Peroxide-based tooth whiteners.
- Do they harm or damage dental work and dental materials? / White fillings. / Silver fillings. / Porcelain restorations.
If tooth-bleaching agents are strong enough to lighten your teeth, you might wonder if they can damage your dental work.
Studies have reported that many types of dental materials are affected by peroxide-base whiteners. And we outlined some of these findings on this page so you'll have an opportunity to be aware of them and talk to your dentist about them.
However, documenting an affect doesn't necessarily mean that it's clinically significant.
Peroxide technique is time-tested.
In light of the fact that so many of the products and methods used today have been around for the last 20 years or so, it seems that at this point the combined experience of the dental community as a whole (as documented in dental literature) suggests that most issues are either well known or else don't pose a great risk or concern. (Heymann 2005) [reference sources]
Harmful effects of peroxide whiteners on dental restorations and materials.
a) White dental fillings.
Some, but not all, studies evaluating the effects of bleaching agents on white fillings (dental composite restorations) have reported effects.
- Peroxide-based whiteners (3.6% and greater) may increase the surface roughness of white fillings at a microscopic level.
- They may also affect their hardness and cause increased microleakage.
A change in surface texture could affect the ease with which bacterial colonies are able to adhere to a tooth, thus leading to (secondary) tooth decay formation. Changes in hardness or increased microleakage would compromise a filling's integrity.
If these effects do take place to any substantial degree, at this point in time their clinical significance has not been definitively demonstrated.
Bond strength of new fillings.
Dental composite fillings restorations placed immediately after whitening treatments have been performed have been shown to have reduced bond strengths (on the order of 25%). This interference is thought to stem from oxygen that's generated during the bleaching process that remains within the tooth's hard tissues. (Haywood 2009)
Studies have shown that allowing a wait period of 2 to 3 weeks provides an opportunity for the oxygen to dissipate. After this point, a normal-strength bond can be created.
Affects on color.
It's possible that peroxide whitener may have a lightening effect on the color of existing white fillings.
- If this effect does take place, it's only marginal.
- This is the exception, not the rule.
In the vast majority of cases, bleaching treatments will have no effect on the color of white fillings.
Other white dental materials.
One type of white dental plastic (methylmethacrylate) may stain orange when it's subjected to a peroxide whitener. Nowadays, this plastic is generally only used to make temporary dental crowns.
b) "Silver" fillings.
Laboratory studies have demonstrated that exposing dental amalgam (the metal used to make "silver" fillings) to peroxide triggers the release of mercury and silver.
This effect can take place for up to 80 hours after the exposure. The concentration of the whitener plays a role in the rate at which this reaction occurs.
This effect may be more likely to take place with new dental amalgams (it may be inhibited by dental biofilms coating a restoration). For this reason, your dentist may want to delay starting your whitening treatments if a number of new silver fillings have recently been placed.
Tarnish / Greening.
Amalgam fillings have the potential to tarnish, or even develop a green tint, when subjected to whitening treatments. This effect is more likely with higher peroxide concentration and longer treatment durations.
For this reason, fillings in teeth that hold an especially prominent position in a smile are often replaced with white ones before the bleaching process is begun.
C) Dental cements.
Studies have shown that dental cements may be partially eroded or stained by peroxide whiteners. However, the clinical significance of this has yet to be demonstrated.
D) Porcelain restorations.
25 years of exposing porcelain-surfaced restorations to peroxide whitener (like with the use of tray-based technique) has not shown any clinically significant damage.
From a clinical standpoint, the most significant issue encountered is that a person's natural teeth will lighten but their porcelain restorations won't.
This can either be a detriment or an asset.
- To correct a mismatch that's created, the porcelain restorations will need to be replaced so to match the new color of the natural teeth.
- Whitening treatments are sometimes used to lighten dark natural teeth back to the lighter shade they were when neighboring crowns were originally placed.
The exception to the rule about porcelain restorations not changing color is veneers. Whitening treatments may lighten them. This page describes why this effect takes place.
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