الفهرس 
acknowledgmentOnly 14 pages are availabe for public view
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Abstract
With the introduction of laser to the field of dentistry, a great attention was directed towards it’s ability to vanish completely all the intracanal microorganisms before root canal obturation in an attempt to improve endodontic treatment procedures. This study was conducted to study; the thermal effects of intracanallasing with Nd:YAG laser on the external tooth surface and to establish safe energy levels to be delivered into root canal to sterilize infected root canal. As well as studying the effect of laser irradiation on the permeability of the dentinal tubules of the root canal wall.
One hundred specimens of extracted human teeth were used. The roots were endodontically treated and divided into three main test groups. In the first group (thermal test) thirty teeth were used and temperature was measured for each outer root surface before and after at three levels (coronal, middle and apical) using a thermocouple device. The teeth were
divided into three subgroups, ten in each subgroup in which different laser sessions were used, (Two, and four sessions without irrigation and four sessions with irrigation with. NaOCL).