الفهرس 
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Abstract
This study investigated the shear bond strength of adhesive resin cement to dentin prepared with diamond and carbide instruments and cleaned from temporary cement remnants by using four different cleaning techniques.
Materials & Methods: Freshly extracted eighty sound human molars of the same age group were collected. Calculus and tissue remnants were removed with ultrasonic scaler then stored in 0.5% chloramine solution for 7 days then subsequently stored in distilled water at 4°C.
The teeth were mounted in acrylic resin blocks using a specially designed cubic split mold of (1.5x1.5x1.5cm) in order to allow their positioning on the milling machine that was used to standardize the teeth preparations. An acrylic plate was specially designed to accommodate the cubic mold and to fix the acrylic tooth block on the table of the milling machine.
All the samples were prepared with diamond stone and then half of the samples were further finished with tungsten carbide bur.
Eighty discs with 6 mm diameter and 2 mm thickness were made with a provisional restorative material (Protemp 3M ESPE, USA) to simulate provisional restorations using a teflon mold. The discs of temporary restorative material were cemented on the prepared dentin surfaces using eugenol free zinc oxide temporary cement (Provilat Promedica Dental Material GmbH, Neumunster, Germany) under static load of 3 Kg.
After one week, each temporary disc was removed from the corresponding dentin surface then the temporary cement contaminated dentin surfaces were cleaned with one of four cleaning techniques: manual scaler, OptiClean bur, Ultrasonic scaler or pumice.
Eighty composite discs were constructed using posterior resin composite filling material (Filtek Z350 3M Co. USA) to simulate the permanent restoration. The discs were fabricated using a teflon mold of smaller inner diameter (4 mm inner diameter and 2mm height). The permanent discs were then cemented on their corresponding samples using self-etch adhesive resin cement. The shear bond strength test was performed using a universal testing machine at a cross head speed of 0.5 mm/min. The specimens were loaded till failure then the load required to de-bond the specimen was recorded in Newton (N) and the shear bond strength values in (MPa) were calculated for all tested groups. Statistical analysis for the shear bond strength test results were performed using SPSS 15.0 software for Windows (SPSS Inc., Chicago, It, USA). Analysis of variance test (ANOVA) and Student’s “t” test were used to compare the results of the groups.
Results: The shear bond test results showed that cleaning the dentin samples from the remnants of temporary cement using either Ultrasonic scaler or OptiClean bur have revealed statistically significantly higher mean shear bond strength than that reported with the use of either pumice or manual scaler, with the highest resin/dentin mean shear bond strength reported with the ultrasonically cleaned dentin samples. No statistically significant difference was seen between the pumice and manual scaler groups or between the ultrasonic scaler and OptiClean groups. For all cleaning techniques; the rough samples revealed higher mean shear bond strength values than the smooth samples.
Conclusion: It was concluded that the use of ultrasonic scaler for cleaning the dentin surface from remnants of temporary cement and preparing the dentin surface with diamond stone could result in a higher resin/dentin shear bond strength compared to other cleaning techniques and surface preparations in the current study.