Effective management of dental caries throughout the lifespan of an individual depends on an ongoing process that involves not only detection and diagnosis of existing caries lesions, with a focus on understating lesion activity, but also an assessment of caries risk, both at the tooth and patient level (Fig 17-1). This information helps to determine the activity of the caries disease process at the tooth level, which unfortunately is still the strongest indicator of future caries activity or risk at the individual level. However, the assessment of risk factors further aids in understanding why there is disease activity and what factors drive the progression of this disease activity, as well as which factors aid in lesion arrest. Thus, information from both an assessment of lesion activity and caries risk factors is necessary, together with an understanding of the patient’s needs and desires, available evidence supporting treatment alternatives, and the dental practitioner’s clinical expertise should be used to reach a clinical decision on how to effectively control existing lesions and prevent occurrence of new caries lesions in a personalized manner for each individual. In the future, as caries risk tools become informed by richer and newer evidence sources, and validated across patient groups in different countries, they may become increasingly more accurate in their ability to predict the caries disease process before it develops, and help target preventive interventions in a more cost-effective manner.
Risk assessment is an essential component of targeted health care delivery. Dentistry has entered an era of “personalized care,” in which targeting care to individuals or groups based on their risk has been advocated as a means to make use of limited existing resources, especially when the disease process is unequally distributed among the population. Caries risk assessment is defined as the process of establishing the probability of an individual to develop new caries lesions over a certain time period, and/or the probability that there will be a change in severity and/or activity of currently present lesions.1,2 But a risk assessment involves much more than just caries prediction. It also involves identification of factors that cause or increase/decrease risk of disease, to then target cost-effective interventions to manage the caries disease process and determine the periodicity of these services.3 In fact, caries risk assessment has been considered an essential component of cariology curricula in dental education,4 and caries management systems (eg, International Caries Classification and Management System) (Fig 17-2).
What does validation of a caries risk form entail?
Validation of a caries prediction tool involves longitudinal follow-up of caries-related changes over time, with the outcome expressed as continuous values, eg sensitivity, specificity, and area under receiver operating characteristic curves (AUC).3 Because of the multifactorial and chronic nature of the dental caries disease process, studies on risk assessment tend to be complex, with multiple factors influencing risk at the individual, family, and community level, and challenging the prediction throughout the lifetime.7 However, caries experience/activity is still considered one of the greatest indicators of future risk.8 Usually, demographic, social, behavioral, and biologic variables, along with the clinical/radiographic examination and supplementary tests, are used to develop a caries risk profile or category (for example low, moderate, or high caries risk),9 which needs to be reassessed periodically over time. For a clinician, the concepts of assessment of risk and prognosis are important parts of clinical decision-making. In fact, the dental practitioner’s overall subjective impression of the patient has good predictive power for caries risk,2,10 although this is not always factored in existing caries risk forms.9
Existing evidence suggests that it is difficult to accurately identify “at risk” patients, and the evidence on targeting preventive measures for high-risk individuals is still limited. Most studies on risk assessment have been conducted in children, and there is very little evidence from adults.11 However, most experts and dentistry organizations contend that when the wellbeing of the patient is considered, it is more important to carry out a risk assessment incorporating the best available evidence than just doing nothing due to lack of strong evidence. Yet a survey of clinical practices within the US Practice-Based Research Networks suggests that a significant proportion of dental practitioners had not adopted caries treatments based on assessment of caries risk.12
Risk tools available for use in practice
Caries risk tools must be inexpensive and have a high level of accuracy to be cost-effective,13 and they must be quick and require limited armamentarium to be acceptable.14 There are numerous strategies and tools available for caries risk assessment in daily practice, including an informal assessment, use of structured paper forms, and use of computer-based programs (eg, Cariogram; Fig 17-2a). While the Cariogram is probably the most studied caries risk tool across the world, the majority of other caries risk tools are expert-based with limited validation.15
How is low, moderate, and high caries risk defined in most forms?
In general, in most risk forms a low caries risk assessment is based on a combination of the following factors: no caries lesion development or progression for a recent period of time; low amount of plaque; low frequency of sugar intake; no presence of salivary problems; and adequate exposure to protective factors. In addition, the following factors, whether appearing singly or in combination, would yield a moderate to high risk assessment of caries6,18:
- development of new caries lesions
- presence of active lesions
- placement of restorations due to active disease since the patient’s last examination
- detrimental change in amount of plaque
- incremental frequency of carbohydrate consumption
- decrease in saliva flow
- decrease in exposure to caries-protective factors.
What is the roll of caries risk assessment in interprofessional settings?
As imprecise as most risk tools are, they can be particularly helpful when used by individuals not trained to examine the oral cavity and assess caries lesion activity. For example, expanded partnership with the medical community is a promising strategy for reducing disparities in dental caries among young children. A validated caries risk instrument for use in primary health care settings would aid with triaging children at higher risk for preventive and referral strategies. The validity of caries risk tools for use in medical settings in the US is currently being investigated.18
Detecting dental caries is important to plan treatment; however, it merely represents part of the caries diagnostic process. The assessment of lesion activity, whether a lesion is active or inactive, and lesion severity (depth, and presence or absence of cavitation) are essential for appropriate control and management of the caries process.
The ability of a dental practitioner to accurately assess the lesion activity will be reflected in the management strategy to be implemented, whether noninvasive, minimally invasive, or an operative treatment. Not considering lesion activity could lead to superfluous treatment on inactive lesions, or even operative treatment involving unnecessary tissue removal. If the concept of caries lesion activity is understood, clinicians can use it routinely as part of the daily caries diagnostic process in favor of their patients.