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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 2019-07-25

      Maxillomandibular advancement surgery after long-term use of a mandibular advancement device in a post-adolescent patient with obstructive sleep apnea

      Keun-Ha Lee , Kyung-A Kim, Yong-Dae Kwon, Sung-Wan Kim, and Su-Jung Kim

      Abstract : Patients with obstructive sleep apnea (OSA) whose phenotype belongs to a craniofacial vulnerability are referred from sleep doctors to orthodontists. In adults, for osseo-pharyngeal reconstruction (OPR) treatment, permanent maxillomandibular advancement (MMA) surgery and use of a temporary mandibular advancement device (MAD) are applied. This case report demonstrates successful treatment of OSA through application of phased MAD and MMA in a 16-year-old male with craniofacial deformity and residual growth potential. This patient showed skeletal and dentoalveolar changes after 7-year MAD use throughout post-adolescence, which affected the design and timing of subsequent MMA surgery, as well as post-surgical orthodontic strategy. This case report suggests that OPR treatment can be useful for treatment of OSA in post-adolescent patients, from an orthodontic point of view, in close collaboration with sleep doctors for interdisciplinary diagnosis and treatment.

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    • Original Article l 2019-07-25

      Three-dimensional changes in lip vermilion morphology of adult female patients after extraction and non-extraction orthodontic treatment

      Zhi-Yu Liu , Jie Yu, Fan-Fan Dai, Ruo-Ping Jiang , and Tian-Min Xu

      Abstract : ObjectiveTo investigate the three-dimensional lip vermilion changes after extraction and non-extraction orthodontic treatment in female adult patients and explore the correlation between lip vermilion changes and incisor changes.MethodsForty-seven young female adult patients were enrolled in this study (skeletal Class III patients were excluded), including 34 lip-protruding patients treated by extraction of four first premolars (18 patients requiring mini-implants for maximum anchorage control and 16 patients without mini-implants) and 13 patients requiring non-extraction treatment. Nine angles, seven distances, and the surface area of the lip vermilion were measured by using pre- and post-treatment three-dimensional facial scans. Linear and angular measurements of incisors were performed on lateral cephalograms.ResultsThere were no significant changes in the vermilion measurements in the non-extraction group. The vermilion angle, vermilion height, central bow angle, height/width ratio, and vermilion surface area decreased significantly after the orthodontic treatment in the extraction groups, but the upper/lower vermilion proportion remained unchanged. Significant correlations were found between the changes in incisor position and those in vermilion angles, vermilion height, and surface area.ConclusionsExtraction of the four first premolars probably produced an aesthetic improvement in lip vermilion morphology. However, the upper/lower vermilion proportion remained unchanged. The variations in the vermilion were closely related to incisor changes, especially the upper incisor inclination changes.

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    • Case Report l 2019-11-25

      Longitudinal management of recurrent temporomandibular joint ankylosis from infancy to adulthood in perspective of surgical and orthodontic treatment

      Seung-Weon Lim, Jin-Young Choi, and Seung-Hak Baek

      Abstract : This study was performed to describe the longitudinal management of recurrent temporomandibular joint (TMJ) ankylosis from infancy to adulthood in perspective of surgical and orthodontic treatment. A 2-year-old girl was referred with chief complaints of restricted mouth opening and micrognathia due to bilateral TMJ ankylosis. For stage I treatment during early childhood (6 years old), high condylectomy and interpositional arthroplasty were performed. However, TMJ ankylosis recurred and symptoms of obstructive sleep apnea (OSA) developed. For stage II treatment during early adolescence (12 years old), gap arthroplasty, coronoidectomy, bilateral mandibular distraction osteogenesis, and orthodontic treatment with extraction of the four first premolars were performed. However, TMJ ankylosis recurred. Because the OSA symptoms reappeared, she began to use a continuous positive airway pressure device. For stage III treatment after completion of growth (20 years old), low condylectomy, coronoidectomy, reconstruction of the bilateral TMJs with artificial prostheses along with counterclockwise rotational advancement of the mandible, genioglossus advancement, and orthodontic treatment were performed. After stage III treatment, the amount of mouth opening exhibited a significant increase. Mandibular advancement and ramus lengthening resulted in significant improvement in the facial profile, Class I relationships, and normal overbite/overjet. The OSA symptoms were also relieved. These outcomes were stable at the one-year follow-up visit. Since the treatment modalities for TMJ ankylosis differ according to the duration of ankylosis, patient age, and degree of deformity, the treatment flowchart suggested in this report could be used as an effective guideline for determining the appropriate timing and methods for the treatment of TMJ ankylosis.

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    • Original Article l 2020-01-25

      Accuracy and reliability of measurements performed using two different software programs on digital models generated using laser and computed tomography plaster model scanners

      Leonardo T. Camardella, Edwin M. Ongkosuwito, E. Willemijn Penning, Anne Marie Kuijpers-Jagtman, Oswaldo V. Vilella, and K. Hero Breuning

      Abstract : ObjectiveThe aim of this study was to compare the accuracy and reliability of measurements performed using two different software programs on digital models generated using two types of plaster model scanners (a laser scanner and a computed tomography [CT] scanner).MethodsThirty plaster models were scanned with a 3Shape laser scanner and with a Flash CT scanner. Two examiners performed measurements on plaster models by using digital calipers and on digital models by using Ortho Analyzer (3Shape) and Digimodel® (OrthoProof) software programs. Forty-two measurements, including tooth diameter, crown height, overjet, overbite, intercanine and intermolar distances, and sagittal relationship, were obtained.ResultsStatistically significant differences were not found between the plaster and digital model measurements (ANOVA); however, some discrepancies were clinically relevant. Plaster and digital model measurements made using the two scanning methods showed high intraclass coefficient correlation values and acceptable 95% limits of agreement in the Bland-Altman analysis. The software used did not influence the accuracy of measurements.ConclusionsDigital models generated from plaster casts by using laser and CT scanning and measured using two different software programs are accurate, and the measurements are reliable. Therefore, both fabrication methods and software could be used interchangeably.

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    • Original Article l 2019-05-25

      Cone-beam computed tomography-guided three-dimensional evaluation of treatment effectiveness of the Frog appliance

      Mujia Li , Xiaoxia Su , Yang Li, Xianglin Li, and Xinqin Si

      Abstract : ObjectiveTo evaluate the effectiveness of the Frog appliance in three dimensions by using cone-beam computed tomography (CBCT) images.MethodsForty patients (21 boys and 19 girls), averaged 11.7 years old, with an Angle Class II division 1 malocclusion were included in our study. They had either late mixed dentition or early permanent dentition, and the maxillary second molars had not yet erupted. All patients underwent CBCT before and after the treatment for measuring changes in the maxillary first molars, second premolars, central incisors, and profile. Paired-samples t-test was used to compare the mean difference in each variable before treatment and after the first phase of treatment.ResultsThe maxillary first molars were effectively distalized by 4.25 mm (p < 0.001) and 3.53 mm (p < 0.05) in the dental crown and root apex, respectively. The tipping increased by 2.25°, but the difference was not significant. Moreover the teeth moved buccally by 0.84 mm (p < 0.05) and 2.87 mm (p < 0.01) in the mesiobuccal and distobuccal cusps, respectively, whereas no significant changes occurred in the root apex. Regarding the anchorage parts, the angle of the maxillary central incisor's long axis to the sella-nasion plane increased by 2.76° (p < 0.05) and the distance from the upper lip to the esthetic plane decreased by 0.52 mm (p = 0.01).ConclusionsThe Frog appliance effectively distalized the maxillary molars with an acceptable degree of tipping, distobuccal rotation, and buccal crown torque, with only slight anchorage loss. Furthermore, CBCT image demonstrated that it is a simple and reliable method for three-dimensional analysis.

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    • Original Article l 2021-03-25

      Reasons influencing the preferences of prospective patients and orthodontists for different orthodontic appliances

      Guido Artemio Marañón-Vásquez , Luísa Schubach da Costa Barreto, Matheus Melo Pithon, Lincoln Issamu Nojima, Matilde da Cunha Gonçalves Nojima, Mônica Tirre de Souza Araújo, Margareth Maria Gomes de Souza

      Abstract : Objective: To evaluate the reasons influencing the preferences for a certain type of orthodontic appliance over another among prospective patients (PP) and orthodontists. Methods: A total of 49 PP and 51 orthodontists were asked about their preferences for the following appliances: clear aligners (CA), lingual metallic brackets (LMB), polycrystalline and monocrystalline ceramic brackets, and buccal metallic brackets (BMB). The participants rated the importance of 17 potential reasons that would explain their choices. The reasons that contributed most to these preferences were identified. Non-parametric tests (Fisher’s exact, χ2 and Mann–Whitney tests) and multivariate analyses (regression and discriminant analysis) were used to assess the data (α = 0.05). Results: CA and BMB were the most chosen appliances by PP and orthodontists, respectively. LMB was the most rejected option among both groups of participants (p < 0.001). Rates of the importance of pain/discomfort, smile esthetics, finishing details, and feeding/speech impairment showed the highest differences between PP and orthodontists (p < 0.0005). Discriminant analyses showed that individuals who considered treatment time and smile esthetics as more important were more likely to prefer CA, while those who prioritized finishing details and cost were more likely to choose BMB (p < 0.05). Conclusions: Reasons related to comfort and quality of life during use were considered as more important by PP, while those related to the results and clinical performance of the appliances were considered as more relevant by orthodontists.

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    • Original Article l 2019-09-25

      Effects of pre-applied orthodontic force on the regeneration of periodontal tissues in tooth replantation

      Won-Young Park , Min Soo Kim, Min-Seok Kim, Min-Hee Oh, Su-Young Lee, Sun-Hun Kim, and Jin-Hyoung Cho

      Abstract : ObjectiveThis study aimed to investigate the effect of pre-applied orthodontic force on the regeneration of periodontal ligament (PDL) tissues and the underlying mechanisms in tooth replantation.MethodsOrthodontic force (50 cN) was applied to the left maxillary first molars of 7-week-old male Sprague–Dawley rats (n = 32); the right maxillary first molars were left untreated to serve as the control group. After 7 days, the first molars on both sides were fully luxated and were immediately replanted in their original sockets. To verify the effects of the pre-applied orthodontic force, we assessed gene expression by using microarray analysis and real-time reverse transcription polymerase chain reaction (RT-PCR), cell proliferation by using proliferating cell nuclear antigen (PCNA) immunofluorescence staining, and morphological changes by using histological analysis.ResultsApplication of orthodontic force for 7 days led to the proliferation of PDL tissues, as verified on microarray analysis and PCNA staining. Histological analysis after replantation revealed less root resorption, a better arrangement of PDL fibers, and earlier regeneration of periodontal tissues in the experimental group than in the control group. For the key genes involved in periodontal tissue remodeling, including CXCL2, CCL4, CCL7, MMP3, PCNA, OPG, and RUNX2, quantitative RT-PCR confirmed that messenger RNA levels were higher at 1 or 2 weeks in the experimental group.ConclusionsThese results suggest that the application of orthodontic force prior to tooth replantation enhanced the proliferation and activities of PDL cells and may lead to higher success rates with fewer complications.

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    • Original Article l 2019-11-25

      Effect of archwire stiffness and friction on maxillary posterior segment displacement during anterior segment retraction: A three-dimensional finite element analysis

      Choon-Soo Park, Hyung-Seog Yu, Jung-Yul Cha, Sung-Seo Mo, and Kee-Joon Lee

      Abstract : ObjectiveSliding mechanics using orthodontic miniscrews is widely used to stabilize the anchorage during extraction space closure. However, previous studies have reported that both posterior segment displacement and anterior segment displacement are possible, depending on the mechanical properties of the archwire. The present study aimed to investigate the effect of archwire stiffness and friction change on the displacement pattern of the maxillary posterior segment during anterior segment retraction with orthodontic miniscrews in sliding mechanics.MethodsA three-dimensional finite element model was constructed. The retraction point was set at the archwire level between the lateral incisor and canine, and the orthodontic miniscrew was located at a height of 8 mm from the archwire between the second premolar and first molar. Archwire stiffness was simulated with rectangular stainless steel wires and a rigid body was used as a control. Various friction levels were set for the surface contact model. Displacement patterns for the posterior and anterior segments were compared between the conditions.ResultsBoth the anterior and posterior segments exhibited backward rotation, regardless of archwire stiffness or friction. Among the conditions tested in this study, the least undesirable rotation was found with low archwire stiffness and low friction.ConclusionsPosterior segment displacement may be unavoidable but reducing the stiffness and friction of the main archwire may minimize unwanted rotations during extraction space closure.

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    • Original Article l 2020-01-25

      Distribution and phenotypes of hemifacial microsomia and its association with other anomalies

      Il-Hyung Yang, Jee Hyeok Chung, Sunjin Yim, Il-Sik Cho, Seung-Weon Lim, Kikap Kim, Sukwha Kim, Jin-Young Choi, Jong-Ho Lee, Myung-Jin Kim, and Seung-Hak Baek

      Abstract : ObjectiveTo investigate the distribution and phenotypes of hemifacial microsomia (HFM) and its association with other anomalies.MethodsThis study included 249 Korean patients with HFM, whose charts, photographs, radiographs, and/or computed tomography scans acquired during 1998–2018 were available from Seoul National University Hospital and Dental Hospital. Prevalence according to sex, side involvement, degree of mandibular deformity, compensatory growth of the mandibular body, and Angle's classification, and its association with other anomalies were statistically analyzed.ResultsPrevalence was not different between male and female patients (55.0% vs. 45.0%, p > 0.05). Unilateral HFM (UHFM) was more prevalent than bilateral HFM (BHFM) (86.3% vs. 13.7%, p < 0.001). Although distribution of the Pruzansky–Kaban types differed significantly in patients with UHFM (I, 53.0%; IIa, 18.6%; IIb, 24.7%; III, 3.7%; p < 0.001), no difference was observed in occurrence between the right and left sides (52.6% vs. 47.4%, p > 0.05). Among patients with BHFM, prevalence of different Pruzansky–Kaban types on the right and left sides was greater than that of the same type on both sides (67.6% vs. 32.4%, p < 0.05). Despite hypoplasia of the condyle/ramus complex, compensatory growth of the mandibular body on the ipsilateral side occurred in 35 patients (14.1%). Class I and II molar relationships were more prevalent than Class III molar relationships (93.2% vs. 6.8%, p < 0.001). Forty-eight patients (19.3%) had other anomalies, with 50.0% and 14.4% in the BHFM and UHFM groups (p < 0.001).ConclusionsPatients with HFM require individualized diagnosis and treatment planning because of diverse phenotypes and associations with other anomalies.

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    • Original Article l 2019-05-25

      Palatal en-masse retraction of segmented maxillary anterior teeth: A finite element study

      Jae Hyun Park , Yoon-Ah Kook, Yukio Kojima, Sunock Yun, and Jong-Moon Chae

      Abstract : ObjectiveThe aim of this finite element study was to clarify the mechanics of tooth movement in palatal en-masse retraction of segmented maxillary anterior teeth by using anchor screws and lever arms.MethodsA three-dimensional finite element method was used to simulate overall orthodontic tooth movements. The line of action of the force was varied by changing both the lever arm height and anchor screw position.ResultsWhen the line of action of the force passed through the center of resistance (CR), the anterior teeth showed translation. However, when the line of action was not perpendicular to the long axis of the anterior teeth, the anterior teeth moved bodily with an unexpected intrusion even though the force was transmitted horizontally. To move the anterior teeth bodily without intrusion and extrusion, a downward force passing through the CR was necessary. When the line of action of the force passed apical to the CR, the anterior teeth tipped counterclockwise during retraction, and when the line of action of the force passed coronal to the CR, the anterior teeth tipped clockwise during retraction.ConclusionsThe movement pattern of the anterior teeth changed depending on the combination of lever arm height and anchor screw position. However, this pattern may be unpredictable in clinical settings because the movement direction is not always equal to the force direction.

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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