Microbiopsies of Surface Dental Enamel as a Tool to Measure Body Lead Burden

Abstract

Lead (Pb) poisoning is preventable but continues to be a public health problem in several countries. Measuring Pb in the surface dental enamel (SDE) using microbiopsies is a rapid, safe, and painless procedure. There are different protocols to perform these microbiopsies, but the reliability of dental enamel lead levels (DELL) determination is dependent upon biopsy depth (BD). It is established that DELL decrease from the outermost superficial layer to the inner layer of dental enamel. The aim of this study was to determine DELL obtained by two different microbiopsy techniques on SDE termed protocol I and protocol II. Two consecutive enamel layers were removed from the same subject group (n = 138) for both protocols. Protocol I consisted of a biopsied site with a diameter of 4 mm after the application of 10 μl HCl for 35 s. Protocol II involved a biopsied site of 1.6 mm diameter after application of 5 μl HCl for 20 s. The results demonstrated that there were no significant differences for BD and DELL between homologous teeth using protocol I. However, there was a significant difference between DELL in the first and second layers using both protocols. Further, the BD in protocol II overestimated DELL values. In conclusion, SDE analyzed by microbiopsy is a reliable biomarker in protocol I, but the chemical method to calculate BD in protocol II appeared to be inadequate for measurement of DELL. Thus, DELL could not be compared among studies that used different methodologies for SDE microbiopsies.

The authors acknowledge the valuable collaboration of the directors and teachers of the Projeto Girassol, Projeto Agente Jovem, and Centro Irmã Adelaide, and the volunteers and their families involved in this investigation. We thank Prof. Dr. Thomas Attin for the use of the profilometer (Clinic for Preventive Dentistry, Periodontology and Cariology, University of Zurich, Zurich, Switzerland). This work was supported by FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo), grants 01/09641-1 and 06/56530-4; CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico); and the Projeto Milênio Redoxoma. KPKO was recipient of a fellowship from CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior).