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. 2023 Jul 17;24(1):25.
doi: 10.1186/s40510-023-00474-3.

Impact of molar teeth distalization by clear aligners on temporomandibular joint: a three-dimensional study

Barakat Al-Tayar  1   2 , Majedh A A Al-Somairi  3 , Lina H ALshoaibi  1 , Xiaoli Wang  1 , Junbin Wang  1 , Jiajie Liu  1 , Baher Al-Tayar  4   5 , Xiaoli An  6 , Qingzong Si  7
Affiliations

Impact of molar teeth distalization by clear aligners on temporomandibular joint: a three-dimensional study

Barakat Al-Tayar et al. Prog Orthod. .

Abstract

Background: Maxillary molar distalization is a common technique used in the non-extraction treatment of Angle Class II malocclusion that can effectively correct the molar relationship and create spaces for anterior teeth alignment. However, this approach may also impact the temporomandibular joint (TMJ) due to predictable changes in the posterior vertical dimension. Despite its widespread use, Class II malocclusions correction by molar distalization with clear aligners has not been investigated for their effects on the TMJ. Therefore, this study aimed to analyze the impact of sequential molar distalization using clear aligners on the TMJ.

Methods: Three-dimensional CBCT scans of 23 non-growing patients (7 males, 16 females; mean age 29.8 ± 4.6 years) with skeletal class I or II malocclusion and a bilateral molar class II relationship treated by sequential upper molars distalization with orthodontic clear aligners (Invisalign, Align Technology, San Josè, Ca, USA). A total of 46 joints were examined before and after molar distalization using Anatomage InvivoDental 6.0.3. Linear and angular measurements of the mandibular joint were measured, including joint parameters, inclination, position, and the dimension of the condyle and articular fossa. In addition, 3D volumetric spaces of the joint were analyzed. All data were statistically analyzed by paired T test to determine the differences between the pre-and post-orthodontic procedures.

Results: No statistically significant differences were found in all primary effects resulting from maxillary molars distalization by clear aligners on TMJ components measurements and joint spaces between T0 and T1. Meanwhile, statistically significant differences were observed in the linear position of the upper molars and the molar relationship parameter with at least P ≤ 0.05.

Conclusion: Treatment by sequential upper molars distalization with clear aligners does not lead to significant TMJ parameters changes in condyle and fossa spaces, dimensions, and positions.

Keywords: 3D analysis; Class II malocclusion; Clear aligners; Cone-beam computed tomography; Molar distalization; Temporomandibular joint.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Illustrations for one of the treated patients. a Sequence of tooth movement with distalization of the upper molars, from (1 to 4). Figures extracted from ClinCheck® (Align Technology, San Josè, California, USA) b Lateral images extracted from the patient CBCT scan, before the orthodontic treatment with sequential distalization T0 and after treatment T1 c lateral intra-oral view of a patient before the orthodontic treatment T0 and after treatment T1
Fig. 2
Fig. 2
Craniofacial Landmarks and reference planes
Fig. 3
Fig. 3
3D temporomandibular joint reference points and measurements: a, b sagittal views, c axial view, d coronal view
Fig. 4
Fig. 4
Slice locator of 3D landmarks determination
Fig. 5
Fig. 5
3D volumetric total joint space with 2D identification points
Fig. 6
Fig. 6
a–f Statistical graphs of the differences between the right and left TMJ measurements between T0 and T1. *P < 0.05; **P < 0.01; ***P < 0.0001; ns non-significant
See this image and copyright information in PMC

References

    1. Guo L, Feng Y, Guo HG, Liu BW, Zhang Y. Consequences of orthodontic treatment in malocclusion patients: clinical and microbial effects in adults and children. BMC Oral Health. 2016;16(1):112. doi: 10.1186/s12903-016-0308-7. - DOI - PMC - PubMed
    1. Cenzato N, Nobili A, Maspero C. Prevalence of dental malocclusions in different geographical areas: scoping review. Dent J. 2021 doi: 10.3390/dj9100117. - DOI - PMC - PubMed
    1. Fichera G, Ronsivalle V, Santonocito S, Aboulazm KS, Isola G, Leonardi R, et al. Class II skeletal malocclusion and prevalence of temporomandibular disorders. An epidemiological pilot study on growing subjects. J Funct Morphol Kinesiol. 2021 doi: 10.3390/jfmk6030063. - DOI - PMC - PubMed
    1. Alhammadi MS, Halboub E, Fayed MS, Labib A, El-Saaidi C. Global distribution of malocclusion traits: a systematic review. Dental Press J Orthod. 2018;23(6):40.e1–.e10. 10.1590/2177-6709.23.6.40.e1-10.onl. - PMC - PubMed
    1. Mayoral Herrero G. Extraction versus non-extraction. Does the pendulum swing too much? Orthod Fr 1992;63(Pt 2):443–53. - PubMed

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