Editorial Type:
Article Category: Research Article
 | 
Online Publication Date: 17 Jun 2024

Difference in discrepancies of mandibular incisor compensation relative to Menton deviation between Class III roll- and yaw-dominant asymmetries

,
, and
Page Range: 631 – 640
DOI: 10.2319/022324-141.1
Save
Download PDF

ABSTRACT

Objectives

To compare mandibular incisor compensation relative to Menton (Me) deviation between skeletal Class III patients with roll- and yaw-dominant mandibular asymmetries.

Materials and Methods

Sixty skeletal Class III patients (21.62 ± 2.69 years) with facial asymmetry were divided into roll- or yaw-dominant asymmetry groups. Mandibular skeletal and incisor measurements were carried out using cone-beam computed tomography data, and values were compared between the two asymmetry groups or between moderate and severe asymmetry subgroups using independent t-test or Mann-Whitney U-test. The relationship between skeletal and dental measurements was assessed using Pearson correlation coefficient.

Results

Relative to the mandibular midsagittal plane, the yaw-dominant group presented significantly greater mandibular dental midline deviation in distance (LI-mid deviation, 2.15 mm) and angulation (4.20°) toward the nondeviated side than the roll-dominant group (P < .001). The ratio of amount of LI-mid deviation to Me deviation was significantly greater in the yaw-dominant group (26.44%) than in the roll-dominant group (1.76%; P < .001). In the yaw-dominant group, the LI-mid deviation was significantly greater in the severe asymmetry subgroup than in the moderate asymmetry subgroup, and the amount of mandibular incisor compensation was positively correlated with Me deviation and mandibular yaw.

Conclusions

Mandibular incisor compensation differed significantly between the roll- and yaw-dominant asymmetry groups. The yaw-dominant group demonstrated significant mandibular dental midline deviation, and dental compensation of the anterior teeth was positively correlated with Me deviation and mandibular yaw.

Keywords: Mandibular incisor compensation; Facial asymmetry; Mandibular roll; Mandibular yaw

INTRODUCTION

Recently, three-dimensional (3D) analysis and virtual orthognathic surgery simulation have become mandatory components of systematic treatment planning for patients with moderate-to-severe facial asymmetry to ensure predictable treatment outcomes.1–3 Facial soft tissue symmetry can be achieved through proper surgical repositioning of the bone segment, that might begin with adequate correction of the deviated positions of the teeth.4 Thus, appropriate dental decompensation may be considered essential for satisfactory improvement of facial asymmetry.

Previous studies reported dental compensation in patients with asymmetry: buccal and lingual tipping of the maxillary and mandibular molars, respectively, on the menton deviated side (Dv), extrusion of the maxillary molar on the nondeviated side (NDv); and mesiodistal tipping of incisors.5–7 According to the equilibrium theory, the tooth position generally manifests in accordance with the adjacent skeletal or soft tissues,8–10 suggesting that dental compensation can differ significantly by the facial asymmetry type.11–14 Previous research reported that tooth position differed vertically and transversely between the sides in roll- and yaw-dominant mandibular asymmetry types, respectively.11 Particularly, mesiodistal tipping of the mandibular incisor was greater in the yaw-dominant type than in the roll-dominant type; however, no significant difference in the position of the maxillary incisors was observed. Although appropriate identification of the dental midline during presurgical orthodontic treatment is essential for optimal positioning of the entire dentition, it is quite challenging to judge the proper dental midline in patients with facial asymmetry exhibiting deviated and distorted mandibles. Generally, the mandibular dental midline is shifted more to the Dv with the increase of menton (Me) deviation. As the asymmetry type can influence the amount of mandibular incisor compensation relative to Me deviation, the decompensation movement for the mandibular incisors might be different according to asymmetry types even though the Me deviation is the same. However, few studies to date have reliably evaluated the differences in mandibular incisor compensation relative to Me deviation according to asymmetry types and provided clinical guidelines.

Therefore, this study aimed to compare mandibular incisor compensation between Class III patients with roll- and yaw-dominant mandibular asymmetry types and investigate factors that contributed to the altered incisor position. The null hypothesis was that there would be no significant differences in the mandibular incisor compensation between the two groups.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board of Kyungpook National University Dental Hospital (KNUDH-2024-01-03-00).

The sample size calculation was based on a previous study that used cone-beam computed tomography (CBCT) to examine dental compensation in patients with facial asymmetry.5 It was carried out using G power (version 3.1.9.7; Hein-rich Heine University of Dusseldorf, Dusseldorf, Germany), taking a two-sided significance level of 0.05, power of 0.80, and an effect size of 0.75 into consideration. The results showed that the optimal study sample should consist of 29 patients in each group. Therefore, to increase power, the current study included 30 patients in each group.

The inclusion criteria were: patients with moderate-to-severe facial asymmetry (>4 mm Me deviation relative to the midsagittal plane [MSP]), skeletal Class III relationship (point A-nasion-point B angle < 0°), no dental spacing and prosthesis, and <3 mm dental crowding. Patients with a history of orthodontic treatment, orthognathic surgery, or craniofacial anomalies or trauma were excluded from this study.

A total of 60 patients (40 men, 20 women; mean age, 21.62 ± 2.69 years; range, 18.00–31.42 years) who were diagnosed in the Department of Orthodontics at Kyungpook National University Dental Hospital in Daegu, Korea between January 2010 and December 2021 were included in this study. Diagnostic CBCT data (120 kVp, 15 mA, 19 cm field of view, 0.377 mm voxel size, 9.6 s scan time) were acquired using a CB MercuRay scanner (Hitachi, Osaka, Japan). The CBCT imaging software (Invivo 6 Anatomy, Anatomage, San Jose, Calif, USA) was used to carry out skeletal and dental measurements. Landmarks and reference planes used in this study are described in Table 1 and Figure 1. Skeletal and dental variables were measured relative to the MSP, Frankfort horizontal plane (FHP), mandibular midsagittal plane (MnMSP), and mandibular horizontal plane (MHP) (Table 2 and Figure 2).

Figure 1.Figure 1.Figure 1.
Figure 1. Landmarks and reference planes used in this study. Cd indicates condylion; Cg, crista galli; FH, Frankfort horizontal; Go_inf, gonion inferior point; MF, mental foramen; MF-mid, midpoint of right and left MF; MHP, mandibular horizontal plane; MnMSP, mandibular midsagittal plane; MSP, midsagittal plane; Op, opisthion; Or, orbitale; PM, protuberance menti; Po, porion.

Citation: The Angle Orthodontist 94, 6; 10.2319/022324-141.1

Figure 2.Figure 2.Figure 2.
Figure 2. 3D skeletal and dental measurements. (A) Skeletal measurements. (B) Mandibular incisor measurements relative to the mandibular midsagittal plane. LI-apex, the midpoint of the root apex of the right and left mandibular incisors; LI-CRe, the midpoint of the center of resistance of the right and left mandibular incisors; LI-mid, the midpoint of incisal edges of the right and left mandibular incisors; Mn, mandibular.

Citation: The Angle Orthodontist 94, 6; 10.2319/022324-141.1

Table 1. Landmarks and Reference Planes
Table 1.
Table 2. Skeletal and Dental Measurementsa
Table 2.

The study sample was divided into the roll- and yaw-dominant asymmetry groups based on the degree of mandibular roll and yaw deviation as follows: The roll-dominant asymmetry group with ≥5° roll and <3° yaw deviation and the yaw-dominant asymmetry group with ≥5° yaw and <3° roll deviation.11,15 Each group was further divided into two subgroups (moderate asymmetry: Me deviation >4 mm and <8 mm; severe asymmetry: Me deviation ≥8 mm) to allow further investigation by the extent of Me deviation.

Statistical Analysis

All variables were measured by a single investigator (HJK), and intraobserver reliability was assessed by repeating measurements at a 4-week interval in 10 randomly selected patients and calculating the intraclass correlation coefficient. The method error was calculated using Dahlberg’s formula. The Kolmogorov–Smirnov test was used to examine normality of the data distribution, and the groups and subgroups were compared using the independent t-test (for normal distribution) or Mann–Whitney U-test (for non-normal distribution). The chi-square test was carried out to compare sex distribution between the groups. To assess the relationship between dental and skeletal measurements, the Pearson’s correlation coefficient was calculated. Simple linear regression analysis was performed to reveal the relationship between the Me deviation and mandibular incisor compensation. All statistical analyses were performed using SPSS software (version 22; IBM, Chicago, IL) with a significance level of < .05.

RESULTS

Regarding the reliability of measurements, the intraclass correlation coefficient was 0.997 (mean; range: 0.996–0.998). According to Dahlberg’s formula, the method errors were 0.77 mm (mean; range: 0.64–0.89) and 0.88° (mean; range: 0.71–1.01).

No significant differences were observed in the sex distribution, age of the sample, and the cephalometric measurements between the groups (Table 3).

Table 3. Distribution of Demographic Characteristics and Cephalometric Measurements in the Roll- and Yaw-Dominant Groupsa–c
Table 3.

Comparison of skeletal CBCT measurements between the groups (Table 4) showed that the roll-dominant asymmetry group had a significantly greater bilateral difference in the ramus height (P < .001) and inclination than the yaw-dominant group (P = .001). The yaw-dominant group showed a significantly greater difference in the body length between sides than the roll-dominant group (P < .001). When calculating the ratio of mandibular yaw to the sum of mandibular roll and yaw, the yaw-dominant group (93.14 ± 18.41%) was significantly greater than the roll-dominant group (17.63 ± 14.79%; P < .001). In terms of mandibular incisor measurements, relative to the MnMSP, the yaw-dominant group demonstrated significantly greater distances from the midpoint of the mandibular incisor edge (LI-mid deviation: 2.15 ± 1.35 mm) or center of resistance (LI-CRe deviation: 1.28 ± 0.91 mm) and greater angulation of the mandibular incisor (LI angulation: 4.20 ± 3.15°) compared with the roll-dominant group (P < .001; LI-mid deviation: 0.29 ± 1.23 mm; LI-CRe deviation: 0.21 ± 0.82 mm; LI angulation: 0.22 ± 2.58°). Therefore, the mandibular midline deviated toward the NDv to a greater extent in the yaw-dominant group compared to the roll-dominant group. The ratio of the extent of dental compensation to Me deviation was 26.44% and 15.99% at the LI-mid and LI-CRe points, respectively, in the yaw-dominant group, and this was higher than the values observed in the roll-dominant group (LI-mid: 1.76%; LI-CRe: 1.58%; P < .001).

Table 4. Comparison of Skeletal and Dental Measurements Between the Roll- and Yaw-Dominant Groupsa–c
Table 4.

When comparing the severe and moderate asymmetry subgroups of the roll-dominant asymmetry group (Table 5), there were significant differences in the bilateral difference of the ramus height and mandibular roll and yaw. Dentally, there were statistically significant differences in the LI-mid or LI-CRe deviation between the two subgroups (P < .05). However, the mean values of dental deviation were less than 1.0 mm or 1.0°, and the ratio of the dental compensation to the Me deviation did not differ significantly. Interestingly, the moderate asymmetry subgroup showed dental midline deviation toward the Dv. In the yaw-dominant asymmetry group (Table 6), the severe asymmetry subgroup showed significantly greater bilateral differences in the ramus height and inclination, and mandibular yaw compared with the moderate asymmetry subgroup. The LI-mid and LI-CRe also deviated further toward the NDv in the severe asymmetry subgroup compared with the moderate asymmetry subgroup; however, the ratio of dental compensation to Me deviation was not significantly different.

Table 5. Comparison of Skeletal and Dental Measurements Between Severe and Moderate Asymmetry Subgroups of the Roll-Dominant Groupa,b
Table 5.
Table 6. Comparison of Skeletal and Dental Measurements Between Severe and Moderate Asymmetry Subgroups of the Yaw-Dominant Groupa–c
Table 6.

The Me deviation was positively correlated with the LI-mid or LI-CRe deviation in both groups (Table 7). In addition to the Me deviation, in the yaw-dominant group, the mandibular yaw was positively correlated to the distance and angulation of the mandibular incisor compensation toward the NDv. On the other hand, the mandibular roll did not show a significant correlation with the amount of dental compensation in both groups. According to the simple linear regression analysis of the yaw-dominant group shown in Table 8, the model revealed that the LI-mid or LI-CRe deviation could be predicted by the Me deviation with the following equations: (LI-mid deviation) = 0.639 + 0.176 × (Me deviation); (LI-CRe deviation) = 0.339 + 0.110 × (Me deviation).

Table 7. Pearson’s Correlation Coefficient Between Skeletal and Dental Measurementsa,b
Table 7.
Table 8. Simple Linear Regression Analysis of the Relationship Between Me Deviation and LI-mid Deviation, and Between Me Deviation and LI-CRe Deviation in the Yaw-Dominant Groupa,b
Table 8.

DISCUSSION

Mandibular incisor compensation was significantly different between the roll- and yaw-dominant asymmetry groups even though the two groups did not show significant differences in the amount of Me deviation (Figure 3). This finding was consistent with previous research.11 In addition, this study compared the LI-mid and CRe deviations and LI angulation to yield the required tooth movement for midline correction, such as controlled/uncontrolled tipping or bodily movement. Although there were three types of mandibular asymmetry, the yaw- and translation-dominant types demonstrated similar compensatory anterior tooth tipping, and the translation-dominant type had a lesser extent of Me deviation than the yaw-dominant type.11 Hence, the scope of this study was focused on comparing the roll- and yaw-dominant groups only, which presented distinctive characteristics of mandibular anterior tooth compensation.

Figure 3.Figure 3.Figure 3.
Figure 3. Roll- and yaw-dominant mandibular asymmetries and schematic illustration of mandibular incisor compensation in each group. LI-CRe, the midpoint of the center of resistance of the right and left mandibular incisors; LI-mid, the midpoint of incisal edges of the right and left mandibular incisors; MHP, mandibular horizontal plane; MnMSP, mandibular midsagittal plane.

Citation: The Angle Orthodontist 94, 6; 10.2319/022324-141.1

The yaw-dominant group presented with noticeable incisor compensation toward the NDv by 2.2 mm at the LI-mid, and by 1.3 mm at the LI-CRe. Therefore, 2.2 mm of controlled tipping movement of the mandibular incisor to the Dv would be necessary, including a 1.3 mm movement at the LI-Cre, during the presurgical orthodontic treatment. Conversely, in the roll-dominant group, the distance or angulation of the mandibular incisor deviation, showing less than 0.5 mm or 0.5°, was not clinically significant. Thus, mandibular incisor decompensation would not be crucial for roll-dominant asymmetry patients. Concerning the ratio of the incisor deviation to the Me deviation, the yaw-dominant group showed significantly greater values than the roll-dominant group did. That is, even in patients with the same degree of Me deviation, greater mandibular midline correction would be required in patients with yaw-dominant mandibular asymmetry compared with the roll-dominant group. Nonetheless, in the yaw-dominant group, the amount of dental midline deviation appeared to be only 26% of the Me deviation, and this was much lower than expected. This might be attributed to the fact that the incisors are not mediolaterally close to the lip, cheek, or tongue, but anteroposteriorly, in contrast to the molars, which showed more buccolingual tipping caused by mediolaterally different forces between the cheek and tongue.9,16

Regarding the results of the Pearson’s correlation analysis, the LI-mid and LI-CRe deviations were positively correlated with the Me deviation in both groups. However, as presented in Figure 4A, the absolute values of LI-mid deviation in the roll-dominant group were mostly less than 1.0 mm, indicating limited clinical significance. In the yaw-dominant group, however, the clinically significant dental compensation was positively correlated with the mandibular yaw (Figure 4B). Hence, mandibular yaw might be a critical determinant that directly affects the mandibular dental midline deviation. This finding might be attributable to the fact that mandibular yaw can lead to asymmetric lower lip force on the anterior teeth, particularly in patients with mandibular prognathism.17 Additionally, considering that the mandibular molar showed significant lingual tipping at the Dv in yaw-dominant asymmetry patients,11 the lingually tipped molars can transfer compensating force up to the anterior teeth through the tooth contact points, likely leading to the incisor compensation toward the NDv. In contrast, mandibular roll did not show a significant correlation with mandibular incisor compensation to the NDv because this is, instead, associated with the vertical movement of the sides (Figure 4C). Consequently, mandibular yaw seems to primarily cause the mandibular midline deviation. Therefore, sufficient midline decompensation should be taken into consideration in patients with yaw-dominant asymmetry. Interestingly, the ratio of dental midline deviation to Me deviation was not correlated to the Me deviation or mandibular yaw, meaning that the ratio is relatively consistent and the proper amount of dental decompensation can be predicted based on the skeletal measurements.

Figure 4.Figure 4.Figure 4.
Figure 4. Scatter plots showing the relationship between mandibular incisor midline deviation and skeletal measurements. (A) Menton deviation. (B) Mandibular yaw. (C) Mandibular roll.

Citation: The Angle Orthodontist 94, 6; 10.2319/022324-141.1

When calculating the required amount of dental decompensation using the equations by simple linear regression analysis, if a skeletal Class III patient with yaw-dominant asymmetry shows an 8 mm Me deviation, the mandibular dental midline needs to be moved toward the Dv by 2.0 mm. This is consistent with the current result that the ratio of the LI-mid deviation to Me deviation was approximately 26%. In addition, by calculation with the equation for the LI-CRe deviation, this tooth movement should be along with a 1.2 mm movement at the LI-CRe. Thus, it would be beneficial to use Class II intermaxillary elastics on the NDv with a thick and stiff mandibular archwire for incisor decompensation, with controlled tipping toward the Dv.

Clinically, the maxillary dental midline or tooth position can be effectively judged by comparing it to the interpupillary line, nose, or philtrum when inspecting the frontal view of patients with their mouth open.18 On the other hand, evaluation of mandibular tooth position is challenging to clinicians due to the distorted mandible and discrepancy between the skeletal and soft tissue menton.15,19 Therefore, the tooth movement guide suggested in this study might be quite valuable, particularly in facial asymmetry patients with mandibular yaw.

This study provided worthwhile insight into the factors contributing to mandibular incisor compensation in facial asymmetry patients. However, there was a limitation that this study dealt with only roll- and yaw-dominant mandibular asymmetry groups. Therefore, further research on mandibular incisor compensation with other asymmetry types would be necessary.

CONCLUSIONS

  • The null hypothesis was rejected, and there were significant differences in mandibular incisor compensation between the roll- and yaw-dominant asymmetry groups.

  • The yaw-dominant group demonstrated significantly greater mandibular midline deviation compared with the roll-dominant group, and dental compensation was positively correlated with Me deviation and mandibular yaw, but not with mandibular roll.

  • The required amount of mandibular midline correction was approximately 26% of the amount of the deviation of Me in the yaw-dominant group.

REFERENCES

  • 1.

    McCormick SU, Drew SJ. Virtual model surgery for efficient planning and surgical performance. J Oral Maxillofac Surg. 2011;69(

    3
    ):638–644.

  • 2.

    Barone S, Cevidanes L, Miranda F, et al. Enhancing skeletal stability and Class III correction through active orthodontist engagement in virtual surgical planning: a voxel-based 3-dimensional analysis. Am J Orthod Dentofacial Orthop. 2024;165(

    3
    ):321–331.

  • 3.

    Hong M, Kim MJ, Shin HJ, Cho HJ, Baek SH. Three-dimensional surgical accuracy between virtually planned and actual surgical movements of the maxilla in two-jaw orthognathic surgery. Korean J Orthod. 2020;50(

    5
    ):293–303.

  • 4.

    Kim HJ, Noh HK, Park HS. Use of a novel body mandibular plane (mental foramen-protuberance menti) in analyzing mandibular asymmetry compared with conventional border mandibular plane. Angle Orthod. 2023;93(

    2
    ):195–204.

  • 5.

    Kim HJ, Hong M, Park HS. Analysis of dental compensation in patients with facial asymmetry using cone-beam computed tomography. Am J Orthod Dentofacial Orthop. 2019;156(

    4
    ):493–501.

  • 6.

    Tyan S, Park HS, Janchivdorj M, Han SH, Kim SJ, Ahn HW. Three-dimensional analysis of molar compensation in patients with facial asymmetry and mandibular prognathism. Angle Orthod. 2016;86(

    3
    ):421–430.

  • 7.

    Kusayama M, Motohashi N, Kuroda T. Relationship between transverse dental anomalies and skeletal asymmetry. Am J Orthod Dentofacial Orthop. 2003;123(

    3
    ):329–337.

  • 8.

    Weinstein S, Haack DC, Morris LY, Snyder BB, Attaway HE. On an equilibrium theory of tooth position. Angle Orthod. 1963;33:1–26.

  • 9.

    Takada J, Ono T, Miyamoto JJ, Yokota T, Moriyama K. Association between intraoral pressure and molar position and inclination in subjects with facial asymmetry. [Eratum in Eur J Orthod. 2018;40(2):225]. Eur J Orthod. 2011;33(

    3
    ):243–249.

  • 10.

    Proffit WR. Equilibrium theory revisited: factors influencing position of the teeth. Angle Orthod. 1978;48(

    3
    ):175–186.

  • 11.

    Kim HJ, Noh HK, Park HS. Mandibular asymmetry types and differences in dental compensations of Class III patients analyzed with cone-beam computed tomography. Angle Orthod. 2023;93(

    6
    ):695–705.

  • 12.

    Li J, Liu Y, Ge X, et al. A cross-sectional study on three-dimensional compensatory characteristics of maxillary teeth in patients with different types of skeletal Class III malocclusion with mandibular asymmetry. Clin Oral Investig. 2023;27(

    9
    ):4973–4985.

  • 13.

    Chen YJ, Yao CC, Chang ZC, Lai HH, Yeh KJ, Kok SH. Characterization of facial asymmetry in skeletal Class III malocclusion and its implications for treatment. Int J Oral Maxillofac Surg. 2019;48(

    12
    ):1533–1541.

  • 14.

    Kim KA, Lee JW, Park JH, Kim BH, Ahn HW, Kim SJ. Targeted presurgical decompensation in patients with yaw-dependent facial asymmetry. Korean J Orthod. 2017;47(

    3
    ):195–206.

  • 15.

    Kim HJ, Noh HK, Park HS. Differences in facial soft tissue deviations in Class III patients with different types of mandibular asymmetry: a cone-beam computed tomography study. Korean J Orthod. 2023;53(

    6
    ):402–419.

  • 16.

    Takada J, Ono T, Takahashi S, Honda E, Kurabayashi T. Changes in horizontal jaw position and intraoral pressure. Angle Orthod. 2008;78(

    2
    ):254–261.

  • 17.

    Chen S, Cai Y, Chen F. Lip closing force of Class III patients with mandibular prognathism: a case control study. Head Face Med. 2014;10:33.

  • 18.

    Park HS.

    Treatment planning for orthognathic surgery using 3D CT analysis
    . In: ParkHS.Microimplants in Orthognathic Surgical Orthodontics.
    Daegu
    :
    Dentos
    ; 2015:7–18.

  • 19.

    Kim WS, Lee KH, Hwang HS. Comparison of asymmetric degree between maxillofacial hard and soft tissue in facial asymmetric subjects using three-dimensional computed tomography. Korean J Orthod. 2005;35(

    3
    ):163–73.

Copyright: © 2024 by The EH Angle Education and Research Foundation, Inc.
Figure 1.
Figure 1.

Landmarks and reference planes used in this study. Cd indicates condylion; Cg, crista galli; FH, Frankfort horizontal; Go_inf, gonion inferior point; MF, mental foramen; MF-mid, midpoint of right and left MF; MHP, mandibular horizontal plane; MnMSP, mandibular midsagittal plane; MSP, midsagittal plane; Op, opisthion; Or, orbitale; PM, protuberance menti; Po, porion.

Figure 2.
Figure 2.

3D skeletal and dental measurements. (A) Skeletal measurements. (B) Mandibular incisor measurements relative to the mandibular midsagittal plane. LI-apex, the midpoint of the root apex of the right and left mandibular incisors; LI-CRe, the midpoint of the center of resistance of the right and left mandibular incisors; LI-mid, the midpoint of incisal edges of the right and left mandibular incisors; Mn, mandibular.

Figure 3.
Figure 3.

Roll- and yaw-dominant mandibular asymmetries and schematic illustration of mandibular incisor compensation in each group. LI-CRe, the midpoint of the center of resistance of the right and left mandibular incisors; LI-mid, the midpoint of incisal edges of the right and left mandibular incisors; MHP, mandibular horizontal plane; MnMSP, mandibular midsagittal plane.

Figure 4.
Figure 4.

Scatter plots showing the relationship between mandibular incisor midline deviation and skeletal measurements. (A) Menton deviation. (B) Mandibular yaw. (C) Mandibular roll.

Contributor Notes

a Assistant Professor, Department of Orthodontics, School of Dentistry, Kyungpook National University, Daegu, Korea.
b Professor and Chair, Department of Orthodontics, School of Dentistry, Kyungpook National University, Daegu, Korea.
Corresponding author: Dr Hyo-Sang Park, Professor, Department of Orthodontics, School of Dentistry, Kyungpook National University, 2175 Dalgubul-Daero, Jung-Gu, Daegu 41940, Korea. (e-mail: parkhs@knu.ac.kr)
Received: 01 Feb 2024
Accepted: 01 May 2024
  • Download PDF