Resumo de eventos cient??ficos
Molecular characterization of ex-vivo natural bovine dental enamel
Autor
ZAMATARO, CLAUDIA B.
PEREIRA, DAISA L.
GOMES, GABRIELA V.
ALVES, NATHALIA Z.
CASTRO, PEDRO A.A.
DIAS, DERLY A.
ZEZELL, DENISE M.
SCAPIN, MARCOS A.
ENCONTRO DE OUTONO, 41.
Resumen
Bovine teeth are widely used to infer results on a human population. Considering this, an analysis of the mineral
content of bovine enamel, focusing the hidroxiapatite (HA), was carried out to evaluate the homogeneity of the
sample universe for future experiments with laser irradiation as a substitute of human teeth enamel. Twelve
samples of 5 x 5 mm bovine enamel were prepared and polished plane. The mineral content was calculated
through surface microhardness (SMH) and morphology by scanning electron microscopy (SEM). Main molecular
components of the enamel were analysed by Energy Dispersive X-ray Spectroscopy (EDS). Surface microhardness
is an indirect indicator of the mineral content of the samples, which was 258.2 (38.8) KHN. The compounds
present in the samples, the values of Calcium and Phosphate oxides and the ration Ca/P were analizes. As
expected Phosphorus pentoxide and Calcium oxide were the main constituent of the samples (57.4 to 59.9%).
The CaO/P2O5 ratio shows a variation with linear correlation (R2 = 1). The elemental ratio (Ca/P) shows
a change in the elemental content with linear correlation (R2 = 1). 30% of the samples presented Strontium
oxide, 30% had Zirconium dioxide, 10% had Magnesium oxide and 40% had Silicon dioxide. All samples showed
Sulfur trioxide, Iron trioxide and Chlorine. 10% did not shown Zinc oxide. 5% had Potassium oxide and Nickel
oxide in its composition. The surface microhardness results, although only for the initial homogenization of the
sample universe, showed a Knoop hardness number within a spectrum similar to that of natural hydroxyapatite
of human origin. The EDS results show that bovine enamel hydroxyapatite present great similarity with that
from human enamel hydroxyapatite from the point of view of chemical composition. These results corroborate
the use of bovine hydroxyapatite in substitution of hydroxyapatite of human origin. Despite the inter-species
similarity, it is possible to note that in the same species the composition of hydroxyapatite varies. In the bovine
species, the feeding, the period of formation of the dental germs and the origin are more standardized and
controlled than in humans. Nevertheless, it is possible to notice a variation of the components elements of
bovine dental enamel, and it is necessary to restrict an interval of hardness and Ca/P values to homogenise the
samples properties for use in any experiment. Funda????o de Amparo ?? Pesquisa do Estado de S??o Paulo (FAPESP) Conselho Nacional de Desenvolvimento Cient??fico e Tecnol??gico (CNPq) FAPESP: 05/51689-2 CNPq: INCT 573.916/2008-0; 830615/1999-7