Internal bleaching of teeth: an analysis of 255 teeth

Abstract Background: Studies about bleaching have not analysed factors that affect the outcome. This aim of this study was to analyse the outcome of, and the factors associated with bleaching. Methods: Internal bleaching was done on 255 teeth in 203 patients. Colour was assessed pre‐operatively, postoperatively and at recalls. The cause and type of discolouration, number of applications, bleaching outcome, and colour stability were assessed. Results: The most common teeth were upper central (69 per cent) and lateral (20.4 per cent) incisors. Trauma was the most common cause (58.8 per cent), followed by previous dental treatment (23.9 per cent), pulp necrosis (13.7 per cent) and pulp canal calcification (3.6 per cent). Dark yellow and black teeth required more applications of bleach than light yellow and grey teeth. Colour modification was “good” (87.1 per cent) or “acceptable” (12.9 per cent). Teeth restored with glass ionomer cement/composite resin had good colour stability, but this was less predictable with other restorations. No teeth had external invasive resorption. Conclusions: Bleaching endodontically treated teeth was very predictable, especially for grey or light yellow discolourations. Glass ionomer cement/composite restorations were effective at preventing further discolouration. Patient age and tooth type did not affect treatment outcome and no cases of external invasive resorption were observed.