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KJO Korean Journal of Orthodontics

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pISSN 2234-7518
eISSN 2005-372X
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    • Case Report l 2019-05-25

      Total arch distalization with interproximal stripping in a patient with severe crowding

      Min-Ho Jung

      Abstract : When a patient shows severe crowding, premolar extraction should be considered to provide required available space for alignment. If the third molars have already erupted and demonstrate a poor prognosis, third molar extraction and distalization of the posterior dentition can be used instead of premolar extraction to obtain space. Interproximal stripping (IPS) may also be used to gain space in cases of crowding. This case report describes the treatment of a 25-year-old man with severe crowding and mild lip protrusion. Although the crowding in the lower arch was severe enough to require first premolar extraction, distalization of the entire lower dentition with orthodontic mini-implants, extraction of the lower third molars, and IPS could successfully resolve the crowding and lip protrusion.

      Abstract  
    • Original Article l 2020-01-25

      Comparison of three midsagittal planes for three-dimensional cone beam computed tomography head reorientation

      Eon-Hwa Lee, Hyung-Seog Yu, Kee-Joon Lee, Sang-Sun Han, Hwi-Dong Jung, and Chung-Ju Hwang

      Abstract : ObjectiveThis study compared three prominent midsagittal planes (MSPs) to identify the MSP that best approximates the true symmetrical MSP.MethodsForty-three patients (mean age, 23.0 ± 8.20 years) were grouped as follows: group 1 consisted of 10 patients with skeletal Class I and a menton (Me) deviation of < 2 mm; group 2, 11 patients with skeletal Class III and a Me deviation < 2 mm; group 3, nine patients with skeletal Class III and a Me deviation of 2 to less than 4 mm; and group 4, 13 patients with skeletal Class III and an Me deviation ≥ 4 mm. The candidate MSPs were established by three-dimensional (3D) cone beam computed tomography (CBCT) reorientation methods (RMs): (1) the MSP perpendicular to the Frankfort horizontal (FH) plane while passing through the crista galli and basion; (2) the MSP including the nasion, incisive foramen, and basion; (3) the MSP including the nasion, anterior nasal spine, and posterior nasal spine. The mean absolute distances (MADs) to the MSPs were calculated from the coordinates of 1,548 points on 129 CBCT images. The differences in the values of the 3D coordinates among RMs were compared.ResultsThe MADs of the three RMs showed significant differences (p < 0.05). Most of the differences in values of the coordinates were not significant among RMs.ConclusionsAlthough the differences in distance among the three MSPs were minor, the MSP perpendicular to the FH plane while passing through the crista galli and basion best approximated the true symmetrical MSP.

      Abstract  
    • Original Article l 2020-11-25

      Characterization of dental phenotypes and treatment modalities in Korean patients with Parry–Romberg syndrome

      Sunjin Yim , Il-Hyung Yang, Seung-Hak Baek

      Abstract : Objective: To investigate the dental phenotypes and treatment modalities (Tx- Mod) in Korean patients with Parry–Romberg syndrome (PRS) using longitudinal data. Methods: The samples consisted of 10 PRS patients, who were treated and/or followed-up at Seoul National University Dental Hospital between 1998 and 2019. Using a novel PRS severity index based on the numbers of the atrophy-involved area and asymmetry-involved item, we classified them into mild (n = 3), moderate (n = 2), and severe (n = 5). Dental phenotypes, including congenitally missing tooth (Con-Missing-Tooth), microdontia, tooth with short root (Short-Root), tooth with dilacerated root, and delayed eruption/impacted tooth, were investigated along with Tx-Mod. Results: The side of occurrence of all dental phenotypes showed 100% concordance with the side of PRS involvement. The most two common dental phenotypes were Con-Missing- Tooth and Short-Root (n = 29 and n = 17 in six patients). The sums of the average number of Con-Missing-Tooth and Short-Root increased from mild PRS to moderate PRS and severe PRS cases (1.0, 6.0, and 6.2). In terms of Tx- Mod, growth observation due to mild atrophy, fixed orthodontic treatment, and grafting were used for mild PRS cases. Tx-Mod for moderate PRS cases involved growth observation for surgery due to an early age at the initial visit. For severe PRS cases, diverse Tx-Mod combinations including unilateral functional appliance, fixed orthodontic treatment, growth observation, grafting, and orthognathic surgery were used. Conclusions: The novel PRS severity index may be useful to provide primary data for individualized diagnosis and treatment planning for PRS patients.

      Abstract  
    • Original Article l 2019-05-25

      Influence of changing various parameters in miniscrew-assisted rapid palatal expansion: A three-dimensional finite element analysis

      Soungjun Yoon , Dong-Yul Lee, and Seok-Ki Jung

      Abstract : ObjectiveThis study aimed to analyze the effect of changing various parameters of the bone-borne rapid palatal expander (RPE) using the finite element method (FEM).MethodsIn eight experimental groups, we investigated the effect of the number, position, and length of miniscrews; positional changes of the expander; and changes in the hook length on maxillary expansion. In finite element analysis, we compared the magnitude and distribution of stress, and the displacement changes following expansion of the bone-borne RPE.ResultsWhen we compared the number and position of miniscrews, placing miniscrews in the anterior and posterior sides was advantageous for maxillary expansion in terms of stress distribution and displacement changes. Miniscrew length did not significantly affect stress distribution and displacement changes. Furthermore, anteroposterior displacement of the expander did not significantly affect transverse maxillary expansion but had various effects on vertical changes of the maxilla. The maxilla rotated clockwise when the miniscrews were placed in the anterior region. The hook length of the expander did not show consistent results in terms of changes in stress distribution and magnitude or in displacement changes.ConclusionsThe findings of this study suggest that changes in the location and length of the miniscrews and displacement of the bone-borne RPE could affect the pattern of the maxillary expansion, depending on the combination of these factors.

      Abstract  
    • Reader's Forum l 2021-03-25

      READER’S FORUM

      Nalin Katkoria Priyanka, Sekar Santhosh Kumar, Shivangi Ramteke, and Balasubramanian Madhan
    • Original Article l 2020-01-25

      Comparison of inclination and vertical changes between single-wire and double-wire retraction techniques in lingual orthodontics

      Bui Quang Hung, Mihee Hong, Wonjae Yu and Hee-Moon Kyung

      Abstract : ObjectiveThe Heat Induction Typodont System (HITS), used in some recent studies, has a distinct advantage over previous tooth movement simulation methods. This study aimed to compare inclination and vertical changes between the single-wire and double-wire techniques during en masse retraction with different lengths of lever arms in lingual orthodontics using an upgraded version of the HITS.MethodsDuet lingual brackets, which have two main slots, were used in this study. Forty samples were divided into four groups according to the length of the lever arm (3-mm or 6-mm hook) and the retraction wire (single-wire or double-wire). Four millimeters of en masse retraction was performed using lingual appliances. Thereafter, 3-dimensional-scanned images of the typodont were analyzed to measure inclination and vertical changes of the anterior teeth.ResultsIncisor inclination presented more changes in the single-wire groups than in the double-wire groups. However, canine inclination did not differ between these groups. Regarding vertical changes, only the lateral incisors in the single-wire groups presented significantly larger values than did those in the double-wire groups. Combining the effect of hook lengths, among the four groups, the single-wire group with the 3-mm hook had the highest value, while the double-wire group with the 6-mm hook showed the least decrease in crown inclination and extrusion.ConclusionsThe double-wire technique with an extended lever arm provided advantages over the single-wire technique with the same lever arm length in preventing torque loss and extrusion of the anterior teeth during en masse retraction in lingual orthodontics.

      Abstract  
    • Original Article l 2021-03-25

      Effect of micro-osteoperforations on external apical root resorption: A randomized controlled trial

      Azaitun Akma Shahrin , Sarah Haniza Abdul Ghani, Noraina Hafizan Norman

      Abstract : Objective: This study aimed to investigate the effect of micro-osteoperforations (MOPs) on external apical root resorption (EARR) during the initial orthodontic alignment phase of maxillary anterior crowding. Methods: Thirty patients (25 females, 5 males; mean age, 22.66 ± 3.27 years) who presented with moderate crowding of the upper labial segment and underwent extraction-based fixed appliance treatment were recruited. They were randomly allocated to receive adjunctive therapy with MOPs (n = 15) or treatment with fixed appliances only (control group; n = 15). EARR was measured from long-cone periapical radiographs taken at the start and the sixth month of treatment. A correction factor for the enlargement difference was used to calculate EARR. Data were analyzed with descriptive statistics and repeated-measures analysis of variance. Results: The mean root lengths of 168 teeth were measured and showed no statistically significant difference (p > 0.05) after six months of fixed appliance treatment in the MOP (mean difference [MD] = 0.13 mm; 95% confidence interval [CI] = −0.10–0.35) and control group (MD = 0.14 mm; 95% CI = −0.10–0.37). Most of the roots in the MOP and control groups (42.86% and 52.38%, respectively) showed only mild resorption. Less than 8% of the roots in both groups (7.14% in the MOP group and 4.76% in the control group) showed moderate resorption. Conclusions: Acceleration of orthodontic tooth movement with adjunctive MOPs therapy during the alignment phase does not exacerbate EARR in patients with moderate crowding of the upper labial segment in comparison with controls.

      Abstract  
    • Original Article l 2021-01-25

      Relationship between vertical components of maxillary molar and craniofacial frame in normal occlusion: cephalometric calibration on the vertical axis of coordinates

      Ah-Reum Han , Jongtae Kim , Il-Hyung Yang

      Abstract : Objective: The aim of this study was to evaluate the correlation between the vertical position of maxillary first molar and vertical skeletal measurements in lateral cephalograms by using new linear measurements on the vertical axis of coordinates with calibration. Methods: The vertical position of maxillary first molar (U6-SN), and the conventionally used variables (ConV) and the newly derived linear variables (NwLin) for vertical skeletal patterns were measured in the lateral cephalograms of 103 Korean adults with normal occlusions. Pearson correlation analyses and multiple linear regression analyses were performed with and without calibration using the anterior and posterior cranial base (ACB and PCB, respectively) lengths to identify variables related to U6-SN. Results: The PCB-calibrated statistics showed the best power of explanation. ConV indicating skeletal hyperdivergency was significantly correlated with U6-SN. Six NwLin regarding the position of palatal plane were positively correlated with U6-SN. Each multiple linear regression analysis generated a two-variable model: sella and nasion to palatal plane. Among the three models, the PCBcalibrated model yielded highest adjusted R2 value, 0.880. Conclusions: U6-SN could be determined by the vertical position of the maxilla, which could then be used to plan the amount of molar intrusion and estimate its clinical stability. Cephalometric calibration on the vertical axis of coordinates by using PCB for vertical linear measurements could strengthen the analysis itself.

      Abstract  
    • Reader's Forum l 2020-05-25

      READER’S FORUM

      Seo-Rin Jeong, Hyein Kim

Journal Info.

March, 2021
Vol.51 No.2

Frequency: 6 times

Journal Impact Factor

  • 1.476
    2018 IF

  • 1.523
    5-Year IF

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Clinical Journal of Korean Association of Orthodontists