Tooth whitening: concepts and controversies

The cosmetic impairment oftooth discolouration, especially in the anterior region, can be treated by a number of invasive therapies such as indirect crowns and veneers, microabrasion, or by the placement of direct composite. In certain clinicalsituations,the procedure oftoothwhitening or bleaching can be employed as a lessinvasive alternative to restoration with either ceramic or composite. Bleaching of teeth can be achieved either by an external – or vital – approach (nightguard vital bleaching) (Heywood 1991), where vital teeth are bleached by direct contact with an agent such as carbamine peroxide, or by an internal – or non-vital – approach, where non-vital teeth are bleached with an agent such as sodium perborate in a walking bleach technique (Attin et al 2003). 

A third approach, which is a modification of both techniques, can be employed when bleaching vital and non-vital teeth in the same arch. This is called inside/outside bleaching (Settembrini et al 1997). The aim ofthisreviewisto discuss the concepts involved in both the vital and non-vital bleaching of teeth, and to provide advice, based on the evidence from current literature, to reduce the risks of complications and to ensure successful bleaching therapy.

Causes oftooth discolouration
Tooth discolouration may be described asintrinsic, extrinsic or a combination of both (Hattab et al 1999). It varies in appearance, aetiology,severity, localisation and adherence to tooth structure (Dahl and Pallesen 2003).