[Enhancement of enamel crystallinity with gel method during orthodontic treatment. The 1st report: Application of electron probe X-ray microanalyser].

This paper is to review the gel method of strengthening tooth enamel substance around bonded brackets and morphological observations and elemental analyses of the chopped cross section of the three below-mentioned groups were carried out by electron probe X-ray microanalyser (EPMA) for a relative review. Group I: bracket-bonded extracted tooth enamel in application of the silica-hydro gel method. Group II: bracket-bonded extracted tooth enamel in application of the gelatin gel method. Group III: bracket-bonded extracted tooth enamel in application of neither method. The results obtained were as follows: 1) As a result of making morphological observations through secondary electron image and back scattered electron image, the adhesive condition of the brackets and the state of the chopped cross sections were favorable and these combined observation proved effective as a supplementary method of elemental analysis. 2) Through qualitative analyses, Ca, P, F, O, Na, Mg and Cl were recognized as content elements on the experimental side (the non-bracket side) as well as on the control side (the bracket side) from group I through III. 3) In making ultrahigh-speed wide-area surface analyses (elemental concentration map), the incorporation of F was recognized from enamel cuticle to approximately 200 microns in group I and to 50-100 microns in group II, and the distribution of Ca was totally consistent, and P showed the slight downward trend from enamel cuticle to dentoenamel junction. 4) The incorporation of F was acknowledged to be until 150-200 microns on the experimental side of group I and to be until 80 microns on the experimental side of group II by line analyses. 5) As regards F on the experimental and the control side in group I as well as in group II through a quantitative analysis, the experimental side clearly revealed a high concentration of F and acknowledged 1% level to be a significant distinction. From the foregoing results through the electron probe X-ray microanalyser, strengthening tooth enamel substance in vitro by application of the gel method proved to be effective, and the silica-hydro gel method was indicated to be superior to the gelatin gel method.