Effects of varying attachment positions on palatal displacement of maxillary incisors with clear aligner therapy

Ahmed, Thameem; Padmanabhan, Sridevi; Sathyanarayana, Haritha Pottipalli

doi:10.1007/s00056-021-00374-3

Cited by 13 publications

(14 citation statements)

References 16 publications

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“…Their mechanical properties were obtained from previous studies [ 2 , 11 ] and are shown in Table 1 . It was worthy of note that most scholars still agreed that it was reasonable to study tooth movement tendency even if the PDL was assigned linear material properties in FEA [ 7 , 12 , 13 ]. Bonding was established at the following interfaces: ligament bone, tooth ligament, and tooth attachments.…”

Section: Methodsmentioning

confidence: 99%

Torque movement of the upper anterior teeth using a clear aligner in cases of extraction: a finite element study

et al. 2022

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Background Clear aligner treatment has become popular over recent years. It is necessary to identify methods by which we could avoid the bowing effect in extractions with clear aligner. The present study was to identify the appropriate method to design torque movement involving the upper anterior teeth of extraction cases, in order to maintain or improve the axis and torque of the upper anterior teeth with a clear aligner during movement and closure of the extraction space. Results As the height of the power ridge increased, the rotation angle of the upper central incisor in the sagittal direction decreased gradually and the location of the rotation center changed significantly; the rotation center moved in the apical direction and then changed to the crown side. The highest von-Mises stress of the upper central incisor root, periodontal ligaments, and alveolar bone, showed little change as the power ridge height increased. When the axial inclination of the upper central incisor was normal (U1-SN = 105°), the tendency of movement for the upper central incisor approached translation with a power ridge height of 0.7 mm (corresponding distorted angle: 5.8415). When the axial inclination of the upper central incisor was oversized (U1-SN = 110°), the axial inclination of the upper central incisor reduced to normal following completion of the anterior segment retraction with a power ridge of 0.4 mm (corresponding distorted angle: 3.4265). Conclusion Analysis indicates that pure palatal tipping movement of the upper anterior teeth is generated without torque control, thus resulting in the bowing effect. The required torque control of the upper anterior teeth with oversize axial inclination is weaker than that of the upper anterior teeth with normal axial inclination because limited torque loss is expected for oversize axial inclination teeth. Variation sensitivity of the rotation center should be considered carefully due to biological problems when designing translation of the upper anterior teeth with normal axial inclination.

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Section: Methodsmentioning

confidence: 99%

Torque movement of the upper anterior teeth using a clear aligner in cases of extraction: a finite element study

et al. 2022

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“…Alveolar socket models and PDL of the maxilla were created using the Boolean operation in SolidWorks 2021 (Dassault Systèmes, Massachusetts, USA). Third, a horizontal rectangular attachment, with dimensions of 3 mm × 2 mm × 1 mm, was built using SolidWorks and positioned at the center of the clinical crown [9,19] (Fig. 1).…”

Section: Data Collection and Model Establishmentmentioning

confidence: 99%

“…Unlike fixed appliances, the clear aligner is composed of thermoplastic materials and attachments, which provide a consistent and gentle force [8]. For esthetic purposes, attachments are mainly used as retention aids made of resin and bonded to the target teeth surface [9]. They can change the direction of orthodontic forces applied to the teeth to guide them toward the target position.…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of the attachment position in molar intrusion with clear aligners: a finite element study

et al. 2022

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Objective To evaluate the biomechanical effects of different attachments’ position for maxillary molar intrusion with clear aligner treatment by finite element analysis. Methods Cone-beam computed tomography images of a patient with supra-eruption of the maxillary second molars were selected to construct three-dimensional models of the maxilla, periodontal ligaments, dentition, and clear aligner. The models were divided into four groups depending on the attachment location on the first molar: (1) no attachment (NA), (2) buccal attachment (BA), (3) palatal attachment (PA), and (4) bucco-palatal attachment (BPA). After applying an intrusion of 0.2 mm on the second molar, displacements and stress distributions of the teeth, aligner, and periodontal ligament were analyzed with the finite element software. Results All groups displayed equivalent movement patterns of aligners. The NA and BA groups showed buccal tipping of the second molar, while the PA group showed palatal tipping. The BPA group had the highest intruding value and the lowest buccal/palatal tipping value. All groups showed mesial tipping of the second molar. Stress distribution in the periodontal ligament strongly correlated with the attachment position. The BPA group showed the best stress distribution. Conclusion Combined BA and PA could effectively prevent buccal and palatal tipping and showed the best efficiency in intruding the second molar. The second molar showed an unavoidable tendency to tip mesially, regardless of the attachment position.

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“…Mechanical properties were inferred from previous studies [24,25]. It is worth noting that most researchers still agree that it is reasonable to study tooth movement tendency even if the PDL is assigned linear material properties in FEA [12,26,27]. Clear aligner and composite attachments: We assumed a linear elastic isotropic and homogeneous behavior.…”

Section: Materials Properties Related To Modelingmentioning

confidence: 99%

“…This form of analysis can contribute to our biomechanical understanding of orthodontic devices. Over recent years, FEA has been widely applied in different fields of dentistry, from fixtures to the simulation of dental movements [9][10][11][12][13][14]. An increasing body of evidence demonstrates that researchers are applying this technology to investigate the biomechanical principles underlying the use of clear aligners.…”

Section: Introductionmentioning

confidence: 99%

The three-dimensional displacement tendency of teeth depending on incisor torque compensation with clear aligners of different thicknesses in cases of extraction: a finite element study

et al. 2022

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Background Despite the popularity of clear aligner treatment, the effect of the thickness of these aligners has not been fully investigated. The objective of this study was to assess the effects of incisor torque compensation with different thicknesses of clear aligner on the three-dimensional displacement tendency of teeth in cases of extraction. Methods Three-dimensional finite element models of the maxillary dentition with extracted first premolars, maxilla, periodontal ligaments, attachments, and aligners were constructed and subject to Finite Element Analysis (FEA). Two groups of models were created: (1) with 0.75 mm-thick aligners and (2) with 0.5 mm-thick aligners. A loading method was developed to simulate the action of clear aligners for the en masse retraction of the incisors. Power ridges of different heights were applied to both groups to mimic torque control, and the power ridges favoring the translation of the central incisors were selected. Then, we used ANSYS software to analyze the initial displacement of teeth and the principle stress on the PDL. Results Distal tipping, lingual tipping and extrusion of the incisors, distal tipping and extrusion of the canines, and mesial tipping and intrusion of the posterior teeth were all generated by clear aligner therapy. With the 0.5 mm-thick aligner, a power ridge of 0.7 mm could cause bodily retraction of the central incisors. With the 0.75 mm-thick aligner, a power ridge of 0.25 mm could cause translation of the central incisors. Aligner torque compensation created by the power ridges generated palatal root torque and intrusion of the incisors, intrusion of the canines, mesial tipping and the intrusion of the second premolar; these effects were more significant with a 0.75 mm-thick aligner. After torque compensation, the stress placed on the periodontal ligament of the incisors was distributed more evenly with the 0.75 mm-thick aligner. Conclusions The torque compensation caused by power ridges can achieve incisor intrusion and palatal root torque. Appropriate torque compensation with thicker aligners should be designed to ensure bodily retraction of anterior teeth and minimize root resorption, although more attention should be paid to the anchorage control of posterior teeth in cases of extraction.

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Effects of varying attachment positions on palatal displacement of maxillary incisors with clear aligner therapy

Cited by 13 publications

References 16 publications

Torque movement of the upper anterior teeth using a clear aligner in cases of extraction: a finite element study

Torque movement of the upper anterior teeth using a clear aligner in cases of extraction: a finite element study

Effectiveness of the attachment position in molar intrusion with clear aligners: a finite element study

The three-dimensional displacement tendency of teeth depending on incisor torque compensation with clear aligners of different thicknesses in cases of extraction: a finite element study

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