The things we do for whiter teeth

Teeth bleaching can make your pearlies whiter... but at what cost to your dental health?

By: Lanny Boutin

  In the quest for whiter teeth our ancestors used ashes, bleach, even urine. Today dentists use peroxide.
  Peroxide gel is placed into a moulded rubber tray, like a mouth guard and worn over the teeth, a few hours each day for at least seven days. The gel releases oxygen, slowly oxidizing stains, at a cost of three to four hundred dollars per treatment.
 

In the late 1980's the manufactures blocked the FDA's attempt to reclassify bleaching from cosmetic to a drug

  The University of Maryland's Baltimore Dental School, found that 10% carbamide peroxide gel, used daily for 14 days, whitened teeth an average of 6.96 shades.
  But the Canadian Dentist Association's Statement on Tooth Whiteners recommends bleaching "be used selectively and carefully, as no long term safety data is available". This is because in the late 1980's the manufactures blocked the FDA's attempt to reclassify bleaching from cosmetic to a drug.
  It's estimated ten to fifteen percent of patients experience some degree of tooth sensitivity and even though researchers have found little evidence of permanent pulp damage, Dr. Rick Easton, a clinical assistant professor of dentistry, at the University of Alberta, notes "the bleaching agent gets into the pulp of the tooth, that's what causes the sensitivity; it's irritating the nerve."
  Dr. Xinyi Yu, Director of Clinical Research for Den-Mat Corporation (makers of Rembrandt tooth whiteners), believes that "some of the tooth's protective protein layer is being removed during bleaching, exposing the interior structure of the tooth to peroxide".
 

Peroxide has the potential to irritate soft tissue and increase the release of mercury from amalgam fillings

  And even though sensitivity typically stops soon after the bleaching is finished, Easton notes, "that even low levels of repeated trauma can cause tooth death".
  A study from the University of North Carolina found "bleaching significantly lowered a tooth's stores of calcium and phosphorus and reduces the thickness of the material around its core". A similar Hungarian study found bleaching "increased the depth of small groves on the teeth".
  Researchers also note peroxide has the potential to irritate soft tissue and increase the release of mercury from amalgam fillings.
  Once swallowed, it seems to be safe. Our livers make around 7 grams of hydrogen peroxide each day, it's also found in processed foods, coffee and some vegetables.
  Dr. Dittakavi Sarma, an expert in chemical carcinogens, and professor in the Department of Medicine and Pathobiology, at the University of Toronto notes, "peroxide is a weak cancer promoter".
  Perhaps ashes wasn't such a bad idea, after all...

Lanny Boutin is an Edmonton freelance writer who specializes in health and family.

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