Dynamic measurement of orthodontic force using a tooth movement simulation system based on a wax model

Abstract

BACKGROUND: Orthodontic force is often statically measured in general, and only the initial force derived from appliances can be assessed. OBJECTIVE: We aimed to investigate a technological method for measuring dynamic force using tooth movement simulation. METHODS: Tooth movement was simulated in a softened wax model. A canine tooth was selected for evaluation and divided into the crown and root. A force transducer was plugged in and fixed between the two parts for measuring force. Forces on this tooth were derived by ordinary nickel–titanium (Ni–Ti) wire, hyperelastic Ni–Ti wire, low-hysteresis (LH) Ti–Ni wire and self-made glass fibre-reinforced shape memory polyurethane (GFRSMPU) wire. These forces were measured after the tooth movement. RESULTS: The canine tooth moved to the desired location, and only a 0.2 mm deviation remained. The changing trends and magnitudes of forces produced by the wires were consistent with the data reported by other studies. The tooth had a higher moving velocity with ordinary Ni–Ti wires in comparison to the other wires. Force attenuation for the GFRSMPU wire was the lowest (40.17%) at the end of the test, indicating that it provided light but continuous force. CONCLUSIONS: Mimicked tooth movements and dynamic force measurements were successfully determined in tooth movement simulation. These findings could help with estimating treatment effects and optimising the treatment plan.