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

https://www.mediafire.com/file/7h9nf2cemw5vl40/pdf-54045-80957.pdf/file

Fluoride varnish or remineralizing pastes can be used after whitening to strengthen enamel and lessen level of sensitivity while preserving your brighter smile.