Teeth can discolour over time due to medication, food staining and presence of tartar
What causes yellow teeth
Genes determine the initial colour of teeth and its evolution over time with age. The transparency and thickness of the teeth also vary among individuals. An opaque and thick tooth reacts better to teeth whitening treatments. Transparency is the sole element which cannot be corrected by a whitening treatment. Your dentist will be able to identify the source of your teeth's discolouration.
Food stains
Regular consumption of red wine, coffee and tea affects the colour of your teeth. They act on two levels:
Coffee and tea consumed in too large quantity will leave a deposit on your teeth which end up staining the enamel
Acidic foods such as citrus fruit or vinegar contribute to the erosion of enamel. When tooth enamel becomes thinner and transparent more dentin which is yellow in colour shows through
Tartar
Bacteria, saliva and food residues combine to form a film (biofilm) which solidifies at the base of the teeth to form plaque. After calcifying, plaque transforms into what is commonly known as tartar. Tartar impacts both the health and aesthetic of the teeth. In fact it gives teeth a yellow, brown, or greyish appearance. The rate of which tartar forms can be affected by:
Quality of brushing: better brushing techniques means more plaque is removed and less likely that tartar will be able to develop
Exogenous factors: tobacco, radiation and some medication can cause a decrease or suppression of the saliva flow and therefore an increased risk of plaque and tartar formation
