Biomechanical analysis of effective mandibular en-masse retraction using Class II elastics with a clear aligner: a finite element study

Wang, Qiuyu; Dai, Danni; Wang, Jianrong; Chen, Yanfang; Zhang, Chao

doi:10.1186/s40510-022-00417-4

Cited by 16 publications

(19 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[33]Orthodontists must remember, particularly young ones, that preventive measures must be taken in advance, such as the position of the attachment,[26]the amount of activation in each aligner[28]and the sequence of motions, [21]and related auxiliary techniques. [34,35]Otherwise, the correction time will be increased.…”

Section: Discussionmentioning

confidence: 99%

Risk Factors for Maxillary Central Incisors Torque Loss in Orthodontic Treatment of Premolar Extraction Cases with Clear Aligners：a retrospective study

wang

2024

Preprint

View full text Add to dashboard Cite

Background：Torque loss of maxillary central incisor teeth occurs frequently during space closure with clear aligners (CA).The aim of this study was to analyse the percentage reduction in upper incisor lingual inclination and risk factors for upper incisor angle after Invisalign treatment in extraction cases. Methods：Records were obtained from 52 patients (average age 27.6 years) who initiated with Invisalign at four different orthodontic practices. Data was collected from cephalometric radiographs, doctors' case notes, and CA Web site databases. All patients who were treated with CAs were divided into maxillary incisors Lingual tipping (L) and non-maxillary incisors Lingual tipping (NL) groups based on whether U1-NA(°) was less than 17.1 (Mean -1 SD). Cephalometric data before and after therapy were analysed using a paired t-test. Differences between the L and NL groups were examined through independent sample t-tests, chi-square tests, and Wilcoxon rank sum tests. Correlation factors, including CC difficulty scores, age, gender, pre-treatment upper central incisor inclination, skeletal classification, divergence, orthodontist, treatment length, and refinements number, were identified using univariate and multivariate linear regression analysis. Results：After treatment, 61.5% of the patients experienced upper incisor lingual inclination. Significant differences were observed between the groups in terms of the number of refinements, treatment length, and age (P＜0.05). The number of refinements was directly proportional to the duration of treatment. A statistical difference was observed between orthodontists and the number of refinements. However, adolescents had significantly less refinement. A multivariate linear regression analysis revealed negative correlations between age (P=0.002), treatment length (P=0.002), and different orthodontists (P=0.013) with the reduction of the upper incisor angle after treatment. Conclusions：The upper central incisors exhibit torque loss in extraction cases treated with Invisalign. The risk of a reduction in the angle of the upper incisors after treatment is increased by factors such as the patient's age (older patients), longer treatment times, and young orthodontists. It is recommended that these factors be closely monitored and guided during clinic visits.

show abstract

Section: Discussionmentioning

confidence: 99%

Risk Factors for Maxillary Central Incisors Torque Loss in Orthodontic Treatment of Premolar Extraction Cases with Clear Aligners：a retrospective study

wang

2024

Preprint

View full text Add to dashboard Cite

show abstract

“…Chang (2004) found that, with Class II intermaxillary elastics, the initial bodily displacements were concentrated in the anterior part of the upper dentition. Wang et al (2022) evaluated the displacement and stress distribution of mandibular dentition by various positions of Class II elastics during en masse retraction in clear aligner therapy. They found lingual tipping of the lower central incisors and mesial tipping of the lower first molars, producing mandibular anchorage loss.…”

Section: Discussionmentioning

confidence: 99%

“…Chai et al (2009) conducted an FEM study analysing the stress distribution in mandibles advanced with Forsus FRD and found that the concentration of the stress was observed in the anterior part of the condyle, mandibular notch and lower molars, and the areas of maximum displacement were observed at the chin and lower incisors. In a FEM study of Class II elastics and clear aligners, Wang et al (2022) found that the stress on the PDL was concentrated in the lower first molars: there was compressive stress in the mesial cervical region and tensile stress in the buccal-distal cervical region. In the present study, we also found the highest concentration of stress in the lower arch at the first molars in the Class II elastics model, but we noted compressive stress in the buccal distal region and tensile stress in the mesial cervical region.…”

Section: Discussionmentioning

confidence: 99%

Comparative evaluation of the dentoalveolar effects of three Class II correctors: A finite element analysis study

Plaza-Ruiz,

Rojas-Plaza,

Basto-Tacuma

et al. 2023

J Orthod

View full text Add to dashboard Cite

Objective: To compare the stress distribution and total strain applied to the dentition, periodontal ligament (PDL) and cortical and trabecular bones by three Class II correctors using finite element analysis. Design: Three-dimensional analysis of stresses and total strain of the dentition with three Class II correctors. Setting: Computational study. Methods: Three-dimensional finite element models of Class II elastics, the Forsus Fatigue Resistant Device (FRD) and the Carriere Motion Appliance (CMA) were constructed from a cone-beam computed tomography (CBTC) image of an orthodontic Class II patient. The distribution of stress (von Mises and principal stress) and the total strain (mm) in maxillo-mandibular dentition, PDL, cortical and trabecular bone were analysed. Results: The highest von Mises yield and the maximum principal stress in the three models were found at the teeth, followed by the cortical bone, trabecular bone and PDL. The maximum stress and total deformation were located at the upper canines and lower molars in the Class II elastics and CMA models, in the upper first molars in the Forsus FRD and CMA, and in the lower first premolars in the Forsus FRD. In addition, stress was distributed in the anterior and posterior regions of the teeth, and the total deformation was found in the distal direction in the upper arch and in the mesial direction in the lower arch. Conclusion: The stress concentrations in the three models were located close to the active components of each appliance, producing specific patterns of stress distribution and displacement that should be taken into account when planning the type of appliance to be used for the correction of the Class II malocclusion.

show abstract

“…Over recent years, the FEM has proven to be an effective tool to simulate tooth displacement patterns in orthodontics. However, the previous FE-based models only involved a single dentition within their study purposes [ 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Effects of upper-molar distalization using clear aligners in combination with Class II elastics: a three-dimensional finite element analysis

et al. 2022

View full text Add to dashboard Cite

Introduction The effects of upper-molar distalization using clear aligners in combination with Class II elastics for anchorage reinforcement have not been fully investigated yet. The objective of this study is to analyze the movement and stress of the whole dentition and further explore guidelines for the selection of traction methods. Methods Three-dimensional (3D) finite element models are established to simulate the sequential molar distalization process, including the initial distalization of the 2nd molar (Set I) and the initial distalization of the 1st molar (Set II). Each group set features three models: a control model without Class II elastics (model A), Class II elastics attached to the tooth by buttons (model B), and Class II elastics attached to the aligner by precision cutting (model C). The 3D displacements, proclination angles, periodontal ligament (PDL) hydrostatic stress and alveolar bone von Mises stress in the anterior area are recorded. Results In all of the models, the maxillary anterior teeth are labial and mesial proclined, whereas the distal moving molars exhibit distal buccal inclination with an extrusion tendency. With the combination of Class II elastics, the anchorage was effectively reinforced; model C demonstrates superior anchorage reinforcement with lower stress distribution in comparison with model B. The upper canines in model B present an extrusion tendency. Meanwhile, the mandibular dentition in models B and C experience undesired movement tendencies with little discrepancy from each other. Conclusions Class II elastics are generally effective for anchorage reinforcement as the upper-molar distalization is performed with clear aligners. Class II elastics attached to an aligner by precision cutting is a superior alternative for maxillary anchorage control in cases that the proclination of upper incisors and extrusion of upper canines are unwanted.

show abstract

Biomechanical analysis of effective mandibular en-masse retraction using Class II elastics with a clear aligner: a finite element study

Cited by 16 publications

References 37 publications

Risk Factors for Maxillary Central Incisors Torque Loss in Orthodontic Treatment of Premolar Extraction Cases with Clear Aligners：a retrospective study

Risk Factors for Maxillary Central Incisors Torque Loss in Orthodontic Treatment of Premolar Extraction Cases with Clear Aligners：a retrospective study

Comparative evaluation of the dentoalveolar effects of three Class II correctors: A finite element analysis study

Effects of upper-molar distalization using clear aligners in combination with Class II elastics: a three-dimensional finite element analysis

Contact Info

Product

Resources

About