When to not brush your teeth is probably the last thing you would expect to hear from a dentist, but Best Young Dentist award winner Dr Shaadi Manouchehri, who offers tips and expert advice took to her Instagram account to share with her 114,000 followers this crucial bit of information.

Besides brushing teeth in the morning and evening, there are many other occassions where people would want to give their teeth and mouth a deep clean, but according to the dentist for some of those instances, doing that would actually cause more harm than good.

"These are the three times you should never ever ever ever brush your teeth because you will just damage them and end up going to the dentist to basically have new teeth, because you've worn down your teeth. And these are probably things you're doing every day because no one has told you," warns the dentist.

According to Dr Shaadi Manoucheri who has been a dentist for 10 years now, you should never brush your teeth after these three things:

1. After vomiting 

"I know this what you want to do, this is the only thing you probably want to do after you've vomited," she sympothised with her viewers. However, the dentist went on to explain that vomiting makes the mouth acidic and so going to brush you teeth straight afterwards would just wear the teeth away.

2. After breakfast

The dentist also put to bed the debate of brushing before or after breakfast, this is because when our mouth also becomes acidic when we eat, the bacteria in our mouth is also metabolising the food consumed and creating acid so when you brush your teeth straight after the acid is being rubbed all over the them.

Ending the explanation, she emphasises to viewers that "you must brush before having breakfast."

3. After eating fruit

Again, it has to do with acid and fruits are "very" acidic. They also have high sugar contents depending on what fruit you are having. The reason brushing your teeth after eating fruit is has a "similar concept" to the previous reason.

She says: "You're rubbing the acid and also the sugar. So sugar get metabolised into acid by bacetria in the mouth and it is having the same effect, so it can damage the enamel of the tooth."

Instead, the dentist advises to wait at least 30 to 60 minutes before brushing or "go in with a mouth wash straight away if you want a refresh."