"Open Wider, Please"
Can tooth decay be prevented? Canadian research now in progress suggests a possible clue
THE DENTIST places the mirror and explorer back on the tray and says, “Five to be filled this time, and this fellow back here”— jabbing the cheek in the vicinity of a molar— “ought to come out. Not right away necessarily,” he adds casually, “but it’s pretty far gone. Sooner or later it’s going to cause trouble.”
The patient musters a grin. “But why,” he cries mentally, “should this happen to me?”
The chances are that it is not the first time he has thought this. If he is of middle age and one of the 3,000,000 people in this country who visit a dentist regularly, he probably has from 10 to 20 fillings in his head already and the molar marked for the forceps may not be his first loss.
Both in Canada and the United States we have the notion that our teeth are good. We seem to think that the glittering smiles which greet us from the Hollywood screens and the tooth paste advertisements are reflections of our collective mouths. They are not. The state of our dental health is extremely poor. Dr. A. H. Merritt, New York,
formerly president cf the American Dental Association, says that tooth decay is as prevalent today in the United States as it was one hundred years ago. Dr. Edmund A. Grant, as director of Dental Services for the Toronto Board of Health, probably looks into more mouths than any dentist in the Dominion and not only does he believe that Dr. Merritt’s statement would apply to Canada but he goes one better and says that our teeth are worse now than they were a century ago.
As a nation we were unaware how black the picture was until we went to war. When the cream of our manhood trooped to the recruiting stations one out of five was rejected because of poor teeth. Americans received as great a shock when their
country was brought into the war. They, too, discovered that one out of every five men failed to meet their Army dental requirements.
We couldn’t go on rejecting 20% of our fighting manpower because of bad or insufficient teeth alone. So the dental requirement standard was altered. It was decided not to look these would-ba war horses in the mouth—until they were in uniform. Then their teeth could be fixed. This has placed a great strain on Canada’s dental facilities. Of the country’s 4,000 dentists 1,000 are now in the Royal Canadian Dental Corps. The five Canadian dental colleges are sending more than 90% of their graduates straight into the Corps.
This naturally means that the dentists remaining in civilian practice have more work to do than ever before; more in fact than they can comfortably handle. Many Canadian communities are without a dentist and have little hope of getting one.
Normally our 4,000 dentists were kept fairly busy treating the 3,000,000 people who visited them regularly and the other 3,000,000 who went once in a while. The other half of the population never goes near a dentist. Fear, which is groundless, may keep some away; lack of money keeps others away and plain indifference keeps the rest away.
Whatever the causes for so many “absentees” from the dentist’s office, lack of need for dental attention is not one of them. Dentists estimate that 95% of the people in this countryhave toothdecay.
What is a Tooth ?
THIS brings us back to the man with the molar which ought to come out.
Apparently there was nothing inherently wrong with his teeth—or with yours. Nor is there any use blaming tooth decay on “soft” teeth, on a calcium deficiency, except in rare cases. Why then should not these teeth, be as free from decay as the bathroom tiles?
To answer that question let’s start with the teeth themselves. What is a tooth? Many definitions describe it as “an appendage situated in the mouth.” Nevertheless teeth have been discovered outside of the mouth on the temple bones of horses, for example, and near the ears of sheep. These, however, are the results of nature’s more freakish moments. Another example of teeth .situated outside of the mouth is found in the upper tusks of the wild boar of the Malay Peninsula. The tusks of the elephant and the poison fangs of the snake which differ so radically in their functions are, of course, examples of teeth, too.
Human teeth—they are in your mouth all right if you are lucky—are made up of four “tissues”— enamel, dentine, cementum and pulp. Dentine in some ways resembles bone and it gives to the tooth its bulk and strength. It needs, however, a harder surface, a sort of protecting cap with which to chew. This is enamel, the hardest substance in human anatomy. To hold the tooth to your jaw you have a membrane of fibres. These fibres are attached to a covering of the root dentine known as cementum, and also to the bone of the jaw. The membrane cushions the shock of chewing. The pulp is the carefully guarded soft-tissue centre of the tooth, containing blood vessels and also nerve fibres which are connected with the nervous system through a small opening at the end of the root of the tooth.
At birth 20 baby teeth are present though none have broken through the gums, and formation of some of the permanent teeth has begun. The first molars of the permanent set are not recognized as permanent by many parents. As a result the first molars, or “six-year molars,” are mistaken for baby teeth and neglected—not that any of the baby teeth should ever be neglected.
Permanent teeth crowd right on the heels of the baby teeth and can be virtually affected by the health of the latter. Formation of the entire set of Continued on page 50
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permanent teeth, excepting the wisdom teeth, is well under way at the age of five. Twenty-eight of the 32 permanent teeth can be identified by form and position in the gums of a four-year-old by means of the X-ray. The wisdom teeth are forming at the age of nine though more than half the baby teeth may still be in use.
Tooth decay is a disease, just as tuberculosis and typhoid are diseases. All dental authorities agree on that point. It has its fancy name and bug with a name even fancier. It is about as common on this continent as the common cold.
Cause of Tooth Loss
TWO principal conditions which bring about tooth loss are “periodontal” disease and “dental caries.” By the former is meant disease that attacks the tissues surrounding the teeth. Pyorrhea, for example, is a periodontal disease.
Many physicians and dentists have recognized for a long time that diseased teeth and mouths can act as a source of bacteria and poisons and cause disturbances in other parts of the body. Mouth infections may spread directly to other regions, for instance, into tonsils and sinuses. Swallowing of bacteria and “decomposition products” may cause diseases of the digestive system such as gastritis and colitis. Bacteria and poisons may also be absorbed directly into the bloodstream, resulting in secondary anaemia and disturbed systemic conditions. Another avenue of infection is through the respiratory route.
The complete list of ailments which can be caused by septic mouth is discouragingly long. It includes diseases affecting the circulatory system, the skeleton, muscles and nerves. Your rheumatism and arthritis may be due to some infection in your teeth. But according to a statement by Dr. Bernard I. Comroe, Associate in Medicine, Medical and Dental Schools, University of Pennsylvania, at the recent conference of the Ontario Dental Association, the removal of teeth, which has been a common feature of the treatment of arthritis, has benefitted only two to three per cent of arthritis patients, according to hundreds of case histories.
Dental caries, in contrast to periodontal disease, is a disease of the tooth itself. It starts and has its entire development in the mouth. Dental caries is a condition which strikes hardest during childhood and adolescence. In one large Canadian city the teeth of 73,702 children were examined in the schools during 1942. Nearly 50,000 required attention.
All tooth decay starts on the outside of the tooth. Stories of teeth having been found “rotten” inside when the enamel appeared whole belong with such talk as a horsehair turning to a snake if left in a bottle of water.
Dental caries generally starts in the pits or in defects on the biting surface, at points where teeth touch
one another sideways, and at the gum line. These are called “the susceptible zones.” It rarely begins under the gum margins and the tonguefacing surfaces of the teeth are much less subject to attack than the cheekfacing surfaces. The lower front teeth on all surfaces are remarkably safe from the ravages of decay. These facts would indicate that decay does not attack haphazardly and that apparently the regions exempt from the destructive processes are protected in some manner.
Once the enamel has been penetrated decay of the dentine doesn’t go on very long before the nervous system is aware of the situation. It is then that the pulp becomes affected and the least pressure on it is agony which communicates itself through the nerves. It’s then also that hot or cold fluids will make the tooth “jump.”
When decay reaches the pulp inflammation starts. This is what we lightly call a toothache—the greatest understatement in the language. If treatment is neglected the pulp dies and poisons may inflame the tissues outside and beyond the tooth. But even under these conditions the dentist can still save the tooth in a great many cases.
The majority of dentists apparently agree on the identity of the bacillus which acts on the sugars and starches caught on the tooth surfaces and causes decay. Its name is the Lactobacillus acidophilus. There are, however, conflicting schools of thought about other factors which contribute to the speeding of decay.
Whether the bug with the terrible name is the only villain of the piece or not, all dentists do agree that particular kinds of food form the background for acid production. These are carbohydrates found principally in refined sugar and refined Hour.
It is not even necessary to swallow these foods. Their mere presence in the mouth, borne by the air, may result in damage. Research dentists who were puzzled by the prevalence of dental caries among the employees in flour and sugar factories established this conclusion. Carbohydrates are to certain bacilli what old Napoleon brandy is to a connoisseur. The traditional English four o’clock tea may be partly responsible for the fact that the English normally have as poor teeth as any people in the world. Theirs are even worse than ours. Their regular teatime menu usually includes tea, sweetened with refined sugar; bread, made with refined flour; and cakes, made with refined sugar and refined flour. That is a daily orgy of carbohydrates guaranteed to threaten any tooth. Wartime rationing has removed the full-fledged tea from the Englishman’s board. Although statistics are lacking, dental authorities claim that improvement of the Englishman’s dental health has been noticeable.
The road to sound teeth by avoidance of dental decay is a hard one. It’s a simple matter to advise drastic
reductions in amounts of carbohydrates eaten. But it’s quite another matter to change the eating habits of a people.
On the other hand, Dr. Arnold D. Mason, Dean of the Faculty of Dentistry at the University of Toronto, states, “It is well known that some people can eat a diet fairly high in carbohydrates and still remain comparatively free from dental caries. These people apparently are protected in some manner against the processes that are concerned in the establishment of the disease. From recently conducted research in our laboratories new light has been shed on the nature of these protective factors. It is our hope that these findings will have a practical application in the prevention of decay.” Emulsion Films
FROM these investigations, together with observations and data of various kinds, the view has been reached that the tooth surface is protected by the formation thereon of fine emulsion films of a complex nature. These are formed from certain components of the saliva and are augmented by certain food factors found in milk, eggs, potato juice and unrefined cereals.
Research Professor Harold K. Box who has been conducting these experiments has this to say, “From evidence presented in recent years of the comparative freedom from decay associated with certain diets, it has become increasingly clear that protective factors are present in some foods.”
It has been shown by South African research workers that calcium and phosphate salts in certain concentrations can protect teeth in test tubes from acid attack. The writer has recently seen some of the experiments which Dr. Box has conducted in the Research Department of the Faculty of Dentistry, University of Toronto. There were teeth suspended in lactic acid solutions and others suspended in equally strong lactic acid solutions plus various other substances. The former teeth showed marked signs of destruction, had lost their lustrous enamel and had developed dull white spots. The teeth which had the benefit of the protective substances in the acid were still shining and undamaged.
Among the protective substances were phosphorus compounds found in the ordinary diet. In one case a component of milk was used and in another a component of cereals.
The Texas State Board of Health recently stumbled on Deaf Smith County where people never saw a dentist, ate an abundance of all the
wrong foods and yet had no tooth trouble at all. Dr. Edward Taylor of the Texas State Board of Health examined 43 mouths, picked from an age group of two years to 50. Every tooth he examined was sound.
When the research men investigated the drinking water they found it to contain an extraordinarily high quantity of fluorine. But that proved not to be the answer. The drinking water in another Texas town had an equally high concentration of fluorine and yet tooth decay existed.
Then field men gathered samples of meat, milk, wheat and vegetables and immediately one fact stood out: these foods were astonishingly high in phosphorus. Carrots contained 50% more than usual; cabbage and lettuce 60%; and turnip greens 30%. Meat and milk were similarly high in phosphorus, and wheat ran 600% above normal.
Foods grown in Deaf Smith County had obtained their superabundance of phosphorus and also calcium from the caliche rock in the area.
The reason for our poor showing in dental health in the past 100 years, found by Doctors Merritt and Grant, is that although dental science has spread its blessings far afield during that period our food has become increasingly rich in carbohydrates.
Most dentists advocate prophylaxis which means “use the toothbrush.” Despite this the toothbrush is by no means as common an article as might be expected. Everyone more than 18 months old with teeth to brush should use a toothbrush, these advocates say. Yet in Canada only 3,000,000 toothbrushes, rather than the possible 10,000,000, are used.
Other dentists declare that while brushing of teeth is valuable from a hygienic point of view and for the health of the gums it has not been proved that it is a major factor in prevention of tooth decay.
Regular dental care, however, has changed the scales against dental caries. Surveys carried out at the University of Toronto of the dental health of certain groups of children showed how tooth decay had been cut down, merely by regular attention which included restorative dentistry, prophylaxis and correction of diets as far as possible. The number of cavities per child was reduced from 5.9 in 1940-1941 to 3.1 in 1942-1943.
New experiments may some day in the not too distant future revolutionize caries prevention, but meanwhile common-sense dental hygiene and a moderately careful diet will help you to keep your teeth.