Incidence of invasive cervical resorption in bleached root-filled teeth.

Invasive cervical resorption, a form of external root resorption, has been reported to be associated with intra-coronal bleaching of root-filled teeth and this has raised concerns about carrying out such bleaching procedures. The purpose of the present study was to examine the incidence of invasive cervical resorption in root-filled teeth which had been bleached using a standardized technique. Three observers examined records and radiographs from a total of 158 patients, whose bleaching treatment had been carried out in a specialist endodontic practice. The sample comprised 204 teeth with a review period of between 1 and 19 years. One-hundred-and-fifty-one teeth (77.94 per cent) had an associated history of traumatic injury. All teeth had been treated with a combination of thermocatalytic and 'walking bleach' procedures using 30 per cent hydrogen peroxide. In 54.41 per cent of teeth, gutta-percha and AH26 root-fillings were kept at the height of the cemento-enamel junction while 18.63 per cent were below and 26.96 per cent were above the CEJ. Sealing cement was not placed over the gutta-percha and AH26 root-fillings in any of the teeth in the study. It was found that a total of four teeth from the sample group (1.96 per cent) had developed invasive cervical resorption during the review period. All of these teeth had a history of traumatic injury and the level of gutta-percha was at the CEJ.(ABSTRACT TRUNCATED AT 250 WORDS)