Teeth Whitening


Tooth whitening

If you want a brighter smile, you can discuss it with your dentist during your next visit. The dentist will begin by cleaning your teeth and carrying out a comprehensive examination to rule out the presence of cavities or defective restorations. Then he can determine the cause behind your tooth discoloration, which is a crucial step in the success of the treatment.


There are many reasons why teeth change colour. First of all, there may be an accumulation of dental plaque and tartar on the surface of the teeth, which becomes stained if you frequently drink coffee, tea, or red wine, or are a heavy smoker. A simple cleaning and polishing may be sufficient to eliminate superficial staining. Sometimes the staining is lodged in the tooth enamel and dentin. Other causes of discoloration are the natural aging of the teeth, the use of tobacco products or some medications, excessive consumption of fluoride at a young age, and cavities.


Some people get better whitening results than others. Teeth with yellow discoloration usually respond better than teeth with a brownish discoloration. A grey discoloration is the result of taking tetracycline in early childhood to treat a disease, or taking minocycline in adolescence or young adulthood to treat acne. This type of discoloration is more resistant to tooth whitening, and may not be totally eliminated in some cases. Restoration work done to your front teeth may have discoloured over time and should be changed for a more appropriate tint.

Tooth Whitening Techniques

  1. At-home WhiteningUnder the supervision of a dentist, you can whiten your teeth at home. Before beginning the treatment, the dentist makes an impression of your teeth from which a stone model is made. This model is used to create a custom plastic mouth tray that adapts perfectly to your teeth. A small quantity of gel containing a concentration of about 10% carbamide peroxide is dispensed into the tray to whiten the teeth. The tray must be worn either during the day or at night, according to your preference or schedule. The treatment lasts approximately two weeks, or longer for persistent stains or to achieve more satisfactory results. Possible side effects are tooth sensitivity and/or gum irritation. Tooth sensitivity usually disappears after the treatment is complete. Your dentist may recommend neutral fluoride or a special toothpaste such as Sensodyne that can be dispensed into your tray for 30 minutes sessions over the course of a few days in order to eliminate sensitivity.

  2. In-office WhiteningIf at-home whitening does not appeal to you, then the dentist can whiten your teeth in his office. He begins by isolating your teeth and protecting your gums with a gel or rubber dam and applying the whitening agent, usually a gel containing a 30-35% concentration of hydrogen peroxide, to your teeth for a few minutes. The product is then removed and a second application is made. It is usually necessary to repeat the procedure three or four times during a session. The procedure lasts 30 to 60 minutes, and more than one visit may be necessary.

  3. Chewing gums and whitening toothpastesAll toothpastes help remove superficial staining of the teeth because of their gentle abrasive action. Some "whitening" toothpastes contain chemicals or abrasive agents that are even more effective in eliminating stains. However, neither these products nor whitening chewing gum will affect a tooth's natural coloration.

  4. Over-the-counter whitening agentsAlthough it may be tempting to try the many over-the-counter whitening products, caution is needed. To save time and money, it is best to consult the dentist. He will let you know if whitening is right for you and what product he recommends.

Whitening natural teeth with the aid of products containing hydrogen peroxide (or carbamide peroxide) in concentrations ranging from 3% to 35% is a popular alternative to certain esthetic treatments offered by modern dentistry.


Tooth whitening poses a degree of risk, however, and is not appropriate for everyone, as it can cause side effects if not performed or supervised by a dentist. Only dentists have the skills to ensure that the process remains hazard free.


In fact, they are the only professionals who can determine whether a patient's state of health will permit tooth whitening. Dentists administer a medical questionnaire and conduct a clinical examination to assess whether tooth whitening poses a threat to the individual patient. Dentists alone have the knowledge to determine the origin or reasons for a patient's dental discoloration, recommend the best treatment and determine its chances of success, and explain the treatment's advantages, risks and inconveniences so the patient can make an informed decision.


For example, a dentist can alert an expectant or nursing mother to the dangers of the process and help her agree to delay the treatment.

Dentists have the professional training and judgment to advise patients with existing or potential oral health problems. Patients in these categories include those with:

  • Weakened immune systems
  • Crohn's disease
  • Chronic heartburn
  • Stomach or digestive tract problems
  • Temporomandibular anomalies
  • Teeth grinding (bruxism) and its manifestations
  • Vulnerability to genotoxic agents
  • Gum or other muquous membrane injuries


Only a dentist can advise patients on the possibility of complications, particularly sensitivity of the following areas:

  • The treated tooth or teeth
  •  Gums
  • Soft tissues
  • Throat

All tooth whitening treatments must be preceded by a meticulous examination of the mouth and teeth, and, if necessary, scaling, cleaning and polishing, because tooth whitening products work better on clean surfaces. The exam will also reveal whether there are cavities that must be filled before the tooth whitening treatment begins. Any gum anomalies, including gingivitis or other problems, must be evaluated and treated, if required, before the teeth are whitened. If a patient suffers from sensitive teeth, the dentist can suggest ways to treat the problem before or during the whitening process.


Tooth whitening may be attempted only once the dentist is satisfied that the treatment is indicated. The dentist applies the proper whitening agent in the office and decides on the duration and frequency of the treatment. He can also suggest a home treatment and supply the patient with a custom mouthguard that conforms perfectly to the patient's teeth. The patient is given a set of syringes containing the whitening product. The dentist explains how to dispense it into the mouthguard and advises or alerts the patient to certain situations such as:

  • The need to carefully follow instructions to the letter
  • The importance of not injecting more whitening gel than necessary into the mouthguard to prevent overflowing
  • The risks of trying to improve, accelerate or intensify the treatment by using too much whitening gel or using it longer or more frequently than recommended
  • The development of tooth sensitivity
  • The development of dental sensitivity (pulpitis), given that peroxide can cross into the enamel, dentin and pulp.
    The dentist records treatment information in the patient's file.

He also makes sure that the patient receives the proper follow-ups. The first follow-up must be done one week after treatment is initiated in order to determine whether the treatment is successful or not.


If the dentist notes that the treatment is more successful or working more quickly than planned, he can decide to shorten or stop the treatment and thereby avoid over-treatment.


The dentist must be accessible to his patient and decide on a course of action if problems arise during treatment and follow-up.

He should also advise the patient about the need for retouches and remain alert to any patients who decide to exceed treatment guidelines.

It has been demonstrated that tooth whitening is not an innocuous treatment. The dangers rise with increased concentration of the gel or overuse.