The influence of electrical current strength on dentine mineralization

Abstract

Objectives: The aim of this study was to investigate the influence of electrical current strength on dentine mineralization via cooperating electrophoresis with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). Methods: Dentine slices with a thickness of 2 mm were prepared by using a diamond saw to perpendicularly slice teeth along their longitudinal axis and polished with a 2000-grit silicon carbide paper under running water.Twenty-one polished dentine slices without cracks or hypo-mineralization were collected and acid-etched with 37% phosphoric acid for 60s to obtain demineralized dentine surface. For investigating the influence of electrical current strength on dentine mineralization, demineralized dentine slices were randomly allocated into experimental group A (n=6), experimental group B (n=6), experimental group C (n=6) and blank control group (n=3). Samples in experimental groups were remineralized with electrophoresis-aided CPP-ACP mineralization system for 8h (group A treated with 2.0 mA, group B treated with 1.0 mA and group C treated with 0.5 mA). Samples in the blank control group were received no treatment. After remineralization, all samples were characterized by scanning electron microscope (SEM). Results: In demineralized dentine slices, the dentine collagen fibers were demineralized, and collagen matrix was exposed (Fig. 1A). After 8 hours mineralization in experimental groups, demineralized dentine collagen matrix was completely remineralized and fully covered with intrafibrillar and interfibrillar crystals (Fig. 1B, C and D). Densely packed crystals were homogeneously distributed along the collagen fibers and imbedded in the spaces between demineralized dentine collagen fibers. The morphology of newly formed crystals varies with different current strength. It was detected that nanosphere-like crystals, sheet-like crystals and ribbon-like crystals were respectively formed in group A (Fig. 1B), group B (Fig. 1C) and group C (Fig. 1D). Conclusions: Electrical current strength has the influence on the morphology of newly formed crystals on demineralized dentine