56 Status before start of bleaching treatment
Before treatment begins, the color of the teeth should be determined and the teeth should be photographed with shade tabs present. Here, the color is found to be A3.5/A4.
57 Outcome of home bleaching treatment
After completion of the treatment, the color of the upper incisors, originally A3.5/A4, has changed to A1/A2.
Courtesy of Ultradent Prod. Inc.
Use of anesthesia during the bleaching treatment is neither necessary nor sensible. The patient should register and report pain reactions (e.g., injuries to the gingiva or disturbances of the pulp caused by heat generation).
Bleaching Effect on Restorations
Patients should be informed that only enamel surfaces will be bleached and not existing restorations. That means that crowns and fillings may appear darker after bleaching treatments. In the case of fillings, one can remove the outmost layer of the filling and replace it with a new filling layer in a suitable tooth color. In the case of crowns, it may be necessary to renew these completely.
Swallowing the Bleaching Agent
In the stomach, carbamide peroxide is broken down into H2O2 and urea. H2O2 then disintegrates into water and reactive oxygen. Urea is produced naturally in the body and is removed by the kidneys.
Home Bleaching
This bleaching method has been available since 1989. It is most effective when treating orange-brown and age-induced discolorations (age-induced staining). Most bleaching agents are slightly acidic. Consequently, it is possible that exposed root surfaces respond very sensitively. Therefore, patients with exposed root surfaces should use desensitizing toothpaste with sodium fluoride right from the beginning (e.g., Sensodyne).
Possible side effects of home bleaching are:
—Gingival irritation (leaky tray)
—Temporomandibular joint disturbance (carrying the tray during the night)
—A feeling of pressure in the stomach (overfilling of the tray and swallowing the excess bleaching agent)
—Hypersensitive dental necks (excessive exposure to tray covering)
Treatment Procedure
1. Professional tooth cleaning, polishing of all tooth surfaces.
2. Determining the tooth color with the patient.
3. Radiographs of the teeth to be bleached (to detect possible internal damage).
4. Photographs with the shade tabs.
5. Diagnose and determine the causes of the tooth color changes (describe external factors).
6. Make a dental impression.
7. Fabricate a bleaching tray.
8. Hand the bleaching agent over to the patient. Demonstrate how to use the tray and the bleaching agent and hand over written instructions.
9. Recall and check the progress of treatment.
58 Adding bleaching agent to the tray
The patient is shown how to fill the bleaching tray. The patient takes the tray and sufficient bleaching agent home.
59 Inserted bleaching tray
To prevent any tooth hypersensitivity, the patient should wear the bleaching tray for only one hour per day over the first few days. Then, the patient can increase the time step-wise until a maximum of five hours per day is reached.
Indications
Yellow-orange and light brown discolorations of teeth are the ideal indications for home bleaching (age-induced staining). Also teeth with a mild form of fluorosis or a slight tetracycline discoloration can be bleached. According to newer studies by Haywood (1997), the success of bleaching tetracycline-induced discolorations increases if the patient is ready to wear a bleaching tray for half a year.
Whenever there are anatomical changes in the enamel surface, the patient should be informed in advance that it is unlikely that an ideal result can be achieved.
Home bleaching is ideal as a part of preprosthetic therapy. If the teeth are bleached before a general dental treatment, an essentially more aesthetic result can be achieved during the restorative phase.
Chemically-induced strong discolorations are a possible contraindication for home bleaching. Here the tooth colors are are usually blue or grayish. Patients with very sensitive teeth are another contraindication. Teeth that already exhibit hypersensitivity to tooth polishing should not be bleached.
60 Bleaching tetracycline discolorations
A distinctive blue-gray discoloration (left) has been significantly brightened (right).
61 Bleaching brown-orange discolorations
A strong brown-orange discoloration (left) has clearly been brightened (right).
Contraindications
Home bleaching is not suitable for:
—patients with a serious systemic illness
—patients using strong medications
—pregnant or breast-feeding women
—patients who suffer from allergic reactions to bleaching agents or the bleaching tray resin
—patients with extensively destroyed or extensively filled teeth
—patients who are heavy smokers or chew tobacco
—patients with temporomandibular joint disorders. The bleaching tray is not a bite splint. In fact, the bleaching tray can temporarily reinforce existing joint disorders,
—patients with extreme blue-gray discolorations
—patients with tooth hypersensitivity
Bleaching Agents
The newest bleaching agents for home bleaching contain carbamide peroxide. Gels containing 10–15% bleaching agent are currently being used. Carbamide peroxide is a compound consisting of urea and hydrogen peroxide. During decomposition, hydrogen peroxide splits off and disintegrates into reactive oxygen and water. A 10% carbamide peroxide solution is as effective as 3% hydrogen peroxide.
There are incidentally also home bleaching products that are purely hydrogen peroxide-based. These bleach 2.76 times faster than the same concentration of carbamide peroxide. One of the first products on offer was BriteSmile. A disadvantage of such products is that an opened package must be stored in the refrigerator.
Home bleaching products must be applied to the teeth by means of a bleaching tray. These trays must have space for the bleaching agent.
62 Bleaching equipment for home use
Many home bleaching products have been introduced on the market over the past few years. However, up until now only few have been given a CE certification.