Modules
Module 3: Caries ManagementCaries Risk Classification Table

3.2 Medical Model

Under the medical model of dental caries management, caries is viewed as a continuum of disease caused by specific pathogens, with patients at varying degrees of risk. To manage the disease, dentists must consider the specific pathogens involved and infectivity, as well as prevention and treatment modalities that address the infection. They must also surgically repair (restore) defects resulting from tooth destruction.

Under the medical model of dental caries management, caries is viewed as an infection rather than as a lesion.3 A limited, identifiable number of bacteria within dental plaque are responsible for caries.

Dental caries can be assessed using a medical model for caries management that recognizes the need to treat the bacterial component of caries rather than simply repairing the damage caused by decay.3,4 Unlike the surgical model, the medical model places shared responsibility for new carious lesions on the dentist and the patient, as new carious lesions indicate that the infection was not treated to a therapeutic endpoint.

The medical model is based on the philosophy that dental caries diagnosis should not only answer the question of whether there a carious lesion but also address the critical issue of whether an active lesion is present, and, if it is, at what rate it is progressing.5 Thus, dental caries diagnosis must be longitudinal, comparing past and current examinations and X-ray findings, rather than a “snapshot” view considering only current examinations and X-ray findings. If restoration is provided without thoughtfully considering alternatives, patients may be receiving care that increases their risk for undesirable side effects.1,6

This new perspective leads to the shifts in treatment assumptions outlined in Table 2. The table has been simplified to emphasize key concepts.2

Table 2: Surgical vs. Medical Model

Surgical Model Medical Model
No bacteria-based diagnosis is required, since everyone has plaque. Bacterial diagnosis is essential because only patients at risk for the clinical manifestations of dental caries are treated.
The entire population must be treated, since everyone forms plaque. Identify patients likely to be infected, and target treatment appropriately.
The goal of treatment is removal of plaque, and treatment must be continuous, since plaque forms continuously. Treatment is directed at eliminating or reducing odontopathogens within plaque and other areas of the mouth.
Patients are recalled for examination and for any new restorations required. Treatment ceases at its therapeutic endpoint, and patients are recalled to diagnose re-infection (if any).
New lesions are due to patient non-compliance. A carious lesion is prima facie evidence that the patient did not keep plaque off the teeth. New lesions are the shared responsibility of the dentist and the patient. They result from a failure to diagnose and treat the infection and/or from patient non-compliance with recommended preventive strategies.