Comparison of stainless steel and titanium-molybdenum alloy closing loop archwires using numeric simulation model based on finite element method.

INTRODUCTION: The objective of this study was to determine and compare the moment-to-force (Mc/F) ratio and the type of tooth movement generated in the anterior and posterior segments in orthodontic space closure with stainless steel and titanium-molybdenum alloy loop archwires. METHODS: Three-dimensional model of the maxilla from which the first premolar was extracted, 18 x 25-mil slot stainless steel brackets, and 16 x 22-mil stainless steel and beta titanium-molybdenum alloy (TMA) closing loop archwires with anterior gable bend of 15 degrees and posterior gable bend of 25 degrees were constructed. The archwires were engaged in the brackets, and 1-mm activations were carried out, which were repeated 5 times. The anterior and posterior segment Mc/F ratio and the type of tooth movement generated by the 2 wires were compared. RESULTS: It was found that the Mc/F ratio for the anterior segment was approximately 5 mm, and for posterior teeth was approximately 10 mm for both stainless steel and TMA closing loop archwire. The anterior teeth exhibited controlled tipping, whereas the posterior teeth showed bodily tooth movement, which was in accordance with the Mc/F ratio that was obtained. CONCLUSIONS: The Mc/F ratio and the type of tooth movement exhibited by stainless steel and TMA closing loop archwires were similar in both anterior and posterior segments.