, also known as tooth
, is a disease
wherein bacterial processes damage hard
). These tissues progressively
break down, producing dental cavities (holes in the teeth). Two
groups of bacteria are responsible for initiating caries:
Streptococcus mutans and Lactobacilli. If left untreated, the
can lead to pain
, tooth loss
, and, in severe cases, death
. Today, caries remains one of the most common
diseases throughout the world. Cariology is the study of dental
The presentation of caries is highly variable; however, the risk
factors and stages of development are similar. Initially, it may
appear as a small chalky area that may eventually develop into a
large cavitation. Sometimes caries may be directly visible, however
other methods of detection such as radiograph
are used for less visible areas of
teeth and to judge the extent of destruction.
Tooth decay is caused by specific types of acid
cause damage in the presence of fermentable carbohydrates
such as sucrose
content of teeth is sensitive to
increases in acidity
from the production of
. Specifically, a tooth
(which is primarily mineral in content) is in a constant state of
back-and-forth demineralization and remineralization
between the tooth
and surrounding saliva
. When the pH at the
surface of the tooth drops below 5.5, demineralization proceeds
faster than remineralization (i.e. there is a net loss of mineral
structure on the tooth's surface). This results in the ensuing
decay. Depending on the extent of tooth destruction, various
treatments can be used to restore
teeth to proper form, function, and aesthetics
, but there is no known method to
large amounts of
tooth structure. Instead, dental health organizations advocate
preventive and prophylactic measures, such as regular oral hygiene
and dietary modifications, to
avoid dental caries.
Caries can be classified by location, etiology, rate of
progression, and affected hard tissues. These classification can be
used to characterize a particular case of tooth decay in order to
more accurately represent the condition to others and also indicate
the severity of tooth destruction.
GV Black Classification of Restorations
Generally, there are two types of caries when separated by
location: caries found on smooth surfaces and caries found in pits
and fissures. The location, development, and progression of
smooth-surface caries differ from those of pit and fissure caries.
G.V. Black created a classification system that is widely used and
based on the location of the caries on the tooth. The original
classification distinguished caries into five groups, indicated by
the word, "Class", and a Roman
. Pit and fissure caries is indicated as Class I; smooth
surface caries is further divided into Class II, Class III, Class
IV, and Class V. A Class VI was added onto Black's classification
and also represents a smooth-surface carious lesion.
The pits and fissures of teeth provide a location for caries
Pit and fissure caries
Pits and fissures are anatomic landmarks on a tooth where the
enamel folds inward. Fissures are formed during the development of
grooves but the enamel in the area is not fully fused. As a result,
a deep linear depression forms in the enamel's surface structure,
which forms a location for dental caries to develop and flourish.
Fissures are mostly located on the occlusal (chewing) surfaces of
teeth and palatal
surfaces of maxillary anterior
Pits are small, pinpoint depressions that are most commonly found
at the ends or cross-sections of grooves. In particular, buccal
pits are found on the facial surfaces of molars
. For all types of pits and fissures,
the deep infolding of enamel makes oral
along these surfaces difficult, allowing dental caries
to develop more commonly in these areas.
The occlusal surfaces of teeth represent 12.5% of all tooth
surfaces but are the location of over 50% of all dental caries.
Among children, pit and fissure caries represent 90% of all dental
caries. Pit and fissure caries can sometimes be difficult to
detect. As the decay progresses, caries in enamel nearest the
surface of the tooth spreads gradually deeper. Once the caries
reaches the dentin
at the dentino-enamel junction
, the decay
quickly spreads laterally. Within the dentin, the decay follows a
triangle pattern that points to the tooth's pulp
. This pattern of decay is typically
described as two triangles (one triangle in enamel, and another in
dentin) with their bases conjoined to each other at the
dentino-enamel junction (DEJ). This base-to-base pattern is typical
of pit and fissure caries, unlike smooth-surface caries (where base
and apex of the two triangles join).
There are three types of smooth-surface caries. Proximal caries,
also called interproximal caries, form on the smooth surfaces
between adjacent teeth. Root caries form on the root surfaces of
teeth. The third type of smooth-surface caries occur on any other
smooth tooth surface.
In this radiograph, the dark spots in
the adjacent teeth show proximal caries.
Proximal caries are the most difficult type to detect. Frequently,
this type of caries cannot be detected visually or manually with a
. Proximal caries
form cervically (toward the roots of a tooth) just under the
contact between two teeth. As a result, radiographs
are needed for early discovery of
proximal caries. Under Black's classification system, proximal
caries on posterior teeth (premolars and molars) are designated as
Class II caries. Proximal caries on anterior teeth (incisors and
canines) are indicated as Class III if the incisal edge (chewing
surface) is not included and Class IV if the incisal edge is
Root caries, which are sometimes described as a category of
smooth-surfaces caries, are the third most common type of caries
and usually occur when the root surfaces have been exposed due to
recession. When the gingiva is
healthy, root caries is unlikely to develop because the root
surfaces are not as accessible to bacterial
. The root surface is more
vulnerable to the demineralization process than enamel because
begins to demineralize at 6.7
, which is higher than enamel's critical pH.
Regardless, it is easier to arrest the progression of root caries
than enamel caries because roots have a greater reuptake of
fluoride than enamel. Root caries are most likely to be found on
facial surfaces, then interproximal surfaces, then lingual
surfaces. Mandibular molars are the most common location to find
root caries, followed by mandibular premolars, maxillary anteriors,
maxillary posteriors, and mandibular anteriors.
Lesions on other smooth surfaces of teeth are also possible. Since
these occur in all smooth surface areas of enamel except for
interproximal areas, these types of caries are easily detected and
are associated with high levels of plaque and diets promoting
caries formation. Under Black's classification system, caries near
the gingiva on the facial or lingual surfaces is designated Class
V. Class VI is reserved for caries confined to cusp
tips on posterior teeth or incisal
edges of anterior teeth.
Other general descriptions
Besides the two previously mentioned categories, carious lesions
can be described further by their location on a particular surface
of a tooth. Caries on a tooth's surface that are nearest the cheeks
or lips are called "facial caries", and caries on surfaces facing
the tongue are known as "lingual caries". Facial caries can be
subdivided into buccal (when found on the surfaces of posterior
teeth nearest the cheeks) and labial (when found on the surfaces of
anterior teeth nearest the lips). Lingual caries can also be
described as palatal when found on the lingual surfaces of
maxillary teeth because they are located beside the hard palate
Caries near a tooth's cervix—the location where the crown of a
tooth and its roots meet—are referred to as cervical caries.
Occlusal caries are found on the chewing surfaces of posterior
teeth. Incisal caries are caries found on the chewing surfaces of
anterior teeth. Caries can also be described as "mesial" or
"distal." Mesial signifies a location on a tooth closer to the
median line of the face, which is located on a vertical axis
between the eyes, down the nose, and between the contact of the
central incisors. Locations on a tooth further away from the median
line are described as distal.
In some instances, caries are described in other ways that might
indicate the cause. "Baby bottle
", "early childhood caries", or "baby bottle
tooth decay" is a pattern of decay
found in young children with their deciduous
(baby) teeth. The teeth most
likely affected are the maxillary anterior teeth
, but all teeth can be
affected. The name for this type of caries comes from the fact that
the decay usually is a result of allowing children to fall asleep
liquids in their bottles or
feeding children sweetened liquids multiple times during the day.
Another pattern of decay is "rampant caries", which signifies
advanced or severe decay on multiple surfaces of many teeth.
Rampant caries may be seen in individuals with xerostomia
, poor oral hygiene, stimulant
use (due to drug-induced dry mouth),
and/or large sugar intake. If rampant caries is a result of
previous radiation to the head and neck, it may be described as
radiation-induced caries. Problems can also be caused by the self
destruction of roots and whole tooth
when new teeth erupt or later from unknown
Rate of progression
Temporal descriptions can be applied to caries to indicate the
progression rate and previous history. "Acute" signifies a quickly
developing condition, whereas "chronic" describes a condition which
has taken an extended time to develop where thousands of meals and
snacks, many causing some acid demineralisation that is not
remineralised and eventually results in cavities.
Recurrent caries, also described as secondary, are caries that
appears at a location with a previous history of caries. This is
frequently found on the margins of fillings and other dental
restorations. On the other hand, incipient caries describes decay
at a location that has not experienced previous decay. Arrested
caries describes a lesion on a tooth which was previously
demineralized but was remineralized before causing a
Affected hard tissue
Depending on which hard tissues are affected, it is possible to
describe caries as involving enamel, dentin, or cementum. Early in
its development, caries may affect only enamel. Once the extent of
decay reaches the deeper layer of dentin, "dentinal caries" is
used. Since cementum is the hard tissue that covers the roots of
teeth, it is not often affected by decay unless the roots of teeth
are exposed to the mouth. Although the term "cementum caries" may
be used to describe the decay on roots of teeth, very rarely does
caries affect the cementum alone. Roots have a very thin layer of
cementum over a large layer of dentin, and thus most caries
affecting cementum also affects dentin.
Signs and symptoms
Dental explorer used for caries diagnosis.
A person experiencing caries may not be aware of the disease. The
earliest sign of a new carious lesion is the appearance of a chalky
spot on the surface of the tooth,
indicating an area of demineralization of enamel. This is referred
to as incipient decay. As the lesion continues to demineralize, it
can turn brown but will eventually turn into a cavitation
("cavity"). Before the cavity forms, the process is reversible, but
once a cavity forms, the lost tooth structure cannot be regenerated
. A lesion which appears
and shiny suggests dental caries was
once present but the demineralization process has stopped, leaving
a stain. A brown spot which is dull in appearance is probably a
sign of active caries.
As the enamel and dentin are destroyed, the cavity becomes more
noticeable. The affected areas of the tooth change color and become
soft to the touch. Once the decay passes through enamel, the
dentinal tubules, which have passages to the nerve of the tooth,
become exposed and cause the tooth to hurt
. The pain may worsen with exposure to heat,
cold, or sweet foods and drinks. Dental caries can also cause
and foul tastes. In highly
progressed cases, infection
from the tooth to the surrounding soft
. Complications such as cavernous sinus thrombosis
There are four main criteria required for caries formation: a tooth
); caries-causing bacteria
; fermentable carbohydrates
(such as sucrose
); and time. The caries process does not have
an inevitable outcome, and different individuals will be
susceptible to different degrees depending on the shape of their
teeth, oral hygiene habits, and the buffering capacity of their
saliva. Dental caries can occur on any surface of a tooth which is
exposed to the oral cavity, but not the structures which are
retained within the bone.
There are certain diseases and disorders affecting teeth which may
leave an individual at a greater risk for caries. Amelogenesis imperfecta
occurs between 1 in 718 and 1 in 14,000 individuals, is a disease
in which the enamel does not fully form or forms in insufficient
amounts and can fall off a tooth. In both cases, teeth may be left
more vulnerable to decay because the enamel is not able to protect
In most people, disorders or diseases affecting teeth are not the
primary cause of dental caries. Ninety-six percent of tooth enamel
is composed of minerals. These minerals, especially hydroxyapatite
, will become soluble when
exposed to acidic environments. Enamel begins to demineralize at a
pH of 5.5. Dentin
are more susceptible to caries than
because they have lower mineral
content. Thus, when root surfaces of teeth are exposed from
gingival recession or periodontal disease, caries can develop more
readily. Even in a healthy oral environment, however, the tooth is
susceptible to dental caries.
The anatomy of teeth may affect the likelihood of caries formation.
Where the deep grooves of teeth are more numerous and exaggerated,
pit and fissure caries are more likely to develop. Also, caries are
more likely to develop when food is trapped between teeth.
A gram stain image of Streptococcus mutans
The mouth contains a wide variety of oral
, but only a few specific species of bacteria are
believed to cause dental caries: Streptococcus mutans
, Actinomyces viscosus
, Nocardia spp.
, and Streptococcus mutans
closely associated with caries, particularly root caries. Bacteria
collect around the teeth and gums in a sticky, creamy-coloured mass
, which serves as a
. Some sites collect plaque more
commonly than others. The grooves on the biting surfaces of
teeth provide microscopic retention, as
does the point of contact between teeth. Plaque may also collect
along the gingiva
Bacteria in a person's mouth convert glucose
, and most
(table sugar) into acids
such as lactic acid
through a glycolytic
process called fermentation
. If left in contact with
the tooth, these acids may cause demineralization, which is the
dissolution of its mineral
process is dynamic, however, as remineralization can also occur if
the acid is neutralized
by saliva or
mouthwash. Fluoride toothpaste or dental varnish may aid
remineralization. If demineralization continues over time, enough
mineral content may be lost so that the soft organic
material left behind disintegrates,
forming a cavity or hole. The impact such sugars have on the
progress of dental caries is called its cariogenicity. Sucrose,
although a bound glucose and fructose unit, is in fact more
cariogenic than a mixture of equal parts of glucose and fructose.
This is due to the bacteria utilising the energy in the saccharide
bond between the glucose and fructose subunits.
The frequency of which teeth are exposed to cariogenic (acidic)
environments affects the likelihood of caries development. After
bacteria in the mouth metabolize
resulting in an acidic by-product which decreases pH. As time
progresses, the pH returns to normal due to the buffering capacity
and the dissolved mineral content
of tooth surfaces. During every exposure to the acidic environment,
portions of the inorganic mineral content at the surface of teeth
dissolves and can remain dissolved for 2 hours. Since teeth are
vulnerable during these acidic periods, the development of dental
caries relies heavily on the frequency of acid exposure.
The carious process can begin within days of a tooth erupting into
the mouth if the diet is sufficiently rich in suitable
carbohydrates. Evidence suggests that the introduction of fluoride
treatments have slowed the process. Proximal caries take an average
of four years to pass through enamel in permanent teeth. Because
enveloping the root surface is
not nearly as durable as the enamel encasing the crown, root caries
tends to progress much more rapidly than decay on other surfaces.
The progression and loss of mineralization on the root surface is
2.5 times faster than caries in enamel. In very severe cases where
oral hygiene is very poor and where the diet is very rich in
fermentable carbohydrates, caries may cause cavities within months
of tooth eruption. This can occur, for example, when children
continuously drink sugary drinks from baby bottles.
Other risk factors
Reduced saliva is associated with increased caries since the
buffering capability of saliva is not present to counterbalance the
acidic environment created by certain foods. As a result, medical
conditions that reduce the amount of saliva produced by salivary glands
, particularly the submandibular gland
and parotid gland
, are likely to lead to
widespread tooth decay. Examples include Sjögren's syndrome
, diabetes mellitus
, diabetes insipidus
, and sarcoidosis
. Medications, such as antihistamines
and antidepressants, can also impair salivary flow. Moreover,
sixty-three percent of the most commonly prescribed medications in
the United States list dry mouth
known side effect. Radiation therapy of the head and neck may also
damage the cell
in salivary glands,
increasing the likelihood of caries formation.
The use of tobacco
may also increase the
risk for caries formation. Some brands of smokeless tobacco
contain high sugar
content, increasing susceptibility to caries. Tobacco use is a
significant risk factor for periodontal disease, which can cause
. As the gingiva loses attachment to the
teeth, the root surface becomes more visible in the mouth. If this
occurs, root caries is a concern since the cementum covering the
roots of teeth is more easily demineralized by acids than enamel.
Currently, there is not enough evidence to support a causal
relationship between smoking and coronal caries, but evidence
does suggest a relationship between
smoking and root-surface caries.
Intrauterine and neonatal lead
tooth decay . Well as lead
, all atoms
and ionic radius
those of calcium
bivalent as cadmium
mimics the calcium
and therefore its exposure may promote tooth
The progression of pit and fissure
caries resembles two triangles with their bases meeting along the
junction of enamel and dentin.
Enamel is a highly mineralized acellular tissue
, and caries act upon it through a
chemical process brought on by the acidic environment produced by
bacteria. As the bacteria consume the sugar and use it for their
own energy, they produce lactic acid. The effects of this process
include the demineralization of crystals in the enamel, caused by
acids, over time until the bacteria physically penetrate the
dentin. Enamel rods
, which are the basic
unit of the enamel structure, run perpendicularly from the surface
of the tooth to the dentin. Since demineralization of enamel by
caries generally follows the direction of the enamel rods, the
different triangular patterns between pit and fissure and
smooth-surface caries develop in the enamel because the orientation
of enamel rods are different in the two areas of the tooth.
As the enamel loses minerals , and dental caries progress, they
develop several distinct zones, visible under a light microscope.
From the deepest layer of the enamel to the enamel surface, the
identified areas are the: translucent zone, dark zones, body of the
lesion, and surface zone. The translucent zone is the first visible
sign of caries and coincides with a 1-2% loss of minerals. A slight
remineralization of enamel occurs in the dark zone, which serves as
an example of how the development of dental caries is an active
process with alternating changes. The area of greatest
demineralization and destruction is in the body of the lesion
itself. The surface zone remains relatively mineralized and is
present until the loss of tooth structure results in a
Unlike enamel, the dentin reacts to the progression of dental
caries. After tooth formation
, which produce enamel, are
destroyed once enamel formation
complete and thus cannot later regenerate enamel after its
destruction. On the other hand, dentin is produced
continuously throughout life by
, which reside at the border
between the pulp and dentin. Since odontoblasts are present, a
stimulus, such as caries, can trigger a biologic response. These
defense mechanisms include the formation of sclerotic and tertiary
In dentin from the deepest layer to the enamel, the distinct areas
affected by caries are the translucent zone, the zone of bacterial
penetration, and the zone of destruction. The translucent zone
represents the advancing front of the carious process and is where
the initial demineralization begins. The zones of bacterial
penetration and destruction are the locations of invading bacteria
and ultimately the decomposition
The faster spread of caries through
dentin creates this triangular appearance in smooth surface
The structure of dentin is an arrangement of microscopic channels,
called dentinal tubules, which radiate outward from the pulp
chamber to the exterior cementum or enamel border. The diameter of
the dentinal tubules is largest near the pulp (about 2.5 μm)
and smallest (about 900 nm) at the junction of dentin and
enamel. The carious process continues through the dentinal tubules,
which are responsible for the triangular patterns resulting from
the progression of caries deep into the tooth. The tubules also
allow caries to progress faster.
In response, the fluid inside the tubules bring immunoglobulins
from the immune system
to fight the bacterial
infection. At the same time, there is an increase of mineralization
of the surrounding tubules. This results in a constriction of the
tubules, which is an attempt to slow the bacterial progression. In
addition, as the acid from the bacteria demineralizes the
hydroxyapatite crystals, calcium
are released, allowing for the
precipitation of more crystals which fall deeper into the dentinal
tubule. These crystals form a barrier and slow the advancement of
caries. After these protective responses, the dentin is considered
Fluids within dentinal tubules are believed to be the mechanism by
which pain receptors are triggered within the pulp of the
The referred to theory is the widely-accepted hydrodynamic theory
of sensitivity. Since sclerotic dentin prevents the passage of such
fluids, pain that would otherwise serve as a warning of the
invading bacteria may not develop at first. Consequently, dental
caries may progress for a long period of time without any
sensitivity of the tooth, allowing for greater loss of tooth
In response to dental caries, there may the production of more
dentin toward the direction of the pulp. This new dentin is
referred to as tertiary dentin. Tertiary dentin is produced to
protect the pulp for as long as possible from the advancing
bacteria. As more tertiary dentin is produced, the size of the pulp
decreases. This type of dentin has been subdivided according to the
presence or absence of the original odontoblasts. If the
odontoblasts survive long enough to react to the dental caries,
then the dentin produced is called "reactionary" dentin. If the
odontoblasts are killed, the dentin produced is called "reparative"
In the case of reparative dentin, other cells are needed to assume
the role of the destroyed odontoblasts. Growth factors
, especially TGF-β
, are thought to initiate the production of
reparative dentin by fibroblasts
cells of the pulp.
Reparative dentin is produced at an average of 1.5 μm/day, but
can be increased to 3.5 μm/day. The resulting dentin contains
irregularly-shaped dentinal tubules which may not line up with
existing dentinal tubules. This diminishes the ability for dental
caries to progress within the dentinal tubules.
(A) A small spot of decay
visible on the surface of a tooth.
(B) The radiograph reveals an extensive
region of demineralization within the dentin (arrows).
(C) A hole is discovered on the side of the
tooth at the beginning of decay removal.
inspection of all visible tooth surfaces using a good light source,
. Dental radiographs
show dental caries before it is otherwise visible, particularly
caries between the teeth. Large dental caries are often apparent to
the naked eye, but smaller lesions can be difficult to identify.
Visual and tactile
inspection along with
radiographs are employed frequently among dentists, particularly to
diagnose pit and fissure caries. Early, uncavitated caries is often
diagnosed by blowing air across the suspect surface, which removes
moisture and changes the optical properties of the unmineralized
Some dental researchers have cautioned against the use of dental
explorers to find caries. In cases where a small area of tooth has
begun demineralizing but has not yet cavitated, the pressure
from the dental explorer could cause a
cavity. Since the carious process is reversible before a cavity is
present, it may be possible to arrest the caries with fluoride
and remineralize the tooth
surface. When a cavity is present, a restoration will be needed to
replace the lost tooth structure.
At times, pit and fissure caries may be difficult to detect.
Bacteria can penetrate the enamel to reach dentin, but then the
outer surface may remineralize, especially if fluoride is present.
These caries, sometimes referred to as "hidden caries", will still
be visible on x-ray radiographs, but visual examination of the
tooth would show the enamel intact or minimally perforated.
An amalgam used as a restorative material in a tooth.
Destroyed tooth structure does not fully regenerate, although
remineralization of very small carious lesions may occur if dental
hygiene is kept at optimal level. For the small lesions, topical
fluoride is sometimes used to encourage remineralization. For
larger lesions, the progression of dental caries can be stopped by
treatment. The goal of treatment is to preserve tooth structures
and prevent further destruction of the tooth.
Generally, early treatment is less painful and less expensive than
treatment of extensive decay. Anesthetics
— local, nitrous oxide
gas"), or other prescription medications — may be required in some
cases to relieve pain during or following treatment or to relieve
anxiety during treatment. A dental
("drill") is used to remove large portions of decayed
material from a tooth. A spoon is a dental instrument used to
remove decay carefully and is sometimes employed when the decay in
reaches near the pulp
. Once the decay is removed, the missing
tooth structure requires a dental
of some sort to return the tooth to functionality
and aesthetic condition.
Restorative materials include dental amalgam
, composite resin
, and gold
. Composite resin and porcelain can be
made to match the color of a patient's natural teeth and are thus
used more frequently when aesthetics are a concern. Composite
restorations are not as strong as dental amalgam and gold; some
dentists consider the latter as the only advisable restoration for
posterior areas where chewing forces are great. When the decay is
too extensive, there may not be enough tooth structure remaining to
allow a restorative material to be placed within the tooth. Thus, a
may be needed. This
restoration appears similar to a cap and is fitted over the
remainder of the natural crown of the tooth. Crowns are often made
of gold, porcelain, or porcelain fused to metal.
A tooth with extensive caries
eventually requiring extraction.
In certain cases, endodontic
may be necessary for the restoration of a tooth.
Endodontic therapy, also known as a "root canal", is recommended if
the pulp in a tooth dies from infection by decay-causing bacteria
or from trauma. During a root canal, the pulp of the tooth,
including the nerve and vascular tissues, is removed along with
decayed portions of the tooth. The canals are instrumented with
endodontic files to clean and shape them, and they are then usually
filled with a rubber-like material called gutta percha
. The tooth is filled and a crown
can be placed. Upon completion of a root canal, the tooth is now
non-vital, as it is devoid of any living tissue.
can also serve as
treatment for dental caries. The removal of the decayed tooth is
performed if the tooth is too far destroyed from the decay process
to effectively restore the tooth. Extractions are sometimes
considered if the tooth lacks an opposing tooth or will probably
cause further problems in the future, as may be the case for
. Extractions may also be
preferred by patients unable or unwilling to undergo the expense or
difficulties in restoring the tooth.
Personal hygiene care consists of proper brushing and flossing
daily. The purpose of oral hygiene is
to minimize any etiologic agents of disease in the mouth. The
primary focus of brushing and flossing is to remove and prevent the
formation of plaque
. Plaque consists
mostly of bacteria. As the amount of bacterial plaque increases,
the tooth is more vulnerable to dental caries when carbohydrates in
the food are left on teeth after every meal or snack. A toothbrush
can be used to remove plaque on accessible surfaces, but not
between teeth or inside pits and fissures on chewing surfaces. When
used correctly, dental floss removes plaque from areas which could
otherwise develop proximal caries. Other adjunct hygiene aids
include interdental brushes
, and mouthwashes
However oral hygiene is probably more effective at preventing gum
disease than tooth decay. The brush and fluoride toothpaste have no
access inside pits and fissures, where chewing forces food to be
trapped. (Occlusal caries accounts for between 80 and 90 percent of
caries in children (Weintraub, 2001). The teeth at highest risk for
carious lesions are the first and second permanent molars.)
Professional hygiene care consists of regular dental examinations
and cleanings. Sometimes, complete plaque removal is difficult, and
a dentist or dental hygienist
be needed. Along with oral hygiene, radiographs may be taken at
dental visits to detect possible dental caries development in high
risk areas of the mouth.
For dental health, frequency of sugar intake is more important than
the amount of sugar consumed. In the presence of sugar and other
carbohydrates, bacteria in the mouth produce acids which can
demineralize enamel, dentin, and cementum. The more frequently
teeth are exposed to this environment, the more likely dental
caries are to occur. Therefore, minimizing snacking is recommended,
since snacking creates a continual supply of nutrition for
acid-creating bacteria in the mouth. Also, chewy and sticky foods
(such as dried fruit or candy) tend to adhere to teeth longer, and
consequently are best eaten as part of a meal. Brushing the teeth
after meals is recommended. For children, the American Dental Association
the European Academy of Paediatric Dentistry recommend limiting the
frequency of consumption of drinks with sugar, and not giving baby
bottles to infants during sleep. Mothers are also recommended to
avoid sharing utensils and cups with their infants to prevent
transferring bacteria from the mother's mouth.
It has been found that milk
and certain kinds
can help counter tooth decay if eaten
soon after the consumption of foods potentially harmful to teeth.
chewing gum containing xylitol (a sugar
alcohol) is widely used to protect teeth in some countries, being
especially popular in the Finnish candy
Xylitol's effect on reducing plaque is probably
due to bacteria's inability to utilize it like other sugars.
Chewing and stimulation of flavour receptors on the tongue are also
known to increase the production and release of saliva, which
contains natural buffers to prevent the lowering of pH in the mouth
to the point where enamel may become demineralised.
Common dentistry trays used to deliver fluoride.
Other preventive measures
The use of dental sealants
is a means
of prevention. A sealant is a thin plastic-like coating applied to
the chewing surfaces of the molars. This coating prevents food
being trapped inside pits and fissures in grooves under chewing
pressure so resident plaque bacteria are deprived of carbohydrate
that they change to acid demineralisation and thus prevents the
formation of pit and fissure caries, the most common form of dental
caries. Sealants are usually applied on the teeth of children,
shortly after the molars erupt. Older people may also benefit from
the use of tooth sealants, but their dental history and likelihood
of caries formation are usually taken into consideration.
Calcium, as found in milk and green vegetables are often
recommended to protect against dental caries. It has been
demonstrated that Calcium
supplements decrease the incidence of dental caries. Fluoride helps
prevent decay of a tooth by binding to the hydroxyapatite crystals
in enamel. The incorporated Calcium makes enamel more resistant to
demineralization and, thus, resistant to decay. Topical fluoride is
also recommended to protect the surface of the teeth. This may
include a fluoride toothpaste
mouthwash. Many dentists include application of topical fluoride
solutions as part of routine visits.
Furthermore, recent research shows that low intensity laser
radiation of argon
lasers may prevent the susceptibility for enamel caries and white
spot lesions. Also, as bacteria are a major factor contributing to
poor oral health, there is currently research to find a vaccine for dental caries
. As of 2004, such a
vaccine has been successfully tested on animals, and is in clinical
trials for humans as of May 2006.
[[Image:Dental caries world map - DALY - WHO2004.svg|thumb|Disability-adjusted life year
for dental caries per 100,000 inhabitants in 2004.
]]Worldwide, most children and an estimated ninety percent of
adults have experienced caries, with the disease most prevalent in
Asian and Latin American countries and least prevalent in African
countries. In the United States, dental caries is the most common
childhood disease, being
at least five times more common than asthma
It is the primary pathological cause of tooth loss in children.
Between 29% and 59% of adults over the age of fifty experience
The number of cases has decreased in some developed countries, and
this decline is usually attributed to increasingly better oral hygiene
practices and preventive measures
such as fluoride treatment
Nonetheless, countries that have experienced an overall decrease in
cases of tooth decay continue to have a disparity in the
distribution of the disease. Among children in the United States
and Europe, twenty percent of the population endures sixty to
eighty percent of cases of dental caries. A similarly skewed
distribution of the disease is found throughout the world with some
children having none or very few caries and others having a high
number. Australia, Nepal, and
Sweden have a low incidence of cases of dental caries
among children, whereas cases are more numerous in Costa Rica and Slovakia.
The classic "DMF" (decay/missing/filled) index is one of the most
common methods for assessing caries prevalence as well as dental
treatment needs among populations. This index is based on in-field
clinical examination of individuals by using a probe, mirror and
cotton rolls. Because the DMF index is done without X-ray
imaging, it underestimates real caries
prevalence and treatment needs.
There is a long history of dental caries. Over a million years ago,
such as Australopithecus
suffered from cavities.
The largest increases in the prevalence of caries have been
associated with dietary changes.Archaeological evidence shows that
tooth decay is an ancient disease dating far into prehistory
from a million years ago through the neolithic
period show signs of caries, excepting
those from the Paleolithic
ages. The increase of caries during
the neolithic period may be attributed to the increase of plant
foods containing carbohydrates
beginning of rice cultivation in South
is also believed to have caused an increase in
text from 5000 BC
describes a "tooth worm" as the cause of caries. Evidence of this
belief has also been found in India, Egypt, Japan, and
Unearthed ancient skulls show evidence of primitive dental work.
Pakistan, teeth dating from around 5500 BC to 7000 BC show
nearly perfect holes from primitive dental
drills. The Ebers
Papyrus, an Egyptian text from
1550 BC, mentions diseases of teeth.
During the Sargonid dynasty
during 668 to 626 BC, writings from the
king's physician specify the need to extract a tooth due to
. In the Roman Empire
, wider consumption of cooked foods
led to a small increase in caries prevalence. The Greco-Roman
civilization, in addition to the Egyptian, had treatments for pain
resulting from caries.
The rate of caries remained low through the Bronze
sharply increased during the Medieval
. Periodic increases in caries prevalence had been small
in comparison to the 1000 AD increase, when sugar cane
became more accessible to the Western
world. Treatment consisted mainly of herbal remedies and charms,
but sometimes also included bloodletting
. The barber surgeons
of the time provided services
that included tooth extractions
Learning their training from apprenticeships, these health
providers were quite successful in ending tooth pain and likely
prevented systemic spread of infections in many cases. Among Roman
Catholics, prayers to Saint
, the patroness of dentistry, were meant to heal pain
derived from tooth infection.
There is also evidence of caries increase in North American Indians
after contact with colonizing Europeans. Before colonization, North
American Indians subsisted on hunter-gatherer diets, but afterwards
there was a greater reliance on maize
agriculture, which made these groups more susceptible to
In the medieval Islamic world
such as al-Gazzar
(in The Canon of Medicine
the earliest known treatments for caries, though they also believed
that it was caused by tooth worms as the ancients had. This was
eventually proven false in 1200 by another Muslim dentist named
Gaubari, who in his Book of the Elite concerning the unmasking
of mysteries and tearing of veils
, was the first to reject the
idea of caries being caused by tooth worms, and he stated that
tooth worms in fact do not even exist. The theory of the tooth worm
was thus no longer accepted in the Islamic medical community from
the 13th century onwards.
During the European Age of
, the belief that a "tooth worm" caused caries was
also no longer accepted in the European medical community. Pierre Fauchard
, known as the father of
modern dentistry, was one of the first to reject the idea that
worms caused tooth decay and noted that sugar was detrimental to
the teeth and gingiva
. In 1850, another
sharp increase in the prevalence of caries occurred and is believed
to be a result of widespread diet changes. Prior to this time,
cervical caries was the most frequent type of caries, but increased
availability of sugar cane, refined flour, bread, and sweetened tea
corresponded with a greater number of pit and fissure caries.
In the 1890s, W.D. Miller conducted a series of studies that led
him to propose an explanation for dental caries that was
influential for current theories. He found that bacteria inhabited
the mouth and that they produced acids which dissolved tooth
structures when in the presence of fermentable carbohydrates. This
explanation is known as the chemoparasitic caries theory. Miller's
contribution, along with the research on plaque by G.V. Black
and J.L. Williams, served as the
foundation for the current explanation of the etiology of caries.
Several of the specific strains of bacteria were identified in 1921
by Fernando E. Rodriguez Vargas
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