Three-dimensional orthodontic force measurement system to evaluate the temperature effect on NiTi wire

Abstract

The movement of teeth during orthodontic treatment should be controlled in all three planes of space including the crown and root position Force and movement should be accurately known in order to move a tooth into the ideal position and avoid undesirable side effects such as additional visits overloading tissue necrosis or even root resorption Nickel-titanium (NiTi) wires are widely used in orthodontics as they combine the shape memory and superelasticity resulting from phase transformation induced by stress or temperature In this study a 3D force measuring system was developed using cone-beam computerized tomography (CBCT) images and software (Mimics 10 01 Geometric studio 12 and Solidworks) The models were fabricated using a 3D printer (Up plus 2) A multi-axis force transducer called Nano17 (ATI USA) was used for the 3D orthodontic force and moment measurements Four different types of NiTi wire (Nitinol Sentalloy 27°C CuNiTi 40°C CuNiTi) with the same size ( 016 x 022 inches) were used Self-ligating brackets (H4 Orthoclassic USA) were bonded on simulated teeth The change in orthodontic force and moment can be observed inside temperature controlled box The results revealed that there was a strong relation between temperature and orthodontic force for most brands of wires except Nitinol (correlation coefficient: Sentalloy=0 964 27°C CuNiTi=0 918 40°C CuNiTi=0 946) Comparison of forces under different temperature among different NiTi wires also reached statistically significant difference However the moment and temperature did not show a very strong correlation Nitinol expressed highest and 40°C CuNiTi expressed lowest moment among four groups The 3D force measurement system can provide practical information for clinical use

Date of Award	2017 Aug 30
Original language	English
Supervisor	Jia-Kuang Liu (Supervisor)