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t_Articles
How does the mouth
relate to good health? The mouth is the entry point for food and the beginning
of the gastrointestinal tract. The ability to chew and swallow is a critical
function required to obtain essential nutrients for the body, the building
blocks of good health. The links between oral health and nutrition are many.
Thus, oral health plays an integral role in assuring adequate nutritional
status.1
Interestingly, oral health and nutrition share an interdependent and
sometimes antagonistic relationship. By promoting healthy development and
maintenance of the mouth's tissues and natural protective mechanisms, good
nutrition promotes good oral health. In contrast, certain foods can cause plaque
development increasing the risk for oral disease. How the foods are eaten can
stimulate saliva flow, reducing the risk. The interactions are complex, with
food and nutrition having the potential for both positive and negative effects
on oral health.
In addition, the mouth serves as a window for the skilled dental practitioner
to view overall health status. The regular dental examination makes it possible
for your dentist to check for gum disease as well as precancerous or cancerous
lesions. More sophisticated screening mechanisms can produce early warnings of
stroke by displaying calcifications in the corotid artery, or
chemotherapy-induced weakening of the jaw.2
Taking care the mouth is an important step on the road to good health. Good
eating habits, regular
brushing, flossing and fluoride are all part of maintaining good health.
Oral Health “ What Causes Dental Caries?
Caries (often
referred to as tooth decay or cavities) is a bacterial disease that is caused or
hindered by many interacting factors – bacteria, saliva flow, minerals, fluoride
in water supply or dentifrices, the properties of the food eaten, frequency of
eating, dental care and dental hygiene.
For many years, the primary focus of oral health care has been the prevention
of cavities in children with an emphasis on dietary influences on caries
formation. With evolving science, specific foods no longer are being singled out
as major or risk factors for caries. In today's world, however, prevention
focuses on fluoride, use of sealants, frequency of eating, and good oral
hygiene.
All these factors interact by encouraging or discouraging the cariogenic
bacteria that cause progressive destruction of tooth enamel, known as
demineralization. Plaque is an almost invisible deposit of bacteria and their
byproducts that constantly forms on everyone's teeth. The bacteria in plaque use
carbohydrates to produce acids that can attack tooth enamel. The decaying action
of the plaque bacteria depends on its ability to adhere to tooth surfaces and to
hold acids on the teeth. After many such attacks, the tooth enamel may break
down, forming a cavity.3
The Role of Saliva
Saliva has a
powerful, protective role in the oral cavity where it preserves the integrity of
the soft tissues and increases the caries resistance of the dental tissues.
Minerals in saliva, such as phosphorus and calcium, also play a role in helping
to reform the tooth enamel, a process known as remineralization. The mechanisms
of repair are not well understood and are being actively studied. Fluoride in
the mouth enhances saliva's role in the remineralization process. Additionally,
saliva contains other substances that serve as buffers to neutralize the acid
created by bacteria. Saliva also works to help remove food particles from the
mouth.
In effect, saliva is to tooth enamel what blood is to the cells of the body.
Just as body cells depend on the blood stream to supply nutrients, remove waste
and protect the cells, enamel depends on saliva to perform similar functions.4
Eating Habits
Sugars (fruit
sugar, milk sugar and table sugar) and cooked starches (cookies and bread,
etc.), known as fermentable carbohydrates, are the only foods that can impact
caries. Because carbohydrates can be used by caries-promoting bacteria to
produce acid and ultimately tooth decay, eating habits rather than the foods
themselves are a key factor in causing or preventing tooth decay.
Frequency of eating is important because the acids are released to work on
the teeth for about twenty to forty minutes following each eating occasion. The
greater the frequency of eating, the more opportunity for the acid to work.
Decay occurs when periods of acid attack or challenge to the tooth
(demineralization) occur more frequently than periods of recovery
(remineralization).
Similarly, those foods that tend to adhere to the teeth pose greater risks of
decay than those that clear the mouth quickly. Consumer perceptions of foods
that stick or adhere to the teeth usually are different from reality, as the
following chart demonstrates. Surprisingly, chips and crackers adhere longer
than jelly beans and caramels.5 This may be because caramels and jelly beans
contain soluble sugars that are washed away more quickly by saliva than foods
such as bread or crackers, that are not dispersed rapidly by saliva, and thus
linger longer on the teeth.
The first column on the chart shows the consumer rating of the "stickiness"
of the food, while the second and third columns show the weight of the food
particles remaining on the teeth, or "sticking" to the teeth, one minute and
five minutes after swallowing.
When consumed with beverages, these rankings may be modified.
High carbohydrate containing foods produce less acid when eaten with a meal
than when eaten alone because saliva production is increased during a meal to
help neutralize acid production and clear food from the mouth. A small piece of
cheese at the end of the meal can help combat the acids produced from
carbohydrate foods during the meal.
Lack of Access to Dental Care
Few data exist on
access to dental care, but a 1987 report by the National Center for Health
Statistics showed that only 5 percent of children in the United States under age
2 had ever seen a dentist. There has been a profound decrease in caries over the
past two decades – a drop from a mean of 18 to 8 decayed, missing or filled
surfaces among I 7-year-olds – and half of 5 to 17 year old children in the
country were free of dental decay. However, data suggest that socioeconomic
status plays a role in caries development. "Closer examination .... disclosed
there was a marked polarization in the distribution of caries among children –
20 percent have 60 percent of the decay .... it is the have-nots that have most
of the dental disease."6
Population-wide
use of dental sealants remains low. However, between the 1986-87 and 1988-94
National Health and Nutrition Examination Surveys (NHANES II and NHANES III),
use of dental sealants more than doubled. Sealants are plastic films painted
onto the chewing surfaces of teeth to protect them from decay. The NHANES III
survey found sealants on the primary teeth of less than 2 percent of children,
and the permanent teeth of 19 percent of children and adolescents. Use of
sealants on permanent teeth was three times as common in white children (22
percent had sealants) as in African American children (8 percent) or Mexican
American youngsters (7 percent).7
Baby Bottle
Tooth Decay
Baby bottle tooth
decay, sometimes known as nursing caries, is a dental condition in which the
teeth of an infant or young child are severely damaged. It is caused by frequent
prolonged exposure of a child's teeth to liquids containing sugars. Even lactose
(the milk sugar found in cow's milk, formula milk and breast milk) can cause
decay when in prolonged contact with the teeth. Bottles containing juices or
other liquids containing sugars are the most common cause.
Normal feeding is
not a problem because the liquids clear from the mouth quickly. But offering a
child a bottle containing sweet liquid many times a day as a pacifier, or
allowing a child to fall asleep with a bottle of formula or juice during naps or
bedtime can lead to serious dental problems.
Simple steps taken by parents and caretakers can prevent or alleviate the
problem, according to Dr. Steven Moss, a pediatric dentist at New York
University. The steps, according to Moss, are:
- After each
feeding, wipe the child's teeth and gums with a damp washcloth or gauze pad to
remove plaque.
- Begin brushing
your child's teeth with a soft toothbrush and a pea-shaped amount of fluoride
toothpaste as soon as the first tooth erupts.
- If your child
needs a comforting bottle at nap time or during the night, fill a nursing
bottle with water rather than formula, juice, milk or sweetened liquids. You
could also give the child a clean pacifier recommended by your dentist or
pediatrician.
- Start visits to
a dentist or pediatric dentist when the child is between six and twelve months
of age. Such visits help assure the child's teeth are developing normally and
that sealants, if indicated, are applied as the child grows. Make appointments
regularly.8
Dental Caries - A Disease in Decline
The Fluoride Factor
Far and away the
most important factor in reducing caries during the last two decades has been
the widespread introduction of fluoride into water supplies as well as
fluoridation of toothpaste. Precisely how fluoride works to treat and, in
effect, prevent formation of dental cavities is still being studied, but the
evidence of effectiveness is overwhelming.9
Widespread use of
fluoride is credited with a dramatic decline in dental caries during the last 20
years in the United States, according to a survey by the National Institute of
Dental Research (NIDR). The number of cavity-free children has increased from 28
percent in the early I970s to 55 percent in the permanent teeth of 5 to 17 year
olds in the 1988-94 National Health and Nutrition Examination Survey (NHANES
III).10 An increase in the number of people who regularly visit their dentist
and an overall improved diet are also cited as factors in the decline of dental
caries, says the NIDR.11
Despite the
overwhelming scientific evidence of the benefits of fluoride, it has had its
share of critics. Dental fluorosis – small, chalky, opaque areas on the surface
of the teeth – is a concern of critics. This condition has been observed in
communities when systemic fluorides are available in greater than optimal
amounts for lengthy periods. A 1991 Public Health Service Review of the benefits
and risks of fluoride concluded that the risks were minimal compared with the
benefits, especially when water supplies were fluoridated according to
government recommendations.
Other Oral
Health Problems
Three forms of
tooth wear may affect the teeth. When teeth wear through tooth to tooth contact
this is termed attrition. Abrasion results from the application of
external mechanical factors such as incorrect toothbrushing. Dental erosion
is defined as the loss of hard tooth tissue caused by acids other than those
produced by bacteria involved in dental caries. Tooth wear is similar to caries
only in that a large number of factors combine to determine if an individual is
at risk.
Some factors in
dental erosion are internal and are seen in persons suffering gastric reflux or
eating disorders “ when acid enters the mouth from the stomach though
regurgitation or vomiting. Other determinants are external with acids entering
the mouth through the consumption of acidic foods, drinks or medicines. Both
external and internal factors may be involved and the picture is often
complicated by the contribution of the other forms of tooth wear, namely
attrition and abrasion, especially in adults. Severe tooth wear is quite rare.
Acidic foods and
drinks include fruits (especially citrus fruits) and their juices, vinegary
foods such as pickles, and fruit based or carbonated soft drinks. Unusual eating
or drinking habits such as sucking on segments of citrus fruits (as athletes may
do) and swishing or holding drinks in the mouth may be a greater factor in tooth
erosion than the amount consumed.
Saliva is the key
protective factor in the mouth to protect the teeth against erosion as well as
against caries. Saliva flow is stimulated when acids enter the mouth as saliva
neutralizes and dilutes the acid and clears it from the mouth. Therefore, the
teeth are more at risk when saliva flow is low - as in some elderly people, in
athletes who are mouth breathing or as a result of medications such as
antihistamines.12
Periodontal
disease is a widespread infectious disorder that destroys the supporting tissues
of the teeth. Seen primarily in adults, it is initiated by plaque. Nutrient
deficiencies may play a role in bringing about the condition, but good oral
hygiene and regular visits to the dentist are the primary preventive
procedures.1
New Directions in Oral Health Research
Over the last
forty years, dental health researchers have shifted their focus from specific
foods, such as candy to the role of carbohydrates in general (starches and
sugars), as well as to examining how eating habits influence plaque build-up.
With fluoride now recognized as a dental caries combatant, future research and
preventive measures are expected to focus on:
- Ways in which
dentists can utilize the routine dental visit as a screening mechanism to
provide early warnings of eating disorders, of cancer, or of soft tissue
problems pointing to osteoporosis. Some contemporary dentists now use the
routine teeth cleaning as a time to administer a special x-ray of the carotid
artery that can detect future risk of stroke or of chemotherapy-induced
weakening of the jaw structure.
- The role of
nutrients (such as vitamin A and protein) on salivary gland structure and
function, and the implications of deficiencies.
- The role of
oxidants (such as vitamin E and carotene) on protective mechanisms against
periodontal damage.13
- The diet and
lifestyle risk factor of tobacco and alcohol in the etiology of oral cancer.
Additional research is needed on such protective factors as antioxidant
nutrients.
- Formation of
new partnerships among dentists, pediatric dentists, dental hygienists and
dietitians in oral health screening, nutrition screening and counseling.
- Influence of
aging, malnutrition and skeletal diseases such as osteoporosis on oral soft
tissues in the elderly.
- Decreased
saliva flow in the elderly.
Global
Perspectives
Dramatic declines
in tooth decay are being seen around the world as well. The World Health
Organization Oral Health Programme has set a Year 2000 Goal of three or less
decayed, missing or filled teeth by age 12. To date, over 100 countries have
achieved that goal. Those countries where fluoride is widely available show the
sharpest declines.14
Key Definitions
- Caries
- Scientific name for dental cavities. It is both singular and plural.
- Cariogenic
- Capable of promoting the development of caries (cavities). Describes any
food containing sugars or cooked starches that can be used to form acid by
bacteria living in plaque on teeth.
- Cavity
- The hole occurring in the outer surface of the tooth enamel.
- Cooked
starches - Contained in cooked foods such as pasta, rice, bread, potatoes,
chips, crackers and baked goods.
-
Demineralization - The process by which minerals are leached out of tooth
enamel. This occurs when the bacteria in plaque produces acids that can attack
tooth enamel.
- Enzyme
- A protein which acts as a catalyst in promoting one or more of the many
chemical reactions in the body. Enzymes in saliva help dissolve cooked
starches into sugars so they become soluble and can clear the mouth or be
fermented by plaque bacteria.
- Fermentable
carbohydrates - Any sugar or cooked starch that can be metabolized by oral
bacteria to produce acid.
- Fructose
- A simple sugar found in honey and fruits.
- Glucose
- A simple sugar, also known as dextrose, found in many foods.
- Plaque
- An invisible, sticky film that forms on teeth, giving them a "fuzzy feel."
Plaque contains bacteria which can ferment sugars and cooked starches in foods
to form acid.
-
Remineralization - The process by which the minerals from saliva enter the
tooth surface to repair it.
- Starch
- A carbohydrate polymer composed of glucose molecules. All starches are
broken down in the body to the simple sugar glucose before they can be used.
- Sucrose
- The scientific name for table sugar, a mixture of the two simple sugars,
glucose and fructose.
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