I love to have tea first thing in the morning, before I brush my teeth. But my wife tells me that this habit could in fact ruin my teeth. Please tell me she’s wrong!

There are differing opinions on whether it is best to brush before or after you eat or drink anything in the morning, but there is no conclusive evidence. However, I have to agree with your wife, and I would recommend that you brush your teeth before drinking your sweet tea or eating breakfast. Let me explain why.

Dental caries (cavities) are caused by the metabolism of food debris by the bacterial plaque (thin film coating on the surface of teeth), which produces acids that break down the tooth enamel. The effects of this acidic environment continue for almost an hour, before saliva begins to act and neutralise it.

By brushing before you eat, you minimise the build-up of bacterial plaque that can cause acid production and cavities. Also, if you use a fluoride toothpaste you introduce fluoride ions into the mouth, helping limit the damage caused by the acid.

If you brush after eating anything cariogenic – foods that can cause tooth decay – the environment in the mouth becomes acidic within seconds, and this can lead to dental issues as you could scrub away acid-softened layers of your enamel. If you brush immediately after you drink anything acidic like citrus fruit juice or soft drinks, you could cause even more damage to the enamel.

So I recommend you brush for at least two minutes before breakfast, with a fluoride toothpaste, and only rinse your mouth with water after breakfast. You can also use a fluoride mouthwash for added benefit.