The Development of the Esthetic Orthodontic Wire

Abstract

The FRP as the esthetic orthodontic wire was fabricated with biocompatible CaO-P₂O₅-SiO₂-Al₂O₃ (CPSA) glass fibers and PMMA. In this study both the mechanical properties and biocompatibility of the FRP wire were investigated. All wires were approximately 0.5mm in diameter Young's modulus could be regulated in proportion to the volume fraction of glass fibers from 20GPa to 40GPa under dry condition corresponding to the conventional metal wires. However, deload/load ratio at 1.0mm in deflection was deteriorated from 80.9% to 23.3% after 30 days exposure to water. The coating layer could well function as the moisture protector so that the deterioration of the ratio was improved to 56.7%. In the histological study of long term implantation of CPSA FRP wires (4 weeks), the organization had almost completed either by separation or by covering with the granulation tissue. Macrophages and foreign body giant cells were scarcely observed. Therefore it could be thought that they had good biocompatibility.