Bond strength of aluminum oxide surface treatment on sandwich restoration

Aims : the aim of this study is to evaluate the effect of aluminum oxide as a surface treatment on shear bond strength of etched and non-etched GIC for sandwich restoration with different types of tooth colored restorations .In addition, failure type was assessed. Materials and Methods: Sixty Teflon molds (5mm diameter and 4mm height) of a chemically cured GIC were prepared. They were divided into two main groups 1st control, 2ed air-abraded with 50μm aluminum oxide particles. Both groups were sub divided into two subgroups 1st control, 2ed etched with 37 % phosphoric acid. Bonding material was applied to the treated surface of all groups and cured. The second split of Teflon mold (3mm diameter and 4mm height) was placed onto the prepared specimen Each subgroups (1st control, 2nd etched with phosphoric acid) were farther subdivided into three subgroups which entrain filled as fallow : 1st split filled with a tg micro hybrid, in 2ed split filled with tg fine glass, and in 3rd split filled with Ceram X. Shear bond strength was measured by using Universal Testing Machine, and mode of failure examined by a stereomicroscope. Results: Anova test showed that there was a highly significant difference for all variables except acid etching effect. Aluminum oxide surface treatment displays superior shear (2.280MPa). TG micro hybrid composite and Ceram X showed highest shear bond strength. Conclusions: Phosphoric acid etching did not improve shear value of sandwich restorations, while uses of aluminum oxide surface treatment, tg micro hybrid and Ceram X filling material gave an improvement on it. The failures were mainly cohesive within the GIC except tg fine glass was cohesive in filling material itself. الأهداف : لتقييم تأثير أوكسيد الألمنيوم كعلاج للسطح على قوة السندات لل (GIC) المعامل و غير المعامل بحامض الفوسفوريك للحصول على حشوة ساندويتش مع أنواع مختلفة من الحشوات البيض و لتقييم نوع الفشل. المواد و طرائق العمل : أعد ستون قالب تفلون (5 ملم قطر و ارتفاع 4 ملم) من GIC ذاتي التفاعل. و قد قسمت هذه القوالب إلى مجموعتين رئيستين الأولى بدون معاملة (قياسية) و المجموعة الثانية عوملت بأوكسيد الألمنيوم. ثم قسمت كلتا المجموعتين الرئيسية إلى مجموعتين فرعيتين الأولى بدون معاملة (قياسية) و المجموعة الثانية عوملت ب 37% من حامض الفوسفوريك. ثم وضعت المادة اللاصقة على السطح المعامل لجميع المجاميع. و وضع الجزء الثاني من قالب تفلون (3 ملم قطرها و ارتفاع 4 ملم) فوق القالب الأول و قسمت كلتا المجموعتين الفرعيتين الأولى و الثانية إلى ثلاثة مجاميع جديدة : الأولى ملأت بمادة ال (tg microhyb