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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 2021-07-25

      Effect of nicotine on orthodontic tooth movement and bone remodeling in rats

      Sung-Hee Lee , Jung-Yul Cha, Sung-Hwan Choi, Baek-il Kim, Jae-Kook Cha, Chung-Ju Hwang

      Abstract : Objective: To quantitatively analyze the effect of nicotine on orthodontic tooth movement (OTM) and bone remodeling in rats using micro-computed tomography and tartrate-resistant acid phosphatase immunostaining. Methods: Thirty-nine adult male Sprague–Dawley rats were randomized into three groups: group A, 0.5 mL normal saline (n = 9, 3 per 3, 7, and 14 days); group B, 0.83 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days); and group C, 1.67 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days). Each animal received daily intraperitoneal injections of nicotine/saline from the day of insertion of identical 30-g orthodontic force delivery systems. A 5-mm nickel-titanium closed-coil spring was applied between the left maxillary first molar (M1) and the two splinted incisors. The rate of OTM and volumetric bone changes were measured using micro-computed tomography. Osteoclasts were counted on the mesial alveolar bone surface of the distobuccal root of M1. Six dependent outcome variables, including the intermolar distance, bone volume fraction, bone mineral density, trabecular thickness, trabecular volume, and osteoclast number, were summarized using simple descriptive statistics. Nonparametric Kruskal–Wallis tests were used to evaluate differences among groups at 3, 7, and 14 days of OTM. Results: All six dependent outcome variables showed no statistically significant among group-differences at 3, 7, and 14 days. Conclusions: The findings of this study suggest that nicotine does not affect OTM and bone remodeling, although fluctuations during the different stages of OTM in the nicotine groups should be elucidated in further prospective studies.

      Abstract  
    • 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 2021-01-15

      Cephalometric Predictors of Future need for Orthognathic Surgery in Korean Patients with Unilateral Cleft Lip and Palate Despite Long-term Use of Facemask with Miniplate

      Sang-Hun Yu , Seung-Hak Baek, Jin-Young Choi, Jong-Ho Lee, Sukwha Kim, Sung-Woon On

      Abstract : Objective: To investigate the cephalometric predictors of the future need for orthognathic surgery in Korean patients with unilateral cleft lip and palate (UCLP) despite long-term use of facemask with miniplate (FMMP). Methods: The sample consisted of 53 UCLP patients treated by a single orthodontist using an identical protocol. Lateral cephalograms were taken before commencement of FMMP therapy (T0; mean age, 10.45 years), after FMMP therapy (T1; mean age, 14.72 years), and at follow-up (T2; mean age, 18.68 years). Twenty-eight cephalometric variables were measured. At T2 stage, the subjects were divided into FMMP-Nonsurgery (n = 33, 62.3%) and FMMP-Surgery (n = 20, 37.7%) groups according to cephalometric criteria (point A-nasion-point B [ANB] < –3°; Wits-appraisal < –5 mm; and Harvold unit difference [HUD] > 34 mm for FMMP-Surgery group). Statistical analyses including discrimination analysis were performed. Results: In FMMP-Surgery group, the forward position of the mandible at T0 stage was maintained throughout the whole stages and Class III relationship worsened with significant growth of the mandibular body and ramus and counterclockwise rotation of the maxilla and mandible at the T1 and T2 stages. Six cephalometric variables at T0 stage including ANB, anteroposterior dysplasia indicator, Wits-appraisal, mandibular body length, HUD, and overjet were selected as effective predictors of the future need for surgical intervention to correct sagittal skeletal discrepancies. Conclusions: Despite long-term use of FMMP therapy, 37.7% of UCLP patients became candidates for orthognathic surgery. Therefore, differential diagnosis is necessary to predict the future need for orthognathic surgery at early age.

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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 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.

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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.

      Abstract  
    • Original Article l 2021-11-25

      Miniscrew insertion sites of infrazygomatic crest and mandibular buccal shelf in different vertical craniofacial patterns: A cone-beam computed tomography study

      Murilo Matias , Carlos Flores-Mir, Márcio Rodrigues de Almeida, Bruno da Silva Vieira, Karina Maria Salvatore de Freitas, Daniela Calabrese Nunes, Marcos Cezar Ferreira, Weber Ursi

      Abstract : Objective: To identify optimal areas for the insertion of extra-alveolar miniscrews into the infrazygomatic crest (IZC) and mandibular buccal shelf (MBS), using cone beam computed tomography (CBCT) imaging in patients with different craniofacial patterns. Methods: CBCT reconstructions of untreated individuals were used to evaluate the IZC and MBS areas. The participants were divided into three groups, based on the craniofacial pattern, namely, brachyfacial (n = 15; mean age, 23.3 years), mesofacial (n = 15; mean age, 19.24 years), and dolichofacial (n = 15; mean age, 17.79 years). In the IZC, the evaluated areas were at 11, 13, and 15 mm above the buccal cusp tips of the right and left first molars. In the MBS, the evaluated areas were at the projections of the first molars’ distal roots and second molars’ mesial and distal roots, at a 4- and 8-mm distance from the cementoenamel junction. Intergroup comparisons were performed with analysis of variance and the Tukey test. Results: There was no statistically significant difference in the IZC bone thickness among the groups. For MBS bone availability, some comparisons revealed no difference; meanwhile, other comparisons revealed increased MBS bone thickness in the brachyfacial (first molars distal roots) and dolichofacial (second molars mesial and distal roots) patterns. Conclusions: There was no significant difference in the IZC bone thickness among the groups. The facial skeletal pattern may affect the availability of ideal bone thickness for the insertion of extra-alveolar miniscrews in the MBS region; however, this variability is unlikely to be clinically meaningful.

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    • Original Article l 2021-09-25

      Comparison of the effects of horizontal and vertical micro-osteoperforations on the biological response and tooth movement in rabbits

      Seok-gon Kim , Yoon-Ah Kook , Hee Jin Lim, Patrick Park, Won Lee, Jae Hyun Park, Mohamed Bayome, Yoonji Kim

      Abstract : Objective: This study aimed to compare the amount of tooth movement after multiple horizontal (MH) and single vertical (SV) micro-osteoperforations (MOPs), and evaluate the histological changes after orthodontic force application in rabbits. Methods: The mandibles of 24 white rabbits were subjected to two experimental interventions: MH and SV MOPs. Defect volume of the MOPs between the two groups was kept similar. A force of 100 cN was applied via a coil spring between the incisor teeth and the first premolars. The amount of tooth movement was measured. Differences in the amount of tooth movement and bone variables at three time points and between the two groups were evaluated using repeated-measures analysis of variance. Results: The first premolar showed a mesial movement of 1.47 mm in the MH group and 1.84 mm in the SV group, which was significantly different at Week 3 (p < 0.05). No significant difference was observed in bone volume and bone fraction between the groups. Tartrate-resistant acidic phosphatase-positive cell count was also significantly greater at Week 3 than at Week 1 in both the SV and MH groups. Conclusions: The amount of tooth movement showed significant differences between Weeks 1 and 3 in the SV and MH MOP groups, but showed no differences between the two groups. Therefore, SV MOP could be considered an effective tool for enhancing tooth movement, especially for molar distalization, uprighting, and protraction to an edentulous area.

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Journal Info.

November, 2021
Vol.51 No.6

Frequency: 6 times

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  • 1.372
    2020 IF

  • 1.737
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Clinical Journal of Korean Association of Orthodontists