Influence of maxillary molar distalization with clear aligners on three-dimensional direction: molar distal movement, intrusion, distal tip and crown buccal torque

Abstract

Background The aim of this study was to evaluate the distal movement, vertical movement, distal tipping and crown buccal torque of maxillary molars after the completion of distalization by comparing the predicted movement with the achieved movement using palatal rugae registration. Methods The study included 22 clear aligner patients (7 males and 15 females), and 79 molars were measured. Two digital models were generated before treatment and after molar distalization and were superimposed after selecting the palatal rugae area for registration in GOM inspect suite software 2022 (GOM; Braunschweig, Germany). The predicted and achieved movements of molar distalization, intrusion, distal tip and crown buccal torque were measured and compared. Result The achieved distalization (1.25 ± 0.79 mm vs. 2.17 ± 1.03 mm, P < 0.001; 1.41 ± 1.00 mm vs. 2.66 ± 1.15 mm, P < 0.001), intrusion (0.47 ± 0.41 mm vs. 0.18 ± 0.54 mm, P < 0.01; 0.58 ± 0.65 mm vs. 0.10 ± 1.12 mm, P < 0.01), distal tip (5.30 ± 4.56° vs. 1.53 ± 2.55°, P < 0.001; 4.87 ± 4.50° vs. − 1.95 ± 4.32°, P < 0.001) and crown buccal torque (1.95 ± 4.18° vs. − 1.15 ± 4.75°, P < 0.001; 0.43 ± 4.39° vs. − 4.27 ± 6.42°, P < 0.001) were significantly different from the predicted values in the two groups (first molar, second molar). Significant regression relationships were found between the achieved distal movement and deviational intrusion (R2 = 0.203, P < 0.0001), distal tip (R2 = 0.133, P < 0.001) and crown buccal torque (R2 = 0.067, P < 0.05). There was a significant correlation between the deviational movements of intrusion and the distal tip (R = 0.555, P < 0.0001). Conclusion Approximately 2 mm maxillary molar distalization was achieved in this study. Deviational movement of intrusion, distal tip and crown buccal torque beyond the clear aligner virtual design appeared to a certain degree after distalization. Thus, more attention should be given to molar intrusion and distal tip and crown buccal torque as the designed distalization increases.

Molar Distalization by Clear Aligners with Sequential Distalization Protocol: A Systematic Review and Meta-Analysis

“…A total of 755 records were also manually retrieved from the references of the full-text reading articles and 15 additional articles were retrieved for full-text reading. A total of 28 of the retrieved articles were excluded because they were master's theses [ 43 , 44 , 45 , 46 ], reviews or editorials [ 47 , 48 , 49 ], inconsistent data [ 50 ], utilized TADs [ 51 , 52 , 53 , 54 , 55 ], or the outcomes were not relevant [ 18 , 25 , 27 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 ]. Therefore, after adhering to the guidelines presented by the PRISMA, 13 articles were included for final analysis [ 19 , 20 , 21 , 22 , 23 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ].…”

Tip, torque and rotation of maxillary molars during distalization using Invisalign: a CBCT study

“…molar angulation (mesiodistal tipping), inclination (buccolingual torque) and rotation is not yet fully documented, as many studies agree such testing requires comparing CBCT before and after treatment [ 18 , 19 ]. Only a single recently published study addressed this question, but only using digital models and clincheck [ 20 ].…”

Evaluation of Buccolingual Inclinations of First Molars Among Different Vertical Facial Patterns in Class II Division I Subjects

“…The present study and similar investigations hold future implications for implementing tailored spacer treatments based on skeletal type and vertical facial pattern. These studies provoke questions regarding the feasibility of buccolingual inclination using clear aligners [ 28 ], the efficacy of torque incorporated in pre-adjusted brackets in achieving physiological tooth positions relative to cortical bone [ 29 ], and the potential for buccolingual inclination modifications to induce horizontal relapse [ 30 ].…”