Avaliação histobacteriológica da dentina após a remoção do tecido cariado em pré-molares humanos in vitro

Abstract

The present research had the objective to analyze qualitatively though histobacteriology, the remaining dentine of upper human premolars after removal of clinically decayed tissue, according to presence, location and distribution of microorganisms in dental tubules in different degrees of depth of carious lesion. It was selected representative histological blades of histological cut in series, obtained during the research of Biffi et al (1982), extracted from patients of both genera and age from 20 to 40 years old. The teeth should present proximal caries and/ or occlusal caries and the removal of decayed tissue would be done in vitro. The three faces (dental, mesial and occusal) were clinically classified according to the depth of the caries in degrees 0, 1, 2, 3, 4 or 5 and microscopically assessed. The blades were tinged using the technique of Hematoxylin and Eosine, Trichrome of Masson and histobacteriological of Gram, modified by Brown and Brenn. The interpretation of histological cuts was realized with the use of a trinocular and photomicroscope. In the descriptive analysis it was possible to check the bacterial penetration in a superficial way and/ or in a deep way in the dentinal tubules both in the pulpal floor or in the amelodentinal junction, as well as the presence of bacterial niches in the cavity preparation. The contaminated tubules showed morphologically inaltered, and in pulp exposure during the removal of deep caries it was verified the introduction of a contaminated dentinal fragment in the pulp tissue. In order to have a statistical analysis of the number of microorganisms, it was applied the Pearson s correlation coefficient, respectively among the different degrees of caries and localization in the amelodentinal junction and pulp floor. It was brought to a conclusion that, in 56,7% of the decayed faces the microorganisms were placed in dentine considered clinically healthy, in which they lodged in dentinal tubules morphologically inaltered; the localization and the distribution of microorganisms in the tubules were variable and independent of the depth of the caries.