Whiten teeth with baking soda and lemon juice? No, mixture can damage enamel

Facebook posts doing the rounds in South Africa and Nigeria claim that readers can simply whiten their teeth at home with a mixture of baking soda and lemon juice.

“We used baking soda and lemon to whiten our teeth at home,” one post reads.

“This easy hack for whitening your teeth apparently works in just two minutes,” says another.

Some posts suggest adding a banana peel to the mixture, others claim that readers should add cloves. 

Other posts even suggest adding normal toothpaste, but all of them suggest the mixture of lemon and baking soda.

Baking soda, also called bicarbonate of soda, is pure sodium bicarbonate. Baking powder is bicarbonate of soda with a powdered acid added to it.

Africa Check has previously debunked false claims about home remedies for cleaning or whitening teeth. 

But is this simple mixture the answer to stained teeth? We investigated.

Some tooth discoloration is unavoidable

Discoloration, staining or darkening of the teeth is sometimes unavoidable with ageing, trauma or disease, Cleveland Clinic, a non-profit academic medical centre in the US, explains.

There are other causes that cause tooth discoloration that are preventable, such as smoking and poor oral hygiene.

Certain foods can also leave your teeth stained or discoloured. For example, tomatoes in pasta sauce and berries contain pigments that stain the surface of your teeth as they cling to tooth enamel, says Colgate, a US oral hygiene brand.

Tooth enamel covers part or all of the crown of the tooth and is the hardest tissue of the body.

Lemon juice can cause tooth erosion 

Several studies have noted that tooth enamel begins to gradually wear away from continuous contact with acids with a lower pH than around 4.5.

The pH scale measures how acidic or alkaline (basic) something is. The scale ranges from zero to 14, with seven being neutral. The lower the pH, the more acidic it is, whereas a higher pH indicates a base.

Lemon juice lies within a range of two to three on the pH scale, making it highly acidic. 

Continuous use of lemon juice and baking soda mixtures to whiten teeth may erode the tooth enamel, leading to tooth sensitivity and decay.

The UK’s National Health Service advises that those seeking teeth whitening should visit their dentist.

“Teeth whitening is a form of dentistry and should only be carried out by a dentist or another regulated dental professional, such as a dental hygienist or dental therapist,” the NHS says.