermocycling resulted in the higher degree of leakage.And the interaction analysis clued to: organosilane have favorable stability.It can lessen the effect of stimulative oral condition.
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