الفهرس يوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
The purpose of this study was to determine the effect of different surface pretreatments on the shear bond strength of two glass-ionomer cements to two different tooth substrates (enamel and dentin) at two different time elapsed between cement application and shear bond strength testing.
Assesement of failure mode followed shear bond strength testing was done using a modified ARI and finally a relation was done between the amount of cement remained, mode of failure, the effect of time elapsed and calcium content of tooth substrates after different surface pretreatments with shear bond strength of the two glass-ionomer cements used.
A total of 360 intact human molar teeth were used in this study. A 320 of those previously selected teeth were randomly used for shear bond strength testing, while the remaining 40 teeth were used for calcium content measurements.
For shear bond strength testing, the 320 teeth were divided into two main groups (of 160 teeth each) according to the type of restorative material used, namely M1 for group of teeth received conventional glass-ionomer cements, M2 for group of teeth received resin-modified glass-ionomer cements. Each of the previously mentioned group was subdivided into two sub-groups (of 80 teeth each) according to tooth substrate, A1 for enamel and A2 for dentin. Each of the two subgroups was further divided into four divisions (20 each), representing different surface pretreatments, normal saline (T1), 10% polyacrylic acid (T2), 35% phosphoric acid (T3) and non-rinse conditioner (T4).
After that, each of the four divisions was subdivided into two subdivisions (10 each) according to the time elapsed between cement application and shear bond strength testing namely S1 (10 minutes after material application) and S2 ( 48 hours after material application).
Assessment of shear bond strength was done using a universal testing machine. An occlusogingival load was then applied to the bonded restoration producing a shear force at the restoration-tooth interface until failure occurred.
After the shear bond strength test was completed, the debonded surfaces for each group were evaluated in a random sequence for the amount of cement remained on the surface using stereomicroscope under a magnification of 20X. The images were subjected to image analysis and then modified ARI were categorized as 0 to 5 scores.