الفهرس 
INTRODUCTION
Causes of Tooth DiscolorationOnly 14 pages are availabe for public view
 |  | from | 114 |  |  |
| | | from | 114 | | |
Abstract
Light activated bleaching is a method of teeth whitening study has been conducted to evaluate effect of halogen light dependent apparatus which is called white light( Wla ) used in teeth bleaching on oral environment and if this widely used apparatus is actually whiten the teeth or not Currently, cosmetics and esthetics are deeply connected to white teeth and this is of major importance for the relationship people in society. Thus, dental bleaching plays an important role as an alternative therapy to reach this objective .when using this therapy; two distinct situations must be considered: vital and non-vital teeth bleaching with the application of chemicals, heat, and light on teeth surface.
With in-office bleaching discolored vital teeth can be successfully whitened by using highly concentrated bleaching regimen .A concentrated light source is then applied to the tooth surface to increase the reaction and
accelerate the decomposition of hydrogen peroxide to oxygen and per
hydroxyl free radical ,which are thought to bleach the teeth .manufactures currently produce many different types of light for use in tooth bleaching including halogen, plasma arc, light emitting diode, and diode lasers.
Aim of this study: is to demonstrate the efficiency of this apparatus in
whitening the teeth.◌ٍsubjects and methods: this longitudinal hospital based study subjects are coming for routine dental checkup. Twenty persons are selected according to inclusion criteria of subject detailed questioner of dental and medical history was taken and pH of saliva and oral temperature and gingival condition (bleeding , redness, swelling) and teeth color are recorded before exposure to the apparatus the persons are exposed to this widely used apparatus according to manufacture instruction then the parameters are recorded again to monitor any change occur due to exposure to the apparatus.