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Are some children more prone to decay than others? If
so what can you do about it?
Some children have more decay than others and are more susceptible
to decay. This can be true of children in the same family.
The only way we can tell is by the amount of decay present:
those who have decay at the age of two are probably going
to have more problems with their permanent teeth.
What can parents do about this?
These children would probably benefit from extra fluoride,
which can reduce their susceptibility to decay by about half.
Fissure sealing may also be recommended for children whose
teeth are ‘at risk’. This involves painting a plastic
coating on the permanent molars. It is particularly useful
for teeth with deep groovesm,which cannot be reached with
a toothbrush.
Meanwhile, limiting the number of times children eat sugary
foods or have sweet drinks, and brushing effectively are the
main weapons against decay.
Children under seven don’t have the manual dexterity
or the mental application to brush effectively, so parents
should do it for them. Technique is less important than the
end result. What matters is that you reach all areas of the
mouth. Use a small-headed brush with soft bristles. The shape
and angle of the head aren’t important.
How Much Fluoride?
Advice to parents has changed in recent years. Whereas it
was thought that fluoride worked best if given by mouth as
drops or tablets, dentists now think that topical application,
in toothpaste, is preferable. Most dentists today recommend
supplementation only for children at high risk of decay –
for example those with decay in their milk teeth. Children
who aren’t at particular risk should get all the fluoride
they need from toothpaste.
If a child has too much fluoride when the permanent front
teeth are developing – around the second birthday –
it can lead to the discoloration know as fluorosis. But working
out how much a child is getting can be difficult. It’s
the total intake – from supplements, toothpaste and the
water you drink – that matters.
All water contains some fluoride (including bottled water),
but you can’t tell how much, unless you call your water
company to ask. If you live in an area with more that 0.7
parts per million of fluoride in the drinking water, don’t
give your child extra fluoride.
Young children often swallow toothpaste and this can pose
a problem. There is evidence of a connection between swallowing
fluoride toothpaste and enamel mottling in children. It’s
been suggested that young children may swallow up to half
the paste on the brush, so children up to six who are caries-free
should just use a pea-sized amount of low-fluoride toothpaste
(around 500 parts per million). You can check the fluoride
content of toothpaste in the list of ingredients – it’s
listed as ppmF. Children over six, and those at high risk,
should use a pea-sized amount of adult-strength fluoride toothpaste
(1,000 or 1,500 ppmF), rather than ‘baby’ toothpastes,
which contain less fluoride.
According to the latest evidence, it is best to spit out toothpaste
but not to rinse. The more frequently children rinse and the
more water they use, the quicker the fluoride is cleared from
the mouth. Not rinsing means fluoride is retained in the mouth
longer, giving better benefit.
The mottling caused by fluoride – fluorosis – is
permanent, but there are ways of cosmetically whitening the
teeth using micro abrasion, a crown or white filling material.
A slow-release fluoride implant developed by Jack Toumba at
Leeds Dental Institute releases fluoride continuously into
the mouth. The implant is made of glass, is about the size
of a grain of rice and is attached by the dentist to the back
tooth with dental cement. One study showed that after two
years, children with this implant had 76 per cent fewer cavities
then those without the implant. The device may be available
in about five years’ time. It won’t completely eliminate
cavities, but it’s expected to reduce them dramatically.
Contributed by Dr Jack Toumba
To Fill or Not?
A 1995 survey of pre-school children showed that only one
in eight of those with decay had had a filling, a figure paediatric
dentists find shocking. There is a widespread belief that
baby teeth don’t have a nerve supply, and so don’t
need to be filled. This is nonsense. If there is decay in
baby teeth it needs filling, otherwise the decay will worsen
and cause pain. Occasionally, if there is no pain and the
tooth is going to fall out naturally within six months it
can be left.
Mercury amalgam fillings are the subject of enormous controversy.
Amalgam is a toxic substance and some experts are concerned
that it may leak out of the fillings and accumulate in the
body tissues. The Department of Health has advised that amalgam
fillings should not be given to pregnant women. However, the
evidence against mercury amalgams is not conclusive, and many
dentists continue to use them.
Removing an amalgam filling can sometimes be more risky than
leaving it in place because fine mercury particles are released
during drilling.
It is hard to match amalgam for its longevity and its ease
of application. In this practice we are using fewer and fewer
amalgam fillings. The alternative materials are improving
all the time.
Which Drink?
No drink other than milk or water is totally safe. Fruit drinks
contain naturally occurring fructose which can cause decay
in just the same way as added sugar.
But sugar isn’t the only problem. We’re also seeing
more acid erosion of teeth, particularly in teenagers and
young adults. Fizzy drinks – even diet drinks –
contain carbonic acid, and orange, apple and grapefruit juice
are also extremely acidic. This changes the acid/alkali balance
in the mouth. The acid begins to dissolve the enamel of the
tooth, the dentine is exposed and the teeth become sensitive.
The best way to avoid this decay is to keep a check on how
often your child drinks and for how long.
If your child is going to drink juice or fizzy drinks, it’s
better to have them with meals, when the mouth is producing
plenty of alkaline saliva, which helps to protect the teeth
from the acidity of the drinks. My advice is to restrict children
to five ‘meal moments’ a day – three main meals
and two snacks. At those times, children can eat and drink
what the like as long as they are brushing twice a day with
a fluoride toothpaste. The rest of the time, stick to milk
or water. When they have a fizzy drink, give them a straw
and make sure they drink it quickly.
Contributed by Dr Jack Toumba
10 Ways To Protect Your Child`s Teeth
- Supervise under-sevens with tooth brushing. If they want
to do it themselves, let them, but still do a final brush
for them when they’ve finished.
- Brush with fluoride toothpaste twice a day. Children over
six can use an adult-strength formula.
- Don’t let them rinse after brushing.
- Only give juice or fizzy drinks with meals or snacks.
Stick to milk or water at other times.
- Use a straw for fizzy drinks.
- Encourage your child to consume drinks as quickly as possible,
rather than sipping them over a long period.
- Limit sweet-eating to straight after meals, when the extra
saliva created by chewing will help to protect the teeth.
If your child’s first teeth are already decayed:
- Give fluoride drops, but ask your dentist’s advice
first.
- Take your child to the dentist so his teeth can be filled.
- Ask about fissure sealing
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D E N T A L I N J U R I E S
DENTAL TRAUMA TO PRIMARY TEETH
Trauma to primary teeth commonly occurs between 2-4 years
of age. This at a time when children begin to walk but are
not very stable on their feet. The most commonly involved
teeth are the primary maxillary central incisors.
So why it it important to seek dental help following dental
trauma to primary teeth?
Injuries to primary teeth have the potential to disturb the
development and health of the underlying permanent teeth.
In order to achieve an optimal treatment outcome, a prompt
assessment of the injury by a dentist is essential. The assessment
would normally involve a thorough history, and detailed clinical
and radiographic checks.
Paediatric dentists are skilled at saving injured primary
teeth although they only do so provided there is no risk to
the underlying permanent teeth, which have a lifelong functional
and aesthetic importance.
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DISCOLOURED PRIMARY INCISORS
Findings: Colour change is a common sign of primary tooth
trauma and may range from yellow to grey to black.
Treatment objectives: Any colour change in a traumatized primary
teeth indicates the necessity for clinical and radiographic
assessment. Although colour changes do not necessarily require
immediate treatment, discoloured primary teeth are more likely
to undergo pathologic changes and should be kept under supervision
to ensure the best possible health of the developing permanent
teeth.
DSPLACED PRIMARY INCISORS
The primary incisors may be displaced in several directions:
1) Intrusion: the tooth is pushed into the tooth socket and
it looks shorter or absent.
2) Extrusion: the tooth is partly pushed out of its socket
and it looks longer in length.
3) Lateral luxation: the tooth is displaced sideways, palatally
or towards the lip.
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TREATMENT OBJECTIVES:
Intrusion injuries present a high risk of damage to the developing
permanent tooth in the alveolar bone. Therefore the treatment
options depend on the relationship between the root of the
primary tooth and the crown of the developing permanent tooth.
X-rays are necessary to determine this relationship. If there
is no evidence of a compromise to the developing permanent
tooth, the primary tooth may be left to spontaneously re-erupt.
However, the tooth should be extracted if it has not re-erupted
within six months.
If the intruded tooth appears to have compromised the developing
tooth, it should be carefully extracted immediately, to avoid
any further damage.
For extruded or laterally luxated teeth, the tooth should
always be monitored even if there has only been a mild displacement.
It may need to be extracted if the displacement is severe.
With any type of displacement, a long term clinical and radiographic
follow-up is essential to monitor the vitality of these teeth
and to ensure that there is no delayed infection of the root
which can damage the developing permanent tooth.
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FRACTURED PRIMARY TEETH:
Findings: Fracture of primary tooth may occur in the crown
or the root of the tooth. The crown fracture may involve the
enamel, enamel and dentine or enamel, dentine and the nerve
(pulp) of the tooth.
Treatment objectives: The rough edges of simple enamel fractures
can be smoothed off. If there is enamel-dentine fracture,
the crown of the tooth needs to be restored to protect the
pulp of the tooth. If the fracture also involves the pulp
of the tooth, then, depending on the stage of development
of the primary tooth, the tooth may need to be extracted or
have root canal treatment carried out.
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AVULSED PRIMARY INCISORS
Findings: This is complete displacement of a tooth out of
its bony socket. There may be associated soft tissue injuries
to the lips and gums.
Treatment objectives: Avulsed primary incisors SHOULD NOT
be re-planted as this may cause damage to the developing permanent
tooth underneath.
The alvusion of the primary tooth itself may cause damage
to the developing permanent tooth underneath. This may be
in the form of disturbance in enamel formation or disturbance
in the eruption time of the permanent tooth.
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PRIMARY TOOTH ROOT FRACTURE:
Findings: This is a rare occurrence, however when it occurs,
the primary tooth may appear displaced or mobile.
Treatment objectives: If the coronal fragment is very mobile
or severely displaced, then this require extraction. The remaining
fractured root should be left undisturbed if deep in the bony
socket. Attempts to remove deep apical fragments can damage
the permanent tooth underneath. The apical fragment is usually
resorbed physiologically.
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PAEDIATRIC DENTAL TRAUMA – PERMANENT TEETH
Dental trauma most often occurs to upper incisors, usually
between 8-12 years of age, and is more common in boys. These
injuries are most commonly related to falls, fights, sporting
injuries and road traffic accidents.
At this age the root development of the incisors is not yet
complete, and prompt referral to a Paediatric Dentist is essential
for immediate assessment and care. This is to optimise the
survival of the nerves of teeth and therefore their continued
development. If there has been damage to the nerve or blood
supply of the tooth, long term follow-up with possible treatment
may be necessary.
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AVULSED PERMANENT INCISOR:
Findings: The tooth is completely displaced from the socket.
Treatment objectives: To replace the tooth as soon as possible
(unless this is contraindicated due to a compromising medical
condition which would require antibiotic cover prior to any
dental treatment).
The survival of avulsed teeth depends very strongly on the
length of time the tooth is out of the mouth and how it is
stored. The best survival outcome is for teeth that are replanted
immediately. If the tooth is out of the mouth for more than
5 minutes, it must be kept moist to prevent further damage
to the dental cells. The tooth may be stored in fresh cold
milk, in the mouth, or in physiologic saline.
The tooth must not be handled by the root and should not be
scrubbed to remove dirt. Holding the tooth by the crown, it
can be gently washed with saline or sterile water followed
by re-implantation. It should then be held in place by biting
on a clean handkerchief and the patient taken to a dentist
immediately.
This tooth should then be splinted for 7-10 days and the patient
should be given appropriate antibiotics, a mouthwash and referred
for a tetanus prophylaxis as required.
The follow-up treatment depends on the stage of root development
of the tooth.
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DISPLACED PERMANENT INCISORS:
Findings: Displacement of the tooth may be seen as one of
the following;
a) Partial displacement of tooth out of bony socket (the tooth
looks longer).
b) Partial displacement of tooth into the bony socket (the
tooth looks shorter).
c) Displacement of the tooth sideways.
Treatment objectives: The main objectives are to re-position
these teeth into the correct position and stabilize them to
prevent further damage to the supporting structures, nerve
and blood supply of the tooth/teeth.
The timing of the re-positioning may be immediate or delayed,
and is dependent upon a number of factors.
The displaced teeth will require long term follow-up with
X-rays and may require root canal treatment if there has been
an irreversible damage to the nerve and blood supply of the
teeth.
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FRACTURED PERMANENT INCISORS:
Findings: The fracture may involve one or all of the following
dental tissues: enamel, dentine, pulp (nerve) of the tooth.
Fracture of enamel and dentine, or enamel, dentine and pulp
is usually associated with sensitivity to cold air and pain.
Treatment objectives: The main objective following this type
of injury is to maintain the vitality of the pulp and prevent
pain.
If the nerve of the tooth is not involved, then the tooth
can be built-up with tooth-coloured filling material. If however,
the nerve is exposed, depending on size of exposure and time
since it occurred, the nerve will need to be treated.
In most cases, even if the nerve is removed, the tooth can
be restored to almost the original shape. The aesthetics of
these teeth are usually slightly compromised until the mid-teens
when advanced restorative work can be carried out.
In the meantime all efforts should be concentrated on saving
the traumatized tooth and monitoring the root development
using X-rays.
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PERMANENT TOOTH ROOT FRACTURE:
Findings: The traumatized tooth may look normal, have increased
mobility or the tooth may look displaced.
Treatment objectives: Multiple dental X-rays are necessary
to assess the level and extent of the fracture.
Some root fractures require immobilization, and prompt treatment
of such fractures increases the chance of healing and hence
tooth survival.
Preventing Dental Decay
The following three articles were originally published in Dental
Digest, which is provided as a service to health professionals
through an educational grant from the Sugar Bureau.
1. FLUORIDE USE IN DENTAL CARE
By J M ten Cate, Academic Centre for Dentistry, Amsterdam, The
Netherlands
The caries preventive effects of fluoride have been known since
the 1930s. But, it has taken a considerable length of time for
the mechanisms of action of fluoride to be unravelled. Our current
understanding of the caries process and the way fluoride interacts
with tooth decay has led to a more rational approach to fluoride
use resulting in increased effectiveness and improved cost effectiveness.
Dental caries is now known to result from an imbalance between
the dissolution of the dental hard tissue and the reprecipitation
of these tissues from the oral fluids. The former occurs when
dietary sugars and starches are metabolised in dental plaque,
forming cariogenic acids and yielding a pH of plaque which can
dissolve dental tissue minerals. Typically this occurs at pH
values below approximately 5.5. The building blocks of the hard
tissues (in particular calcium and phosphate ions) are present
in saliva and the aqueous phase of dental plaque. Consequently,
when the pH of plaque is near neutrality (pH 7.0) these minerals
present in saliva can be deposited onto the tooth surface. When
this occurs at the tooth surface it leads to calculus formation.
When minerals are deposited in porous dental tissues, however,
remineralisation of previously formed caries lesions or the
maturation of the dentition after eruption takes place.
Fluoride interferes with both of these processes mentioned above.
Incorporation of fluoride into the tooth mineral reduces the
potentially erosive and cariogenic effect of acids. Moreover,
the presence of low concentrations of fluoride in saliva, or
plaque, stimulates the precipitation of hydroxyapatite, a main
component of tooth enamel. In this way both sides of the caries
pendulum are favourably affected by fluoride. The presence of
fluoride in dental tissues does not completely protect teeth
from cariogenic acids: dissolution is only slowed down, and
this again depends on whether fluoride ions are available in
the fluids in which the teeth are bathed (i.e. saliva). This
explains why fluoride is only effective in caries prevention
when it is provided to the oral cavity on a regular basis. Fluoride
provided via drinking water, or by regular brushing with fluoride
toothpaste, has been shown to be significantly more effective
than applying fluoride periodically e.g. by topical applications.
Calcium fluoride In addition to the mechanism described above,
fluoride may precipitate onto tooth surfaces as calcium fluoride
(CaF2).1 Elevated levels of fluoride, typically above 10 parts
per million (ppm), are required for this to occur. Calcium fluoride
forms after the topical acidic application of fluoride, for
example with products containing 0.4 or 1.2% fluoride. In the
past, topical applications were formulated with the addition
of phosphoric acid, commonly known as Acidulated Phosphate Fluoride
solutions or gels. The addition of phosphate served to limit
the dissolution of enamel or dentine and thereby the formation
of calcium fluoride. This approach was based on the observation
that calcium fluoride dissolves quickly in water, and it was
assumed that calcium fluoride would be washed away from the
dentition by the oral fluids. However, it was found later that
relatively stable calcium fluoride globules were formed in the
mouth, protected by a protein and phosphate rich coating. Moreover,
these globules have been shown to possess pH- modulated slow
release properties for fluoride. In essence this means that
at low pH values the stabilising coating breaks open releasing
the fluoride. Fluoride is therefore available to act against
dental caries development when it is most needed. Formulation
issues In recent years, questions have been raised over how
the protective effects of fluoridated toothpaste could be increased
further. Should the fluoride content be increased, possibly
beyond the current maximum level permitted, or should the type
of fluoride active in toothpaste be changed? On the latter topic,
there have been many changes to the formulation of toothpaste
over time. The fluoride salt used experimentally in toothpaste
in the 1940s (sodium fluoride) was found to be clinically inactive
as a result of binding to the abrasive used at that time. This
led to the formulation of monofluoro-phosphate and the use of
stannous fluoride, both of which were compatible with calcium-containing
abrasives. In the 1980s abrasives compatible with sodium fluoride
were introduced, e.g. hydrated silica. Besides monofluoro-phosphate
and sodium fluoride, amine fluoride is added to toothpaste and
other caries-preventative products. The mode of action of all
fluoride 'actives' is similar, in that the caries preventative
effect originates from the fluoride anion (F-). In addition
to this, amine and stannous, as counter-ions, have an antimicrobial
effect. Fluoride level in toothpastes The optimal level of fluoride
that should be added to toothpaste has also been the subject
of wide discussion. A number of studies have recently investigated
the use of fluoride in toothpaste at levels exceeding the maximum
level allowed in the USA (1100ppm) or in Europe (1450ppm). Increasing
fluoride addition to 2800ppm resulted in a 20% increase in protective
effect observed.2 This additional benefit, however, is considered
to be relatively small in comparison to other tooth brushing
parameters (frequency of brushing, rinsing after brushing etc.).
It was also argued that the additional risk of fluorosis, at
least as perceived by the public, would not justify further
investigation of this option. Other studies have even questioned
the 1500ppm maximum level applied in Europe,3 as relatively
little data illustrate increased efficacy as a result of increasing
fluoride addition from 1000 to 1450ppm.4 Without question, this
issue requires further investigation to determine the optimum
formulation of toothpaste and obtain universal agreement on
acceptable fluoride levels. Children's toothpaste Fine-tuning
the fluoride level of toothpaste, in terms of maximum benefit
and minimal fluoride ingestion, is also of relevance in designing
a fluoride toothpaste to be used by children. For this reason
a study was performed on the dose-response relationship of a
range of fluoride concentrations in toothpastes using a laboratory-simulated
dental caries model. 'pH cycling' experiments simulate the fluctuations
in pH that occur naturally in the mouth. The effects of treatments
on inhibiting demineralisation and enhancing remineralisation
are differentiated by this method. The greatest net effect on
enamel was observed between the 0 and 250ppm fluoride treatments.
But some additional benefit was observed with increasing fluoride
concentration. Remineralisation also increased gradually with
increasing fluoride concentration. These findings confirm that
increasing the fluoride content of toothpaste gives additional
benefit, with the largest effect observed in the range 0-500ppm
fluoride. A fluoride toothpaste, containing 500ppm, has been
specially developed for children's use and is now available
in many European countries. Fluoridation of drinking water Toothpaste
is obviously not the only vehicle by which fluoride may be supplied
to the dentition and products such as fluoride rinses, lacquers,
gels, and tablets are still prescribed for use. Large differences
exist between countries, in regard to the protocols employed.
These originate to an extent from government preference, but
they are also determined by regional caries prevalence data
and geographical factors. Fluoridation of the drinking water,
either when naturally present or when it is added, is still
the preferred method of administering fluoride to a population.
The reason for this is that water is drunk by consumers in high
volumes and is also used for cooking. The frequency of exposure
of teeth to fluoride is therefore increased. An important consideration
in implementation of water fluoridation is that this method
of fluoride 'application' does not require compliance of the
individual. Toothpaste differs from the other products mentioned
in terms of compliance, as tooth brushing is widely used and
is generally well adhered to as part of the daily oral hygiene
routine of most individuals. Fluoridation of drinking water
has a long and turbulent history. The original discovery of
the caries-protective effects of fluoride was made in regions
where drinking water contained fluoride. A light to heavy staining
of the teeth was found to be associated with low caries prevalence.
Later studies by Dean revealed that the presence of around Ippm
fluoride resulted in a substantial reduction in caries prevalence
and no staining (fluorosis) was apparent.5 Studies and intervention
programs on the addition of fluoride to drinking water have
used this fluoride level. As fluoride is naturally present in
drinking water in many parts of the world, it has been relatively
easy to study the possible side effects resulting from long
term consumption of fluoridated water. These studies have all
shown that fluoride use is safe and is very beneficial to oral
health.6
Promotion of artificial fluoridation of drinking water has proved,
however, to be very difficult. Small groups of individuals,
protesting against fluoride, have often been more influential
than large bodies of dental practitioners or the wealth of data
available from balanced scientific studies. Conclusion Fluoride
is, without question, the most powerful caries preventative
agent, and is probably the only one for which a substantial
efficacy has been shown beyond doubt. It is also a therapeutic
agent which is safe for use, as shown in many long term studies.
The current divergence in caries prevalence and incidence between
various groups in society will probably lead to more individualised
recommendations for oral health schemes and the development
of new products specifically for high risk groups.
References
1. Petzold M. The influence of different fluoride compounds
and CaF2 precipitation and microstructure. Caries Res 2001;35:Suppl
1:45-51.
2. Biesbrock A R et al. Relative anti- caries efficacy of
1100, 1700, 2200, and 2800 ppm fluoride ion in a sodium fluoride
dentifrice over 1 year. Community Dent Oral Epidemiol 2001;29:382-9.
3. Bloch-Zupan A. Is the fluoride concentration limit of
1,500 ppm in cosmetics (EU guideline) still up-to- date? Caries
Res 2001;35:Suppl 1:22-5.
4. 0' Mullane D et al. A three-year clinical trial of a
combination of trimetaphosphate and sodium fluoride in silica
toothpastes. J Dent Res1997;76:1776-1781.
5. Aoba T and Fejerskov O. Dental fluorosis: chemistry and
biology. Crit Rev Oral BioI Med 2002;13:155-170.
6. McDonagh MS et al. Systematic review of water fluoridation.
BMJ 2000;321 :855-859.
Key points.
Fluoride is the most powerful weapon available in the fight
against dental caries. The addition of fluoride to toothpaste
and drinking water increases the frequency of fluoride exposure
to teeth, a factor highly influential in caries prevalence.
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2, DENTIFRICES
By Dr Ralph M Duckworth, Unilever Dental Research, Bebington,
Wirral, CH63 3JW
Good oral hygiene is a prerequisite to maintaining oral health.
The term dentifrice was originally used to describe any mixture,
or preparation, used to clean teeth in conjunction with a
toothbrush. Whilst this definition still applies, toothpaste
and dentifrice have been almost synonymous for more than 50
years. Despite the proliferation of other product forms, the
toothbrush/ toothpaste combination is the most common aid
to oral hygiene practised today. The basic ingredients of
a toothpaste (abrasive particles or cleaning agent, detergent
and water) enable removal of food debris, plaque bacteria
and, to a lesser extent, tartar. The addition of for example
sorbitol, and/or glycerol, and particulate or polymeric thickeners
make the final formulation into a manageable paste. Flavourings
and artificial sweeteners, for example saccharin, are added
to give the paste a pleasant taste. Key components of a modern
dentifrice are the therapeutic agents, which have made an
increasing impact over the past 50 years.
Fluoride is the only anticaries agent with extensive clinical
proof of efficacy. Following epidemiological observations
of an inverse association between caries prevalence and natural
levels of fluoride in drinking water, an era of artificial
water fluoridation arose in the late 1940s and 1950s. The
first successful fluoridated dentifrice, Crest, was introduced
in the USA in 1955. Since then, over 100 clinical trials have
been conducted on a variety of fluoride toothpaste formulations.
On average, 3-year reductions in caries incidence of about
25% were recorded, relative to non- fluoridated control dentifrices.1
The anticaries efficacy of fluoridated toothpaste is linked
to the oral hygiene routine employed. Increased frequency
of brushing has been proven to increase efficacy, whereas
thorough rinsing with water can have a marked detrimental
effect as the fluoride is removed from the mouth.2 Today,
the most common sources of fluoride in toothpastes are sodium
fluoride (NaF) and sodium mono- fluorophosphate (Na2FPO3,
often abbreviated to SMFP). Although NaF is regarded by some
researchers as marginally more effective, SMFP is often used
because it is compatible with a wider range of formulation
ingredients. As high doses of fluoride can cause fluorosis
and be toxic, the fluoride content of toothpaste is regulated
by legislation for safety. In Europe no more than 1500 ppm
F (0.32% NaF, 1.14% SMFP) is permitted, whilst in some other
countries the limit is 1000 ppm F (0.22% NaF, 0.76% SMFP).
As an aid to control tooth decay, toothpastes with this level
of fluoride can be assumed to be 'safe and effective' for
the general population. Young children are at higher risk
of dental fluorosis owing to their tendency to swallow paste
at a time when the permanent teeth are being formed.
The British Society of Paediatric Dentistry has recommended
that such children should use toothpaste containing no more
than 600 ppm F and, moreover, use a small pea-sized amount
of paste per brushing.' For this reason toothpastes with a
lower fluoride content are available for children under the
age of 6. A simple 'rule of thumb' is for adults to use a
paste ribbon of one brush length per brushing and children
to use a ribbon of one brush width. Given the lack of evidence
of an anticaries benefit for fluoridated dentifrices below
500 ppm F, this concentration would seem to be a good compromise.
Another therapeutic ingredient commonly found in dentifrices
is the antimicrobial agent triclosan. Dentifrices containing
triclosan, in combination with either a copolymer, zinc citrate
or pyrophosphate, have demonstrated significant benefits against
plaque, gingivitis and tartar.4 Products targeted at sensitive
teeth (dentine hypersensitivity) are also, quite common. These
dentifrices usually contain either strontium salts, which
may block dentine tubules, or potassium salts, which may affect
tooth nerves, as the active ingredients.
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Recently, dentifrices to combat stains and promote tooth
whitening have increased in popularity. Such products often
contain specially formulated particles that provide improved
physical cleaning or an enzyme to remove stains by chemical
means. Clinical support for the performance of these formulations
is limited compared to the anticaries and anti plaque toothpastes
described earlier but research by the leading manufacturers
is providing more evidence each year.
Brushing the teeth with a dentifrice has formed part of oral
hygiene routines for centuries. William Addis made some of
the first bristle brushes in the UK in the late 1700s, whilst
dentifrices and toothpicks have been recorded since ancient
times.
The traditional dentifrice was formulated simply to aid removal
of food debris from the teeth. Modern formulations, however,
also deliver therapeutic ingredients such as fluoride, to
control tooth decay, antimicrobials to control plaque and
gingivitis, and other components to reduce tartar, bad breath,
and improve whitening.
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References
1. Murray JJ. Rugg-Gunn AJ, Jenkins GN. Fluorides in Caries
Prevention. Oxford: Wright, 1991.
2. Chestnutt IG, Schafer F, Jacobson APM, Stephen KW. The
influence of toothbrushing frequency and rinsing on caries
experience in a caries clinical trial. Community Dent Oral
Epidemiol 1998 26:406-411.
3. Holt RD, Nunn JH, Rock WP, Page J. British Society of Paediatric
Dentistry: A policy document on fluoride dietary supplements
and fluoride toothpastes for children. Int J Paediatric Dent
1996;6:139-142.
4. Duckworth RM. Science and caries prevention. Int Dent J
1993;43:529-539.
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3. CHEESE AND REDUCED RISK OF DENTAL CARIES
Research into dental decay causation has focused primarily
on establishing the relationship between plaque bacteria and
foods, and the role fluoride plays in this system. Recently,
however, interest in the potential protective effects of foods
has grown, with the realization that foods such as milk and
cheese can neutralise cariogenic acids, in addition to aiding
restoration of enamel lost during eating. Milk is known to
be harmful in baby bottle tooth decay, a condition in which
rampant caries develops as a result of a baby repeatedly falling
asleep with a bottle of milk, juice, or other fermentable
carbohydrate-containing drink still in its mouth. The milk
is retained in the mouth for a prolonged period, allowing
plaque micro-organisms to ferment milk lactose into cariogenic
acid.
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Under more normal conditions of consumption, however, milk
has been shown to have minimal effect on plaque acidity and
appears to protect enamel from dissolution. Cheese consumption
also does not result in a reduction in plaque pH. Indeed,
studies have shown that eating cheese after eating a carbohydrate-containing
food returns plaque pH towards neutrality. Enamel demineralisation
is a reversible process, although re-mineralisation is relatively
slow. Re-mineralisation occurs naturally in the mouth because
saliva contains super-saturated concentrations of calcium
and phosphate ions (ions also found in abundance in milk and
cheese). Thus consumption of milk or cheese might be expected
to lead to enhanced re- mineralisation. Indeed, there is evidence
that both exhibit some anti-cariogenic activity.
The available evidence suggests potential dental health benefits
may result from consumption of milk or cheese, especially
at the end of a meal. Further investigation into the precise
molecular basis of such anti- cariogenic effects may help
to improve our understanding of the effects of a wide range
of foods on the caries process. Kashket 5 et al. Cheese consumption
and the development and progression of dental caries. Nutrition
Reviews 2002;60(4):97-103.
Key point - Eating a piece of cheese at the end of a carbohydrate-
containing meal helps to neutralise cariogenic acids, reducing
the risk of dental caries development.
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