Fluoride varnishes are available in different flavours which can be advantageous when treating younger patients.
Fluoride trays filled with fluoride foamThey do not have the bitter taste of some fluoride gels
They are easily and quickly applied.
They dry rapidly and will set even in the presence of saliva.
Because they do not require the use of fluoride trays they are suitable for use in patients with a strong gag reflex.
Due to the small amounts used and the rapid setting time there is only a small or negligible amount of fluoride ingested.
Application requires very little equipment and so it can be applied in settings where a dental operatory is not available.
It has a sticky consistency which helps it to adhere to the tooth’s surface thereby allowing the fluoride to stay in contact with the tooth for several hours.
Based on published findings, professionally applied fluoride varnish does not appear to be a risk factor for dental fluorosis, even in children under the age of 6. This is due to the reduction in the amount of fluoride which may potentially be swallowed during the fluoride treatment because of the small quantities used and the adherence of the varnish to the teeth.

Disadvantages

Due to the colour and adherence of most fluoride varnishes they may cause a temporary change in the surface colour of teeth as well as some filling materials. As the varnish is worn away by eating and brushing the yellowish colour fades.