24 Questions
What is an alternative treatment option for a failed nonvital walking bleach procedure?
External vital bleaching techniques
What percentage of hydrogen peroxide is commonly found in whitening products?
30-35%
What is the purpose of using a light during in-office vital bleaching technique?
To accelerate the oxidation reaction
Why is the use of carbon dioxide laser not recommended for in-office vital bleaching technique?
It may cause hard or soft tissue damage
What is the typical duration of each in-office vital bleaching treatment?
30-45 minutes
What is the purpose of rubber dam isolation in in-office vital bleaching technique?
To prevent leakage of the bleaching agent
What type of teeth may be responsive to external bleaching treatment?
All of the above
How many treatments are typically required for in-office vital bleaching technique?
Two to six treatments
What is the name of the in-office bleaching procedure that employs sodium perborate as the bleaching agent?
Walking Bleach Technique
What is the purpose of applying the bleaching agent in the coronal portion of the tooth?
To prevent unwanted leakage of the bleaching agent
What is the concentration of hydrogen peroxide pastes or gels used in the In-Office Nonvital Bleaching Technique?
30%–35%
What is the characteristic of the walking bleach technique?
It is a slow bleaching process that continues until the next appointment
What is the purpose of undercutting the incisal area in the walking bleach technique?
To retain the temporary restoration
What is the difference between vital and nonvital bleaching?
Vital bleaching is used for living teeth, while nonvital bleaching is used for dead teeth
What is the indication for vital bleaching?
Teeth with discolouration
What is the purpose of placing a protective sealing cement over the gutta-percha in the walking bleach technique?
To protect the periodontal ligament
What is the primary indication for nonvital bleaching?
To lighten discoloured teeth that have undergone endodontic therapy
What is the result of residual oxygen or peroxide residue in the tooth after bleaching?
A decrease in bond strength of composite
What is the recommended delay before applying composite restorative treatment after cessation of bleaching?
1 week
What is the approximate lifespan of bleaching treatment?
1-3 years
Which of the following is a type of nonvital bleaching procedure?
Walking bleach technique
What is the purpose of bleaching treatment?
To lighten the colour of a tooth
Which of the following is a type of vital bleaching procedure?
In-office vital bleaching technique
What is the mechanism of bleaching?
Oxidation of the organic pigmentation in the tooth
Study Notes
Teeth Discolouration
- Teeth can become intrinsically discoloured due to ageing, trauma, or certain medications.
- External vital bleaching techniques can be used as alternative treatment options for failed, nonvital, walking bleach procedures.
Indications for External Bleaching
- Teeth that have been darkened by trauma but are still vital.
- Teeth with a poor endodontic prognosis due to the absence of a radiographically visible canal (i.e., calcific metamorphosis).
- Brown fluorosis stains.
In-Office Vital Bleaching Technique
- Step 1: rubber dam isolation.
- Step 2: 30-35% hydrogen peroxide bleaching.
- Most products consist of paste or gel compositions that contain 30-35% hydrogen peroxide.
- Other additives, such as metallic ion-producing materials or alkalinizing agents, can speed up the oxidation reaction.
- The dentist places the hydrogen peroxide-containing paste or gel on teeth.
- The use of a light to generate heat may accelerate the oxidation reaction of the hydrogen peroxide and expedite treatment through a thermocatalytic effect.
- Use of lights to heat the bleaching agent, however, causes a greater level of tooth dehydration.
In-Office Nonvital Bleaching Technique
- A more current technique uses 30-35% hydrogen peroxide pastes or gels that require no heat.
- This technique is frequently the preferred in-office technique for bleaching nonvital teeth.
- The bleaching agent should be applied in the coronal portion of the tooth, incisal to the level of the periodontal ligament, to prevent unwanted leakage of the bleaching agent through the lateral canals or canaliculi to the periodontal ligament.
Walking Bleach Technique
- The walking bleach technique is an in-office bleaching procedure that does not require the use of heat and employs sodium perborate as the bleaching agent.
- The bleaching process is slower and continues until the patient reports back for the subsequent appointment for assessment and cessation of the treatment.
Vital Bleaching Procedures
- Indications for vital bleaching include:
- Trauma resulting in calcific metamorphosis (i.e., calcification of the pulp chamber, root canal, or both).
- Mild discolourations.
- Bleaching treatment is considered first when intrinsic discolourations are encountered, in keeping with the overall conservative philosophy of tooth restoration.
Classification of Bleaching Treatments
- Nonvital bleaching procedures:
- In-office nonvital bleaching technique.
- Walking bleach technique.
- Vital bleaching procedures:
- In-office vital bleaching technique.
- Dentist-prescribed, home-applied technique.
Effects of Bleaching
- Bleaching generally has an approximate lifespan of 1-3 years, although the change may be permanent in some situations.
- A transitory decrease occurs in the potential bond strength of composite when it is applied to bleached enamel and dentin.
- No loss of bond strength is noted if the composite restorative treatment is delayed at least 1 week after cessation of any bleaching.
This quiz covers the causes of teeth discoloration, including ageing, trauma, and medications, as well as external vital bleaching techniques and their indications.
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