Letter to the Editor

We have read with great interest the article by Moghadam et al. [1] and we found the study interesting because the authors appropriately dealt with the sealing properties of the Calcium Enriched Mixture and Mineral Trioxide Aggregate used as cervical barriers during the treatment of tooth whitening. It is known that the filtration of hydrogen peroxide in the periodontal space can cause root resorptions at the cervical level [1], therefore it is important to have performed the evaluation in question. However, we would like to comment on a few methodological aspects wish might benefit futures related studies.