Nl 1- Biomarkers of Exposure to Fluoride

Biological markers or biomarkers are defined as indicators that signal events in biological systems (human body) or samples. A biomarker is not used as diagnosis test, but as an indicator of a disease or biological alteration. The biomarkers are classified in three types: 1) exposure; 2) susceptibility and 3) biomarkers of effect. For biomarkers of fluoride the examples would be respectively: 1) plasma, bone, teeth, urine, saliva, dental plaque, plaque fluid, hair, nails; 2) genetic factors, acid-base disturbances, renal disturbances, bone growth and nutritional state; 3) reduction in the activity and severity of the dental caries, dental fluorosis and skeletal fluorosis. A biomarker of exposure is a substance of external origin or a metabolic derivate or the product of an interaction between a biological agent and molecules. The biomarker of susceptibility is an indicator that the individual is particularly sensitive to the effect of a substance and for the fluoride this can be a form of understanding the variation of individual dose-response for the same exhibition pattern to fluoride. The biomarkers of effect are the consequences of a previous exhibition: dental or skeletal fluorosis. In spite of the constant use of some biological materials as plasma and saliva in dental research, the use of these materials in pharmacokinetics models for biomarkers of exposure is still limited. One of the advantages in using biomarkers model is the possibility to simplify the collection, storage and analysis of samples. In spite of the fact that fluoride biomarkers are regarded as important auxiliaries in the evaluation of dental fluorosis risks, it is important to recognize that the biomarker model is in a developmental phase.