Kardach Hubert, Biedziak Barbara, Olszewska Aneta, Golusińska-Kardach Ewelina, Sokalski Jerzy
Division of Facial Malformation, Department of Dental Surgery, Poznan University of Medical Sciences, Poland.
Department of Dental Surgery, Poznan University of Medical Sciences, Poland.
Adv Clin Exp Med. 2017 May-Jun;26(3):373-378. doi: 10.17219/acem/61957.
The loss of physical properties of orthodontic chains has been a topic of discussion among scientists and clinicians, motivating efforts to improve elastic materials and minimize the decrease of force. Orthodontic companies have introduced memory elastomers, which, according to the manufacturers, have improved mechanical properties.
The aim of the study was to evaluate the effects of stretching elastomeric chains submerged in 37°C artificial saliva.
The study assessed 2 types of chains. The first phase of the study evaluated 1) the tensile strength of the chains; and 2) elongation at the time of tearing in an environment outside of the oral cavity (without exposition). The second phase of the study evaluated 1) permanent deformation after stretching; 2) elongation at the time of tearing; and 3) the tensile strength of the chain in conditions similar to those present in the oral cavity.
In the experiments using artificial saliva, pronounced force decay was observed in the plastic chain, in which, after just 7 days, force decreased almost by half compared to the initial value, with a continuous downward trend. The memory chain, however, showed increased elasticity, and after the first week of exposition the force decay at the time of tearing was around 20% of the initial value. Force decay at the time of tearing remained at a steady level between 14.4 and 25.4% throughout the whole period of exposition. In the plastic chain this value oscillated between 50.3 and 55.9%. In the experiments assessing permanent deformation of the chains performed after each week of exposition, the specimens prepared from the memory chain stretched from 8 cm to approximately 9.5 cm after exposition, while the specimens prepared from the plastic chain stretched to approximately 13 cm.
Memory chains are more effective in orthodontic treatment due to diminished loss of mechanical and elastic capabilities, when compared to plastic chains.
正畸链物理性能的丧失一直是科学家和临床医生讨论的话题，促使人们努力改进弹性材料并尽量减少力的衰减。正畸公司推出了记忆弹性体，据制造商称，其机械性能有所改善。
本研究旨在评估浸泡在37°C人工唾液中的弹性链拉伸效果。
本研究评估了2种类型的链。研究的第一阶段评估：1）链的拉伸强度；2）在口腔外环境（无暴露）中撕裂时的伸长率。研究的第二阶段评估：1）拉伸后的永久变形；2）撕裂时的伸长率；3）在与口腔内相似条件下链的拉伸强度。
在使用人工唾液的实验中，观察到塑料链出现明显的力衰减，其中仅7天后，力就比初始值下降了近一半，且呈持续下降趋势。然而，记忆链显示出弹性增加，暴露第一周后，撕裂时的力衰减约为初始值的20%。在整个暴露期间，撕裂时的力衰减保持在14.4%至25.4%的稳定水平。在塑料链中，该值在50.3%至55.9%之间波动。在评估每周暴露后链的永久变形的实验中，由记忆链制备的标本在暴露后从8厘米拉伸至约9.5厘米，而由塑料链制备的标本拉伸至约13厘米。
与塑料链相比，记忆链在正畸治疗中更有效，因为其机械和弹性能力的损失更小。
