– Understanding caries

In their new consensus statement on the terminology of dental caries and dental caries management, the European Organisation for Caries Research (ORCA) and the International Association for Dental Research (IADR) define caries as “a biofilm-mediated, diet modulated, multifactorial, noncommunicable, dynamic disease resulting in net mineral loss of dental hard tissues. It is determined by biologic, behavioral, psychosocial and environmental factors. As a consequence of this process, a caries lesion develops.”1 This very modern definition is based on the concept that caries is an imbalance of demineralization and remineralization that results from a dysbiosis of the oral biofilm, the overconsumption of carbohydrates, and insufficient oral hygiene (Fig 1-1).

Thus, the prevention of caries aims to adjust and ensure a healthy balance of the oral microbiome, dietary intake, oral hygiene, and mineral supply to avoid a net loss in enamel and dentin of healthy teeth. Caries therapy can only be successful in the long run if this is achieved when demineralization has already taken place. Therefore, caries prevention and its treatment employ the same concept and are nowadays combined as caries control, management, or care.

Figs 1-1a and b Caries is nowadays understood as an imbalance between de- and remineralizing factors resulting in a net loss of minerals (a). Thus, modern caries management modifies oral hygiene, diet, the biofilm, and the mineral equilibrium, keeping sound tooth surfaces healthy, inactivating existing caries lesions (b), and preventing recurrent demineralization around restorations.

This is also reflected in the ORCA/IADR definition of caries care, management, or control comprising “actions taken to interfere with mineral loss at all stages of the caries disease, including nonoperative and operative interventions/treatment. The terms caries care/management/control may be more appropriate than the term ‘caries prevention’ and because of the continuous de- and remineralization processes, caries control needs to be continued throughout the life course.”1

In consequence, the terms of caries prevention and therapy merge, which is not really surprising as restorative care and accompanying efforts to reduce caries activity have been viewed as secondary and tertiary prevention for a long time. Taking this into account, ORCA/IADR state that caries prevention “traditionally meant inhibition of caries initiation, otherwise called primary prevention. Primary, together with secondary and tertiary prevention, comprising nonoperative and operative treatments, are now summarized under caries care, management, or control.”1

The following chapters regarding caries risk prediction, fluoride use, biofilm and diet control, and promoting oral health are based on this new understanding of caries. As in periodontal disease, the primary goal of all preventive and therapeutic approaches is to achieve a high quality of life by establishing a physiologic, regenerative balance to maintain proper oral health.

Caries epidemiology and its consequences

On a global level, a remarkable caries decline could be achieved for the permanent dentition in children and adolescents in many industrialized regions such as the US, Canada, Europe, or Oceania. Although Germany was not the first country to experience this, consecutive and recent national surveys for all ages allow for a detailed analyses, which reveal trends2,3 that seem to be similar in many countries (Figs 1-2 and 1-3):

  • Caries prevalence has reduced from ten or more affected permanent teeth in adolescents during the 1970s to a mean of less than one decayed, missing, or filled teeth (DMFT) in 12-year-olds nowadays.4
  • About 90% of the caries burden can be prevented and tooth loss is almost eradicated in the permanent dentition in adolescents.2,4
  • After the caries decline, 80% of the adolescents are caries-free on a DMFT level and this is not much changed by lowering the threshold to initial caries lesions.3
  • Thus, the caries distribution is polarized and a so-called high-risk group of about 20% exhibits almost the complete caries burden.2,4
  • The high-risk group is primarily associated with a low socioeconomic status that leads to less sufficient oral hygiene, fluoride exposure, and often more frequent sugar intake.2,5
  • In the primary dentition and especially for early childhood caries, the situation is far from satisfactory in many countries.6 In spite of a less pronounced caries decline in the primary dentition, caries patterns and distribution are equivalent to the situation in adolescents.7 This is also true for caries in adults.2 Most likely a further caries decline will also increase the polarization in adults.
  • Due to the caries distribution after a major caries decline, primary caries prevention needs a dual strategy of maintaining the high levels of oral health in the majority of the population and trying to find intensified measures to improve the situation in the risk group mostly characterized by a low socioeconomic status.3
  • There is a realistic perspective that caries levels even in risk groups can be significantly reduced in the future, as the caries decline in this group was proportional to the reductions in the whole population, at least in German adolescents.4

Figs 1-2a and b Decayed, missing, and filled teeth (dmft/DMFT) in Germany in (a) schoolchildren,3,7 adolescents,3,4 and (b) adults. In many industrialized countries such as Germany, a remarkable caries decline has been recorded for the permanent dentition in adolescents, as well as in adults, and to a lesser extent for the primary dentition in schoolchildren.

Figs 1-3a to d A large percentage of children are caries-free (80%) (a and b), while a small group of children (20%) (c and d) present with high caries rates (80%). The polarization of the caries distribution especially in children leads to two different preventive approaches: Maintaining the high degree of oral health in the majority group of the population and intensifying measures for the high caries risk group.

In contrast to the general caries decline in many industrialized countries, caries levels in the emerging market economies are still at a high level for most of the population, or even on the rise due to increased wealth and sugar consumption.8 This imposes a great challenge to these countries; in spite of choosing the restorative approach as was done by many Western countries, strengthening primary prevention would be a better choice.

The current epidemiologic situation of a polarized caries distribution calls for two distinctly different approaches to primary caries prevention: For the majority of the population, individual and professional prevention can reduce 90% of the caries burden and keep it at a tolerable very low level.

The so-called caries risk group that accumulates about 80% of the caries defects and the according treatment needs is characterized by a low socioeconomic status. It seems that outreach programs and tailored health regulations are necessary to achieve further health gains in the groups with often low self-efficacy or (oral) health literacy. A common risk factor approach and cooperation with other professionals are useful for risk grouptargeted prevention to strengthen health and probably also educational competencies in these individuals and their families.

Early childhood caries

Early childhood caries (ECC) appears to be a persistent and neglected topic with rather high levels in many countries (Fig 1-4), low treatment rates, and, therefore, severe consequences in many small children that clearly affects their well-being and quality of life.9

Fig 1-4 Global epidemiology of early childhood caries (ECC). ECC or caries in the primary dentition seem to be a persistent problem, with severe consequences for the affected children. Preventive approaches in almost all countries have to be intensified to mirror the success often achieved in the permanent dentition.3,1016

Only in recent years has research in caries epidemiology focused on early childhood, followed by representative surveys on the prevalence of ECC. Thus, ECC deserves special attention in order to draw conclusions that might deviate from the situation in the permanent dentition.

ORCA and IADR define ECC as “the early onset of caries in young children with often fast progression which can finally result in complete destruction of the primary dentition [Fig 1-1a]. An epidemiologic definition of ECC is the presence of one or more decayed (noncavitated or cavitated lesions), missing (due to caries), or filled surfaces, in any primary tooth of a child under [the] age of six.” They also state that the appearance of ECC deviates from the common caries distribution where pits, fissures, and proximal surface dominate.1

“Due to the frequent consumption of carbohydrates, especially sugars, and inadequate to absent oral hygiene in small children, ECC demonstrates an atypical pattern of caries attack, particularly on smooth surfaces of upper anterior teeth.”1 This implies that typical ECC is a type of child neglect, as even minimal and easy preventive oral health measures are omitted for a considerable time. It is amazing that this can be found in so many children in developed and emerging countries.6 It also calls for clearly intensified primary caries-preventive measures from the first tooth on.

The National German Oral Health Survey in Children and Adolescents revealed 14% of 3-year-olds had caries on a dmft level in Germany,3 which is at the lower end of an international comparison. The mean value in the affected children (the newly introduced Specific affected Caries Index [SaC]17) was 3.6 dmft, making pulpal involvement, subsequent toothache, and probably a treatment under general anesthesia (GA) due to the high number of carious teeth as well as the low compliance in these small children likely – or a painful, and potentially traumatic experience when extraction in uncooperative children is performed if GA is not available.3

A closer look reveals that in spite of a very low mean caries prevalence of 0.3 dmft in 2-year-olds, a small risk group of children develops “real” ECC from the first tooth onwards (Table 1-1). Here ECC is caused by infant feeding that provides a high sugar content and/or erosive drinks in combination with insufficient or a complete lack of oral hygiene.18 Regarding the “epidemiologic” definition of ECC, in Germany the prevalence increases to almost 35% at a defect level until school age.3,7 The care index of less than 50% is not satisfactory, and clearly lower than in the permanent dentition.3 The young age of the children and the high burden of the disease in many countries make a primary preventive approach to manage the problem of ECC (see Chapters 5 and 9) more logical than the secondary or tertiary prevention (see Chapters 12 to 14) via, for example, restorations or even extractions.

Table 1-1 Mean caries prevalence data (dmft) for all kindergarten children in Greifswald, Germany, 2019, as well as mean values and care index for the subgroup of children with/without caries, fillings, and/or missing teeth due to caries (dmft = 0 and > 0, n ~ 1,500)17


Caries diagnostics

Analogous to the above-mentioned definition of caries as a net loss of minerals, caries diagnostics would assess the change of minerals over time. As caries is a process, this implies that a one-time diagnosis requires a continuous sampling technique or is even per se impossible.

The ORCA/IADR consensus solves this problem by stating that “caries diagnosis is the clinical judgment integrating available information, including the detection and assessment of caries signs (lesions), to determine presence of the disease.”1 This is especially crucial for secondary or tertiary prevention, with the signs or symptoms of caries already being clearly present in an individual. “The main purpose of clinical caries diagnosis is to achieve the best health outcome for the patient by selecting the best management option for each lesion type, to inform the patient, and to monitor the clinical course of the disease.”1 This is relevant to all levels of prevention, as many teeth and surfaces within one individual often present different stages of the caries process.

It is important to comprehend that the diagnosis of caries as a process or caries activity differs from the diagnosis of past mineral loss or even cavitation, which was traditionally defined as “caries diagnostics.” According to ORCA/IADR, caries activity “is a concept that reflects the mineral balance, in terms of net mineral loss, net mineral gain, or stasis over time.”1 Caries active implies caries initiation or progression; caries inactive implies caries arrest or regression.19 The diagnosis of caries activity can actually be used as the gold standard for the success of preventive measures because they should reduce the net mineral loss to zero or even remineralize existing lesions. The detection of cavitation due to caries is a comparatively crude diagnostic approach.

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Jan 3, 2022 | Posted by in General Dentistry | Comments Off on – Understanding caries

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