Currently, Aesthetic Dentistry is one of the main focuses of our daily practice. The search for a whiter and more harmonious smile results in psychological and emotional well-being for the patient.

There are currently two tooth whitening techniques: the outpatient technique and the intensive dental surgery technique, with and without light source activated photosensitive agents.

Outpatient whitening is indicated for cases where teeth are naturally darkened or darkened by pigments acquired from the diet, in smokers, in older patients mainly, to avoid prolonged time in the dental chair, in traumatized or affected teeth due to the use of medication such as tetracycline and dental fluorosis.

The big advantage of this technique is its compatibility with soft tissue and its lower cost. The main disadvantage is the length of time needed for the treatment, which is a factor of great relevance for many patients, who often opt for the intensive technique at the dentist, thus obtaining immediate results. Another disadvantage is the need to produce a mould for the patient's mouth to obtain individual trays for the application of the product. These trays accommodate the bleaching agent that contains Carbapol, providing a slower release of oxygen, requiring 6 to 8 hours to act. Suitable to be carried out at night.

With the laser tooth whitening technique carried out in the dental surgery, 6% to 40% concentration hydrogen peroxide is used, which is light and/or heat activated, causing an increase in the release of oxygen, which is safer and more comfortable for the patient, where visible results are obtained with just one session. The association of light sources results in less time needed, since when the light is projected onto the gel, a fraction of it is absorbed, and this energy is converted into heat, accelerating the release of peroxide hydroxylic radicals.

However, the effectiveness of this technique is still not consensual despite the physicochemical interaction of light with the whitening compound being known. Clinical results acquired in a single session, may not be durable long term due to the instability of tooth colour. A few months after treatment there may be a relapse to the original colour. Another known disadvantage is that it might be potentially harmful to soft tissue. Its cost is also higher.

A third possibility is combined whitening, which reconciles the two types of tooth whitening: a whitening session in the dental surgery for a more effective and quick change in the initial colour of the teeth and, subsequently, the treatment is complemented using the bleaching process at home, to obtain the desired final result. This practice reduces the total treatment time and gives a greater longevity to the final whitening result. The greatest advantage of associating the two methods is that it allows tooth whitening touches and provides the patient with a long-lasting effect.

Dr Marília Freitas is Dentist at HPA – Alvor; Clínica Particular AlgarveShopping – Guia and Clínica Particular Mar Shopping – Loulé