The effects of polishing and bleaching on the colour of discoloured teeth in vivo

Bleaching is an effective method for restoring the colour of discoloured vi tal teeth. Power bleaching, in particular, in which a bleaching solution co ntaining 35% hydrogen peroxide is activated by a strong light source using a plasma arc, makes it possible to bleach teeth effectively in a short time . The purpose of this study was to determine how polishing or power bleachi ng the tooth surface affects tooth colour. The subjects selected were patie nts who had slightly discoloured teeth. The colour of precisely identified sites on six anterior teeth was measured before treatment, after polishing and after bleaching, to ascertain changes in colour. The measurements revea led that tooth colour changes slightly after polishing, but it shows a much greater change after bleaching, and that the post-bleaching change in toot h colour was caused both by elevation of lightness and reduction of yellown ess. They also revealed that the colour difference between pre-treatment an d post-bleaching does not depend on the type of tooth. These results sugges ted that power bleaching is an effective technique for improving slightly d iscoloured vital teeth, regardless of the type of tooth.