الفهرس 
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Abstract
Purpose : To evaluate the bond strength to machinable glass ceramic using conventional silane and multipurpose primer after different surface treatments to composite build up. Materials and methods: A total of 64 lithium disilicate IPS e.max CAD ceramic specimens with dimensions (length=13 mm, width=10 mm and thickness=3mm) were fabricated using milling technology, the specimens were equally divided into 4 main groups (n=16) according to the method of surface treatment as follow, group I: Polished, group II: Acidulated phosphate fluoride (APF) application, group III: Hydrofluoric acid (HF) application, group IV: Monobond Etch & Prime (MEP) application. Each main group was further equally subdivided into 2 subgroups (n=8) according to methods of chemical bonding. Subgroup (A): Conventional silane. Subgroup (B): Multipurpose primer. Composite resin disc (master fill) were fabricated and cemented to the treated ceramic specimens by multistep adhesive resin cement. All bonded specimens were stored in water bath for 5 months and subjected to 10000 thermalcycles. Shear bond strength (SBS) test was performed afterwards. Scanning Electron Microscope (SEM) was used for specimens examination. Results : The statistical analysis were done using two-way ANOVA and serial one-way ANOVA followed by Post Hoc Tukey-HSD test at α =(0.05). Application of multipurpose primer significantly increased SBS (P=0.001). The highest SBS mean value was obtained for APF with multipurpose primer (14.8 ± 2.2 MPa) followed by Monobond Etch & Prime with conventional silane (14.7 ± 2.8 MPa) On the other hand, APF with conventional silane showed the lowest SBS mean value (4.6 ± 2.0 MPa). There was statistically significant difference between polished and APF considering conventional silane and multipurpose primer, and no statistically significant difference was reported between HF and Etch & Prim for conventional silane and multipurpose primer. Conclusions : Multipurpose primer showed a superior bond strength in comparison with conventional silane when used for lithium disilicate IPS e.max CAD ceramic bonding regardless the type of surface treatment. Also, Monobond Etch & Prime could be used instead of HF acid etching and silane application. Micromechanical and chemical bonding are mandatory to achieve a durable bonding to IPS e.max CAD.