Integrated three-dimensional digital assessment of accuracy of anterior tooth movement using clear aligners

Abstract

Objective: To assess the accuracy of anterior tooth movement using clear aligners in integrated three-dimensional digital models.

Methods: Cone-beam computed tomography was performed before and after treatment with clear aligners in 32 patients. Plaster casts were laser-scanned for virtual setup and aligner fabrication. Differences in predicted and achieved root and crown positions of anterior teeth were compared on superimposed maxillofacial digital images and virtual models and analyzed by Student's t-test.

Results: The mean discrepancies in maxillary and mandibular crown positions were 0.376 ± 0.041 mm and 0.398 ± 0.037 mm, respectively. Maxillary and mandibular root positions differed by 2.062 ± 0.128 mm and 1.941 ± 0.154 mm, respectively.

Conclusions: Crowns but not roots of anterior teeth can be moved to designated positions using clear aligners, because these appliances cause tooth movement by tilting motion.

Keywords: Clear aligners; Cone-beam computed tomography; Registration.

Conflict of interest statement

The authors report no commercial, proprietary, or financial interest in the products or companies described in this article.

Figures

Figure 1. Construction of the integrated three-dimensional digital model. A, The integrated model; B, images of the maxilla and mandible; C, images of the complete dentition.

Figure 2. Pretreatment and post-treatment registration of the jaws. A, Maxillary registration. B, Mandibular registration. Blue indicates post-treatment and silver indicates pretreatment. C, Detection map after registration. Dark blue is visible (registration accuracy ≤ 0.15 mm).

Figure 3. Cone-beam computed tomography-based registration of crown and root positions. A, Comparison of pretreatment (yellow) and post-treatment (pink) root positions. A small amount of movement is visible in the apical part while the coronal part appears to have moved to a great extent. B, Detection map after registration. The crown and most of the apical part appear dark blue (registration accuracy ≤ 0.15 mm), while the anterior crown is red.

Figure 4. Discrepancies in crown and root positions after treatment with clear aligners. A, Comparison of achieved (blue) and predicted (pink) crown and root positions. Only the crown reached the predicted position. B, Detection map after registration. The immovable and moved parts of molar teeth appear dark blue (registration accuracy ≤ 0.15 mm), while the crown appears red.