Authors: S. Choi, H. Joo, Y. Cheong, S. Lee, S. Kim, Y.-G. Park, H.-K. Park
Affilation: Kyung Hee University, Korea
Pages: 478 - 481
Keywords: atomic force microscopy, self-ligating brackets, stainless steel archwire, surface roughness
It is well-known that the frictional force between the archwire (AW) and the bracket reduces the efficiency of orthodontic treatment. It is affected not only by geometry of self-ligating brackets but also by physical changes between bracket slots and AW surfaces during sliding movement. This study observed the effect of self-ligating brackets on the surfaces of stainless steel AWs during sliding tooth movement in vivo utilizing atomic force microscope (AFM). From the first bicuspid extraction case, 0.019 × 0.025 inch stainless steel AWs with sliding movement were selected and four groups of AWs were employed; Group 1 and 2 used with stainless steel self-ligating brackets ceramic self-ligating brackets. Group 3 and 4, as control groups, used with conventional stainless steel brackets and intact stainless steel AWs. The sections engaged with brackets of 2nd bicuspids were cut and scanned in the air at resolution of 256 × 256 pixels, with scan speed of 1 line/sec using AFM. All the stainless steel AWs with sliding movement showed severe scratches caused by the fictional interaction between bracket slots and AWs. Stainless steel AWs interacted with stainless steel self-ligating brackets showed the smoothest surface roughness among the three brackets. Those interacted with conventional stainless steel brackets showed the second smooth surface. The stainless steel AWs interacted with ceramic self-ligating brackets showed the roughest surface compared to the others. The findings suggest that the orthodontic treatment with stainless steel self-ligating brackets might be more effective than that with ceramic self-ligating or conventional stainless steel brackets.