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Comparative Study
. 2014 Nov;84(6):1018-25.
doi: 10.2319/112713-869.1. Epub 2014 Apr 9.

Condylar response to functional therapy with Twin-Block as shown by cone-beam computed tomography

Ersin Yildirim  1 , Seniz Karacay, Mustafa Erkan
Affiliations
Comparative Study

Condylar response to functional therapy with Twin-Block as shown by cone-beam computed tomography

Ersin Yildirim et al. Angle Orthod. 2014 Nov.

Abstract

Objective: To evaluate the condylar changes through cone-beam computed tomography (CBCT) images in patients treated with Twin-Block functional appliance.

Materials and methods: In this retrospective study, CBCT images of 30 patients who were treated with the Twin-Block appliance were used. Mandible was segmented and pretreatment and posttreatment (T0 and T1) condylar volume was compared. The angle between sella-nasion-Point A (SNA), angle between sella-nasion-Point B (SNB), angle between Point A-nasion-Point B (ANB), midfacial length (Co-A), mandibular length (Co-Gn), and the distances from right condylion to left condylion (CoR-CoL) were also measured on three-dimensional images. Differences were analyzed with Wilcoxon signed rank tests, and Mann-Whitney U-tests were used to compare the scores of male and female participants. Significance was set at P < .05.

Results: In this study, a decrease in SNA and ANB (P < .05 and P < .01, respectively) and an increase in SNB (P < .01) were found. Additionally, CoR-CoL, Co-Gn, and condylar volume increased at both the left and right sides (P < .01). However, increase at Co-A was not statistically significant (P > .05). Comparison of differences by sex was not statistically significant for all measurements (P > .05).

Conclusion: Twin-Block appliance increases condylar volume, mandibular length, and intercondylar distance by stimulating growth of condyle in an upward and backward direction.

Keywords: Condyle; Cone-beam computed tomography; Functional orthopedic appliance; Temporomandibular joint; Twin-Block.

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Figures

Figure 1. Localization of landmarks.
Figure 1.
Localization of landmarks.
Figure 2. (A) Pretreatment. (B) Posttreatment images.
Figure 2.
(A) Pretreatment. (B) Posttreatment images.
Figure 3. Superimposition points (foramen mentale and antegonial notch) marked on (A) pretreatment and (B) posttreatment images. (C) Superimposition of images.
Figure 3.
Superimposition points (foramen mentale and antegonial notch) marked on (A) pretreatment and (B) posttreatment images. (C) Superimposition of images.
Figure 4. Plane passing tangent to the distal slope of the coronoid process.
Figure 4.
Plane passing tangent to the distal slope of the coronoid process.
Figure 5. (A) Pretreatment volume measurement. (B) Posttreatment values.
Figure 5.
(A) Pretreatment volume measurement. (B) Posttreatment values.
See this image and copyright information in PMC

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