1.Evaluation of the effect of attachments on torque control of palatally positioned maxillary lateral teeth with clear aligners: Finite element analysis
Nurver KARSLI ; Irmak OCAK ; Sevil GÖKCEK ; Ömür Polat ÖZSOY
The Korean Journal of Orthodontics 2025;55(1):58-68
Objective:
The effect of different attachment positions on torque control during the labialization of maxillary lateral incisors with clear aligners was evaluated using finite element analysis.
Methods:
Anatomical data acquired through cone-beam computed tomography, combined with the design of 0.625-mmthick aligners and horizontal attachments, were integrated into the software. Six distinct simulations were generated: (1) attachment-free, (2) labial attachment placed gingivally, (3) labial attachment placed mid-crown, (4) labial attachment placed incisally, (5) palatal attachment, and (6) attachment placed labially and palatally. The evaluation was performed using a default aligner activation of 0.25 mm.
Results:
The crown of the lateral incisor demonstrated labial movement, while the root exhibited palatal movement in all models. Group 6 showed the lowest crown and root displacements on both axes, whereas the attachmentfree group exhibited the greatest crown movement. The aligner experienced maximum deformation at the incisal edge, with deformation progressively decreasing towards the gingival region. Group 6 demonstrated the least deformation of all groups. The Von Mises stresses in the periodontal ligament (PDL) were most pronounced at the gingival level, with higher values on the palatal side than on the labial side.
Conclusions
The use of attachments, particularly the combination of labial and palatal attachments, enables a more precise labialization process, helping to reduce tipping. Increasing crown movement of the lateral incisor elevates stress within the PDL, with the highest stress observed in the palatal region at the gingival level.
2.Evaluation of the effect of attachments on torque control of palatally positioned maxillary lateral teeth with clear aligners: Finite element analysis
Nurver KARSLI ; Irmak OCAK ; Sevil GÖKCEK ; Ömür Polat ÖZSOY
The Korean Journal of Orthodontics 2025;55(1):58-68
Objective:
The effect of different attachment positions on torque control during the labialization of maxillary lateral incisors with clear aligners was evaluated using finite element analysis.
Methods:
Anatomical data acquired through cone-beam computed tomography, combined with the design of 0.625-mmthick aligners and horizontal attachments, were integrated into the software. Six distinct simulations were generated: (1) attachment-free, (2) labial attachment placed gingivally, (3) labial attachment placed mid-crown, (4) labial attachment placed incisally, (5) palatal attachment, and (6) attachment placed labially and palatally. The evaluation was performed using a default aligner activation of 0.25 mm.
Results:
The crown of the lateral incisor demonstrated labial movement, while the root exhibited palatal movement in all models. Group 6 showed the lowest crown and root displacements on both axes, whereas the attachmentfree group exhibited the greatest crown movement. The aligner experienced maximum deformation at the incisal edge, with deformation progressively decreasing towards the gingival region. Group 6 demonstrated the least deformation of all groups. The Von Mises stresses in the periodontal ligament (PDL) were most pronounced at the gingival level, with higher values on the palatal side than on the labial side.
Conclusions
The use of attachments, particularly the combination of labial and palatal attachments, enables a more precise labialization process, helping to reduce tipping. Increasing crown movement of the lateral incisor elevates stress within the PDL, with the highest stress observed in the palatal region at the gingival level.
3.Evaluation of the effect of attachments on torque control of palatally positioned maxillary lateral teeth with clear aligners: Finite element analysis
Nurver KARSLI ; Irmak OCAK ; Sevil GÖKCEK ; Ömür Polat ÖZSOY
The Korean Journal of Orthodontics 2025;55(1):58-68
Objective:
The effect of different attachment positions on torque control during the labialization of maxillary lateral incisors with clear aligners was evaluated using finite element analysis.
Methods:
Anatomical data acquired through cone-beam computed tomography, combined with the design of 0.625-mmthick aligners and horizontal attachments, were integrated into the software. Six distinct simulations were generated: (1) attachment-free, (2) labial attachment placed gingivally, (3) labial attachment placed mid-crown, (4) labial attachment placed incisally, (5) palatal attachment, and (6) attachment placed labially and palatally. The evaluation was performed using a default aligner activation of 0.25 mm.
Results:
The crown of the lateral incisor demonstrated labial movement, while the root exhibited palatal movement in all models. Group 6 showed the lowest crown and root displacements on both axes, whereas the attachmentfree group exhibited the greatest crown movement. The aligner experienced maximum deformation at the incisal edge, with deformation progressively decreasing towards the gingival region. Group 6 demonstrated the least deformation of all groups. The Von Mises stresses in the periodontal ligament (PDL) were most pronounced at the gingival level, with higher values on the palatal side than on the labial side.
Conclusions
The use of attachments, particularly the combination of labial and palatal attachments, enables a more precise labialization process, helping to reduce tipping. Increasing crown movement of the lateral incisor elevates stress within the PDL, with the highest stress observed in the palatal region at the gingival level.
4.Evaluation of the effect of attachments on torque control of palatally positioned maxillary lateral teeth with clear aligners: Finite element analysis
Nurver KARSLI ; Irmak OCAK ; Sevil GÖKCEK ; Ömür Polat ÖZSOY
The Korean Journal of Orthodontics 2025;55(1):58-68
Objective:
The effect of different attachment positions on torque control during the labialization of maxillary lateral incisors with clear aligners was evaluated using finite element analysis.
Methods:
Anatomical data acquired through cone-beam computed tomography, combined with the design of 0.625-mmthick aligners and horizontal attachments, were integrated into the software. Six distinct simulations were generated: (1) attachment-free, (2) labial attachment placed gingivally, (3) labial attachment placed mid-crown, (4) labial attachment placed incisally, (5) palatal attachment, and (6) attachment placed labially and palatally. The evaluation was performed using a default aligner activation of 0.25 mm.
Results:
The crown of the lateral incisor demonstrated labial movement, while the root exhibited palatal movement in all models. Group 6 showed the lowest crown and root displacements on both axes, whereas the attachmentfree group exhibited the greatest crown movement. The aligner experienced maximum deformation at the incisal edge, with deformation progressively decreasing towards the gingival region. Group 6 demonstrated the least deformation of all groups. The Von Mises stresses in the periodontal ligament (PDL) were most pronounced at the gingival level, with higher values on the palatal side than on the labial side.
Conclusions
The use of attachments, particularly the combination of labial and palatal attachments, enables a more precise labialization process, helping to reduce tipping. Increasing crown movement of the lateral incisor elevates stress within the PDL, with the highest stress observed in the palatal region at the gingival level.
5.Evaluation of the effect of attachments on torque control of palatally positioned maxillary lateral teeth with clear aligners: Finite element analysis
Nurver KARSLI ; Irmak OCAK ; Sevil GÖKCEK ; Ömür Polat ÖZSOY
The Korean Journal of Orthodontics 2025;55(1):58-68
Objective:
The effect of different attachment positions on torque control during the labialization of maxillary lateral incisors with clear aligners was evaluated using finite element analysis.
Methods:
Anatomical data acquired through cone-beam computed tomography, combined with the design of 0.625-mmthick aligners and horizontal attachments, were integrated into the software. Six distinct simulations were generated: (1) attachment-free, (2) labial attachment placed gingivally, (3) labial attachment placed mid-crown, (4) labial attachment placed incisally, (5) palatal attachment, and (6) attachment placed labially and palatally. The evaluation was performed using a default aligner activation of 0.25 mm.
Results:
The crown of the lateral incisor demonstrated labial movement, while the root exhibited palatal movement in all models. Group 6 showed the lowest crown and root displacements on both axes, whereas the attachmentfree group exhibited the greatest crown movement. The aligner experienced maximum deformation at the incisal edge, with deformation progressively decreasing towards the gingival region. Group 6 demonstrated the least deformation of all groups. The Von Mises stresses in the periodontal ligament (PDL) were most pronounced at the gingival level, with higher values on the palatal side than on the labial side.
Conclusions
The use of attachments, particularly the combination of labial and palatal attachments, enables a more precise labialization process, helping to reduce tipping. Increasing crown movement of the lateral incisor elevates stress within the PDL, with the highest stress observed in the palatal region at the gingival level.
6.Evaluating anchorage loss in upper incisors during distalization of maxillary posterior teeth using clear aligners in adult patients: A prospective randomized study
Zehra YURDAKUL ; Nurver KARSLI
The Korean Journal of Orthodontics 2024;54(2):117-127
Objective:
To evaluate the effect of clear aligner treatment and differential sequence distalization of maxillary posterior teeth on anchorage loss in the upper incisors (U1s).
Methods:
This study used lateral cephalometries and digital models of 12 patients treated with 33% sequential distalization (group 1, mean age: 22.9 ± 0.7 years, five males, seven females) and 12 treated with 50% sequential distalization (group 2, mean age: 25.83 ± 0.5 years, three males, nine females) acquired before and after distalization of upper second premolars (U5) and upper first molars (U6) and upper second molars (U7). The amount of distalization was determined as 2.5 mm in both the groups. Independent Samples t test was used to compare normally distributed parameters. Mann– Whitney U and Wilcoxon tests were used to compare parameters that were not normally distributed.
Results:
In both groups, the posterior teeth significantly moved by tipping distally and the U1s were displaced anteriorly. Increase in maxillary posterior transverse width (P < 0.001) and distopalatal rotation were observed in U5, U6, and U7 after distalization. It was also observed that U1 was significantly more proclined (1.82°; P < 0.001) and protruded (0.62 mm; P < 0.001), and the overjet (0.45 mm; P < 0.001) increased more in group 1 than in group 2.
Conclusions
After sequential distalization of maxillary posterior teeth, more anchorage loss was observed in the anterior region in group 1 than in group 2.

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