Stefański Tomasz, Kloc-Ptaszna Anna, Postek-Stefańska Lidia
Department of Orthodontics, Medical University of Silesia, Zabrze, Poland.
Institute of Engineering Materials and Biomaterials, Silesian University of Technology, Gliwice, Poland.
Dent Med Probl. 2019 Apr-Jun;56(2):173-177. doi: 10.17219/dmp/105832.
Frictional resistance is an important parameter in orthodontics that influences the effectiveness of archwire-guided tooth movement. Since the consumption of dietary acids has increased considerably over the last 2 decades, there is a rationale for investigating the process of degradation of orthodontic materials in an acidic environment and its effect on clinical efficiency.
The aim of this study was to evaluate the effect of simulated erosive conditions on the frictional behavior between the brackets of 3 different materials and 3 different wire alloys.
Three types of twin orthodontic brackets (stainless steel (SS), monocrystalline ceramic and titanium) and 3 types of archwires of the same dimension (SS, nickel-titanium (Ni-Ti) and beta-titanium (titanium-molybdenum alloy - TMA) were tested in 9 different combinations under simulated erosive and non-erosive conditions (18 groups, n = 10). Bracket-wire specimens in the erosivecondition groups were subjected to a pH cycling regimen with 1% citric acid and artificial saliva for 5 consecutive days. Bracket-wire specimens from the non-erosive-condition groups were incubated only in artificial saliva for 5 days. Static and kinetic friction were determined by measuring the force needed to move the wire through the bracket. A three-way analysis of variance and pairwise comparisons with the Student-Newman-Keuls test were performed.
Irrespective of the conditions, SS brackets with SS wire demonstrated significantly lower mean static and kinetic frictional resistance than other bracket-wire combinations (p < 0.01). Ceramic and titanium brackets generated high frictional forces with all 3 types of wire tested. Erosive conditions did not significantly influence static and kinetic frictional resistance in all bracket-wire groups.
Erosive conditions do not affect the frictional behavior of SS, Ni-Ti and TMA orthodontic archwires at a clinically significant level.
摩擦力是正畸学中的一个重要参数，会影响弓丝引导牙齿移动的效果。由于在过去20年中饮食酸的摄入量大幅增加，因此有理由研究正畸材料在酸性环境中的降解过程及其对临床效果的影响。
本研究旨在评估模拟侵蚀条件对3种不同材料的托槽与3种不同丝材合金之间摩擦行为的影响。
在模拟侵蚀和非侵蚀条件下，对3种类型的双托槽正畸托槽（不锈钢（SS）、单晶陶瓷和钛）和3种相同尺寸的弓丝（SS、镍钛（Ni-Ti）和β钛（钛钼合金-TMA））进行9种不同组合的测试（18组，n = 10）。侵蚀条件组的托槽-弓丝标本连续5天接受pH循环方案，使用1%柠檬酸和人工唾液。非侵蚀条件组的托槽-弓丝标本仅在人工唾液中孵育5天。通过测量使弓丝穿过托槽所需的力来确定静摩擦力和动摩擦力。进行了三因素方差分析以及使用Student-Newman-Keuls检验的两两比较。
无论条件如何，SS托槽与SS弓丝的平均静摩擦力和动摩擦力均显著低于其他托槽-弓丝组合（p < 0.01）。陶瓷和钛托槽与所有3种测试丝材产生的摩擦力都很高。侵蚀条件对所有托槽-弓丝组的静摩擦力和动摩擦力没有显著影响。
侵蚀条件在临床上显著水平下不会影响SS、Ni-Ti和TMA正畸弓丝的摩擦行为。
