The dental retractor has one main objective: to be able to access the entire dentition and gums.
It is therefore mainly used for American teeth whitening where it is necessary to apply gum barriers to protect the gums before treatment.
But in the case of cosmetic tooth whitening with 0.1% hydrogen peroxide, you use trays for the treatment. There is no need for gum barriers. Therefore, there is no need for a dental retractor. Eventually, for the comfort of your client, you can use it.