New Whitening Option for Patients With Heavy Stains

At-home bleaching effective on coffee, cigarette stains

May 15, 2012 -- At-home bleaching using 6% hydrogen peroxide is effective in removing stains caused by coffee or cigarette smoke, according to a new study in the Journal of the American Dental Association.

Extrinsic stains have a multifactorial etiology involving chromogens that are derived from dietary sources or pigmented substances that are used habitually in the mouth, noted the study authors, from Pontifical Catholic University of Paraná and Federal University of Paraná in Brazil (JADA, May 2012, Vol. 143:5, pp. e1-e7).

"Coffee, tea, red wine, orange juice, some soft drinks, and food colorants are considered staining agents that lead to extrinsic tooth discoloration when consumed frequently," they wrote.

However, the literature is limited with regard to data pertaining to the best choice and efficacy of stain-removal techniques, they noted.

40 enamel surfaces tested

To evaluate the stain-removal ability of tooth bleaching and simulated tooth brushing, and to determine enamel susceptibility to restaining, the researchers measured the baseline color of 40 bovine labial enamel surfaces by using a portable colorimeter with a 6-mm diameter tip.

The coffee solution was prepared by dissolving six grams of instant coffee powder in 300 milliliters of boiling water. The specimens were then immersed in the solution for 72 hours at 37°C.

The color readings were taken in accordance with the Commission Internationale de l'Eclairage L*a*b* system against a white background. The specimens were then divided in half and stained with coffee and cigarette smoke.

The other 20 specimens were exposed to a smoking machine that contained smoke from five cigarettes that were smoked to a length of 10 mm beyond the tipping paper that covers the filter. The jar was kept saturated for 10 minutes. The researches repeated this cycle three times.

After the staining procedures, the color measurements were taken again and compared to the color of the specimens at baseline. The specimens were then divided into two subgroups and subjected to at-home bleaching (one hour per day for 21 days) or simulated tooth brushing (120 cycles per day for 21 days), followed by another color measurement.

Both staining procedures were then repeated and another color measurement was taken.

Coffee enhances restraining potential

Here are some of the key results:

• The first color measurement showed that cigarette smoke and coffee staining resulted in similar discoloration (p > .05).
• At the second color measurement, tooth brushing resulted in a significant reduction in color change only for specimens stained with cigarette smoke (p < .001), whereas tooth bleaching resulted in significantly reduced values for specimens stained with cigarette smoke or coffee (p < .05).
• Restaining with cigarette smoke did not increase the color change significantly for specimens that underwent bleaching or toothbrushing (p > .05). In contrast, restaining with coffee resulted in significantly more discoloration for both groups of specimens, irrespective of the stain-removal method (p < .05).
• At the last color measurement, the coffee-stained specimens that underwent toothbrushing experienced the highest mean discoloration, with statistically significant differences between these specimens and the specimens that were stained with cigarette smoke (p < .05).

"The study results show that at-home bleaching removed both coffee and cigarette-smoke staining," the authors concluded. "The restaining potential was greater for specimens stained with coffee than for those stained with cigarette smoke, regardless of the removal method used."

A 2008 study (Brazilian Oral Research, Apr-Jun 2008, Vol. 22(2), pp.106-111) that evaluated the effectiveness of whitening dentifrices for the removal of extrinsic tooth stains had more mixed results. Researchers from the department of restorative dentistry at Vale do Paraíba University in Brazil examined the effect of distilled water, Colgate, Crest Extra Whitening, and Rapid White on specimens stained in a solution of black tea. They found that only the whitening dentifrice Rapid White was effective for the removal of extrinsic stains.

Meanwhile, a Procter & Gamble study presented at the 81st general session of the International Association for Dental Research in 2003 found that effective dentifrices remove extrinsic stains only, while effective bleaching technologies remove both extrinsic and intrinsic color sources.

Green Tea May Strengthen Your Teeth

Researchers Suspect Antimicrobial Molecules Contained Within Green Tea Helps Preserve Teeth (as long as you don't add sugar).

A cup of green tea a day may keep the dentist away.

That's the finding of new research published in Preventive Medicine. The findings show that drinking at least one cup of green tea a day increases the odds of keeping your teeth as you age.

The researchers suspect that antimicrobial molecules called catechins present in green tea and in lesser amounts in oolong tea provide the benefit. But be careful if you like your tea with sugar: sweetener may negate the effect, the team found.

"Green tea may have bacteriocidal effects, which would affect teeth, but only if you drink it without sugar," said Alfredo Morabia, of Columbia University in New York and editor of Preventive Medicine, who wrote an editorial accompanying the new research.

"They also reported that drinking sweet coffee was actually deleterious," he added. "Coffee alone had no problem, but sweet coffee would actually make you lose your teeth." 

THE GIST:

• People aged 40-64 who drank one cup of green tea a day were less likely to lose teeth.
• Drinking unsweetened coffee had no effect on keeping teeth.
• Antimicrobial molecules called catechins may account for green tea's benefits.

Yasushi Koyama of the Tohoku University Graduate School of Medicine and colleagues looked at more than 25,000 Japanese men and women between age 40 and 64 in making the determination.  They found that men who drank at least one cup of tea a day were 19 percent less likely to have fewer than 20 teeth (a full set including wisdom teeth is 32) than those who did not drink green tea. Tea-drinking women had 13 percent lower odds.

One possible explanation for the benefits of tea drinking is that warm drinks wash out your mouth. But coffee, which also provides a mouth rinse, had no benefit, suggesting something else is going on.

Catechins have been shown to kill mouth bacteria associated with tooth decay and gum disease, so the researchers suspect this is what gives green tea its dental benefits.

"Previous research has indicated that regular consumption of green tea may lead to a lower instance of periodontal disease, a leading cause of tooth loss in adults," said Samuel Low of the University of Florida College of Dentistry and President of the American Academy of Periodontology in a statement to Discovery News.

Maintaining healthy teeth and gums is part of maintaining a healthy body, Low said. "That is why it is so important to find simple ways to boost periodontal health, such as regularly drinking green tea -- something already known to possess certain health-related benefits."