Bleaching changes teeth at molecular level

[DrAnil]

Study: Bleaching changes teeth at molecular level

January 9, 2013 — There has been a steady proliferation of whitening products for dentists and consumers, with some in-office products containing high concentrations (35%) of hydrogen peroxide.

 

In a recent study, Brazilian researchers set out to bolster the lack of published data regarding how bleaching can impact the mechanical properties of dental tissues (Journal of Dental Research, December 14, 2012). They took a molecular-level approach and found that high concentrations of hydrogen peroxide can have a dramatic impact on dental hard and soft pulp tissue.

“First, we are showing that 35% of hydrogen peroxide, used in commercial products, changes the enamel surface structure, increasing the roughness of these tissue,” Fabio Nascimento, DDS, PhD, MS, a member of the research team from Biomaterials Research Lab at Universidade Bandeirante de São Paulo (UNIBAN), told DrBicuspid.com in an email. “The phosphate content in enamel and dentin also decreased after bleaching.”

For this study, Dr. Nascimento and his colleagues were interested in the potential effect of 35% hydrogen peroxide (H₂O₂₎ on in vivo activity of dentin cysteine proteases and matrix metalloproteinases (MMPs). Their assumption was that H₂O₂ would promote collagen degradation in dentin because it increased the activity of proteolytic enzymes.

The study included 20 subjects (10 men, 10 women), ages 18-25, who were not tobacco users, had not received whitening treatment, had no gingival recession or restorations, and needed two to four first premolars extracted.

The participants were divided into two groups: bleached and nonbleached (control). The subjects in the bleached group had their right maxillary (n = 14) or mandibular (n = 14) first premolars bleached once per week with 35% H₂O₂ (Whiteness HP Maxx, FGM). Per the manufacturer’s instructions, they received three 15-minute applications during each session. The subjects in the control group had their left upper (n = 14) or lower (n = 14) first premolars extracted without whitening treatment. In total, the subjects provided 56 teeth.

Ten teeth from each group were separated; the rest were used for dentin powder preparation. The researchers collected gingival crevicular fluid from the gingival sulcus of these remaining teeth (n = 36) prior to extraction. Postextraction, the teeth were sectioned, had their pulp removed, and the dental hard tissues were frozen.

Molecular analysis

The researchers analyzed the effect of 35% H₂O₂ under clinical conditions using various imaging methods. Teeth from the experimental and control groups had enamel surface morphologies examined with atomic force microscopy (AFM). The researchers also collected infrared spectra from the enamel and dentin powders of both groups using a spectrometer and a spectrofluorometer. Then they analyzed dentin specimens from either group with confocal fluorescence microscopy. Finally, they measured the presence of reactive oxygen species in the pulp tissue with spectrofluorometry.

“Bleaching is far from a cosmetic procedure.”

— Fabio Nascimento, DDS, PhD, MS

“In my opinion, this study is particularly interesting because it is an in vivo clinical study with a molecular approach,” Dr. Nascimento noted.

The AFM images revealed a smooth surface on the control specimens, while the experimental set had “a much more irregular surface, with several spikes of larger size with deep microporosities,” the researchers noted.

The impact on dentin was noteworthy as well. “The expression of collagen degrading enzymes increased substantially, promoting further degradation in the organic matrix of dentin,” Dr. Nascimento stated.

Both the enamel and dentin were affected. “The bleaching agent containing 35% H₂O₂ induced a significant in vivo alteration in enamel and dentin, which could potentially trigger biological and/or mechanical responses of dental structures,” the study authors wrote.

Limiting the damage

As a result of these findings, the researchers take issue with common characterizations of teeth whitening. “Despite reports that the use of bleaching agents at low concentrations has been considered absolutely safe, analysis of our data shows that the use of 35% H₂O₂ as a bleaching agent … can be clinically adverse in the long-term and/or after recurring bleaching treatments.”

According to Dr. Nascimento, ways to limit the amount of damage of high-concentration hydrogen peroxide to the inner layers of tooth tissue include the following:

• Reducing the hydrogen peroxide concentration
• Reducing the time of each application and increasing the time between applications
• Not using reaction catalysts, such as lamps or lasers

He and his colleagues hope their study findings reach patients as well. “We would like to demonstrate that an in-office bleaching is far from a cosmetic procedure, and it would be great if the clinicians could explain better to their patients about the pros and cons of using this procedure,” Dr. Nascimento noted.

Dentists should also be aware that postbleaching sensitivity is mostly due to a slight inflammation into the pulp chamber (reversible pulpitis) that actually can progress for some undesirable pathology, he added.

“[It] is important to say that bleaching is not at all a dangerous procedure, but the dentists and the patients should know that sometimes the price paid by a purely aesthetic treatment may be too high at the end if the dentist is not sufficiently cautious in applying the bleaching agents,” Dr. Nascimento concluded.

 

        

[Anonymous]

 WOW! Great information. I have just partnered with a manufacturer–one division of a POPULAR Whitening Brand–same location –under different name and the viscosity of this product is such that no senstitivty occurs and the concentrations are much lower than 35% H2O2 producing the same amazing results as the higher concentrations and the light ("LASER") procedures. Thank you for posting this as many patients are asking if whitening their teeth can be harmful.

        

[drsnehamaheshwari]

 Using remineralizing agents doesn’t necessarily help teeth recoup their enamel after whitening procedures.

A new study indicates that following in-office teeth whitening with 35 to 38 percent hydrogen peroxide, the teeth generally don’t regain their enamel.

There are several studies that show bleaching with large quantities of hydrogen peroxide can change the makeup of the enamel. Acta Odontologica Scandinavica (March 2013, Vol. 71:2, pp. 343-348).

        

[drsnehamaheshwari]

A growing number of state laws are giving dentists a monopoly on providing teeth-whitening services in the U.S., according to a report released Tuesday by the Institute for Justice (IJ) and a related lawsuit filed by two nondentists who were prohibited from offering these services in Alabama.

As the teeth-whitening industry has expanded in recent years, so has the push for laws and regulations that control who can and can’t offer teeth-whitening services, according to the IJ, a U.S. civil liberties law firm founded in 1991. The IJ’s report claims this expansion of dental licensing is a form of "economic protectionism."

"In recent years, teeth whitening has exploded into an $11 billion industry encompassing products like gum and toothpaste, as well as services offered by dentists, salons, spas, and mall kiosks," the report states. "At the same time, state dental boards and dental associations have pushed for laws and regulations that would enable licensed dentists and hygienists to capture a greater share of that market by banning anyone else from offering teeth-whitening services."

Since 2005, at least 14 states have changed their laws or regulations to exclude all but licensed dentists, hygienists, or dental assistants from offering teeth-whitening services, according to the IJ. In addition, at least 25 state dental boards have ordered teeth-whitening businesses to shut down, while nine states have brought legal actions against such businesses.

To examine the risks of teeth-whitening businesses, the IJ reviewed complaints filed with state agencies over a five-year period.

"Consistent with scholarly research, the complaints show that risks are minimal," the IJ stated. Of 97 complaints provided by 17 states, only four reported consumer harm, according to the IJ. The rest of the complaints came primarily from dentists, state boards, dental associations, and hygienists.

"Since 2005, at least 30 states have taken action to shut down nondentist teeth whiteners," said Angela Erickson, the IJ researcher who wrote the report, in a news release. "The evidence is overwhelmingly clear that the pressure for this didn’t come from consumers, it came from dentists and dental associations who have a financial stake in keeping others out of business."

Second related lawsuit        

AACD statement on teeth whitening

The American Academy of Cosmetic Dentistry (AACD) believes that teeth whitening constitutes the practice of dentistry and that dental services should be delivered by dental professionals who have been educated to perform procedures in the safest manner possible.

According to the AACD, the following potential issues may occur when teeth whitening is handled in malls and salons by nondental professionals:

Every patient should have an exam and have dental plaque and calculus removed by a professional prior to whitening. Nondental professionals may not advise patients about this before offering these procedures.

Inability to prevent or treat tooth sensitivity due to bleaching.

Failure of nondental professionals to diagnose decay, periodontal disease, and other common dental diseases.

Inadvertent treating with bleaching chemicals of teeth that are decayed close to the (pulp) nerve system, which could result in permanent problems including eventual root canal or extraction.

Bleaching should not be done without consulting a dentist first for postbleaching treatment planning. Planning is key to avoid a potential mismatch of teeth colors that could likely occur with fillings, crowns, bridges, or veneers on any front teeth.

Nondental professionals do not have the appropriate training to be suspicious of and diagnose, or refer for diagnosis, many systemic diseases that have oral symptoms — e.g., diabetes.

Since some of those who use the mall or salon services will not or do not routinely see a dentist, there is a real risk of failure to diagnose serious and possibly life-threatening oral diseases in "patients" who might otherwise have gone to a dentist and been able to get their disease diagnosed and treated.

In a related lawsuit filed today in the Circuit Court for the 10th Judicial Circuit for Jefferson County, Alabama, two nondentists who were banned from offering whitening services to the public claim their entrepreneurial rights are being violated.

In 2011, Alabama amended the state’s Dental Practice Act to declare teeth whitening to be the practice of dentistry, making it a crime, punishable by one year in jail and a $5,000 fine, for nondentists to offer teeth-whitening services.

Plaintiffs Keith Westphal and Joyce Osborn Wilson say the state banned them from offering Alabamans "a comfortable and clean place" to use the prepackaged teeth-whitening products they sell to customers. As a result, Wilson shut down her business and Westphal did not expand his North Carolina teeth-whitening business into Alabama.

Westphal and Wilson are "entrepreneurs who wish to sell legal, over-the-counter teeth-whitening products and provide customers with a clean, comfortable environment in which to apply those products to their own teeth," the suit states, noting that "It is perfectly legal to sell these products to customers who will use them at home without supervision or instruction." Wilson currently sells whiteners over the Internet, and her products are in lawful use in salons and spas in California, Florida, New York, Ohio, Pennsylvania, and Texas, according to the complaint.

Westphal wants to expand his teeth-whitening business from North Carolina to Alabama, but claims he cannot do so without risking fines and jail time because he is not a licensed dentist. He offers whitening services that cost $79 to $129. Westphal’s products have a 16% concentration of hydrogen peroxide, but many commercially available products have hydrogen peroxide concentrations of 35% or higher, the suit states.

Teeth-whitening products are regulated by the U.S Food and Drug Administration as cosmetics and no prescription is required to buy them, according to the plaintiffs.

"Teeth whitening is safer than other oral procedures that are not regulated as the practice of dentistry, such as tongue piercing, which the ADA advises can lead to infections or cracked teeth," the suit states. "There is no evidence that Alabama’s prohibition on nondentist teeth-whitening protects consumers or advances any other legitimate governmental interest. Rather, the primary effect of the law is to protect dentists who offer teeth-whitening services from competition, and "harms consumers by reducing competition and driving up prices."

Zach Studstill, executive director of the Alabama Dental Association, declined to comment, saying he hadn’t seen the lawsuit yet.

"Alabama’s prohibition on nondentist teeth whitening has nothing to do with protecting consumers and everything to do with protecting monopoly profits for dentists," said Arif Panju, an attorney at the IJ Texas chapter. "Teeth-whitening products are safe, and whatever minimal risks they carry are the same whether customers apply those products to their own teeth at home or at a mall or salon."

This is IJ’s second lawsuit challenging a state teeth-whitening prohibition. In 2011, IJ filed a federal lawsuit challenging Connecticut’s similar prohibition. That lawsuit is still ongoing.

Several other states, including Tennessee, Georgia, New Jersey, and New Mexico, have enacted similar legislation. And in North Carolina, the issue went so far that in 2010 the U.S. Federal Trade Commission (FTC) charged the state dental board with anticompetitive conspiracy. The board then sued the FTC, which subsequently ruled that the board had acted illegally. The board has since appealed that decision. 

        

[CaseyWooten]

 Bleaching is the way to brighten your teeth and get rid of discoloured and yellowish  teeth.

        

[drsnehamaheshwari]

Using 10% carbamide peroxide or 10% hydrogen peroxide bleaching agents in conjunction with an abrasive dentifrice can lead to a significant increase in enamel roughness when combined with an abrasive dentifrice, according to a study in Acta Odontologica Scandinavica (May-July 2013, Vol. 71:3-4, pp. 488-497).

Researchers from Ankara University, Near East University, and Drexel University examined the effects of the two bleaching agents on enamel at different times. They also looked at the effect of different superficial cleaning treatments when they are used after these agents.

The researchers divided 140 flat enamel samples into 14 groups, half of which were treated with 10% carbamide peroxide and half with 10% hydrogen peroxide. One group from each half was set aside as the control. Then one group from each was brushed with Ipana toothpaste, Clinomyn toothpaste, Moos Dent toothpaste, Signal toothpaste, Colgate toothpaste, and without a dentifrice, respectively.

The bleaching sessions lasted six hours each day, while the brushing phase took place three times a day for two minutes at a time over a four-week period. At each seven-day interval, the researchers measured average roughness values with a profilometer.

Bleaching with either peroxide agent did not alter the enamel surface roughness, but when the bleaching treatment was combined with abrasive dentifrices, a significant increase in roughness values was observed, the study authors concluded

 

        

[Anonymous]

 Thank you for this information. Interesting. Same as we have always known to be true. One more reason the dental hygienist needs to be the one to recommend the appropriate dentifrice, mouthrinse, xylitol products and other home care aids to support total health.

        

[Author]

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