A new hair colour cannot change the shade of your teeth. It can change the setting your teeth are seen in, and that setting affects how white they appear to other people, to the camera and to you in the mirror. The effect is real but modest, and it is easy to mistake for a change in the teeth themselves.
Your eyes judge tooth colour by comparison
The visual system does not read colour in isolation. It compares each area with what surrounds it, so the same shade can look lighter against a dark background and darker against a pale one, or slightly warmer or cooler depending on the colours nearby. Vision scientists call this simultaneous contrast, and it is the reason a white shirt can make teeth look a touch greyer while a deep navy top can make them look brighter.
Dental research has started to measure this. In a 2010 study in the Journal of Dental Research, Lindsey and Wee showed people pairs of facial portraits in which only the colour of the two front teeth was changed. How easily viewers noticed a difference in tooth colour depended partly on which face the teeth were set in, with its different skin and gum colouring, not just on the teeth. In other words, the face around a smile changes how its colour is read.
We have written about two close relatives of this effect already: how lipstick shade changes how white teeth look, and how skin tone and a tan play the same trick. Hair works through the same mechanism, only from further away.
Hair is a weaker influence than lips or skin
Lips sit right against the teeth and skin surrounds the whole mouth, so both have a direct effect on contrast. Hair frames the face from the edges. It still shapes the overall colour impression of a face, especially in photos, but its pull on tooth colour is smaller and less predictable. We are not aware of any study that has tested hair colour and perceived tooth shade directly, so the points below are an application of general colour perception, not a measured dental finding.
Dark hair and light hair
Lightness contrast is the most reliable part of the effect. Very dark hair framing the face gives the eye a dark reference point, and pale teeth can look lighter beside it. Very light hair, including platinum, white or silver, gives a bright reference point instead, which can make the same teeth look a little less bright by comparison. Many people assume grey hair always flatters a smile. It may, depending on the shade of grey and the lighting, but the opposite is just as possible when the hair is very light.
Warm and cool tones
Beauty advice often says cool, ash or blue based tones make teeth look whiter and warm golden or copper tones make them look more yellow. The colour theory behind this is reasonable: yellow is the main tint in natural teeth, so the colours around them can either emphasise or play down that yellowness. In practice, the result depends on the exact shades, the light and the camera, and any difference from hair alone is usually small.
Framing decides where people look
Hairstyle matters separately from colour. A fringe, face-framing layers or hair worn forward around the cheeks narrow the visible part of the face, so more of the attention falls on the eyes and mouth. Hair pulled back, or a higher hairline, opens the face up and spreads attention across the forehead, cheeks and jaw, so the smile becomes a smaller part of the overall picture.
Neither is better. It simply explains why a smile can seem more noticeable after a haircut even though nothing about the teeth has changed. Facial hair works in a similar way for the lower face, which we cover in how a beard or moustache changes the look of a smile, and the brightness of the eyes plays its own part, as described in the whites of your eyes and tooth shade.
Light often matters more than hair
The colour of the light falling on your face changes hair, skin and teeth at once. Warm indoor lighting adds a yellow cast to everything, which can make teeth look warmer and blunt any contrast from cool hair tones. Daylight, particularly on an overcast day, is cooler and tends to show tooth colour more neutrally. Phone cameras then add their own white balance and filters on top.
So if you have noticed your teeth looking different in recent photos, check the lighting first. Comparing two pictures taken in different rooms, at different times of day, on different phones, tells you very little about your teeth.
A fairer way to check your tooth shade
To check if your teeth have actually changed colour, keep everything else the same:
- Take photos in the same spot, ideally near a window in daylight, with no filter.
- Pull hair back off your face, or keep it the same in each photo.
- Wear a plain, neutral coloured top.
- Compare against an older photo taken in similar conditions.
Even then, a phone photo is only a rough guide. At Lumi, shade is assessed in person, and clinical photographs taken in our photography room give a more consistent record than pictures taken at home.
Questions we are often asked
Will dyeing my hair make my teeth look whiter?
It may change how bright your smile looks in some settings, mostly through light and dark contrast, but it does not change the colour of your teeth. Any difference tends to be small and depends heavily on lighting.
Should I pick a hair colour to suit my teeth?
There is no need. Hair colour is a personal choice, and the effect on how teeth look is minor compared with lighting, lip colour and the actual shade of the teeth.
My teeth seem darker since my hair went grey or I went blonde. Is that possible?
It can be partly an illusion, because very light hair gives the eye a brighter comparison point. Teeth also do tend to darken slightly with age and staining, so if you are unsure, a dentist can check the shade directly and talk through the reasons.
If your smile still looks duller than you expect once hair, clothing and lighting are ruled out, a free cosmetic consultation is a good place to have your tooth shade assessed and your options explained. Current offers are listed on our current deals page.
This article is general information only and does not replace a professional shade assessment.
