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KJO Korean Journal of Orthodontics

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pISSN 2234-7518
eISSN 2005-372X
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    • Reader's Forum l 2022-01-25

      READER’S FORUM

      Jin-Young Choi, Song Hee Oh, and Seong-Hun Kim
    • Original Article l 2021-09-25

      External apical root resorption 6 months after initiation of orthodontic treatment: A randomized clinical trial comparing fixed appliances and orthodontic aligners

      Katia Cristina Toyokawa-Sperandio , Ana Cl?udia de Castro Ferreira Conti, Thais Maria Freire Fernandes, Renata Rodrigues de Almeida-Pedrin, Marcio Rodrigues de Almeida, Paula Vanessa Pedron Oltramari

      Abstract : Objective: To compare the magnitude of external apical root resorption (EARR) 6 months after starting orthodontic treatment using orthodontic aligners (OAs) and fixed appliances (FAs). Methods: This parallel randomized clinical trial included 40 patients randomized into two groups: OA group (n = 20, 160 incisors) and FA group (n = 20, 160 incisors). For evaluation of the tooth length, periapical radiographs and standardized linear measurements of the maxillary and mandibular incisors were acquired before (T0) and 6 months after treatment initiation (T1). EARR was calculated through the difference in length between the two time points (T1?T0). Statistical comparisons were performed by means of using t-tests, chi-squared test and covariance analysis (a = 5%). Results: Rounding of the root apex was observed in both groups; the resorption involved 2.88% of the root length, so 97.12% of the tooth length remained intact. Intragroup comparisons between the two time points revealed a significant difference, with (T1?T0) ranging from ?0.52 to ?0.88 mm in the FA group and from ?0.52 to ?0.85 mm in the OA group. In the intergroup comparisons, only tooth #21 presented a statistically significant difference (OA: ?0.52 ± 0.57 mm, FA: ?0.86 ± 0.60 mm); however, the overall differences between groups were not clinically relevant, ranging from 0.03 to 0.35 mm. Conclusions: OA and FA treatment resulted in a similar degree of EARR in the maxillary and mandibular incisors at 6 months after treatment initiation. However, the amount of resorption was small and does not impair tooth longevity.

      Abstract  
    • Original Article l 2021-09-25

      Effectiveness of low-level laser therapy and chewing gum in reducing orthodontic pain: A randomized controlled trial

      Fatih Celebi , Ali Altug Bicakci, Ufuk Kelesoglu

      Abstract : Objective: The purpose of this study was to evaluate the effects of chewing gum and low-level laser therapy in alleviating orthodontic pain induced by the initial archwire. Methods: Patients with 3?6 mm maxillary crowding who planned to receive non-extraction orthodontic treatment were recruited for the study. Sixty-three participants (33 females and 30 males) were randomly allocated into three groups: laser, chewing gum, and control. In the laser group, a gallium aluminum arsenide (GaAlAs) diode laser with a wavelength of 820 nm was used to apply a single dose immediately after orthodontic treatment began. In the chewing gum group, sugar-free gum was chewed three times for 20 minutes? immediately after starting treatment, and at the twenty-fourth and forty-eighth hours of treatment. Pain perception was measured using a visual analog scale at the second, sixth, and twenty-fourth hours, and on the second, third, and seventh days. Results: There were no statistically significant differences between the groups at any measured time point (p > 0.05). The highest pain scores were detected at the twenty-fourth hour of treatment in all groups. Conclusions: Within the limitations of the study, we could not detect whether low-level laser therapy and chewing gum had any clinically significant effect on orthodontic pain. Different results may be obtained with a higher number of participants or using lasers with different wavelengths and specifications. Although the study had a sufficient number of participants according to statistical analysis, higher number of participants could have provided more definitive outcomes.

      Abstract  
    • Original Article l 2022-01-25

      Accuracy of one-step automated orthodontic diagnosis model using a convolutional neural network and lateral cephalogram images with different qualities obtained from nationwide multi-hospitals

      Sunjin Yim , Sungchul Kim , Inhwan Kim, Jae-Woo Park, Jin-Hyoung Cho, Mihee Hong, Kyung-Hwa Kang, Minji Kim, Su-Jung Kim, Yoon-Ji Kim, Young Ho Kim, Sung-Hoon Lim, Sang Jin Sung, Namkug Kim , Seung-Hak Baek

      Abstract : Objective: The purpose of this study was to investigate the accuracy of one-step automated orthodontic diagnosis of skeletodental discrepancies using a convolutional neural network (CNN) and lateral cephalogram images with different qualities from nationwide multi-hospitals. Methods: Among 2,174 lateral cephalograms, 1,993 cephalograms from two hospitals were used for training and internal test sets and 181 cephalograms from eight other hospitals were used for an external test set. They were divided into three classification groups according to anteroposterior skeletal discrepancies (Class I, II, and III), vertical skeletal discrepancies (normodivergent, hypodivergent, and hyperdivergent patterns), and vertical dental discrepancies (normal overbite, deep bite, and open bite) as a gold standard. Pre-trained DenseNet-169 was used as a CNN classifier model. Diagnostic performance was evaluated by receiver operating characteristic (ROC) analysis, t-stochastic neighbor embedding (t-SNE), and gradientweighted class activation mapping (Grad-CAM). Results: In the ROC analysis, the mean area under the curve and the mean accuracy of all classifications were high with both internal and external test sets (all, > 0.89 and > 0.80). In the t-SNE analysis, our model succeeded in creating good separation between three classification groups. Grad-CAM figures showed differences in the location and size of the focus areas between three classification groups in each diagnosis. Conclusions: Since the accuracy of our model was validated with both internal and external test sets, it shows the possible usefulness of a one-step automated orthodontic diagnosis tool using a CNN model. However, it still needs technical improvement in terms of classifying vertical dental discrepancies.

      Abstract  
    • Original Article l 2022-01-25

      Comparison of soft tissue changes between incisor tipping and translation after premolar extraction

      Wonkyeong Baik , Sung-Hwan Choi, Jung-Yul Cha, Hyung-Seog Yu, Kee-Joon Lee

      Abstract : Objective: This study compared soft tissue changes after extraction of the four premolars followed by maximum retraction of the anterior teeth according to the type of anterior teeth movement: tipping and translation. Methods: Patients who had undergone orthodontic treatment involving the extraction of four premolars were retrospectively selected and divided into either the tipping (n = 27) or translation (n = 26) groups based on the retraction of the incisor root apex and the axis changes of the incisors during the treatment period. Lateral pre- and post-treatment cephalograms were analyzed. Results: There were no significant differences between the tipping and translation groups before treatment. The retraction amounts of the root apex of the upper and lower incisors in the tipping group were 0.33 and 0.26 mm, respectively, and 5.02 and 5.31 mm, respectively, in the translation group (p < 0.001). The posterior movements of soft tissue points A and B in the tipping group were 0.61 and 1.25 mm, respectively, and 1.10 and 3.25 mm, respectively, in the translation group (p < 0.01). The mentolabial sulcus angle increased by 5.89° in the tipping group, whereas it decreased by 8.13° in the translation group (p < 0.001). Conclusions: An increased amount of retraction of the incisor root apex led to the increased posterior movement of soft tissue points A and B, and this appeared more distinct in cases involving the lower incisor and lower lip.

      Abstract  
    • Case Report l 2021-11-25

      A modified presurgical alveolar molding technique for treatment of cleft in Down syndrome

      Merve Gonca , Mehmet Birol Ozel

      Abstract : Craniofacial clefts are extremely rare deformities. Tessier’s classification is a widely accepted system that is based on clinical, radiographical, and surgical observations. The Tessier No. 0 cleft most commonly affects the upper lip, nose, and palate. This case presentation aims to report the outcome of a modified presurgical alveolar molding (PAM) appliance used in the treatment of an infant with Tessier No. 0 cleft as an alternate approach to mold such defects before surgery. The modified PAM appliance consisted of reciprocal parts connected by a helix. The segments were approximated by stripping the appliance at the midline in a V-shaped manner and the force was exerted by the extraoral elastics. The procedure gave results in 8 weeks, which may be regarded as a reasonable duration. The anterior cleft gap, which was 13 mm before the treatment, was reduced to 3 mm after the treatment by using modified PAM appliance. On a 21-month follow-up period, oral reshaping was regarded successful due to stability of the improved oral mold.

      Abstract  
    • Original Article l 2021-11-25

      Effect of lower facial height and anteroposterior lip position on esthetic preference for Korean silhouette profiles

      Kyung-Hyun Seo , Deuk-Hun So, Kyeong-Tae Song, Sung-Kwon Choi, Kyung-Hwa Kang

      Abstract : Objective: The purpose of this study was to evaluate the esthetic preference for various Korean silhouette profiles. Methods: The Korean average male and female profiles were modified by changing the lower facial height and anteroposterior lip position to produce nine types of profiles. In order to test intrarater reliability, the average profile was copied once more to be included for evaluation. A questionnaire containing 10 profiles for each sex, each of which had to be rated for preference on a numerical rating scale from 0 to 10, was administered to 30 adult orthodontic patients, 30 dental students, 30 orthodontists, and 30 dentists excluding orthodontists. The data were statistically analyzed using the intraclass correlation coefficient (ICC), independent t-test, and one-way ANOVA. Results: The ICC of overall intrarater reliability was 0.629. For several profiles, significantly higher scores were given to male profiles than to female profiles (p < 0.05). However, no significant differences were found in the scores for all profiles among the four rater groups. Among the short profiles, a significantly higher score was given to the retruded profile, and among the vertically average and long profiles, a significantly higher score was given to the horizontally average profile (p < 0.001). Among all the profiles, significantly lower scores were given to the protruded profile (p < 0.001). Conclusions: This study revealed good overall intrarater reliability, with several types of male profiles being esthetically preferred over female profiles. Moreover, while retruded and horizontally average profiles were generally preferred, protruded profiles were not.

      Abstract  
    • Original Article l 2021-09-25

      Chewing gum as a non-pharmacological alternative for orthodontic pain relief: A randomized clinical trial using an intention-to-treat analysis

      Diego Junior da, Silva Santos, Jonas Capelli Jr.

      Abstract : Objective: To compare the effectiveness of ibuprofen, acetaminophen, and chewing gum for orthodontic pain relief and to assess if chewing gum can be a non-pharmacological alternative for orthodontic pain relief. Methods: The study enrolled 106 patients of both sexes, aged ≥ 12 years, with body weight > 50 kg, and mild-to-moderate dental crowding in the upper arch. After randomization and allocation concealment, the intervention groups were either administered with ibuprofen (400 mg) or acetaminophen (500 mg) or chewed sugar-free chewing gum immediately after initial archwire placement and every 6 hours for 1 week if the pain persisted. The control group did not receive any pain relief. The pain was assessed on a 100-mm visual analog scale at rest and while biting down at T1 (2 hours), T2 (24 hours), T3 (2 days), T4 (3 days), T5 (7 days), and T6 (21 days). Statistical analyses were performed using the Kruskal?Wallis and post-hoc Mann?Whitney U tests (α = 0.05). Results: The chewing gum group experienced more pain relief than the ibuprofen group at while biting down at T3 (p = 0.04) and at rest at T4 (p < 0.001). The chewing gum group reported more pain relief than the acetaminophen and control groups while biting down at T3 (p = 0.03 and p = 0.0006, respectively) and T4 (both p < 0.001). Conclusions: Chewing gum can be a non-pharmacological alternative for orthodontic pain relief at 2 and 3 days after initial archwire placement.

      Abstract  
    • Original Article l 2022-03-25

      Characterization of facial asymmetry phenotypes in adult patients with skeletal Class III malocclusion using three-dimensional computed tomography and cluster analysis

      Sang-Woon Ha , Su-Jung Kim , Jin-Young Choi , Seung-Hak Baek

      Abstract : Objective: To classify facial asymmetry (FA) phenotypes in adult patients with skeletal Class III (C-III) malocclusion. Methods: A total of 120 C-III patients who underwent orthognathic surgery (OGS) and whose three-dimensional computed tomography images were taken one month prior to OGS were evaluated. Thirty hard tissue landmarks were identified. After measurement of 22 variables, including cant (°, mm), shift (mm), and yaw (°) of the maxilla, maxillary dentition (Max-dent), mandibular dentition, mandible, and mandibular border (Man-border) and differences in the frontal ramus angle (FRA, °) and ramus height (RH, mm), K-means cluster analysis was conducted using three variables (cant in the Max-dent [mm] and shift [mm] and yaw [°] in the Man-border). Statistical analyses were conducted to characterize the differences in the FA variables among the clusters. Results: The FA phenotypes were classified into five types: 1) non-asymmetry type (35.8%); 2) maxillary-cant type (14.2%; severe cant of the Max-dent, mild shift of the Man-border); 3) mandibular-shift and yaw type (16.7%; moderate shift and yaw of the Man-border, mild RH-difference); 4) complex type (9.2%; severe cant of the Max-dent, moderate cant, severe shift, and severe yaw of the Man-border, moderate differences in FRA and RH); and 5) maxillary reverse-cant type (24.2%; reverse-cant of the Max-dent). Strategic decompensation by pre-surgical orthodontic treatment and considerations for OGS planning were proposed according to the FA phenotypes. Conclusions: This FA phenotype classification may be an effective tool for differential diagnosis and surgical planning for Class III patients with FA.

      Abstract  

Journal Info.

May, 2022
Vol.52 No.3

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