Fluoride varnish or remineralizing pastes can be used after whitening to reinforce enamel

https://www.mediafire.com/file/09bysq6f7vq1hxg/pdf-56509-33817.pdf/file

Fluoride varnish or remineralizing pastes can be applied after whitening to enhance enamel and decrease level of sensitivity while keeping your brighter smile.