To examine the correlation between bleaching and external resorption
- N = 11 previously treated and bleached teeth, 10 of which were traumatized
- Teeth were endodontically treated and the pulpal chamber was filled with cotton pellets soaked in
- 30% oxygen peroxide and repeated at 10/15 days. Upon completion of the bleaching treatment, the cavities in all teeth were sealed with only a silicate cement
1 tooth returned in 6 weeks later with external resorption. The rest showed resorption within 12 months and 2 showed ankylosis
Oxygen peroxide can injure the periodontal tissue and cause resorption and ankylosis by allowing bacteria to penetrate dentinal tubules
If this procedure is used, the orifice of the root canal should be covered, e.g. with a zinc-oxide eugenol cement, in order to prevent oxygen peroxide from reaching the root dentin.