Titanium Alloys in Dentistry

Goldberg, A

Abstract

The overall goal of this research project is to develop wires for dental applications which are capable of sustaining large deflections without permanent deformation, possess a range of moduli of elasticity, good formability, and which can be easily joined together or to other common dental alloys. Such wires would be useful in orthodontic appliances and removable partial denture (RPD) clasp assemblies. The clinically desirable characteristics for orthodontic devices would include: (1) the ability to apply lower forces, (2) a more constant force over time, (3) the ability to change wire stiffness over a continuous range without changing the cross-sectional dimensions of the wire, (4) greater ease and accuracy in applying a given force, and (5) the ability to use larger activations and the associated increased """"""""working time"""""""" of the appliance. Similarly in RPD framework design, these wires could provide for highly elastic clasp assemblies which minimize tipping and rotational forces. Several classes of titanium alloys will be investigated to develop the desired range of mechanical properties. The effects of thermal and mechanical processing on the microstructure, surface quality and properties of metastable beta, alpha-beta, martensitic, near beta, and super alpha titanium alloys will be studied. Various metallurgical approaches to optimizing properties will be used including cold drawing, age hardening, multiple step age hardening, rolling and high temperature drawing. Structural analyses will be conducted with optical metallography, TEM, SEM and the electron microprobe. Resistivity measurements will be used to monitor the precipitation age hardening reaction. Welding titanium alloys together and to common dental alloys will be studied. Orthodontic and RPD appliances will be constructed from the subject alloys and evaluated. These analyses will differentiate the effects of mechanical design and material properties.