Teeth whitening is the most conservative treatment for discolored teeth compared to more invasive procedures like composites, veneers, or crowns. It not invasive because it doesn’t remove tooth structure. This article explores whether teeth whitening can harm dental ceramics like crowns and veneers by examining the effects on surface roughness and gloss based on the findings from studies and scientific evidence.
Dental Ceramics: What are they?
Dental ceramics are integral to restorative dentistry, chosen for their excellent aesthetic properties, biocompatibility, and resistance to wear and discoloration. Common types include:
- Feldspathic Ceramics: Known for their superior aesthetic properties.
- Glass Ceramics: Such as lithium disilicate, offering a balance of strength and beauty.
- Alumina and Zirconia: Renowned for their high strength and durability.
- Hybrid Ceramics: Composites of ceramic and polymer, designed to merge the best attributes of both materials.
Some stains respond more favorably to bleaching than others. For example, smoking and chromogenic food stains respond well to bleaching, whereas blue/gray tetracycline stains respond the slowest. Yellow discoloration responds quickly in contrast to white spots, which don’t respond to bleaching but become less noticeable as the tooth background is whitened. Understanding the nature of the stain along with an accurate diagnosis can help determine which patients will respond more favorably to bleaching.
Teeth whitening: mechanism of action
Teeth whitening agents are oxidizing substances that penetrate the enamel and dentin to break down color-causing particles. Hydrogen peroxide works by diffusing through these layers and releasing free radicals. These free radicals react with unsaturated bonds in the pigments, converting larger, colored compounds into smaller, colorless hydroxyl groups. These simpler molecules reflect less light, making the teeth appear whiter. Carbamide peroxide, another whitening agent, is essentially hydrogen peroxide stabilized with urea, with hydrogen peroxide being the active ingredient responsible for whitening.
The effect of teeth whitening on dental ceramics
Two critical parameters in evaluating the impact of teeth whitening on dental ceramics are surface roughness and gloss.
Surface Roughness: Refers to the texture of the surface at a microscopic level. Increased roughness can lead to higher plaque accumulation, staining, and wear.
Gloss: Refers to the shine or luster of the surface. A reduction in gloss can affect the aesthetic appearance of the restoration, making it look dull and less natural.
- Surface Roughness: dental ceramics exhibited substantial increase in surface roughness. This is likely due to the polymer component, which may be more susceptible to the chemical effects of bleaching agents.
- Gloss: The gloss of ceramics was also significantly reduced after bleaching, suggesting that these materials might be more vulnerable to the aesthetic degradation caused by bleaching agents.
- Hybrid ceramics exhibits the worst roughness and gloss alteration.
Most two important effects are
- Surface roughness.
- Potential loss of glossiness.
The best time to whiten the teeth
The best time to whiten the teeth is before crown/veneer placements. Here is why:
- Easier to match the color. Imagine that the the crown/veneer is already installed, it is technically harder to match the color vs the teeth are whitened first then a crown is placed based on the benchmark color.
- Roughness may lead to stain accumulation, microcracks and increased wear.
- Loss of glossiness may lead to color mismatch.
Recommendation for patients who are looking to get dental crowns and veneers and teeth whitening
Scientific community suggests that while bleaching agents can effectively whiten natural teeth, they can have adverse effects on dental ceramics, particularly concerning surface roughness and gloss. Here are the implications for dental practice:
1. Patient Education: Dental professionals should inform patients with ceramic restorations about the potential risks of using bleaching agents. Patients should be made aware that while their natural teeth may become whiter, their ceramic restorations may become rougher and lose their gloss, leading to a mismatch in appearance.
2. Material Selection: When planning restorations, dentists might consider the likelihood of the patient undergoing future bleaching treatments. Materials less susceptible to surface roughness and gloss changes, such as certain types of glass ceramics, might be preferable.
3. Post-Bleaching Care: For patients who have already undergone bleaching, dental professionals can offer polishing treatments to restore the gloss of ceramic restorations. Regular follow-up appointments can help manage any long-term effects on the restorations.
4. Alternative Whitening Methods: For patients with significant ceramic restorations, alternative whitening methods such as professional cleanings or the use of whitening toothpaste might be recommended instead of chemical bleaching agents.
5. Selective office whitening method: Dentist can whiten natural teeth only in office controlled setting using systems like professional teeth whitening.
