Nakhaei Samaneh, Agahi Raha Habib, Aminian Amin, Rezaeizadeh Masoud
Assistant Professor, Department of Orthodontics, Birjand Dental School, Birjand University of Medical Science, Birjand, Iran.
Oral and Dental Disease Research Center, Kerman Dental School, Kerman University of Medical Science, Kerman, Iran.
Dental Press J Orthod. 2017 Mar-Apr;22(2):45-54. doi: 10.1590/2177-6709.22.2.045-054.oar.
: The aim of the present study was to evaluate color changes and force degradation of orthodontic elastomeric ligatures in different stretching patterns during a 8-weeks period.
: Two elastomers with the minimum and two with the maximum color changing, and gray elastomers of two brands (American Orthodontics and Ortho Technology) were selected according to an opinion poll with clinicians and color changes after 4 weeks of intraoral use were evaluated. These elastomers were mounted on special jigs fabricated using a CAD-CAM technique, underwent different stretching patterns and the force was measured in 0, 24 hours, 2, 4 and 8 weeks. During in vivo part of the study, force levels of elastomers were measured after 4 weeks on a material testing machine. Data were analyzed with four-way ANOVA and Tukey post hoc tests.
: All the elastomers showed color changing but the degree of color stability was significantly different. The mean force degradation was higher in 1-mm stretch groups. After 8 weeks, the average residual force of elastomers was 1.45 ± 0.18 N and the maximum force decay was seen in the elastomers that exhibited the maximum initial force.
: There is significant relationship between the stretching pattern and the amount of residual force of elastomers. Elastomers with higher initial forces exhibited higher percentages of force loss after 8 weeks. It seems that there is a relationship between initial color and color changing of elastomers.
本研究旨在评估正畸弹性结扎圈在8周内不同拉伸模式下的颜色变化和力的降解情况。
根据对临床医生的民意调查，选择了两种颜色变化最小的弹性体和两种颜色变化最大的弹性体，以及两个品牌（美国正畸公司和正畸技术公司）的灰色弹性体，并评估了口腔内使用4周后的颜色变化。这些弹性体被安装在使用CAD-CAM技术制造的特殊夹具上，经历不同的拉伸模式，并在0、24小时、2、4和8周时测量力。在研究的体内部分，4周后在材料试验机上测量弹性体的力水平。数据用四因素方差分析和Tukey事后检验进行分析。
所有弹性体均呈现颜色变化，但颜色稳定性程度存在显著差异。1毫米拉伸组的平均力降解较高。8周后，弹性体的平均残余力为1.45±0.18牛，初始力最大的弹性体中力衰减最大。
拉伸模式与弹性体残余力大小之间存在显著关系。初始力较高的弹性体在8周后力损失百分比更高。弹性体的初始颜色与颜色变化之间似乎存在关联。
