Preparation and characterization of thermoplastic materials for invisible orthodontics

Zhang, Ning; Bai, Yuxing; Ding, Xuejia; Zhang, Yu

doi:10.4012/dmj.2011-120

Cited by 76 publications

(106 citation statements)

References 31 publications

(33 reference statements)

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“…In addition, water absorption by PETG differed depending on the type of thermoplastic material 23. Zhang et al30 reported that water absorption increased when polyurethane was added to PETG during the development of a new thermoplastic material for TOAs.…”

Section: Discussionmentioning

confidence: 99%

Effects of thermoforming on the physical and mechanical properties of thermoplastic materials for transparent orthodontic aligners

et al. 2018

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ObjectiveThe aim of this systematic multiscale analysis was to evaluate the effects of thermoforming on the physical and mechanical properties of thermoplastic materials used to fabricate transparent orthodontic aligners (TOAs).MethodsSpecimens were fabricated using four types of thermoplastic materials with different thicknesses under a thermal vacuum. Transparency, water absorption and solubility, surface hardness, and the results of three-point bending and tensile tests were evaluated before and after thermoforming. Data were analyzed using one-way analysis of variance and Student's t-test.ResultsAfter thermoforming, the transparency of Duran and Essix A+ decreased, while the water absorption ability of all materials; the water solubility of Duran, Essix A+, and Essix ACE; and the surface hardness of Duran and Essix A+ increased. The flexure modulus for the 0.5-mm-thick Duran, Essix A+, and eCligner specimens increased, whereas that for the 0.75-/1.0-mm-thick Duran and eClginer specimens decreased. In addition, the elastic modulus increased for the 0.5-mm-thick Essix A+ specimens and decreased for the 0.75-mm-thick Duran and Essix ACE and the 1.0-mm-thick Essix ACE specimens.ConclusionsOur findings suggest that the physical and mechanical properties of thermoplastic materials used for the fabrication of TOAs should be evaluated after thermoforming in order to characterize their properties for clinical application.

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Section: Discussionmentioning

confidence: 99%

Effects of thermoforming on the physical and mechanical properties of thermoplastic materials for transparent orthodontic aligners

et al. 2018

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“…6 Common polymers used to fabricate thermoplastic retainers are polyester, polypropylene, and polyurethane. 7 Because retainers are essential in preventing orthodontic relapse, it is crucial to have an effective cleaning technique to facilitate long-term use of the retainers. There are, however, some problems associated with long-term use of clear retainers, including loss of translucency and material integrity, discoloration, and plaque and calculus retention.…”

Section: Introductionmentioning

confidence: 99%

Long-term effects of seven cleaning methods on light transmittance, surface roughness, and flexural modulus of polyurethane retainer material

Agarwal

Wible

Ramir

et al. 2018

The Angle Orthodontist

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Objectives: To evaluate the long-term effects of seven different cleaning methods on light transmittance, surface roughness, and flexural modulus of a polyurethane retainer material. Materials and Methods: Polyurethane retainer specimens (Viverat, Align Technology Inc) (70 specimens, n ¼ 10 per method, 50.8 mm 3 12.7 mm 3 1.0 mm) were exposed to seven cleaning methods twice a week for 6 months. Before treatment and after 6 months, light transmittance, surface roughness, and flexural modulus of the specimens were quantified. Qualitative assessment of randomly selected specimens from each solution was performed at baseline and after 6 months using a scanning electron microscope. Statistical analyses were performed at the .05 significance level. Results: Of the three test variables, light transmittance through the specimens was the only one that changed significantly from baseline to 6 months for all cleaning solutions, with all of them causing a decrease. However, except for 0.6% sodium hypochlorite showing a change in surface roughness values and 2.5% vinegar and toothbrushing showing an increase in flexural modulus, none of the other four cleaning methods resulted in significant changes in surface roughness or flexural modulus values for the polyurethane specimens between baseline and after 6 months. Conclusions: Of the seven cleaning methods, Invisalignt cleaning crystals, Polidentt, and Listerinet showed the least amount of change in light transmittance values for the polyurethane specimens over 6 months, and they had no effect on surface roughness and flexural modulus values. (Angle Orthod. 2018;88:355-362.)

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“…The first, conducted by Zhang et al 14 in 2011, investigated the resistance to traction, stress relaxation, and water absorbed by various samples of aligner materials in the form of single-and multilayer disks. Later in 2013, Fang et al 11 focused their research on the stress release of five samples (polyethylene terephthalate, PET-G, and copolyesters) at different temperatures (208C and 378C).…”

Section: Introductionmentioning

confidence: 99%

Stress relaxation properties of four orthodontic aligner materials: A 24-hour in vitro study

Lombardo

Martines

Mazzanti

et al. 2016

The Angle Orthodontist

132

111

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Objective: To investigate the stress release properties of four thermoplastic materials used to make orthodontic aligners when subjected to 24 consecutive hours of deflection. Materials and Methods: Four types of aligner materials (two single and two double layered) were selected. After initial yield strength testing to characterize the materials, each sample was subjected to a constant load for 24 hours in a moist, temperature-regulated environment, and the stress release over time was measured. The test was performed three times on each type of material.

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Preparation and characterization of thermoplastic materials for invisible orthodontics

Cited by 76 publications

References 31 publications

Effects of thermoforming on the physical and mechanical properties of thermoplastic materials for transparent orthodontic aligners

Effects of thermoforming on the physical and mechanical properties of thermoplastic materials for transparent orthodontic aligners

Long-term effects of seven cleaning methods on light transmittance, surface roughness, and flexural modulus of polyurethane retainer material

Stress relaxation properties of four orthodontic aligner materials: A 24-hour in vitro study

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