Dear doctor;

I have been using Sensodine toothpaste for a while now but some people say it has too much fluoride. What does fluoride really do and why is it harmful? How can I get toothpaste without fluoride? Safari M, Gisementi.

Dear Safari,

Sensodyne toothpaste is widely used for its property of reducing sensitivity of teeth to hot or cold. It has various ingredients such as sodium lauryl sulphate, which serves as a cleansing agent by mixing oil and water so it can be rinsed well. Glycerin present imparts texture and a pleasant sweet taste, although not meant to be eaten but provides some calories also. Sodium fluoride prevents tooth decay and erosion. However, in large quantity, fluoride is not safe for health. Apart from teeth, it may affect other cells as well. It can cause bone disorders, thyroid problems, low intelligence, among others. There can also be discoloration and breakage of enamel of teeth. As such most of the tooth pastes contain fluoride within the safe limits of maximum 1,500ppm, hence are safe for adults.  One has to be cautious while using these type of tooth paste for small children as they tend to swallow paste or eat it if they like the taste.