TY - JOUR ID - TI - Effect of different metal surface treatments and thermocycling on shear bond strength and microleakage of the flexible acrylic at Co/Cr interface AU - Ghazwan AA AU - Nabeel AH نبيل عبد الفتاح هاطور PY - 2011 VL - 23 IS - special issue SP - 10 EP - 14 JO - Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد SN - 18171869 23115270 AB - Background: Optimum bond strength at the valplast nylon (V.N.)-Co/Cr interface of a prosthesis is essential for thesuccess of that prosthesis. The junction between metal alloy and resin is an area of clinical concern. The aim of studyevaluation of the effect of different metal surface treatments and thermocycling on the shear bond strength andmicroleakage at the V.N.-Co/Cr interface.Material and method: A total No. of 140 samples were prepared and divided into two main groups according to thetype of test carried out. Group {A} referred to the metal samples of microleakage test which consists of 60 metalsamples, which were then subdivided into two groups; each one consists of 30 metal samples, according to thenumber of thermal cycles: (A1 subjected for 1000 thermal cycles and A2 for 3000 thermal cycles). Samples of eachgroup were then subdivided into three subgroups; each one consists of 10 metal samples, according to the type ofsurface treatment that was applied. Each group either had an air abrasion (A1a and A2a) or application of metalbonding agent (Metal Primer) (A1P and A2P) or combination of air abrasion and Metal Primer application (A1C andA2C). Each metal sample was divided into experimental half which received one type of surface treatment andcontrols half which was kept untreated. Group {B} referred to the metal samples of shear bond test which consists of80 metal samples. The samples of this group were then subdivided into two groups; each one consists of 40 metalsamples, according to the thermocycling: (B1 subjected for group without thermocycling and B2 for thermocycledgroup with 1000 cycles). Samples of each group were then subdivided into four subgroups; each one consists of 10metal samples, according to the type of surface treatment that was applied. Each group was either untreated (B1Uand B2U) or had an air abrasion (B1a and B2a) or application of metal bonding agent (Metal Primer) (B1P and B2P) orcombination of air abrasion and Metal Primer application (B1C and B2C). Before thermocycling the valplast nylon wasapplied to the metal samples.Result: The results showed that the metal samples treated with metal primer II had the highest value of shear bondand lowest value of microleakage followed by the metal samples treated with metal primer II combined with airabrasion. The metal samples treated with air abrasion only had the lowest value of shear bond and highest value ofmicroleakage The results of present study showed that specimens had a reduced shear bond in comparison withthe specimens of the same treatments after different thermocycling period

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