Stress analysis of multiloop edgewise arch wire with various degree of tip back bend : a study using the finite element method

Lee, Young Il; Cha, Kyung Suk; Ju, Jin Won; Lee, Jin Woo

Abstract

This study have been carried out to find out the mechnical effect of Multiloop Edgewise Arch Wire(MEAW) making use of the finite element method. The tip back bend of MEAW taken in this analysis is 5degrees,12degrees and 15degrees. In addition, Class II or up & down elastic is applied to find out stress distribution and their values in PDL. A adult male of normal was selected to create the models of teeth and PDL. And the model of MEAW was also created using commercial finite element code (ANSYS version 5.2). The MEAW is forcibly engaged with a class II or up & down elastic, to determine the initial stress generated in PDL. Comparing the compressive and tensile stress at each reference-planes, following
results
are obtained. 1. When a MEAW of 5degrees, 10degrees, 15degrees tip back bend was engaged with Class II or up & down elastic, the distribution of compressive, tensile stress in entire PDL is similar in each case. 2. The values of compressive and tensile stress in PDL is higher in 15degrees tip back bend case than in 10degrees or 5degrees tip back bend case. 3. In the distal PDL of 1st and 2nd molar, compressive stress appears. The compressive area is more wide and its values is higher in PDL 2nd molar than those in 1st molar. The compressive area and its values become more wide and higher according to the increase of the tip back bend. 4. The value of compressive stress are comparatively smaller in PDL of molars than those in premolars. 5. Comparing class II and up & down elastic case, tensile stress values in anterior teeth PDL are smaller and their distribution is more wide in up & down elastic case than class II elastic case. On another hand, there is no difference in distribution and stress values in PDL of posterior teeth between two cases. 6 Comparing the tensile area in PDL of anterior teeth, tensile stress values are maximum in PDL of canine.