Assistant professor, Orthodontic Section, Department of Growth and Development, College of Dentistry, University of Nebraska Medical Center, Lincoln, Neb.
Postdoctoral research associate, Department of Internal Medicine, Pulmonary, Critical Care, Sleep & Allergy Division, University of Nebraska Medical Center, Omaha, Neb.
Am J Orthod Dentofacial Orthop. 2014 Jan;145(1):64-71. doi: 10.1016/j.ajodo.2013.09.011.
Invisalign plastic aligners (Align Technology, Santa Clara, Calif) are used to correct malocclusions. The aligners wrap around the teeth and are in contact with gingival epithelium during treatment. The purpose of this study was to evaluate the cellular responses of oral epithelium exposed to Invisalign plastic in vitro.
Oral epithelial cells were exposed to eluate obtained by soaking Invisalign plastic in either saline solution or artificial saliva for 2, 4, and 8 weeks. Cells grown in media containing saline solution or saliva served as controls. Morphologic changes were assessed by light microscopy. The 3-[4, 5-dimethythiazol- 2-yl]-2, 5-diphenyl tetrazolium bromide assay and flow cytometry were used to determine cell viability and membrane integrity, respectively. Cellular adhesion and micromotion of epithelial cells were measured in real time by electrical cell-substrate impedance sensing.
Cells exposed to saline-solution eluate appeared rounded, were lifted from the culture plates, and demonstrated significantly increased metabolic inactivity or cell death (P <0.05). Saliva eluates did not induce significant changes in cell viability compared with untreated cells. Flow cytometry and electric cell-substrate impedance sensing showed that cells treated with saline-solution eluate exhibited compromised membrane integrity, and reduced cell-to-cell contact and mobility when compared with saliva-eluate treatment.
Exposure to Invisalign plastic caused changes in viability, membrane permeability, and adhesion of epithelial cells in a saline-solution environment. Microleakage and hapten formation secondary to compromised epithelial integrity might lead to isocyanate allergy, which could be systemic or localized to gingiva. However, these results suggest that saliva might offer protection.
Invisalign 塑料矫治器（Align Technology，加利福尼亚州圣克拉拉）用于矫正错牙合。矫治器包裹在牙齿周围，在治疗过程中与牙龈上皮接触。本研究旨在评估体外暴露于 Invisalign 塑料的口腔上皮细胞的细胞反应。
将口腔上皮细胞暴露于将 Invisalign 塑料浸泡在盐溶液或人工唾液中 2、4 和 8 周获得的浸提液中。在含有盐溶液或唾液的培养基中生长的细胞作为对照。通过光镜评估形态变化。3-[4,5-二甲基噻唑-2-基]-2,5-二苯基四氮唑溴盐（MTT）比色法和流式细胞术分别用于确定细胞活力和细胞膜完整性。通过电细胞-底物阻抗传感实时测量上皮细胞的细胞黏附和微运动。
暴露于盐溶液浸提液的细胞呈圆形，从培养板上提起，并表现出明显增加的代谢不活跃或细胞死亡（P<0.05）。与未处理的细胞相比，唾液浸提液不会引起细胞活力的显著变化。流式细胞术和电细胞-底物阻抗传感显示，与唾液浸提液处理相比，用盐溶液浸提液处理的细胞表现出受损的细胞膜完整性，并且细胞间接触和迁移性降低。
在盐溶液环境中，暴露于 Invisalign 塑料会导致上皮细胞活力、膜通透性和黏附性发生变化。上皮完整性受损导致的微渗漏和半抗原形成可能导致异氰酸酯过敏，可能是全身性的，也可能局限于牙龈。然而，这些结果表明唾液可能提供保护。
