Cosmetic dentistry has become an integral part of restorative practice. It is perceived that whiter teeth enhance the beauty of a person's smile. As a result, demand for whiter teeth has increased in today's patients.
BLEACHING
It is lightening of discoloration of teeth through application of chemical agents to oxidise the organic pigmentation of teeth.
REASONS FOR DISCOLORATION
1. Extrinsic discoloration-
- Highly colored food items
- Caffeinated beverages
- Red wine
2. Intrinsic discoloration-
- Intra pulpal hemorrhage
- Pulp necrosis
- Antibiotic stains ( tetracycline )
- Fluorosis ( 1-2ppm)
- Metallic restorations
BLEACHING AGENTS
1. Hydrogen peroxide (H2O2)- Concentration of 30% (superoxol) is used for in office bleaching. It diffuses easily through enamel and dentin and breaks down water into perhydroxyl ions and nascent oxygen [0].
These molecules open up the carbon ring of pigment molecule and convert them into colorless [OH] compounds.
2. Sodium perborate- Decompose into sodium metaborate, H2O2 and [O]. Used for intracoronal bleaching procedure.
3. Carbamide peroxide- Urea+ H2O2
Used in concentration 10% to 35%. Most popular bleaching agent for at home vital bleaching procedures.
PROCEDURES
1. Non- vital:- For intact anterior teeth that have necrosed due to necrosis.
A.In-office bleaching-
Done by a dentist at his office by using 30% H2O2. The solution is applied on the teeth
and then activated by applying heat. Procedure is repeated 4-6 times. Recall every week till
the desired result is achieved.
B. Walking bleach-
Sodium perborate + H2O2 In this the bleaching action occurs in 3-5 days out of the office in between the patient's visits. Effect is visible after 1-2 treatments after subsequent weekly visits.
2. Vital:- The tooth is not necrosed and stains are due to beverages, medicine etc.
A.In-office thermocatalytic bleaching
B. Power bleaching-
Powerful light source such as laser or xenon plasma arc lamp is used for release of
[O] from H2O2.
C. Mcinnes Solution-
5:5:1 of Hcl: 30%H2O2: Ether solution is used. It is used specially for the fluorosed teeth.
D. Night guard-
10-20% of Carbamide peroxide solution is used.A clear plastic sheet custom tray is fabricated for the patient. At night after brushing the patient is instructed to apply small amount of gel on the tray and place it in the mouth. Overnight contact of bleaching gel with the teeth will cause the bleaching action. In the morning, the tray is removed and cleaned. 2-6 weeks are required for removal of moderate stains.
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