치과 교정용 심미 NiTi 선재의 물리적 기계적 특성 비교

Abstract

The objectives of this study were to compare the surface characteristics, physical properties, and esthetic maintenance of the e sthetic NiTi archwires that generate an appropriate orthodontic force. In this study,two polymer-coated NiTi archwires and two metal-coated NiTi archwires were selected as esthetic NiTi archwires. In addition, four uncoated NiTi archwires that came in the same size and shape (0.016" round) as the aforementioned esthetic NiTi archwires by the same manufacturers were tested. In each wire, chemical composition, three-point bending test at 36.5℃, friction test, surface roughness, and SEM images of coating layer after friction test were observed. The results were as follows:1. The chemical composition analysis found that the coating layers of Ultraesthetic SE NiTi Tooth colored archwire (PG, G&H) and Perfect NiTi coated archwire (PH, Hubit) were made of the same polymer while the c oating layer o f White wire Sentalloy (MT, Tomy) was made of Au-Rh a lloy and that of Experimental Ag coated NiTi (MB, Biomaterials Korea) was made of Ag. 2. According to the three point bending test, the polymer coated NiTi archwires showed less unloading force values than uncoated NiTi archwires, whereas metal coated NiTi archwires showed more unloading force values than uncoated NiTi archwires (p<0.05). 3. The friction test illustrated that the static and kinetic frictional forces of the coated NiTi archwires were statistically higher than those of the uncoated NiTi archwires. 4. S urfac e roughness was inc reased s ignific antly in t he p olymer c oated NiTi a rc hwires ( p<0.05) and inc reased in proportion to fric tional forc e of the coated NiTi arc hwires and i t was statistic ally s ignificant (p<0.05). 5. After friction test, SEM surface images showed severe deterioration in the polymer coating layer and minor exfoliation in the metal coating layer.