Caries Risk Assessment and Criteria for Intervention. When Should You Intervene?
Deciding when to restore a carious cavity and when to monitor a lesion has historically been largely subjective and prone to substantial variation between practitioners. The aim of this chapter is to provide objective criteria that a practitioner can use to decide as to when operative intervention is indicated.
After completing this section practitioners will be familiar with caries risk assessment and how the caries risk assessment of a patient weights the decision to intervene or not, as the case may be. Similarly, objective criteria are discussed which can be applied to individual lesions to assist practitioners in deciding to intervene more appropriately.
A decision when to intervene in the management of caries is probably amongst the most important decisions a dentist makes. Tooth preparation is irreversible and places the tooth on the restorative staircase. Eventually all restorations fail and where repair and refurbishment procedures cannot usefully extend the life of the restoration, a replacement (typically, larger) restoration will be required. Inevitably when failed restorations are removed and replaced, more tooth tissue is lost and the preparation becomes more extensive, possibly requiring a cuspal coverage indirect restoration, which requires further tooth reduction. At some point on the restorative staircase it is likely that the pulp becomes involved. It is crucial, therefore, that operative intervention should be delayed until indicated clinically or absolutely necessary and the nature of the intervention should be limited to preserve tooth tissue but also to prolong the life of the restored unit.
Until relatively recently, the threshold for operative intervention was held to be: when a carious cavity was shown to be in dentine radiographically or when the lesion was visibly cavitated. If these criteria were adopted universally, arrested or static lesions would be restored unnecessarily. Consequently, it is now the accepted convention that lesions are restored if they are into dentine and there is evidence that they are progressing. Cavitated lesions continue, by definition, to require restoration. Operative management of lesions extending into dentine is favoured in patients who have a high or medium risk of developing new lesions.
Caries risk assessment is defined as the risk that a patient will develop new lesions of caries or existing lesions will continue to progress, assuming that all aetiological factors (diet, time, susceptible surface and plaque levels) remain equal. It is an important assessment as it helps a clinician to decide whether to monitor or to restore caries. It also influences the recall period for patients in regular dental care, let alone the frequency that further radiographs should be taken for monitoring purposes. Patients are assessed as being at high, medium and low risk of developing further lesions. It is important to accept that patients can change their caries-risk status – moving from low to high by changing their diet (for example, students leaving home and altering their diet, older patients, patients post radiotherapy, or past smokers sucking sweets more frequently than normal to combat the effects of a dry mouth or in place of a cigarette).
The following factors influence the caries risk for an individual patient:
The patient’s diet, especially if the diet is rich in fermentable carbohydrates, i.e. cariogenic.
The frequency of consumption of fermentable carbohydrates.
The presence and amount of cariogenic bacteria, specifically lactobacillus and streptococcus mutans, in the plaque biofilm.
Saliva—both the amount (volume) and buffering capacity (quality).
Socio-economic status and social history. Caries is a disease of deprivation and therefore patients with low socio-economic status are more likely to develop new lesions and existing lesions are more likely to progress.
Previous disease experience—which is usually assessed by the number of restorations, although it may mean that the patient has previously attended a practitioner with a low intervention threshold. Other useful indicators are missing teeth, i.e. not those removed for orthodontic reasons.
Current disease experience (for example, the number of “white spot” lesions and the presence of cavitated lesions).
Attendance pattern. Regular attenders are likely/>