الفهرس 
acknowledgmentOnly 14 pages are availabe for public view
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Abstract
Acid etching has been the conventional method to promote adhesion for many years and untill nowadays. Recently , current intersets are devoted towards finding new methods of enamel etching.
In the present study, two types of laser etching (Super pulsed CO2 s ,Pulsed Nd YAG lasers) and Argon ion beam etching methods were compared to conventional phosphoric acid etching and they were evaluatcd via:
(i) SEM photomicrograph of enamel buccal surface after etching to determine the morphological changes associated with the different enamel conditioning methods
(ii) SEM photomicrograph of bucco-palatal longitudinally sectioned etched teeth to determine the extension of enamel tags
(iii)SEM photomicrograph of enamel buccal surface after debonding to study the integrity of enamel surface.
(iv)Evaluation of the the tensile bond strength of the four etched groups and determination of their failure sites.