The main purpose of tooth whitening through the daily use of whitening toothpastes is to improve the appearance of the teeth, reducing the amount of stains and whitening the colour.
The teeth may have a more yellowish or brownish colouration than desired due to both internal causes (genetic inheritance and ageing) and external causes such as tobacco, coffee, tea, some drinks or certain medications (like tetracyclines).
Extrinsic stains are those caused by an accumulation of pigments on the enamel, the outermost layer of the tooth, and intrinsic stains are those that occur in the dentin, the tissue that is under the enamel. Both types of stains can be either permanent or temporary.
Intrinsic stains are those where the pigment is found inside the tooth or is part of the internal structure of the tissue. The stains can be generalised, affecting the full set of teeth or localised, affecting a single tooth.
Generalised intrinsic stains usually occur while the teeth are forming, although sometimes they can affect the already developed tooth, as in the case of ageing. The reasons that these intrinsic stains appear are very different: systemic diseases (liver, metabolic, endocrine disorders, etc.), intake of substances such as tetracyclines, fluorosis (due to an excessive intake of fluoride during the tooth formation process), deficiency of certain vitamins or minerals (vitamin A, C, D, phosphorus or calcium), etc.
On the other hand, localised intrinsic stains usually appear once the tooth is already formed, as a consequence of a foreign agent. This type of staining can appear due to bleeding or a trauma, calcifications or necrosis, but also as a consequence of tooth diseases such as decay.
Extrinsic stains, which are those that form on the tooth's surface, can be due to multiple causes. In general terms, these types of stains have a better prognosis for teeth whitening.
Factors related to the appearance of extrinsic stains
Foods like tea, coffee, wine, or fizzy drinks can cause discolouration to the surface of the teeth. Sometimes, when there is prolonged contact with the pigment, it can become associated with the organic content of the enamel and transform into an intrinsic colouration, permanently darkening the tooth.
Tobacco is also related to the appearance of stains on the teeth. The action mechanism is similar to that of food, although in this case, the penetration of nicotine and other substances can reach the dentinal tubules and hinder its removal.
Other causes of the appearance of superficial stains on the teeth may be the prolonged use of chlorhexidine-based mouthwashes (an antiseptic used to treat gingivitis and periodontitis) or the build up of tartar.
Control of bacterial plaque
To ensure correct oral health and achieve white stain-free teeth, it is essential to control the levels of bacterial plaque.
Mechanical control, through tooth brushing and cleaning the gaps between the teeth, is a universally recommended practice for the entire population.
Tips for good tooth brushing
To maximise the preventive action of tooth brushing, the following tips should be taken into consideration:
- Tooth brushing is recommended for two minutes at least twice a day, once before going to sleep. Brushing before bed is the most important because we produce less saliva during the night, which is a natural protector against the formation of bacterial plaque.
- Systematically brushing all tooth surfaces is important in order to remove plaque.
- The brush head must be the right size so that all areas of the oral cavity to be reached. An average hardness is most recommended for the general population.
- Rotating-oscillating electric toothbrushes have been shown to be more effective in reducing plaque and gum inflammation than manual toothbrushes.
- Cleaning the back of the tongue should be part of the brushing routine to avoid halitosis.
- To maximise the effects of the toothpaste, it is advisable not to rinse with water after brushing and simply spit out any excess toothpaste.
- Mouthwash and dental floss is recommended in order to complete the dental hygiene process. This ensures that the gaps between the teeth are thoroughly cleaned. Interdental hygiene is especially important in patients with gum disease.