Fluoride varnish or remineralizing pastes can be applied after whitening to enhance enamel

https://milowbea115.theburnward.com/do-whitening-strips-in-fact-work-a-dentist-s-viewpoint

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