How white should your teeth actually be?

You don’t have to look far to find seemingly perfect white smiles — especially if you spend time on social media.

It may have you second-guessing the appearance of your own teeth in the bathroom mirror.

But there are many variations of what is considered “natural” white.

How our teeth appear in the mirror, or even in photos, may not be an accurate picture of their true colour, according to experts.

Unsplash / A.C.

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So how white should our teeth actually be and why do the front teeth usually look whiter?

How white should our teeth be?

Monica Farrelly, oral health promoter from the Australian Dental Association, Sydney/Gadigal land, says there is “no definitive measure” of how white our teeth should be.

“When we’re looking at doing whitening, fillings, crowns and veneers, we look at a range of shades,” Dr Farrelly says.

She says the standard shade guide that most dentists use has about 16 “normal shades” of white.

“So just like our hair, eye colour, skin colour, there’s natural variance in terms of how white people’s teeth are,” she says.

Dr Farrelly says it can be difficult for people to understand what a natural smile is because people’s teeth colour can be altered.

“I think it’s important to recognise that people do whitening at home and at dental practices,” she says.

“They might also have crowns or veneers, which cover the surfaces of the teeth and are made out of porcelain.

“And a lot of people digitally enhance their photos nowadays as well, so it’s not actually our real tooth colour.”

Teeth change colour inside and out

Tooth colour also varies with age, says Laurence Walsh, an emeritus professor from the University of Queensland’s School of Dentistry.

He says baby teeth look “unusually white” because of their mineral structure.

“Then adult teeth begin to erupt from about the age of six onwards and those teeth have a colour which is richer in yellow and red,” he says.

That internal colour of the tooth becomes more obvious because of “tiny little pipes called tubules which fill up with mineral as we age”.

“And that changes the way that light behaves as it comes through a tooth,” he says.

“So, for example, in our 50s, 60s and 70s, the teeth look fundamentally a type of yellow colour.”

Walsh says it is a “normal age-related change”, which can be sped up by any trauma or damage to a tooth.

“People who clench their teeth, people who grind their teeth, those people create small amounts of trauma, that speeds up this natural process,” he says.

Dr Farrelly says foods and drinks can also cause the surface of teeth to discolour, and this is likely what people “notice more”.

“We say anything that can stain a white shirt can stain a tooth,” she says.

“So, coffee, tea, alcohol, darkly coloured or pigmented food, smoking, that will all contribute to staining teeth.”

A person’s complexion, mirrors and lighting can all affect how teeth colour appears. (file image)

Unsplash / Getty Images

Are white teeth a sign of a healthy mouth?

While white teeth may be aesthetically pleasing, our experts say they are not a guaranteed sign of oral health.

“Teeth are 3D in nature, so when we’re looking at just the colour, we’re probably looking more at the front surface of the teeth,” Dr Farrelly says.

“Colour alone doesn’t show us if there’s any cavities or decay, if there’s any issues with the gums, if there’s any infection below what we can see on the surface.”

Why do my front teeth look whiter?

Walsh says this is likely due to the “perceived colour” of a tooth, not the true colour.

“Perceived colour is affected by the frame [around the tooth],” he says.

“Someone who’s got lipstick on versus no lipstick, the tooth appears to be lighter and brighter, because now we’ve put a frame beside it that is darker.”

He says another “sneaky thing” that sometimes confuses people’s perceptions is mirrors and lighting.

“The silver reflective layer in a mirror absorbs some violet and blue light, meaning things that are reflected off the mirror are always more yellow than they really are,” he says.

“Then you’ve got your house lighting, which is already rich in yellow.

“Then you’re looking at this reflection in the mirror thinking, ‘Gee, my teeth look a bit yellow.'”

He says in reality if you went out into sunlight, “your teeth aren’t as yellow as you think — you’ve been influenced by the colour environment”.

What to do if you are worried about tooth colour

If you are worried about the colour of your teeth and you are considering at-home whitening, our experts recommend you consult with a dentist first.

“The dentist is assessing if your teeth are healthy foremost and if it’s suitable to have the whitening because we don’t want to whiten holes or decay, for example,” Dr Farrelly says.

If you can afford to have a dentist do the whitening, “they also custom-fit the trays so that you don’t get burns of the gums or whiten exposed roots, which will result in sensitivity.”

Walsh says dentists can also clean all the external stains off the teeth first.

“Not only does that give us the true colour, but it removes those stain materials that are also antioxidants,” he says.

“So, if you put peroxide on top of those, they chemically fight the action of the bleach.”

This article contains general information only. You should consider obtaining independent professional advice in relation to your particular circumstances.

– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand