| 摘要 |
PURPOSE:To provide a dental orthodontic bracket consisting of the sintered compact of partially stabilized zirconia having an excellent aesthetic characteristic, high strength, high toughness and excellent thermal stability. CONSTITUTION:This dental orthodontic bracket consists of the sintered compact of the partially stabilized zirconia which consists essentially of ZrO2, is stabilized with one or >=2 kinds of rare earth metal oxides selected from a group consisting of Gd2O3, Yb2O3, Ho2O3 and Dy2O3 or is stabilized by this rare earth metal oxides and/or La2O3 and Y2O3 and in which the ratio of the Y2O3 in the stabilizing agents is 30 to 70mol%. The raw material powder is molded and the molding is sintered at 1200 to 1450 deg.C. Then, the bracket shaped to have the good operability approximate to the operability of a metallic bracket is thus obtd. without any restriction in design. The deterioration in the strength does not arise even if the bracket is subjected to the surface treatment for the purpose of improving the adhesive. Coloration to the color tones approximate to the color tones of the natural teeth is possible and the aesthetic characteristic is excellent. |
