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KJO Korean Journal of Orthodontics

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pISSN 2234-7518
eISSN 2005-372X
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    • Original Article l 2020-07-25

      Construction reproducibility of a composite tooth model composed of an intraoral-scanned crown and a cone-beam computed tomography-scanned root

      Seung-Weon Lim , Ryu-Jin Moon, Min-Seok Kim, Min-Hee Oh, Kyung-Min Lee, Hyeon-Shik Hwang, Tae-Woo Kim, Seung-Hak Baek, Jin-Hyoung Cho

      Abstract : Objective: To evaluate the construction reproducibility of a composite tooth model (CTM) composed of an intraoral-scanned crown and a cone-beam computed tomography (CBCT)-scanned root. Methods: The study assessed 240 teeth (30 central incisors, 30 canines, 30 second premolars, and 30 first molars in the maxillary and mandibular arches) from 15 young adult patients whose pre-treatment intraoral scan and CBCT were available. Examiner-Reference (3 years’ experience in CTM construction) and Examiners-A and Examiner-B (no experience) constructed the individual CTMs independently by performing the following steps: image acquisition and processing into a three-dimensional model, integration of intraoral-scanned crowns and CBCT-scanned teeth, and replacement of the CBCT-scanned crown with the intraoral-scanned crown. The tooth axis angle in terms of mesiodistal angulation and buccolingual inclination of the CTMs constructed by the three examiners were measured. To assess the construction reproducibility of CTMs, intraclass correlation coefficient (ICC) assessments were performed. Results: The ICC values of mesiodistal angulation and buccolingual inclination among the 3 examiners showed excellent agreement (0.950–0.992 and 0.965–0.993; 0.976–0.994 and 0.973–0.995 in the maxillary and mandibular arches, respectively). Conclusions: The CTM showed excellent construction reproducibility in mesiodistal angulation and buccolingual inclination regardless of the construction skill and experience levels of the examiners.

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    • Case Report l 2020-07-25

      Camouflage treatment of posterior bite collapse in a patient with skeletal asymmetry by using posterior maxillary segmental osteotomy

      Haitham Badr , Soo-Yeon Lee, Hong-Sik Park, Joo-Young Ohe, Yoon-Goo Kang, Hyo-Won Ahn

      Abstract : Orthodontic treatment of posterior bite collapse due to early loss of molars and the consequent drift of adjacent teeth is complicated. When the posterior bite collapse occurs in patients with facial asymmetry, both transverse and vertical compensation are necessary for camouflage orthodontic treatment. In such cases, posterior maxillary segmental osteotomy (PMSO) can be an effective alternative procedure that simplifies the orthodontic treatment and shows long-term stability through dental compensation within the alveolar bone housing. This case report aimed to describe the orthodontic treatment of maxillary occlusal plane canting caused by severely extruded maxillary teeth in a patient with skeletal facial asymmetry that was corrected with PMSO along with protraction of the lower second molar to replace the space of the extracted first molar. The treatment duration was 18 months, and stable results were obtained after 2 years of retention.

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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.

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    • 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.

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    • Original Article l 2020-03-25

      Changes in maximum lip-closing force after extraction and nonextraction orthodontic treatments

      Tae-Hyun Choi, So-Hyun Kim, Cheul Kim, Yoon-Ah Kook, Brent E. Larson, and Nam-Ki Lee

      Abstract : ObjectiveThe aims of the present study were to evaluate the changes in the maximum lip-closing force (MLF) after orthodontic treatment with or without premolar extractions and verify the correlation of these changes with dentoskeletal changes.MethodsIn total, 17 women who underwent nonextraction orthodontic treatment and 15 women who underwent orthodontic treatment with extraction of all four first premolars were included in this retrospective study. For all patients, lateral cephalograms and dental models were measured before (T0) and after (T1) treatment. In addition, MLF was measured at both time points using the Lip De Cum LDC-110R? device. Statistical analyses were performed to evaluate changes in clinical variables and MLF and their correlations.ResultsBoth groups showed similar skeletal patterns, although the extraction group showed greater proclination of the maxillary and mandibular incisors and lip protrusion compared to the nonextraction group at T0. MLF at T0 was comparable between the two groups. The reduction in the arch width and depth and incisor retroclination from T0 to T1 were more pronounced in the extraction group than in the nonextraction group. MLF in the extraction group significantly increased during the treatment period, and this increase was significantly greater than that in the nonextraction group. The increase in MLF was found to be correlated with the increase in the interincisal angle and decrease in the intermolar width, arch depth, and incisor?mandibular plane angle.ConclusionsThis study suggests that MLF increases to a greater extent during extraction orthodontic treatment than during nonextraction orthodontic treatment.

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    • Original Article l 2020-03-25

      Sex-, growth pattern-, and growth status-related variability in maxillary and mandibular buccal cortical thickness and density

      Sydney Schneider, Vaibhav Gandhi, Madhur Upadhyay, Veerasathpurush Allareddy, Aditya Tadinada, and Sumit Yadav

      Abstract : ObjectiveThe primary objective of this study was to quantitatively analyze the bone parameters (thickness and density) at four different interdental areas from the distal region of the canine to the mesial region of the second molar in the maxilla and the mandible. The secondary aim was to compare and contrast the bone parameters at these specific locations in terms of sex, growth status, and facial type.MethodsThis retrospective cone-beam computed tomography (CBCT) study reviewed 290 CBCT images of patients seeking orthodontic treatment. Cortical bone thickness in millimeters (mm) and density in pixel intensity value were measured for the regions (1) between the canine and first premolar, (2) between the first and second premolars, (3) between the second premolar and first molar, and (4) between the first and second molars. At each location, the bone thickness and density were measured at distances of 2, 6, and 10 mm from the alveolar crest.ResultsThe sex comparison (male vs. female) in cortical bone thickness showed no significant difference (p > 0.001). The bone density in growing subjects was significantly (p < 0.001) lower than that in non-growing subjects for most locations. There was no significant difference (p > 0.001) in bone parameters in relation to facial pattern in the maxilla and mandible for most sites.ConclusionsThere was no significant sex-related difference in cortical bone thickness. The buccal cortical bone density was higher in females than in males. Bone parameters were similar for subjects with hyperdivergent, hypodivergent, and normodivergent facial patterns.

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    • Case Report l 2020-01-25

      Distalization with a modified C-palatal plate for severe upper crowding and a missing lower incisor

      Jae Hyun Park, Traci Saito, Sun Kyong Yoo, Mohammed Alfaifi, and Yoon-Ah Kook

      Abstract : This case report presents the orthodontic treatment of a 25-year-old patient with skeletal Class II and severe maxillary arch crowding, moderate mandibular arch crowding, anterior crossbite, and a missing lower incisor. He was treated with molar distalization using a modified C-palatal plate and temporary anchorage devices to create sufficient space for retraction. The total treatment duration was 21 months. After treatment, his occlusion and smile esthetics showed significant improvement. The modified C-palatal plate represents a treatment modality that enhances the prospects of non-extraction treatment and reduces the need for extraction.

      Abstract  
    • Original Article l 2019-11-25

      Predictors of midpalatal suture expansion by miniscrew-assisted rapid palatal expansion in young adults: A preliminary study

      Hyerin Shin, Chung-Ju Hwang, Kee-Joon Lee, Yoon Jeong Choi, Sang-Sun Han, and Hyung Seog Yu

      Abstract : ObjectiveWe sought to determine the predictors of midpalatal suture expansion by miniscrew-assisted rapid palatal expansion (MARPE) in young adults.MethodsThe following variables were selected as possible predictors: chronological age, palate length and depth, midpalatal suture maturation (MPSM) stage, midpalatal suture density (MPSD) ratio, the sella-nasion (SN)-mandibular plane (MP) angle as an indicator of the vertical skeletal pattern, and the point A-nasion-point B (ANB) angle for anteroposterior skeletal classification. For 31 patients (mean age, 22.52 years) who underwent MARPE treatment, palate length and depth, MPSM stage and MPSD ratio from the initial cone-beam computed tomography images, and the SN-MP angle and ANB angle from lateral cephalograms were assessed. The midpalatal suture opening ratio was calculated from the midpalatal suture opening width measured in periapical radiographs and the MARPE screw expansion. Statistical analyses of correlations were performed for the entire patient group of 31 subjects and subgroups categorized by sex, vertical skeletal pattern, and anteroposterior skeletal classification.ResultsIn the entire patient group, the midpalatal suture opening ratio showed statistically significant negative correlations with age, palate length, and MPSM stage (r = −0.506, −0.494, and −0.746, respectively, all p < 0.01). In subgroup analyses, a strong negative correlation was observed with the palate depth in the skeletal Class II subgroup (r = −0.900, p < 0.05).ConclusionsThe findings of this study indicated that age, palate length, and MPSM stage can be predictors of midpalatal suture expansion by MARPE in young adults.

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    • Case Report l 2019-03-25

      Sequential traction of a labio-palatal horizontally impacted maxillary canine with a custom three-directional force device in the space of a missing ipsilateral first premolar

      Shuliang Yang, Xiao Yang, Anting Jin, Nayong Ha, Qinggang Dai, Siru Zhou, Yiling Yang, Xinyi Gong, Yueyang Hong, Qinfeng Ding, and Lingyong Jiang

      Abstract : Orthodontic treatment is more complicated when both soft and hard tissues must be considered because an impacted maxillary canine has important effects on function and esthetics. Compared with extraction of impacted maxillary canines, exposure followed by orthodontic traction can improve esthetics and better protect the patient's teeth and alveolar bone. Therefore, in order to achieve desirable tooth movement with minimal unexpected complications, a precise diagnosis is indispensable to establish an effective and efficient force system. In this report, we describe the case of a 31-year-old patient who had a labio-palatal horizontally impacted maxillary left canine with a severe occlusal alveolar bone defect and a missing maxillary left first premolar. Herein, with the aid of three-dimensional imaging, sequential traction was performed with a three-directional force device that finally achieved acceptable occlusion by bringing the horizontally impacted maxillary left canine into alignment. The maxillary left canine had normal gingival contours and was surrounded by a substantial amount of regenerated alveolar bone. The 1-year follow-up stability assessment demonstrated that the esthetic and functional outcomes were successful.

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Journal Info.

January, 2021
Vol.51 No.1

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