Determination of the flexural modulus of elasticity of orthodontic archwires

ObjectiveTo design a protocol for the determination of the flexural modulus of elasticity of wire with high accuracy and precision.MethodsCantilever bending was used at long span and low loads, using a laser displacement sensor. Various wires were tested for proof-of-concept: stainless steel, Elgiloy, Wiptam and a gold alloy, with primary attention being paid to the source and magnitude of errors.ResultsThe moduli of elasticity were determined with a median relative error of ∼0.15%, with a worst case of 0.56%, taking into account all measurement errors. The precision was such as to permit distinctions between the values for the wires of different thermomechanical history.SignificanceThe determination of the elastic modulus of wires may be made with good precision using cantilever bending providing attention is given to all sources of error. These results represent the most reliable measures of modulus of elasticity of orthodontic archwires to date.