The Present State of Decay
First the good news. Tooth decay has decreased since 1960. At present, fifty percent of under twenty-one year olds are cavity/filling free. The decay process itself seems to be progressing more slowly than it did fifty years ago. While we’re not certain about what is responsible for this improvement we do have a number of likely candidates:
• Fluoride. The use of fluoride is a contentious issue with some people advocating its use and others opposing it as a poison. Fluoride and its cavity-preventing effect was noticed by an American (Dr. Fredrick McKay in 1908 ) who found mottling of the teeth (a discoloration that results from over-fluoridation) in his town folk but a much reduced incidence of dental decay. Both effects were found to be a result of naturally occurring fluoride in their water supply.
Fluoride has two different types of effects. Fluoride, if present, is deposited into the growing tooth structure in kids. This fluoride produces a much stronger enamel. Fluoride comes from fluoridated water, from supplemental drops or from naturally occurring fluoride all at a very low level (approximately 1 part per million). Not all cities or towns have fluoridated water. Most of the West Coast of the United States and Canada do not.
Topical effects of fluoride benefit both adults and children. This fluoride deposits onto the surface of teeth making them more resistant to decay. This fluoride comes from toothpaste, rinses or applications at your dentist. This fluoride is at a much higher concentration (1000 to 15,000 parts per million) which is why we recommend that you apply a pea-sized amount of toothpaste for young children knowing that they will swallow some.
• Dietary changes. Processed foods can be more cavity promoting so a change to more natural foods may be responsible in some part. A decrease in the frequency of eating carbohydrates appears to reduce decay.
• Improved oral hygiene. Brushing (now with electric brushes) and flossing are more common than in the past.
• Increased use of antibiotics. Since decay is a bacterial infection antibiotics may help to reduce it.
• The main bacteria responsible for decay (s. mutans) seems to have become less aggressive.
Now for the "not so good” news.
Tooth decay remains the most common bacterial infection of humans. In the non-industrialized world, decay is on the increase and they have fewer dentists than we do. Even in the modern Canadian dental practice we see decay daily. Pit and fissure cavities (on the biting surface of the teeth) are becoming more common than on the sides of the teeth. This is why your dentist recommends pit and fissure sealants for children and some adult teeth. In the 21 to 45 age group decay increases then levels off with increasing age. Above sixty years of age root cavities become much more common. This can be caused by periodontal disease exposing more of the root surface of the teeth and from decreased saliva flow. A large number of prescription drugs reduce saliva flow and reduce the beneficial washing effect saliva has in the mouth.
In the average Canadian dental practice roughly a third of our patients have 70% of the tooth decay which we treat. There are a number of possible reasons for this imbalance. In a subsequent article I will outline these reasons and some strategies to reduce this decay.
Larry Hill DMD