|
|
|
| Effect of thermoforming time on the thickness and elastic modulus of orth-odontic thermoplastic materials |
| SHI Jiayi1 ZHANG Yiwei2 XU Baohua3 |
1.General Department, Peking University Hospital of Stomatology, Beijing 100081, China;
2.School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China;
3.Dental Medical Center, China-Japan Friendship Hospital, Beijing 100029, China
|
|
|
|
Abstract Objective To investigate the effect of thermoforming time on the thickness and elastic modulus of orthodontic thermoplastic materials. Methods Orthodontic thermoplastic materials with thicknesses of 0.380, 0.625, and 0.760 mm were selected and divided into untreated group, thermoforming 60 s group, and thermoforming 90 s group according to the thermoforming time, with ten specimens in each group of different materials. The thickness and elastic modulus of the three groups were measured by electronic vernier caliper and universal material testing machine, and the effects of different thermoforming times on the thickness and elastic modulus of the three groups were compared. Results For the thermoplastic materials of 0.380, 0.625, and 0.760 mm, the thickness of thermoforming 60 s group and thermoforming 90 s group was lower than that of the untreated group, and the thickness of thermoforming 90 s group was lower than that of thermoforming 60 s group, and the differences were statistically significant (P＜0.05). For the 0.380 mm thermoplastic material, the elastic modulus of the thermoforming 60 s group and the thermoforming 90 s group was higher than that of the untreated group, and the difference was statistically significant (P＜0.05). There was no significant difference in elastic modulus between different treatment groups of the thermoplastic materials of 0.625 and 0.760 mm (P＞0.05). Conclusion The thickness of thermoplastic material becomes thinner after thermoforming. The longer the thermoforming time, the thinner the material, and the elastic modulus of thermoplastic material of 0.380 mm increased significantly. In orthodontic clinical work, it is necessary to fully understand the properties of materials, and select appropriate materials for treatment according to the patients’ own conditions and different orthodontic treatment needs and difficulties.
|
|
|
|
|
|
[1] Bichu YM，Alwafi A，Liu X，et al. Advances in orthodontic clear aligner materials [J]. Bioact Mater，2023，22：384-403.
[2] Ihssen BA，Willmann JH，Nimer A，et al. Effect of in vitro aging by water immersion and thermocycling on the mechanical properties of PETG aligner material [J]. J Orofac Orthop，2019，80（6）：292-303.
[3] Elkholy F，Schmidt S，Amirkhani M，et al. Mechanical Characterization of Thermoplastic Aligner Materials：Recommendations for Test Parameter Standardization [J]. J Healthc Eng， 2019，2019（10）：1-10.
[4] 李江洪，王影，曹瑞军，等.医用热压膜材料理化性能研究[J].中国塑料，2018，32（12）：56-60，117.
[5] Albertini P，Mazzanti V，Mollica F，et al. Stress Relaxation Properties of Five Orthodontic Aligner Materials：A 14-Day In-Vitro Study [J]. Bioengineering（Basel），2022，9（8）：349.
[6] Fang DY，Li FM，Zhang YL，et al. Changes in mechanical properties，surface morphology，structure，and composition of Invisalign material in the oral environment [J]. Am J Orthod Dentofacial Orthop，2020，157（6）：745-753.
[7] 国家质检总局.GB／T1040.3-2006 塑料拉伸性能的测定 第3部分：薄膜和薄片的试验条件[S].北京：中国标准出版社，2006.
[8] Ammann R，Tanner C，Schulz G，et al. Three-dimensional analysis of aligner gaps and thickness distributions，using hard x-ray tomography with micrometer resolution [J]. J Med Imaging（Bellingham），2022，9（3）：031509.
[9] Hamdoon SM，AlSamak S，Ahmed MK，et al. Evaluation of biofilm formation on different clear orthodontic retainer materials [J]. J Orthod Sci，2022，11（1）：34.
[10] Alhendi A，Khounganian R，Ali R，et al. Structural Conformation Comparison of Different Clear Aligner Systems：An In Vitro Study [J]. Dent J（Basel），2022，10（5）：73.
[11] Hertan E，McCray J，Bankhead B，et al. Force profile assessment of direct-printed aligners versus thermoformed aligners and the effects of non-engaged surface patterns [J]. Prog Orthod，2022，23（1）：49.
[12] 柳大为，李晶，郭亮，等.舌侧矫治器关闭间隙上前牙牙周膜应力变化的三维有限元分析[J].北京大学学报（医学版），2018，50（1）：141-147.
[13] Inoue S，Yamaguchi S，Uyama H，et al. Influence of constant strain on the elasticity of thermoplastic orthodontic materials [J]. Dent Mater J，2020，39（3）：415-421.
[14] Porojan L，Vasiliu RD，Porojan SD，et al. Surface Quality Evaluation of Removable Thermoplastic Dental Appliances Related to Staining Beverages and Cleaning Agents [J]. Polymers（Basel），2020，12（8）：1736.
[15] Alkan ■，Kaya Y，Keskin S. Computerized occlusal analysis of Essix and Hawley retainers used during the retention phase：a controlled clinical trial [J]. J Orofac Orthop，2020， 81（5）：371-381.
[16] Ginoux G，Paux J，Allaoui S. New preparation method of microstructurally and mechanically standardized PETG specimens by material extrusion additive manufacturing and machining [J]. Additive Manufacturing，2023，66：103471.
[17] Spanier C，Schwahn C，Krey KF，et al. Fused filament fabrication（FFF）：influence of layer height on forces and moments delivered by aligners-an in vitro study [J]. Clin Oral Investig，2023，27（5）：2163-2173.
[18] Tamburrino F，D’Antò V，Bucci R，et al. Mechanical Properties of Thermoplastic Polymers for Aligner Manufacturing：In Vitro Study [J]. Dent J（Basel），2020，8（2）：47.
[19] 张宁，白玉兴，张昆亚，等.不同厚度热压膜材料的力学性能研究[J].北京口腔医学，2009，17（4）：184-186.
[20] Hussein AM，Mohammed-Salih HS，Al-Sheakli II. Effects of various cleaning agents on polypropylene and copolyester thermoplastic orthodontic retainer materials [J]. J Taibah Univ Med Sci，2022，17（5）：861-868.
[21] Noora H，Zai-qing Q，Pentti A，et al. Effect of weld microstructure on brittle fracture initiation in the thermally-aged boiling water reactor pressure vessel head weld metal [J]. 矿物冶金与材料学报（英文版），2021，28（5）：867-876.
[22] 龙旭，申子怡，贾啟普，等.纳米压痕下单/多层薄膜弹塑性本构的无量纲分析[J].中国科学：物理学 力学 天文学，2023，53（1）：55-65.
[23] 张博凯.胶体聚合物弹性模量的微观理论：键长的效应[J].物理学报，2021，70（12）：316-322.
[24] 郭一凡.抗菌/亲水TPU材料的制备[D].北京：北京化工大学，2021.
[25] Javier Q. Thermal Resistance Properties of Polyurethanes and its Composites：A Short Review [J]. Journal of Research Updates in Polymer Science，2019（12）：19. |
|
|
|
