Why do teeth darken? A brief history of shades of white

White has many shades, just take a look at the paint catalogue to realise that.

White can be warm or cold, or a shade of grey. When describing a colour shade to another person, they will not necessarily think of the same colour as us. It turns out that the colour rating is subjective, which makes it different in the eyes of each of us. In the world of dentistry, the problem of colours has been solved by systematising shades of white in dental colour charts. A unified colour scale called dental colour chart allows the dentist to communicate well with both the patient and the prosthetic technicians.

The colour of our teeth depends on our genetics, lifestyle, diet and the environment. This is why dentists use tooth shade reference guides for teeth whitening and cosmetic dental procedures, such as veneers, crowns, and bridges. Patients can choose preferred teeth shade from the colour chart and dentists can show patients before and after images of what they may expect in tooth shade change.

The VITA classical A1-D4 shade guide is considered to be one of the most accurate tools for determining tooth shade in dentistry. This classic teeth colour shade chart is designed with a logical and systematic progression of shades, allowing dental professionals to quickly and easily identify the correct colour for any tooth.
What’s more, VITA shade guide has been carefully adjusted to match natural teeth colour as closely as possible. This provided dentists with a reliable colour reference tool that enables them to select appropriate teeth restorations or teeth whitening treatments.

The Vita Shade Guide categorises original tooth shade into four main shades with a range of 16 tones, ranging from A1 – D4:

• A for reddish brown tooth colour
• B for reddish yellow tooth colour
• C for grey tooth shades
• D for reddish grey tooth shades

Each of the categories is further divided into several levels of darkness – usually from 1 to 4.

Colour perception depends on the type of light, background lighting, the experience of the examiner and the level of eye strain. It is worth noting that the natural colour is the result of many parameters – including the colour, colour temperature of the light and the transparency of the hard tissues of the tooth, hence the dentin of milk teeth is blue-white, and the dentin of permanent teeth is yellow. The colour of the teeth changes with their hydration – fully hydrated teeth have a deeper colour and greater translucency.

It is therefore essential to emphasise how important it is to match the colour in the right light conditions. When taking photos, it is necessary to choose the right lighting and white balance. The colour of the teeth should be matched in daylight. Before and after documentation must always be done in the same lighting conditions, as colour is extremely important for technicians when it comes to all prosthetic work.

At the Materna Dental clinic in Poznań, we take photos of patients in our own, well-equipped photo studio.

Tooth discoloration is considered to be any deviation from the norm in the colour of the natural pigment. Tooth discoloration can be caused by external or internal factors.

External factors causing teeth discoloration include: poor oral hygiene, tar compounds in cigarettes and the penetration of colouring substances from food products.

A diet rich in teeth staining products and insufficient oral hygiene will certainly result in teeth discoloration. The most intensively staining products are coffee, tea, sweets, berries, carbonated drinks, red wine, beetroots and also some spices like curry, turmeric and paprika. Products containing acids, on the other hand, damage the enamel and thus make it easier for food dyes to penetrate the teeth.

Poor oral hygiene causes accumulation of dental plaque, which is a sticky yellow film that forms from bacteria in the mouth and food debris. Dental plaque then hardens and mixes with minerals present in the saliva forming tartar. Tartar is a hardened layer on the surface of the teeth and also under the gum line. Without proper oral hygiene, tartar will build up on your teeth and lead to gum disease and tooth decay. Only a dentist or hygienist can successfully remove tartar from your teeth. You will not be able to remove it by brushing and flossing at home.

Healthy diet and good oral hygiene are very important, but they will not win the fight against nicotine. It has been proven that smoking cigarettes accelerates the process of bone resorption, contributes to yellowing of dental plaque, the formation of discoloration and plaque on teeth, and erosion of enamel.

• Teeth injuries – Enamel cracks can also be caused by trauma to the teeth. The resulting gaps can accumulate sediment and substances that cause discoloration.
• Baby bottle caries – Discoloration on children’s teeth can appear from bottle caries. Nursing caries, also called baby bottle tooth decay, is a form of tooth decay that is caused by children sleeping with bottles filled with milk or juice. It usually affects children between the ages of one and two years. White spots, streaks on the front teeth, and in advanced cases black spots at the gum line are visible. For the youngest, we recommend dietary supplements that strengthen teeth. An interesting solution are also steel crowns protecting milk teeth.
• External factors causing discoloration include: genetic predispositions, general diseases, dental malformations, metabolic disorders, malnutrition and metal poisoning.
• Certain medications like high blood pressure tablets, antihistamines or antibiotics, like doxycycline or tetracycline.

It is worth noting that the colour of our teeth is determined genetically, hence some people will simply have a darker shade than the others. The colour is primarily determined by the physical and chemical structure of the tooth, which is why diseases have a direct impact on the formation of tooth discoloration.

Hypothyroidism causes milky white hyperpigmentation, hyperthyroidism causes blue-white discoloration, porphyrias reddish-grey, hyperbilirubinemia greenish, and fluorosis chalk or brown. Gastroesophageal reflux disease can also be a common problem, which, in addition to tooth discoloration, leads to damage to the enamel. In the case of malnutrition, a lack of essential minerals can have an irreversible effect on the appearance of teeth. Patients with eating disorders like anorexia and bulimia nervosa complain of damage to the oral cavity, discoloration and tooth loss. Bruxism, which manifests itself as teeth grinding, leads to abrasion of the enamel, and further to the exposure of dentin, which may manifest itself in darkening of the edges of the teeth.

As we age, the enamel tends to yellow, becomes darker and is more prone to discoloration. The changes are caused by the abrasion of the enamel and the deposition of pigments in the dentin. Unfortunately, we can’t stop time. But we can remove stains using different teeth whitening methods.

Bleaching is carried out without chemicals and consists in removing discoloration with polishing and cleaning agents. Teeth whitening will not give as good an effect as teeth whitening, hence this procedure is less popular.

Teeth whitening is a chemical reaction and takes place through the process of oxidation with the help of oxygen radicals. Some of the most popular teeth whitening methods are teeth whitening using the BEYOND lamp or teeth whitening trays. The whitening effects of these procedures are excellent- your teeth may be whitened by up to 8 shades.

It is worth remembering that teeth whitening will only work on your natural teeth. The procedure will not whiten crowns, caps, veneers, bridges or fillings. These will remain unchanged. Also, while yellow teeth may bleach well, brown teeth may not respond as well, and some of them may not improve at all. This is why it is important to talk to your dentist first, before deciding to whiten your teeth. In addition, the procedure will not be effective if your tooth colour changes due to medications or is caused by an injury. Your dentist will be able to advise you which treatment is best for you, what results you can expect and if there are any risks involved – like developing tooth sensitivity.

Would you like that bright, pearly smile to be a reality? Our teeth whitening treatments can help you achieve a smile you can be proud of. Call us to find out more!