Lower pH values are recorded in plaque within cavities than in plaque on inactive lesions or sound surfaces in the same individuals. Consequently, sucrose is the most cariogenic sugar, although the other sugars are also harmful.
Since sucrose is also the sugar most commonly eaten, it is a very important cause of dental caries. Fluoride slows down the progression of lesions.
Since salivary buffering capacity has been lost, an acid environ- ment is encouraged and persists longer. This in turn encourages aciduric bacteria which relish the acid conditions and continue to metabolize car- bohydrate in the low-pH environment.
The stage is set for uncontrolled carious attack. Lesions may start on enamel enamel caries or on exposed root cementum and dentine root caries. Primary caries denotes lesions on unrestored surfaces.
A pro- gressive lesion is described as an active carious lesion Figure 1. This concept of activity is very important as it impinges directly on management because active lesions require active management. However, the distinction between active and arrested may not be straightforward. Arrested caries on the mesial aspect of the lower second molar.
The lesion was well into dentine, but the tissue was hard and shiny. Note it is plaque-free. The tooth had been in this state for at least 10 years. Different teeth and surfaces are involved, depending on the area of plaque stagnation and the severity of the carious challenge.
A moderate challenge may also involve the approximal surfaces of posterior teeth. A severe challenge will cause the anterior teeth, which normally remain caries-free, also to become carious. Rampant caries is the name given to multiple active carious lesions occurring in the same patient, frequently involving surfaces of teeth that are usually caries-free.
It may be seen in the permanent dentition of teenagers and is usually due to poor oral hygiene and taking frequent cariogenic snacks and sweet drinks between meals Figure 1. Rampant caries in young men: a Note these teeth look clean. This patient is now making strenuous attempts to remove plaque with a toothbrush. These lesions are on their way to arrest. Compare this with Figure 1. This shows the devastating result of a combination of poor oral hygiene and a high-sugar diet.
Radiation caries. This patient has been irradiated in the region of the salivary glands for the treatment of a malignant tumour. Heavy plaque deposits are obvious over the lesions. Early childhood caries is a term used to describe dental caries present- ing in the primary dentition of young children. Bottle caries or nursing caries are names used to describe a particular form of rampant caries in the primary dentition of infants and young chil- dren. The clinical pattern is characteristic, with the four maxillary deciduous incisors most severely affected Figure 1.
Rampant caries of deciduous teeth. Epidemiological surveys are of great importance to politicians because they should indicate areas of need where public money may be spent appropriately. Prevalence is the proportion of a population affected by a disease or condition at a particular time.
Incidence is a measurement of the rate at which a disease progresses. In order to measure incidence, therefore, two examinations are required—one at the beginning and one at the end of a given time period. The incidence of the condition is then the increase or decrease in the number of new cases occurring in a population within that time period. This measurement is known as the DMF index and is an arithmetic index of the cumulative caries attack in a population. In young children missing deciduous teeth may have been lost as a result of natural exfoliation, and these must be differentiated from teeth lost due to caries.
Epidemiologists take enormous trouble to achieve standardization of examination and recording techniques. They will practice and check their diagnoses during a clinical trial to try to ensure reproducibility. Despite this, even a trained and experienced worker will not be completely consistent on the same day, let alone consistent with others in studies spanning years.
Dentists do not practice and check their diagnostic reproducibility in the same way as epidemiologists. In addition, there is likely to be variation between dentists in their recording of disease. Epidemiologists carrying out national surveys may be limited in their access to clinical facilities because these surveys are not necessarily carried out in a dental surgery.
Thus, access to good lighting, the ability to clean and dry teeth and the opportunity to examine radiographs may not be available. Unless radiographs are required for clinical care, it would be unethical to use ionizing radiation. Enamel lesions are not recorded, which means that epidemiological surveys inevitably underestimate the caries problem. This may be very important because the earlier stages of lesion formation, which are not recorded, should be managed by non- operative preventive treatments so that the progression of lesions is con- trolled.
The later stages cavities may also require restorations, in addition to preventive treatments. This has indeed happened. As a consequence of this unfortunate terminology and a lack of understanding of the carious process, some dental schools closed.
However, it is now realized that in many people the carious process is delayed and thus lesions may present as cavities as the person grows older. In addition, the improvement in the caries status means there will be fewer extractions and thus many more teeth requiring dental care. For these reasons, more dental per- sonnel are now needed. It must also be remembered that the arithmetic means of DMF T are meaningless at the level of the individual patient.
For most of the twentieth century caries was seen as a disease of economically developed countries, with a low prevalence in the developing world.
To give an example, studies in the s show dental caries as a major problem in the former socialist countries of eastern Europe. The picture for permanent teeth in older children is more positive with further reductions in obvious decay experience in and year-old children. Time trends in caries experience of children in England and Wales between and Reproduced by kind permission of the International Dental Journal.
As caries prevalence falls, the least susceptible sites smooth and approximal surfaces reduce by the greatest proportion, while the most susceptible sites occlusal surfaces reduce by the smallest proportion. There are large regional inequalities in dental health, with people in Northern Ireland, Scotland and the north of England having the worst caries status Figure 1.
Reproduced by kind permission of Blackwell Munksgaard. Community Dent. Oral Epidemiol. Adults National surveys of adult dental health, carried out in UK every 10 years, show steady and substantial improvements with the most dramatic improve- ments being in young adults.
Northern Ireland, Scotland and the north of England remain the parts of the UK with the poorest dental health. The dental state of older people in residential homes is a disgrace. The clients are there because they can no longer look after themselves, and yet carers often do not clean mouths.
It is unacceptable to ignore such an intimate part of the body—it eats, its speaks, it smiles, it kisses—and our profession must face this challenge Figure 1. Gross caries in a client in a residential home. Reproduced by kind permission of Dr Debra Simons.
In addition a number of other variables are important such as social class, income, education, knowledge, attitudes and behaviour. It makes the point that the process does not have to progress. When the destructive forces outweigh the reparative powers of saliva, the process will progress.
Conversely, if the reparative forces outweigh the destructive forces, the process will arrest. Early diagnosis is important because, once carious lesions have cavitated, only operative intervention can replace the tissue. Fill- ings do not prevent caries, because new lesions can develop adjacent to restorations.
A diagrammatic representation of the carious process as an alternating process of destruction and repair. Sound enamel or dentine will become carious in time if plaque bacteria are given the substrate they need to produce acid. Fluoride used in toothpaste, water, or mouthwashes and applied topically will delay progression of the lesion Chapter 6. Holes in teeth that are not cleansable are likely to progress.
The role of operative dentistry in caries management is to facilitate plaque control Chapter 9. An important role for the dental profession, therefore, is to provide patients with knowledge so they understand their essential role in this control. In addition, patients need to be persuaded to accept responsibility for their own mouths Chapter 8.
Further reading and references 1. Fejerskov, O. Blackwell Munksgaard, Oxford. Burt, B. W B Saunders, Philadelphia. Renson, C. Singapore, 15, — Bratthal, D. Marthaler, T. Caries Res. Downer, M. Dent J. Sweeney, P. Nuttall, N. BDJ Books, London. Simons, D. Lancet, , The crystals are so tightly packed that the enamel has a glass-like appearance and it is translucent, allowing the colour of the dentine to shine through it.
Even though crystal packing is very tight, each crystal is actually separated from its neigh- bours by tiny intercrystalline spaces or pores. Thus, the intercrystalline spaces enlarge and the tissue becomes more porous.
This increase in porosity can be seen clinically as a white spot. Dentine is a vital tissue permeated by tubules containing the cell processes of the odontoblasts. This vital tissue defends itself from any assault, such as caries, by tubular sclerosis. This is the deposition of mineral along and within the dentinal tubules resulting in their gradual occlusion. In addition, the odontoblasts form tertiary dentine at the pulp—dentine border in response to the stimulus.
Both these reactions are protective because they make the dentine less permeable. To see the white spot lesion the plaque overlying it must be removed with a brush and the tooth thoroughly dried with a three-in-one syringe Figure 1. This can be done occlusally Figure 2. The active lesion is matt and feels rough if a sharp probe is gently drawn across it.
Figure 2. White spot lesions buccal to the lower premolars. These lesions are arrested. They are shiny, plaque-free, and remote from the gingival margin. The upper canine erupted slowly and was plaque covered for much of this time. A white spot lesion now arrested covers most of its labial face. The white spot lesions at the cervical margins of the upper incisors are plaque covered and may be active. A beautiful series of scanning electron microscope SEM studies, carried out in orthodontic patients due to have a premolar extracted, showed what was happening at the tooth surface.
Bands allowing plaque to accumulate beneath them were put onto teeth. After 4 weeks they were removed and the classic matt, chalky white spots had formed. The SEM pictures showed that after 4 weeks of plaque accumulation there was marked dissolution of sur- face enamel Figure 2.
This partly explains why the surface is matt. Regular plaque control was now re-established and 3 weeks later the surface was hard and shiny and the white spot less obvious. Now the SEM pictures showed abrasion of the surface: the eroded area had been partly removed Figure 2. A clinical and SEM picture of a white spot lesion formed under an orthodontic band after 4 weeks of plaque stagnation. Clinically, the lesion is opaque with a matt surface. Ultrastructurally, there is dissolution of the perikymata overlappings and dissolution of the surface enamel.
Originally published in Textbook of Clinical Cariology Munksgaard, and reproduced with permission. A clinical and SEM picture of a white spot lesion formed under an orthodontic band after renewal of plaque control. The lesion surface is now shiny and hard as a result of abrasion or polishing of the partly dissolved surface of the active lesion. The section is in water and viewed in polarized light. The main part of the lesion the body of the lesion is seen as a dark area deep to a rela- tively well mineralized surface zone.
If the section is now taken out of water and put into a liquid called quino- line, dark areas now outline the body of the lesion. The lesion is cone shaped. The body of the lesion B appears dark beneath a relatively intact surface zone SZ. A dark zone DZ can be seen outlining the lesion. The body B of the lesion appears translucent. Longitudinal ground section of a natural occlusal carious lesion examined in quinoline in polarized light.
The lesion forms in three directions, guided by prism direction assuming the shape of a cone with its base towards the enamel—dentine junction. The undermining shape of this lesion is purely a function of anatomy. The body of the lesion, which looked dark in water, now looks translucent because quinoline has the same refractive index as enamel and has entered the porous spaces. A section through a white spot lesion on an occlusal surface is seen in Figure 2.
The dentine is involved in the lesion in Figure 2. These lesions cannot be detected by gently drawing a sharp probe across them because they feel the same as normal enamel. Histo- logically these lesions show wide, well-developed dark zones at the front of the lesion within the body of the lesion and at the surface of the lesion Figure 2. A small amalgam restoration is also present. These lesions are likely to have formed years earlier at the gingival margin compare with Figure 1.
Longitudinal ground section of an arrested carious lesion in a tooth extracted from a patient aged 65 years. The section is examined in quinoline with polarized light and shows wide, well-developed dark zones at the advancing front of the lesion, within the body of the lesion and at the surface of the lesion.
The clinician can now help the patient tip the balance in favour of arrest rather than progression of lesions. An arrested white spot is more resistant to acid attack than sound enamel. It may be regarded as scar tissue and should not be attacked with a dental drill. A sharp probe has been jammed into the white spot lesion on the buccal aspect of this extracted molar. It is however, useful to draw a sharp probe gently across the lesion surface to feel whether it is matt active or shiny arrested but the probe should not be used as a bayonet!
This is to do with porosity and the relative refractive indices of air, water, and enamel. Enamel has a refractive index of 1. The difference in refractive index affects the light scattering, and the lesion looks white. If the tooth is now dried, the water is replaced with air, which has a refractive index of 1. The difference in refractive index between the air and the enamel is greater than between the water and the enamel.
This explains why the lesion looks more obvious, or an earlier lesion can be detected. It follows the direction of the enamel prisms and can be thought of as multiple individual lesions each at a different stage of progression. This explains why in the more advanced lesion, where there appears to be a small hole in the tooth, something apparently so small on the surface can be so large when entered with a burr Figure 2.
Now the toothbrush cannot reach into the hole to remove the plaque and the lesion is bound to progress. A hemisected occlusal lesion where there is a cavity in the tooth down to the dentine. At this stage the lesion spreads laterally along the enamel- dentine junction. Notice the shape of the cavity. It is wider at the base than at the top.
This would prevent the patient cleaning plaque out of the hole. Dentine is a vital tissue, permeated by the tubules containing the cell processes of the odontoblasts, and it defends itself by the tubular sclerosis within the dentine and the formation of tertiary dentine also called reactionary dentine or reparative dentine at the pulp-dentine border Figure 2. Tubular sclerosis is the deposition of mineral within the dentinal tubules and it requires the presence of a vital odontoblast.
It can be seen in the light microscope where a traverse through the centre of the enamel lesion crosses the enamel—dentine junction. Demineralization of outer dentine is now surrounded by sclerotic reactions corresponding to the less advanced peripheral parts of the enamel lesion. It is very important to realize Figure 2.
A ground section of a molar crown viewed in transmitted light. The enamel is cavitated. Tubular sclerosis is seen as a translucent zone in the dentine TZ. Reactionary dentine RD is also present since the pulp horn is partially obliterated. By courtesy of Professor N. Diagram of DZ histological changes in TZ enamel and dentine before Dead tract cavitation of the enamel. This protected area results in an ecological shift towards anaerobic and acid- producing bacteria.
Diagram of histological changes after cavitation. Note that Destruction Penetration Body demineralization of Demin. This is known as the zone of destruction. Beneath this, tubular invasion of bacteria is frequently seen which is called the zone of penetration because the tubules have become penetrated by microorganisms.
Beyond this is an area of demineralized dentine which does not yet contain bacteria Figure 2. When lesions progress rapidly, so-called dead tracts may form. Here the odontoblast processes have been destroyed without producing tubular sclerosis.
These tubules are invaded by bacteria and groups of tubules coalesce forming liquefaction foci Figure 2. Destruction may also advance along the incremental lines of growth which are at right angles to the tubules to produce transverse clefts Figure 2.
The defence reactions of tubular sclerosis and tertiary dentine formation continue as a response to these destructive processes. Both processes reduce the permeability of the dentine, although tertiary dentine is less well miner- alized than primary or secondary dentine and contains irregular dentinal tubules. In places the tubules appear to have been pushed apart by aggregations of bacteria called liquefaction foci. The tissue appears to have split at right angles to the tubules along the incremental lines of growth.
These splits are called transverse clefts. This is called repara- tive dentine. The duration and intensity of the stimulus is partly responsible for the type of response. In a slowly progressing carious lesion in dentine, the stimuli reaching the pulp are bacterial toxins and thermal and osmotic shocks from the external environment. Chronic pulpitis as indicated by the tertiary reactionary dentine formation. By courtesy of Professor R. There is active emigration of neutrophils Figure 2.
The outcome of this process is often localized necrosis, and in time this may involve the entire pulp. Early acute pulpitis showing the widely dilated pulp vessels and early emigration of leucocytes. There is patchy oedema of the dying odontoblast layer. Unfor- tunately the pain is often not well localized to the offending tooth, and the patient may not even be able to indicate which quadrant is involved. Since clinical symptoms relate so poorly to pulp pathology, there is an obvious problem here.
A useful rule of thumb is to divide clinical pulpitis into reversible and irreversible pulpitis. In reversible pulpitis the clinician hopes to be able to preserve a healthy vital pulp. The clinical diagnosis of reversible pulpitis is made when the pain evoked by a hot, cold, or sweet stimulus is of short duration, disappearing when the stimulus is removed. Alternatively, the tooth may be extracted.
However, once the peri- apical tissues are involved, another set of symptoms may develop. Since demineralization precedes bacterial penetration, the acid presumably dif- fuses ahead of the organisms. The pH of carious dentine can be low, and members of the dentine bacterial community in active lesions tend to be acidogenic.
Thus lactobacilli predominate, with fewer mutans streptococci. The reasons for the ecological shift in the bacterial community could include the avail- ability of the protein substrate and the low pH. Within the zone of destruction there is a more mixed bacterial popula- tion, including organisms that can degrade the dentine collagen.
This col- lagen degradation is preceded by demineralization of the mineral fractions of dentine. These ecological shifts within the carious cavity may be of practical importance as well as academic interest. In the advanced dentine lesion what is driving the carious process? The answer to this question is highly rele- vant to the operative management of carious dentine.
Does carious dentine have to be removed in order to arrest the carious lesion? Perhaps the lesion could be arrested by sealing off these organisms from the mouth. It is already known that sealing organisms in the tooth results in another ecological shift towards bacterial populations which are no longer cariogenic. These questions will be discussed again in Chapter 9. Clinically, actively progressing lesions are soft and wet. Because of the speed of development of the lesion the defence reactions will not be well developed.
In contrast, arrested or slowly progressing lesions have a hard or leath- ery consistency. Histologically the defence reactions of tertiary dentine and tubular sclerosis are marked. It is very important to realize that even caries of dentine does not auto- matically progress. Before the enamel surface is cavitated these lesions can be arrested by preventive treatment.
However, in many mouths root surfaces become exposed to the oral environment by gingival recession and these surfaces are now susceptible to root caries, and indeed are more vulnerable to mechanical and chemical destruction than enamel Figure 1. Thus gingival recession is a pre- requisite for exposure of a root surface, so it is hardly surprising that root caries is commonly seen in older people. It is associated with periodontal disease because this a major cause of gingival recession.
However, this does not mean that all patients with exposed root surfaces will automatically get root caries, since cariogenic plaque is the essential prerequisite. Clinically both active soft and arrested or slowly progressing lesions hard or leathery may be seen. Active lesions are usually close to the gingival margin in the area of plaque stagnation Figure 1.
Note it is the consis- tency of the lesion, rather than its colour, which is the guide to its activity. Early root surface lesions have been shown on microradiographs a radiograph of a ground section to be radiolucent zones i.
This implies that mineral is likely to have precipitated from the saliva. Deep to the lesion there is frequently a hypermineralized area of tubular sclerosis and tertiary dentine is seen at the pulpal surface of the dentine corresponding to the involved tubules. Destruction of apatite crystals thus appears to take place below the surface before bacteria penetrate into the root cementum and dentine.
In this respect enamel caries and root caries are similar. However, bacteria seem to penetrate into the tissue at an earlier stage in root caries than in coronal caries. Root lesions are very vulnerable to mechanical damage, and probing with a sharp instrument should be almost totally avoided.
It is also preferable to establish good plaque control but avoid root scaling until lesions have had the chance to arrest. The optimum management for root caries is again preventive treatment.
There is no evidence that these entombed bacteria con- tinue the carious process. The dentine beneath is stained brown and in places has a dry and crumbly texture. This is residual caries that the dentist left when the tooth was originally restored. If cultured, few microorganisms are found.
It is likely the organisms have died because their source of nutrient from the mouth has been cut off by the restoration, and from the pulp, by tubular sclerosis and tertiary dentine. I do not know the answer to this! A brown colour is produced when protein breaks down in the presence of sugar think of cutting up an apple and leaving it. Further reading Fejerskov, O.
The diag- nosis of caries presents a number of traps for the unwary. Another pitfall would be to detect demineralization without considering whether this is active and ongoing or already arrested. This information is important in terms of management. Diagnosis adds the aspect of activity to simple detection of lesions.
However, it must also be remembered that caries diagnoses are always made in conditions of uncertainty. All diagnostic methods have inherent errors and it is just not possible to separate disease from no disease and active from arrested lesions. For one thing, the carious process is a continuum and it is not easy to judge where a particular lesion or patient lies on that continuous scale.
Validity means that the test measures what it is intended to measure, e. Reliability or reproducibility means the test can be repeated with the same result, e. The person should be consistent with himself or herself intra-examiner reproducibility and consistent with others inter-examiner reproducibility. It is thus possible to make a diagnosis, take appropriate action and the reassess at a subsequent visit. Active lesions require some form of active management whereas arrested lesions do not.
The patient is central to the management of the carious process. It is the patient who will control the process, not the pro- fessional. Epidemiological surveys inform the politi- cians who commission them of the state of health and disease of the popu- lation.
These surveys should assist them to direct money appropriately. Diagnostic thresholds used in epidemiology and practice. Most lesions arrestable by preventive care are hidden below the water. Reproduced by kind permission of Professor Nigel Pitts. For con- venience the levels are graded D for decay followed by a number.
The higher the number, the more advanced the lesion. The hierarchy of these decisions and their relationship to the management required, have been elegantly represented as an iceberg Figure 3. For the dentist in the surgery the D1 threshold enamel lesion, no cavity is appropriate. This stage allows non-operative, preventive treat- ments which, if successful, should arrest the lesion. In epidemiological surveys see page 13 diagnosis is at the D3 level, which inevitably under- estimates the caries status by only recording lesions which are likely to require operative care.
If deposits of calculus or plaque are present, the mouth should be cleaned before attempt- ing accurate diagnosis. Do not remove plaque automatically, without thinking. After all, the process occurs within the plaque. Its presence or absence will be relevant to your decision about the activity of the lesion. When the teeth have been cleaned, each quadrant of the mouth is isolated with cotton wool rolls to prevent saliva wetting the teeth once they have been dried.
Thorough drying should be carried out with a gentle blast of air from the three-in-one syringe. White spot lesions are more obvious when teeth are dry see page 29 and saliva can even obscure small cavities. Sharp eyes can be used to look for the earliest signs of demineralization. Good bitewing radiographs are also essential in diagnosis. In this tech- nique the central beam of X-rays is positioned to pass at right angles to the long axis of the tooth, and tangentially through the contact area.
A beam-aiming a b Figure 3. It is not. Reproduced by kind permission of Dental Update. A bitewing radiograph is being taken. Figure 3. Clinically there was no obvious cavity although the enamel was discoloured. The type of radiograph resulting can be seen in Figure 3. Drying is very important because, as explained on page 29, it gives the clinician an idea of the porosity and depth of the lesion.
Active lesions tend to be plaque covered, close to the gingival margin and may have a matt appearance indicative of surface loss of tissue see Figure 1.
These lesions may feel rough if the tip of a sharp probe is gently drawn across them be gentle—the probe is an explorer, not a bayonet! Arrested lesions, on the other hand, may have been abandoned by the gingival margin and may have a plaque free, shiny, lustrous surface see Figure 2. Sometimes these lesions are brown because the porosities have absorbed exogenous stain from the mouth.
Lesions may vary in colour from yellowish or light brown, through mid- brown to almost black. Active lesions are plaque covered, soft or leathery in consistency and may be cavitated. Arrested lesions are hard and are often located in a plaque free area coronal to the gingival margin Figure 3. Arrested lesions may be cavitated. Although lesion consistency is important in diagnosing activity, great care should be taken when using a sharp instrument on these surfaces.
A Figure 3. Root surface caries in an area of plaque stagnation close to the gingival margin. Arrested root caries in a plaque-free area, coronal to the gingival margin. It may be safer to test the consistency of the lesion by gentle use of a periodontal probe or the back of an excavator. It should be noted that colour is not a good indica- tor of lesion activity. It seems likely that the colour of the lesion is due to exogenous staining from such items as tea, coffee, red wine, or chlorhexidine mouthwashes.
Root surface lesions tend to spread laterally and coalesce with minor neighbouring lesions and may thus eventually encircle the tooth. Com- monly, the lesions extend only 0. They do not always spread apically as the gingival margin recedes, but new lesions may develop later at the level of the new gingival margin.
This may occur irrespective of an arrested lesion being located more coronally at the cement-enamel junction of the tooth. Ideally the plaque should be disclosed and brushed away. Visual examination and examination of bitewing radiographs are both important.
The active, uncavitated lesion is white, often with a matt surface. The corresponding inactive lesion may be brown. The enamel lesions are not visible on a bitewing radiograph. The enamel lesion that is only visible on a dry tooth surface is in the outer enamel.
There was no lesion in dentine on a bitewing radiograph. This lesion was visible in dentine on a bitewing radiograph. Soft, demineralized dentine is present. The more mesial is a microcavity but the cavity on the distal aspect exposes dentine. The lesion was visible on a bitewing radiograph.
This is a large lesion with much soft, demineralized dentine. Chapter 4. Chapter 5. Chapter 6. Radiography for caries diagnosis: Ingegerd Mejare, Edwina Kidd. Chapter 7. Chapter 8. What is good diagnostic practice?
Part II. Clinical Caries Epidemiology. Chapter 9. Chapter The impact of diagnostic criteria on estimates of prevalence, extent, and severity of dental caries: Nigel Pitts. Part III. Dental Caries in a Biological Context. The oral microflora and biofilms on teeth: Phil Marsh, Bente Nyvad. Erosion of the tooth: Mogens Joost Larsen. Part IV. Non-Operative Therapy. The control of dental caries: non-operative treatment: Edwina Kidd, Ole Fejerskov.
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