Changes in mechanical properties, surface morphology, structure, and composition of Invisalign material in the oral environment

Fang, Dongyu; Fangming, LI; Zhang, Yulong; Bai, Yuxing; Wu, Benjamin M.

doi:10.1016/j.ajodo.2019.05.023

Cited by 31 publications

(15 citation statements)

References 20 publications

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“…Since only one type of composite resin (Filtek Z350 XT) was used, it is not possible to generalize the results to all resins. Previous studies have indicated that aligner materials deliver decreased forces over time and show signs of aging [ 33 , 34 ]. In this study, participants were instructed to change aligners every 7–14 days.…”

Section: Discussionmentioning

confidence: 99%

Surface wear of attachments in patients during clear aligner therapy: a prospective clinical study

Li,

Yang

2024

Prog Orthod.

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Background This prospective clinical study aimed to quantitatively evaluate the surface wear of attachments and investigate the associated risk factors. Additionally, the wear values and regions of three types of commonly used attachments were explored. Methods Participants were recruited from the population of patients who received clear aligner therapy from October to December 2022. Intraoral scanning was performed on eligible participants before treatment (T0), immediately after initial bonding of attachments (T1), and at 2 months (T2), 4 months (T3), 6 months (T4), and 8 months (T5) after starting treatment. The attachment volume, average depth and regions of attachment wear were measured using superimposed digitized models. The Kruskal–Wallis test was performed to compare data between multiple groups. Multiple linear regression analyses were performed to evaluate risk factors for the volume of attachment wear. Results A total of 47 patients with 617 attachments were included. As treatment time increased, the attachment volume decreased significantly (P = 0.003). The initial attachment volume was positively related to the volume of attachment wear (β = 0.527, P < 0.001). The volume of attachment wear was significantly greater in females than in males (β = 0.147, P = 0.020) and in optimized attachments than in conventional attachments (β = 0.308, P < 0.001). The wear of 3-mm rectangular attachments progressed from edges to buccal surfaces, with the deepest wear at corners of gingival edges; the wear of the optimized attachments was primarily located on surface ridges. The wear volume ratio of the optimized root control attachments was significantly greater than that of the 3-mm rectangular attachments at T3 (P = 0.011), T4 (P < 0.001), and T5 (P < 0.001). Conclusions The volume of attachment wear increased gradually with treatment time. Sex, attachment type, and initial attachment volume were risk factors for the volume of attachment wear. The deepest wear regions of 3-mm rectangular attachments were at the corners of gingival edges, while the deepest wear regions of optimized attachments were at surface ridges. Four months after treatment, optimized root control attachments showed more relative wear than 3-mm rectangular attachments.

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Section: Discussionmentioning

confidence: 99%

Surface wear of attachments in patients during clear aligner therapy: a prospective clinical study

Li,

Yang

2024

Prog Orthod.

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“…According to the existing research, at 37 °C, the elastic modulus of Invisalign is 842 ± 63 MPa, which is composed of TPU materials [ 18 ]. At 37 °C, the elastic modulus of Duran and Erkodur is 2015 ± 132.229 MPa and 1365.150 ± 262.883 MPa, respectively, both of which are composed of PTEG [ 19 ]. MC-S is a multilayer composite material, including TPU and PETG.…”

Section: Discussionmentioning

confidence: 99%

Stress and movement trend of lower incisors with different IMPA intruded by clear aligner: a three-dimensional finite element analysis

Xiao

Jin

et al. 2023

Prog Orthod.

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Background During the intrusion of lower incisors with clear aligners (CAs), root disengagement from the alveolar bone often occurs, resulting in serious complications. This study aimed to determine the potential force mechanism of the mandibular anterior teeth under the pressure of CA, providing theoretical data for clinical practice. Methods In this study, a 3D finite element model was established, including the CA, periodontal ligament, and mandibular dentition. Incisor mandibular plane angles were set as 5 groups: 90°, 95°, 100°, 105°, and 110°. The 4 mandibular incisors were intruded by 0.2 mm, while the canines were the anchorage teeth. The stress, force systems, and potential movement trends of mandibular anterior teeth were obtained. Results The compressive stress of the incisors was concentrated in the lingual fossa, incisal ridge, and apex. With the increase in IMPA, the moment of central incisors changed from lingual crown moment to labial crown moment, with the turning point between 100° and 105°, but the center of resistance (CR) was always subjected to the force toward the lingual and intrusive direction. The force and moment toward the labial side of the lateral incisors were greater than those toward the central incisors. The canines always tipped distally and received extrusive force with no relationship with IMPA. Conclusions With the increase in the initial IMPA, the direction of labiolingual force on the mandibular incisors was reversed. However, the root of the lower incisors always tipped labially, which indicated fenestration and dehiscence.

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“…In general, for this reason further systematic clinical studies must be conducted. Frequently, aligners are not only worn for 12 hours, albeit over 2 weeks and changed afterwards ( 30 ). Further tests, which are reproducible for a period of 2 weeks, must be conducted to find out how the mechanical properties change, and which forces are still acting after 2 weeks and how much they deviate from the maximum forces.…”

Section: Discussionmentioning

confidence: 99%

Comparative mechanical testing for different orthodontic aligner materials over time - in vitro study

Nowak¹,

Othman²,

Ströbele³

et al. 2022

J Clin Exp Dent

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Changes in mechanical properties, surface morphology, structure, and composition of Invisalign material in the oral environment

Cited by 31 publications

References 20 publications

Surface wear of attachments in patients during clear aligner therapy: a prospective clinical study

Surface wear of attachments in patients during clear aligner therapy: a prospective clinical study

Stress and movement trend of lower incisors with different IMPA intruded by clear aligner: a three-dimensional finite element analysis

Comparative mechanical testing for different orthodontic aligner materials over time - in vitro study

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