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Changing Concepts in Cariology: Forty Years OnAbstract: The
caries lesion is a sign or symptom resulting from numerous pH
fluctuations in biofilms on teeth. The lesion may or may not
progress and lesion progression can be controlled, slowed down or
arrested. Control of the biofilm is the treatment of caries, the
most important measure being to disturb the biofilm mechanically
using a fluoride-containing toothpaste. The informed patient
controls caries and the role of the dental professional is to
advise how this should be done. This is the non-operative treatment
of caries and it is worthy of payment. It should be mandatory as
part of any operative treatment to ensure that the patient
understands, and is able to perform, adequate plaque
control.Clinical Relevance: It is very unfortunate that the current
remuneration scheme (Unit of Dental Activity) in Health Service
practice in England and Wales prevents practitioners adopting a
modern biological approach to caries control.Dent Update 2013; 40:
277286
Edwina Kidd, BDS, FDS RCS(Eng), PhD, DSc, Emerita Professor of
Cariology, Kings College, London, UK and Ole Fejerskov, DDS, PhD,
Dr Odont, Professor of Anatomy, Faculty of Health Sciences,
University of Arhus, Denmark.
Edwina Kidd
Changing concepts in cariology: forty years onForty years on,
when afar and asunderParted are those who are reading today,When
you look back, and forgetfully wonderWhat you were like in your
work and your play,Then, it may be, there will often come oer
you,Glimpses of past and some of it wrong,Visions of studies shall
float them before you,Echoes of teaching shall bear you along,What
is new for the patient our hope to fulfil,Teeth unto death are
chiefly our will.(With apologies to Edward Ernest Bowen and Harrow
School.)
A personal introductionEdwina Kidd was in the staff
room at the London Hospital Dental
School when Ted Renson carried in his baby, Dental Update,
Volume 1, Number 1. It was a revelation to see such a beautifully
produced, colour illustrated and readily understandable production.
The cariology article in that first number concerned the white spot
lesion and was written by Leon Silverstone.1 The authors of the
current paper (EK and OF) met in Leons laboratory (a euphemism for
a large cupboard) at the London Hospital at that time. One (EK) was
a junior lecturer at The London whose PhD Leon was supervising; the
other (OF), already a Professor of Oral Pathology in Denmark, had
recently been appointed to a chair in Cariology and needed to
change research focus from soft to hard tissues. He was in London
to research aspects of fluorosis and work with Leon, Newell Johnson
and Ron Fearnhead. Having met in a long, thin cupboard, where
communication was inevitable, we subsequently worked together for
40 years (Figure 1). We now combine in this anniversary issue to
take a helicopter journey over contemporary Cariology, discussing
aspects of the subject as understood in 2013 and highlighting
changes in understanding from the 1970s.
The relevance of cariologyDental caries is ubiquitous it
is omnipresent in all populations and is as old as mankind. The
caries incidence rate varies extensively between and within
populations. With increasing age, signs and symptoms of dental
caries accumulate and, in most adult populations, the caries
prevalence approaches 100 percent. Prevention and operative
treatment of caries lesions, and their sequelae, occupy the
majority of the dental profession life-long around the
Ole Fejerskov
Figure 1. Forty years on!
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278 DentalUpdate May 2013
world and the cost of dental health care is a major societal
burden. The majority of dental restorations are made because of
dental caries. Caries and failed restorative care are the main
causes for tooth loss in all contemporary populations.
The current concept of caries and caries control
Dental caries is a dynamic process. It is a chemical dissolution
brought about by metabolic activity in a microbial deposit
(biofilm) covering a tooth surface at any given time. Over time the
outcome of these fluctuations may result in a disturbance of the
equilibrium between the tooth mineral and the surroundings. Mineral
loss, subsequent lesion formation and possible cavity formation in
teeth, is a symptom of imbalance in this dynamic process. The
metabolism in the biofilm is an ubiquitous, natural process; part
of having teeth. However, its possible consequence, lesion
formation and progression, can be controlled so that a clinically
visible lesion never forms or an established lesion arrests.2
The following points encapsulate our current view of
caries:3
Caries is ubiquitous; It is a sign or symptom resulting from
numerous pH fluctuations in biofilms on teeth. The resulting de-
and re- mineralization of the tooth surface may result in the
formation of a clinically detectable lesion (the sign/symptom);
These lesions may or may not progress; Lesion progression can be
controlled, slowed down or arrested; Everyone is at risk of lesion
formation from cradle to grave; Caries is the predominant cause of
tooth loss in all ages.
In the 1970s, it was suggested that caries could be prevented
and the concept of caries control was not emphasized. The
distinction between the process in the biofilm and its reflection,
the lesion in the tooth, was not made clear. Although it was
realized that all ages were susceptible to caries, prevention was
mainly taught in paediatric departments, and it was suggested that
periodontal disease was the more important cause of tooth loss in
the elderly.
When GV Black published his comprehensive textbook in 19084 he
emphasized that clinical diagnosis and treatment decisions should
have a sound biologic rationale. Although it became appreciated by
the middle of the 20th Century that dentistry is a biomedical
specialty, the technical advances with high-speed drilling seemed
to distort the true application of biological knowledge in the
optimal treatment of dental caries. Dental caries became synonymous
with a cavity in the tooth and the automatic reaction was that the
treatment should be drill and fill.
In the growing field of caries epidemiology, dental caries was
recorded as DMF teeth/surfaces where D stood for Decay and decay
meant a cavity. The knowledge about aetiology and pathology of
caries was often taught in dental curricula in departments of
microbiology, pathology and physiology, as well as in the growing
disciplines of the 50s and 60s of dental public health, departments
of paediatrics and preventive dentistry. However, the clinical
relevance of cariology to restorative clinical departments was not
emphasized in all schools (The London being a notable exception!)
and knowledge to be applied at the chairside was fragmented. To
some extent this was understandable because, in a clinical
department, the students were supposed to produce fillings and
crowns and bridges. Thus the appreciation of the need for
concomitant disease control as part of any long-term successful
restorative treatment was limited, or non-existent.
What constitutes treatment of caries?
This question is incredibly important. Since lesion formation
and progression can be controlled, control of the biofilm is the
treatment of caries. The most important control measure is to clean
teeth regularly, and thus disturb the biofilm mechanically, with a
fluoride-containing toothpaste. If sugar intake is high and
frequent, the pH fluctuations in the biofilm may result in
overgrowth of cariogenic micro-organisms, making lesion formation
and progression more likely.5 Thus dietary advice may have a role
to play.
From these statements it is obvious that it is the informed
patient that actually controls caries. So what then is the role of
the dental professional? It is to advise, so that all our patients
are aware of the importance of good tooth-cleaning, appropriate use
of fluoride and a sensible diet. This is the non-operative
treatment of caries. Note that the examination of the patient and
giving appropriate advice are time-consuming, skilful and worthy of
payment. However, in the 1970s treatment (as opposed to prevention)
of caries was by filling teeth, which is very unfortunate because
fillings mask the problem of poor plaque control and the dentist
takes responsibility away from the patient. You have decay, let me
treat it for you by cutting it away and replacing with a filling.
Fillings are even claimed by some to be secondary prevention which
is nonsense! For a while fillings will appear to be successful, but
if the real cause of the problem is not addressed, caries will
recur adjacent to the filling. To place restorations without
addressing the reason the lesion has formed in the first place is
tantamount to repairing a fire damaged building without
extinguishing the flames. Fillings are a part of plaque control and
important in the management of cavitated lesions, but they are not
the most important aspect of caries control.
Forty years ago, in the United Kingdom and Denmark, there were
departments of conservative, operative or restorative dentistry
where, although the pathology of dental caries might be taught,
rewards were only given for fillings. Undergraduates had points
quotas with points given for restorations. There were no similar
rewards for non-operative treatments. Students would thus qualify
in the UK tailor-made for a National Health Service which also gave
rewards for operative dentistry (fee per item of operative
treatment) but not for the non-operative caries control
measures.
It is now tempting to take a sneaky look across the Atlantic
where, even today, there are few departments of cariology and
operative dentistry reigns supreme. This is of great importance to
the young dentist who is emerging from the dental school egg with
debts of a quarter of a million pounds. And before
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280 DentalUpdate May 2013
we get too smug about this, let us remind ourselves of what has
just happened in England and Wales to university fees, now 9000 per
year in dental schools. Add to this living costs for five years and
it is obvious that this problem is ours already.
Caries diagnosisA diagnosis has been described
as a mental resting place on the way to a treatment decision.
What in diagnosis is relevant to that treatment decision as far as
caries is concerned? The activity of the lesion is of great
importance (Figure 2). Lesions judged as active (by this we mean if
nothing changes, the lesion will progress) require non-operative
treatments and a review of the efficacy of the treatment is to
check that lesions do not progress and appear to be arrested. The
other aspect of great relevance is whether a cavity is present that
traps plaque and precludes cleaning (Figure 3). If the patient
cannot access the plaque, the lesion is almost bound to progress.
These lesions must either be filled or perhaps made accessible to
cleaning,6
so that the patient can disturb/remove most of the biofilm with
a fluoride-containing toothpaste. Any lesion, at any stage of
progression, is arrestable by cleaning alone provided the pulp is
not irreparably damaged. This diagnosis is best performed by a
careful clinical-visual examination of clean, dry teeth. It was
realized that, while a sharp probe was useful to feel the surface
of the lesion to detect roughness indicating activity, the probe
must be used gently. It is not a bayonet and rough use to test for
stickiness actually damages the surface of the lesion and
encourages plaque accumulation.
Radiographs are an aid to diagnosis for approximal lesions.
However, while a radiograph gives some appreciation of lesion
depth, a single radiograph cannot assess either activity or
cavitation. It must also be remembered that there may be false
positive and negative findings on these two-dimensional shadows.
Radiographs do not alone define the truth. A subsequent picture,
taken after a period of time with a film holder and beam aiming
device to ensure comparable geometry, should be
examined for lesion progression or arrest.Decisions, about
activity
and cavitation, are inevitably best guesses. This is not a
disaster because dentists should review patients and thus review
the decisions. However, the opportunity for review should have
implications for decision-making. If a lesion is suspected as
active, it should be treated non-operatively so as not to miss the
opportunity to arrest the lesion. However, if a dentist is unsure
whether an approximal lesion is cavitated, and therefore unsure
whether a filling is required, the better decision is to institute
non-operative treatment and reassess rather than prescribe a
restoration because this is an irrevocable decision. We know from
research started at the London Hospital by Richard Elderton in the
early 70s, that placement of a restoration may start a cascade of
restoration and re-restoration, each replacement resulting in
further tooth removal, until we simply run out of hard tissue and
the tooth is lost.7
In the 1970s, there was no appreciation of the relevance of
lesion activity to the treatment decision. Approximal lesions
tended to be treated operatively when they were just in dentine on
radiograph and in Denmark even when confined to enamel.8 The
current threshold for operative treatment, in contemporary low
caries populations, tends to be lesions that are well into dentine
because the less advanced lesions are often not cavitated when
opened. These should be treated non-operatively and thus given a
chance to arrest following improved oral hygiene and fluoride
application.
In the 1980s and 1990s, there was a flurry of activity in the
use of machines to aid diagnosis, for example electrical
conductance measurements and fluorescence techniques, such as
DIAGNOdent (KaVo, Biberach, Germany). The idea was to take the
subjectivity out of the task as well as to diagnose
demineralization at an earlier stage so that non-operative caries
control measures could be instituted in a timely fashion. After
considerable research effort, and many publications, it was
acknowledged that these machines can only detect demineralization
and not
Figure 2. (a) Active, non-cavitated, occlusal lesion. The
biofilm must be gently removed with the side of an explorer or
toothbrush otherwise this lesion will not be seen. (b) Arrested,
non-cavitated pit or fissure lesions often present as darkly
stained. Removal of any biofilm important to aid diagnosis.
a
b
Figure 3. (a) Active caries lesion with small cavity. This is
not cleansable and restoration is required to aid plaque control.
(b) Arrested occlusal caries lesion. The undermined enamel margins
have fractured away and the cavity is cleansable. No restoration
needed to control caries.
a
b
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make judgements on what matters most, namely activity and
cavitation. It was thus eventually concluded that a visual-tactile
examination of clean, dry teeth, together with careful thought,
were preferable to any machine.9
Occlusal lesions have given particular food for thought. In the
1970s, it was considered that the lesion formed in the depth of the
fissure and was difficult to see and impossible to access for
thorough cleaning. In the 1980s, dentists noticed that they were
missing quite advanced lesions on clinical examination but finding
large lesions in dentine on radiograph (Figure 4). The term hidden
caries was used to describe lesions missed on clinical examination
but found on radiograph, and fluoride was blamed for masking the
diagnosis. It was subsequently shown that the occlusal lesion forms
at the entrance to the fissure and it can be diagnosed visually,
provided plaque is removed from the fissure entrance. This was a
very important finding because it implied that these lesions could
be controlled by cleaning alone. The
erupting premolar/molar, in particular, should be carefully
cleaned by a parent, with the brush coming in at right angles to
the arch (Figure 5). Occlusal lesions can be prevented/controlled
by careful cleaning over the eruption period, and fissure sealants
are not required.10
Unfortunately, the profession seems to have been very slow in
adopting a chart that allows the salient features of lesion
activity and cavitation to be visually recorded, although such a
chart has been developed (Figure 6) and described in Dental
Update!11
Assessment of caries riskQuestion: Who is at risk from
lesion development? Answer: Everyone with teeth, from cradle to
grave, because the metabolism in the biofilm is a natural part of
having teeth. In recent years, there has been much interest in
whether this concept of risk assessment can be further refined so
that caries control measures may be targeted appropriately before
any lesions form. Caries risk
assessment will also guide appropriate recall intervals. After
much research, it can be stated that no single factor or
combination of biological factors will accurately predict risk, on
an individual patient basis, except the presence of early
non-cavitated lesions and a history of lesions and fillings.12 This
makes a careful clinical visual-tactile diagnosis even more
important. However, all our patients should be taught good oral
hygiene with a fluoride-containing toothpaste and the relevance of
diet to caries. This is called a whole population approach and is
appropriate to any disease that potentially occurs in everyone.
The one factor that will predict increased risk is dramatically
reduced salivary flow (hyposalivation). Resting flow should be
measured when this is suspected because, if the clinicians
suspicion is confirmed, the patient is at risk of rapid lesion
development. Frequent recall and strenuous effort will be required
to control lesion progression in these types of patients. The
management majors on plaque control and fluoride (Figure 7). These
are some of the most difficult patients to manage; those one
worries about in the darker reaches of the night.
EpidemiologyIt was in the early 1980s that
data from around the developed world showed a decline in caries
prevalence and incidence (rate of development). In UK, decennial
National Surveys have shown this decline. In Denmark, all children
enrolled in the school dental health service were examined
annually, resulting in unique longitudinal data. Initially, the
caries decline caused some panic. If dental caries was solved, what
were dentists to do? Several dental schools closed in the developed
world and, ironically, in England the school that trained
therapists was also closed. The dental profession was climbing into
the boat and pushing off. After a few years it was realized that
the decline in caries prevalence and incidence, far from obviating
the need for dentists, actually might require more dental personnel
because there are so many more teeth to look after. Why have there
been changes in caries prevalence
Figure 4. (a) The clinical picture shows a lesion with a cavity
in the central fossa. To see this, the tooth must be clean and dry.
The clinician mistakenly diagnosed this lesion as arrested. (b)
However, the radiograph shows an extensive radiolucent lesion in
dentine and a restoration is required. This makes the point that it
is always important to examine radiographs carefully. They aid
diagnosis.
Figure 5. (a) The occlusal surface of this first per-manent
molar is at its most vulnerable during the period from first
eruption until it is in occlusion (arrow points to erupting tooth).
(b) Brushing the occlusal surface of the erupting molar. The parent
assists, bringing the brush in at right angles to the arch.
a
b
a
b
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282 DentalUpdate May 2013
Figure 6. Chart with red (active) and blue (inactive) colours to
indicate lesion activity. Lines and circles differentiate
non-cavitated from cavitated lesions.
Figure 7. Cancer patient who has mastered caries control
subsequent to resection of the left mandible and radiation therapy
of the head and neck. The patient received regular professional
tooth cleaning and topical fluoride therapy in conjunction with
meticulous self-performed oral hygiene.
and incidence? The likely explanation would seem to be the
advent of fluoride, particularly in toothpaste. It should also be
noted that caries distribution in populations is now more and more
skew and often concentrated in socially deprived people, to the
extent that rampant caries in a child should make the dentist
consider whether the child is seriously neglected.
The role of plaque controlSince the metabolism in the
biofilm is responsible for caries lesion development, plaque
control is the most important part of non-operative treatment.
The reader may be interested to know that this was stressed in
1908 by GV Black when he wrote his Textbook of Operative
Dentistry.4 Today, as in the 1970s, almost all toothpastes contain
fluoride and oral hygiene is an ideal route for fluoride
application.
The role of fluorideSo if fluoride explains much
of this alteration, what is its mechanism of action? In the
1970s, it was thought that, to be effective, fluoride had to be
incorporated into developing enamel and the fluoridated apatite so
formed would be more resistant to acid attack. Several studies had
shown the significant effect of fluoridated water on dental caries,
not least in the United States and Holland. This concept of
incorporation into enamel would basically mean that children, in
particular, would be the target group for fluoride prevention.
However, in 1981, one of the cupboard companions (OF), together
with two Danish colleagues, put together the evidence from research
works around the world to show that the important mechanism of
fluoride was its topical effect.13 Fluoride, present at the point
of acid attack in the oral
fluids, delays lesion development and progression and it does it
at any age. The fluoride does not have to be in water, it can be in
toothpaste, mouthwash, varnish, gels. All systemic effects may
result in unnecessary development of dental fluorosis14 but are not
needed to obtain maximum caries control. It should also be
appreciated that changing criteria for the decision to restore has
resulted in fewer fillings and this has also played a major role
for the change in DMFT in many countries.15
The role of dietThe evidence linking sugar
and caries is irrefutable, although there is no linear
relationship between daily sugar consumption and caries experience
on a population basis. Unfortunately, there is less evidence that
it is possible to alter diets and persuade people to eat
differently. We only have to consider the current obesity epidemic
to realize the difficulty. Caries decline occurs in most
populations without a concomitant decrease in sugar consumption
(Figure 8). Changes in socio-economic conditions, widespread use of
fluorides, increased appreciation of the role of oral hygiene and
changing restorative thresholds have had a major impact on the
caries situation. For this reason, our major focus in caries
control should move from diet to oral hygiene, with a
fluoride-containing toothpaste. However, this does not mean that we
should ignore diet. All our patients should be aware of the
relationship of sugar to caries and dietary advice is still needed
in those developing several new lesions at any stage in life. It is
especially important for those with decreased salivary flow, where
dietary advice is mandatory.
When do we need fillings?As discussed earlier, from a
purely cariological perspective, fillings should be considered a
somewhat strange way of performing plaque control! Thus they are
required when the patient cannot clean plaque out of a hole in a
tooth, for instance a cavitated occlusal (Figures 3a and 4) or an
approximal surface. This means that many root caries lesions do
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May 2013 DentalUpdate 285
Figure 10. (a) Cervical lesions covered by plaque. (b) The same
cavities 14 days later after removing overhanging enamel and
showing the patient how to clean. The teeth were then brushed twice
a day with a toothbrush and fluoride paste. At this stage, from a
cariological point of view, these lesions were stable but very
ugly. For this reason, they were restored with composite (c). This
was taken immediately after removal of the rubber dam and the teeth
had dried out, which explains a small colour difference that will
disappear rapidly as the teeth rehydrate.
not require restoration because they can be arrested by plaque
control and fluoride (Figure 9). Thus, unless appearance is a
problem (Figure 10), it is preferable to avoid restorations. This
was not practised in the
1970s. Lesions, as seen in Figure 9, would have been restored
and this was not easy because suitable adhesive restorative
materials were in their infancy and even these cannot last
forever.16
In the 1970s, fissure sealants were recently developed and were
applied to sound fissures to prevent lesion formation on molars and
premolars. Remember that the caries prevalence was much higher in
those years. However, the contemporary indications for sealants are
much less. Caries prevalence is reduced, it is unusual to see
occlusal lesions in premolars and occlusal lesion formation can be
controlled by cleaning with fluoride toothpaste. The contemporary
indication for sealants would be in patients who are not cleaning
effectively, despite advice.
Delivery of caries control treatments in the NHS in England and
Wales
When Dental Update was born practitioners were rewarded on a fee
per item of operative treatment basis. There were no fees for
preventive treatments, such as oral hygiene instruction, fluoride
application, diet analysis and fissure sealant application.
Figure 8. The blue bars show the decline in caries experience
(DMFT) in Denmark in 12-year-old chil-dren between 1974 and 1997.
This pattern is typical of developed countries. The red bars show
the sugar consumption (kg/individual/year over the same years). The
decline in caries is not likely to be due to changed sugar
consumption because this has not changed.
Figure 9. (a, b) There are 8 years between the two photographs.
In (a) the root lesions are active, plaque-covered and soft to
gentle probing. In (b) the lesions are arrested, hard and shiny.
The non-operative treatment has involved removal of a rim of
unsupported enamel at the occlusal aspect of the lesion, and daily
plaque removal with fluoride toothpaste. The lesions are not
visible and do not need restoration.
a
b
a
b
c
There was a fee for scaling and polishing and one of us (EK)
used this fee to cover preventive advice. In her hands money was
lost, but it did not haemorrhage.
In 2006 the fee structure was altered, with a new contract, and
fees were divided into three bands. This system is still in
operation and, in the opinion of one of the authors (EK), it is a
problem and should have been discontinued long ago. Non-operative
treatments are part of Band 1 which comprises diagnosis, treatment
planning and maintenance, attracting a single Unit of Dental
Activity (UDA), which will represent about 15 minutes of surgery
time at best. For this fee the practitioner should carry out:
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Cariology
History and examination; Special tests such as radiographs;
Diagnosis and treatment planning; Agreeing the plan with the
patient and gaining consent; Scale and polish, if required; All
non-operative treatments, oral hygiene advice, fluoride advice and
application if appropriate, diet analysis and advice.
One of the authors is on record asking advice from the
Department of Health as to how this can be done for a single UDA11
but, as in the Walrus and the Carpenter,17 answer came there none.
Literary buffs will recall that in the poem there could be no
answer because the oysters were dead, they had all been eaten.
This combining of diagnosis and preventive treatment into a
single band precludes the hygienist (the preventive therapist) from
working in the Health Service in many practices because the dentist
would then have to split the derisory fee. Many hygienists only
work privately, which is ironic because caries is concentrated in
socially deprived people who cannot afford to pay privately. Band 2
treatment includes everything in Band 1 plus simple treatment
(fillings, extractions and surgical procedures). The fee is the
same, one filling or ten, so the dentist naturally dreads the
patient with a high level of disease and, again, social deprivation
may be relevant. How depressing that this contract was introduced
on the watch of a socialist government, has been running for 6
years, and it has not been suspended by the Coalition while pilot
work is undertaken on a new contract.
Basically, we are not, as a profession, responding to the need
of populations, but still believing that we have to fight dental
caries with metals, composites and adhesives is this really
evidence-based dental care?18
Which brings us to a final point: All the knowledge,
evidence-based, may not be the key to success because, in the final
analysis, it comes down to politics. The key to dental health is
simple and not expensive. Our goal should be to ensure that, in all
populations around the world, most people should be able to
maintain a
functioning dentition from cradle to grave. In the upcoming
third edition of our mutual textbook, we will soon document how
this goal is achievable today. Indeed, it has been achievable for
many years with the knowledge that we now have about the nature of
dental caries.
AcknowledgementsFigures 2, 3, 4, 7, 8, 9, 10
are reproduced with permission from: Dental Caries. The Disease
and Its Clinical Management. Fejerskov O, Kidd E (eds). Oxford:
Blackwell Munksgaard, 2008.
The dentist who took each photograph and cared for the patient
is acknowledged by a signature on the picture. This acknowledgement
is important because illustrations of this quality are difficult to
produce but invaluable teaching material.
References1. Silverstone LM. Dental caries: the
problem. Dent Update 1973; 1: 1926.2. Fejerskov O, Nyvad B. Is
dental caries
an infectious disease? Diagnostic and treatment consequences for
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Copenhagen: Quintessence Publishing, 2003: pp141152.
3. Fejerskov O. Concepts of dental caries and their consequences
for understanding the disease. Community Dent Oral Epidemiol 1997;
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4. Black GV. Operative Dentistry 1: Pathology of the Hard
Tissues of the Teeth. Chicago, IL: Medico-Dental Publishing Co,
1908.
5. Marsh PD, Nyvad B. The oral microflora and biofilms on teeth.
In: Dental Caries. The Disease and Its Clinical Management.
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6. Kidd EAM. Should deciduous teeth be restored? Reflections of
a cariologist. Dent Update 2012; 39: 159166.
7. Elderton RJ. Preventive (evidence based) approach to quality
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11. Page J, Kidd E. Practical suggestions for implementing
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12. Hausen H. Caries prediction. In: Dental Caries. The Disease
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13. Fejerskov O, Thylstrup A, Larsen ML. Rational use of
fluorides in caries prevention. A concept based on possible
cariostatic mechanisms. Acta Odont Scand 1981; 39: 241249.
14. Kalsbeek H, Verrips E, Dirks OB. Use of fluoride tablets and
effect on prevalence of dental caries and dental fluorosis.
Community Dent Oral Epidemiol 1992; 20: 241245.
15. Nadanovsky P, Sheiham A. Relative contribution of dental
services to the changes in caries levels in 12-year-old children in
18 industrialized countries in the 1970s and early 1980s. Community
Dent Oral Epidemiol 1995; 23: 331339.
16. Qvist V. Longevity of restorations: the death spiral. In:
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O, Kidd E (eds). Oxford: Blackwell Munksgaard, 2008: pp443455.
17. Carroll L. The Walrus and the Carpenter. From: Through the
Looking Glass and What Alice Found There. London: MacMillan &
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J Oral Rehab 2008; 35: 135151.
Further readingDental Caries. The Disease and
Its Clinical Management. Fejerskov O, Kidd E (eds). Oxford:
Blackwell Munksgaard, 2008.