ROLE OF CEMENTOENAMEL JUNCTION ON THE RADICULAR PENETRATION OF 30-PERCENT HYDROGEN-PEROXIDE DURING INTRACORONAL BLEACHING IN-VITRO

Intracoronal bleaching of nonvital teeth with 30% hydrogen peroxide is occasionally associated with external cervical root resorption. The e xact mechanism by which bleaching induced root resorption occurs is no t yet fully understood. The relationship of cementum to the enamel at the cementoenamel junction may have clinical significance. Seventeen s ingle rooted human mandibular premolars extracted atraumatically for o rthodontic reasons were used. The radicular hydrogen peroxide penetrat ion in each tooth was measured in vitro by an indirect colorimetric me thod. Thereafter, the teeth were examined with a scanning electron mic roscope to determine the type of the cementoenamel junction. It was fo und that the radicular penetration of 30% hydrogen peroxide was relate d to the type of cementoenamel junction.