**3. Caries risk markers on the orthodontic treatment**

Diagnostic tests may serve multiple clinical objectives that benefit the individual patient. The clinician may use tests to: a) identify predisposing risk factors to modify risk and prevent disease; b) identify early disease-associated biochemical or physical changes prior to clinical signs of disease to halt the changes and reverse damage prior to loss of function; and c) determine which specific type of disease is involved to guide selection of the most effective therapy (Kornman, 2005; Sánchez & Sáenz, 2003).

Risk markers are biologic markers that either indicate disease or disease progression but are not causal or represent historical evidence of the disease, risk factors are characteristics of the person or environment that, when present, directly result in an increased likelihood that a person will get a disease and, when absent, directly result in a decreased likelihood of disease.

Risk factors for prediction of caries activity have been described by Featherstone (2000) and involve a balance between well-described pathological and protective factors. The pathological factors are primarily the levels of acidogenic bacteria, the frequency of fermentable carbohydrate ingestion, and the level of saliva flow. The protective factors include salivary proteins and antibacterial components, salivary composition of key minerals—for example, calcium and fluoride—and protective dietary components (Kornman, 2005; Featherstone, 2000).

About caries risk factors that it must be valued we can mention the following ones:
