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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 2021-01-25

      Evaluation of mandibular buccal shelf characteristics in the Colombian population: A cone-beam computed tomography study

      Natalia Escobar-Correa , Maria Antonia Ramírez-Bustamante, Luis Alejandro Sánchez-Uribe, Juan Carlos Upegui-Zea, Patricia Vergara-Villarreal, Diana Milena Ramírez-Ossa

      Abstract : Objective: To evaluate the mandibular buccal shelf (MBS) in terms of the angulation and bone depth and thickness according to sex, age, and sagittal and vertical skeletal patterns in a Colombian population using cone-beam computed tomography (CBCT). Accordingly, the optimal site for miniscrew insertion in this area was determined. Methods: This descriptive, retrospective study included 64 hemi-arches of 34 patients. On CBCT images, the angulation, buccal bone depth (4 and 6 mm from the cementoenamel junction [CEJ] of MBS), and buccal bone thickness (6 and 11 mm from the CEJ of MBS) were measured at the mesial and distal roots of the mandibular first and second molars. Results: There were no statistically significant differences in the angulation, depth, and thickness of MBS between male and female patients. The values for the bone around the distal root of the mandibular second molar were significantly greater than the other values. The osseous characteristics were significantly better in participants aged 16–24 years. Class III patients exhibited the best osseous characteristics, with the bone depth at 6 mm being significantly different from that in Class I and Class II patients. Although values tended to be greater in patients with low angles, the difference was not statistically significant. Conclusions: MBS provides an optimal bone surface for miniscrew insertion, with better osseous characteristics at the distal root of the mandibular second molar, 4 mm from CEJ. Adolescent patients, Class III patients, and patients with a low angle exhibit the most favorable osseous characteristics in the MBS area.

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    • Original Article l 2021-07-25

      Quantitative cone-beam computed tomography evaluation of hard and soft tissue thicknesses in the midpalatal suture region to facilitate orthodontic mini-implant placement

      Song-Hee Oh , Sae Rom Lee , Jin-Young Choi, Seong-Hun Kim , Eui-Hwan Hwang, Gerald Nelson

      Abstract : Objective: To identify the most favorable sites that optimize the initial stability and survival rate of orthodontic mini-implants, this study measured hard and soft tissue thicknesses in the median and paramedian regions of the palate using cone-beam computed tomography (CBCT) and determined possible sexand age-related differences in these thicknesses. Methods: The study sample comprised CBCT images of 189 healthy subjects. The sample was divided into four groups according to age. A grid area was set for the measurement of hard and soft tissue thicknesses in the palate. Vertical lines were marked at intervals of 0, 1.5, and 3.0 mm lateral to the midpalatal suture, while horizontal lines were marked at 2-mm intervals up to 24 mm from the posterior margin of the incisive foramen. Measurements were made at 65 points of intersection between the horizontal and vertical lines. Results: The palatal hard tissue thickness decreased from the anterior to the posterior region, with a decrease in the medial-to-lateral direction in the middle and posterior regions. While the soft tissue was rather thick around the lateral aspects of the palatal arch, it formed a constant layer that was only 1–2-mm thick throughout the palate. Statistically significant differences were observed according to sex and age. Conclusions: The anterolateral palate as well as the midpalatal suture seem to be the most favorable sites for insertion of orthodontic mini-implants. The thickness of the palate differed by age and sex; these differences should be considered while planning the placement of orthodontic mini-implants.

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    • Original Article l 2021-01-25

      Part II. What drives Korean adults to seek orthodontic treatment: Factors contributing to orthodontic treatment decisions

      Min-Hee Oh , Ae-Hyun Park , MinSoo Kim, Eun-A Kim, Jin-Hyoung Cho

      Abstract : Objective: This study aimed to identify the perceptions of orthodontic treatment among Korean adults and determine the factors that drive them to seek orthodontic treatment. Methods: A total of 2,321 adults aged 19–64 years were surveyed using an internet research system from a specialized research company. The participants were divided into the following groups based on their experience of and willingness to undergo orthodontic treatment: experience, acceptance, and non-acceptance groups. The characteristics of the participants were compared using analysis of variance with post-hoc analysis. Multinomial logistic regression analysis was performed in all three models with the non-acceptance group as a reference. Results: In terms of demographic characteristics, age, gender, marital status, and education had significant influences on orthodontic treatment decisions in adults in the experience and acceptance groups (p < 0.001). When all the factors were analyzed, age, marital status, past dental treatment experience, regular oral examinations, demand for orthodontic treatment, optimal treatment period, health insurance coverage, information on orthodontic treatments, perceptions regarding orthodontic treatment, and psychosocial impact of dental esthetics significantly influenced orthodontic treatment decisions in adults in the experience and acceptance groups (p < 0.001). Conclusions: These findings suggest that various factors influence orthodontic treatment decisions in adults. Individuals who seek orthodontic treatment were found to undergo more regular dental treatment and oral examination than those who did not. They also had a better perception of orthodontic treatment and more negative values for the psychosocial impact of dental esthetics.

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    • Original Article l 2020-11-25

      Comparison of slot sizes and parallelism of metal brackets manufactured through metal injection molding and computerized numerical control

      Jae-Sung Park , In-Tae Song, Jae-Hee Bae, Soo-Min Gil, Kyung-Hwa Kang

      Abstract : Objective: To investigate and compare the slot sizes and parallelism of metal injection molding (MIM) and computerized numerical control (CNC) brackets. Methods: The following four MIM bracket series with 0.022-inch (in) slots were selected for investigation: Di MIM mini Twin (Ortho Organizers), Mini Diamond Roth (Ormco), Gemini MBT (3M Unitek), and Formula R Roth (Tomy). The following four CNC bracket series with 0.022-in slots were selected for investigation: Econoline MBT (Adenta), Legend mini MBT (GC Orthodontics), Crown mini MBT (Adenta), and Evolve MBT (DB Orthodontics). The slot dimensions were measured using an optical microscope (XTCam-D310M; Mitutoyo) with a resolution of 1 μm. The results were statistically analyzed using one-way analysis of variance and the Tukey post-hoc test with a significance level of 0.05. Results: The results indicated that all the investigated slot sizes were oversized with respect to the manufacturers’ specifications (0.022 in). Among the eight bracket series, the Di MIM bracket (MIM) was the most oversized by 10.4%, whereas the Evolve bracket (CNC) was the least oversized by 2.6%. The slots in seven of the bracket series had divergent walls instead of parallel ones. The Evolve bracket alone had parallel slot walls. Conclusions: Regardless of the manufacturing method, all the slot sizes of the brackets investigated in this study were significantly oversized; most of the slot walls were nonparallel, except for those of the Evolve bracket. This study could not establish that the CNC method was more accurate than the MIM method in manufacturing bracket slots.

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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 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 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.

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    • Original Article l 2021-01-25

      The global distribution of permanent canine hypodontia: A systematic review

      Saritha Sivarajan , Shani Ann Mani, Jacob John, Mona M. Salah Fayed, Yoon-Ah Kook, Mang Chek Wey

      Abstract : Objective: To systematically review studies on canine agenesis prevalence in different populations and continents, based on the jaw, sex, location, and associated dental anomalies. Methods: Electronic and hand searches of English literature in PubMed, Web of Science, Scopus, OpenGrey, and Science Direct were conducted, and the authors were contacted when necessary. Observational studies (population-based, hospital/clinic-based, and cross-sectional) were included. For study appraisal and synthesis, duplicate selection was performed independently by two reviewers. Study quality was assessed using a modified Strengthening the Reporting of Observational Studies in Epidemiology checklist, with main outcome of prevalence of canine agenesis. Results: The global population prevalence of canine agenesis was 0.30% (0.0−4.7%), highest in Asia (0.54%), followed by Africa (0.33%), and the least in Europe and South America (0.19% in both continents). Canine agenesis was more common in the maxilla (88.57%), followed by both maxilla and mandible (8.57%), and the least common was mandible-only presentation (2.86%). The condition was more common in females (female:male ratio = 1.23), except in Asia (female:male ratio = 0.88) and Africa (female:male ratio = 1). In Asia, unilateral agenesis was almost twice as prevalent as bilateral, but in Europe, the bilateral form was more common. Conclusions: The overall prevalence of canine agenesis is 0.30%, with the highest prevalence in Asia, followed by Africa, Europe, and South America. The condition is more common in the maxilla than the mandible, and in females than males (except in Asia and Africa), with unilateral agenesis being more common in Asia and the bilateral form showing a greater prevalence in Europe.

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    • Original Article l 2020-03-25

      Immediate effects of mandibular posterior displacement on the pharyngeal airway space: A preliminary study

      Yeonju Choi , Yong-Il Kim, Seong-Sik Kim, Soo-Byung Park, Woo-Sung Son and Sung-Hun Kim

      Abstract : ObjectiveThis study aimed to evaluate the immediate effects of mandibular posterior displacement on the pharyngeal airway space (PAS) by using cephalometric evaluations and to investigate how the surrounding structures are schematically involved.MethodsIn this retrospective study, 38 subjects with functional Class III malocclusion and two lateral cephalograms were selected. The first lateral cephalogram was taken with the mandible in the habitual occlusal position, and the second in anterior edge-to-edge bite. Paired t-test was used to analyze changes in the PAS, hyoid bone, tongue, and soft palate, followed by mandibular posterior displacement. Pearson's correlation analysis was used to determine the relationship between the amount of mandibular posterior displacement and other variables.ResultsA statistically significant decrease was observed in the PAS following mandibular posterior displacement. Along with mandibular posterior displacement, the tongue decreased in length (p < 0.001) and increased in height (p < 0.05), while the soft palate increased in length, decreased in thickness, and was posteriorly displaced (p < 0.001). The hyoid bone was also posteriorly displaced (p < 0.05). There was no correlation between the amount of mandibular posterior displacement and the measured variables.ConclusionsThe PAS showed a statistically significant decrease following mandibular posterior displacement, which was a consequence of retraction of the surrounding structures. However, there were individual variances between the amount of mandibular posterior displacement and the measured variables.

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Journal Info.

November, 2021
Vol.51 No.6

Frequency: 6 times

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Journal Impact Factor

  • 1.372
    2020 IF

  • 1.737
    5-Year IF

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Clinical Journal of Korean Association of Orthodontists