The effect of sodium hypochlorite on shear bond between composite and porcelain specimens

Aim of Study : This in vitro study was conducted to evaluate the shear bond strength of intra oral por-celain repair system using 10 % sodium hypochlorite and different acid etch. Materials and methods : Forty specimens were prepared in form of metal disks (8mm in diameter, 15mm height) and porcelain was applied according to the manufacturer instructions. The specimens randomly divided into 4 equal groups. In Group I, II the samples were treated with 9 % hydrofluoric acid for one minute. While groups III, IV were treated with 37 % phosphoric acid for one minute, after washing the specimens with water and dryness, groups II, III the surfaces treated with 10 % sodium hypochlorite for one minute while group I and IV leaved untreated. After that, the surfaces of all samples were washed and dried and silane coupling agent (MonoBond-S Vivadent, Liechtenstein) was applied according to the manu-facturer instructions, then bonding agent (Excite) (Vivadent, Liechtenstein) and composite (tetric N–ceram) (Vivadent, Liechtenstein) were applied according to the manufacturer instructions. All the sam-ples were stored in normal physiological saline for 7 days. Then the samples were the rmocycled ma-nually between two water baths After that Shear bond strength was tested using universal testing ma-chine. Results : using ANOVA and Duncan’s multiple range tests. The result showed that there was highly significant difference between groups treated with 10 % sodium hypochlorite with untreated one. There was significant difference between samples acid etched using hydrofluoric acid with those etched with phosphoric acid. Conclusions : Sodium hypochlorite and hydrofluoric acid significantly increase the shear bond strength between composite resin and porcelain fused to metal specimens. الأهداف : الهدف من هذه الدراسة هو قياس الربط القصي بين مادة الخزف و مادة الراتنج الكمبوزنت المستعملة في ترميم التيجان و الجسور الخزفية باستخدام 10% صوديوم هيبوكلورات و حوامض مختلفة. المواد و طرائق العمل : تم تحضير 40 قرص من المعدن بقطر 8 ملم و ارتفاع 15 ملم و تم إضافة الخزف حسب تعليمات الشركة المصنعة. قسمت العينات عشوائيا إلى أربعة مجاميع متساوية تم معاملة عينات المجموعة الأولى و الثانية (بحامض الهايدروفلوريك بتركيز 9%) لمدة دقيقة واحدة في حين تم معاملة المجموعتين الثالثة و الرابعة (بحامض الفسفوريك بتركيز 37%) لمدة دقيقة واحدة بعد غسل العينات بالماء و تجفيفها عوملت المجموعتين الثانية و الثالثة (ب 10% صوديوم هيبوكلورات) لمدة دقيقة واحدة في حين تركت المجموعتين الأولى و الرابعة بدون معاملة بعد ذلك تم