• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.457-471
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• 1997

The Purpose of this study was to estimate relative importance among the causative factors o( arch length discrepancy(ALD) and Possibility of prediction of the ALD in the mixed dentition. The sample consisted of the casts of the 142 young adults who had no abnormal muscle function, no skeletal abnormalities and Class I molar relationship. We classified the sample by gender and the extent of ALD, and measured mesiodistal diameters of each tooth and the dimensions of the dental arch. The computerized statistical analyses was carried out with SPSS win program. The results were as follows ; 1. Most of the variables of spacing group and some variables of dental arch dimension of crowding group were significantly different between genders. But in normal group, there were few differences. 2. In male crowding and female spacing group, mainly measurements of tooth dimension were significantly different from those of normal group. 3. In male spacing and female crowding group, measurements of dental arch dimension were significantly different from those of normal group. 4. The measurements of dimension of dental arch were highly correlated with ALD in correlation analysis and factor analysis. 5. Prediction equations for adult's ALDs by means of what can be measured in the mixed dentition(mesiodistal dimensions of incisors and first molar, intermolar width and arch length) showed R square from $63\%$ to $80\%$.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.1
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• pp.85-94
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• 2022

This retrospective study aimed to evaluate the difference in measurement between conventional orthodontic analysis and artificial intelligence orthodontic analysis in pediatric and adolescent patients aged 7 - 15 with the mixed and permanent dentition. A total of 60 pediatric and adolescent patients (30 mixed dentition, 30 permanent dentition) who underwent lateral cephalometric radiograph for orthodontic diagnosis were randomly selected. Seventeen cephalometric landmarks were identified, and 22 measurements were calculated by 1 examiner, using both conventional analysis method and deep learning-based analysis method. Errors due to repeated measurements were assessed by Pearson's correlation coefficient. For the mixed dentition group and the permanent dentition group, respectively, a paired t-test was used to evaluate the difference between the 2 methods. The difference between the 2 methods for 8 measurements were statistically significant in mixed dentition group: APDI, SNA, SNB, Mandibular plane angle, LAFH (p < 0.001), Facial ratio (p = 0.001), U1 to SN (p = 0.012), and U1 to A-Pg (p = 0.021). In the permanent dentition group, 4 measurements showed a statistically significant difference between the 2 methods: ODI (p = 0.020), Wits appraisal (p = 0.025), Facial ratio (p = 0.026), and U1 to A-Pg (p = 0.001). Compared with the time-consuming conventional orthodontic analysis, the deep learning-based cephalometric system can be clinically acceptable in terms of reliability and validity. However, it is essential to understand the limitations of the deep learning-based programs for orthodontic analysis of pediatric and adolescent patients and use these programs with the proper assessment.

• The Journal of the Korean dental association
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• v.27 no.1 s.236
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• pp.6-7
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• 1989

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.248-261
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• 1999

In order to define a current set of Korean children norm with mixed dentition, following study was done. The subjects were 102 healthy dentition contestants(48boys, 54girls). Standardized lateral head roentgenograms were taken, and Ricketts analysis was done. Results were as follows: 1. Length of anterior cranial base, posterior facial height, corpus length were longer in male than in female(p<0.05), and Porion was located posteriorly in male than in female(p<0.01). 2. Through facial depth, Pogonion of male was more forwardly positioned(p<0.05), mandible was significantly steeper in female, and maxillary anterior teeth were significantly tipped forward in male(p<0.05). 3. Variables such as length of anterior cranial base, upper molar position(p<0.01) and corpus length(p<0.05) were significantly changed by age. 4. Maxillary height, facial depth, mandibular plane angle, convexity were changed by age, but not significantly(p>0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.270-277
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• 2005

The purpose of this study was to clarify the palatal volume and anterior palatal slope of the children with class II div.1 malocclusion and normal occlusion in mixed dentition(Hellman dental age III A) using three-dimensional laser scanner. Samples were consisted of 31 children with skeletal class II div.1 malocclusion in mixed dentition and 29 children with normal occlusion and profile among the contestants in 2000-2004 Healthy Dentition Contest in Seoul. Totally 60 maxillary study model were taken. Each cast was scanned by three-dimensional laser scanner (Breuckmann opto-TOP HE, INUS, Korea) and shaped into the three-dimension image by Rapidform 2004 program(INUS, Korea). And the palatal volume and anterior palatal slope of each cast were calculated by Rapidform 2004 program(INUS, Korea). The values were statistically compared and evaluated by independent samples t-test with 95% of significance level. The results were as follows: 1. Palatal volume was significantly lesser in children with class II div.1 malocclusion than that of normal occlusion in mixed dentition(p<0.05). 2. No significant difference in the anterior palatal slope and palatal height was found between the children with class II div.1 malocclusion and normal occlusion in mixed dentition(p>0.05). 3. Palatal length was significantly greater in children with class II div.1 malocclusion than that of normal occlusion in mixed dentition(p<0.01). 4. Intercanine and intermolar width were significantly lesser in children with class II div.1 malocclusion than those of normal occlusion in mixed dentition(respectively p<0.05 and p<0.01).

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.295-303
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• 2002

This study was performed to establish the cephalometric standards in Downs analysis and to compare them with other races. The lateral cephalograms of 88 Korean children (47 boys, 41 girls) with normal occlusion and acceptable profile between 7 and 11 years of age were taken and Downs analysis was done. Results were as follows: 1. Norms of Korean boys, girls and both sexes at 7, 9, 11 years of age by Downs analysis were established. 2. There were no statistically significant differences between boys and girls about ten measurements in each group, but significant differences in the occlusal plane angle, lower 1 to occlusal plane angle, interincisal angle, upper 1 to APog plane among 3 groups(p<0.05)(p<0.01). 3. Facial angle, AB plane angle, Y-axis, lower 1 to occlusal plane angle and lower 1 to mandibular plane angle showed increasing tendency whereas angle of convexity, mandibular plane angle, occlusal plane angle and interincisal angle did decreasing tendency according to aging. 4. In comparison among races, measurements in Korean children were generally larger than those of Caucasian and Greek except for small interincisal angle, but Korean were similar to Japanese, Chinese, Israeli, Negro about all measurements.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.253-261
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• 2006

Estimating the size of unerupted teeth is an essential aspect of orthodontic diagnosis and treatment planning in the mixed dentition. Several methods were introduced and used for the prediction. The most common methods among these would be Moyers probability chart and Tanaka and Johnston equations. These are currently used widely, but they were developed for Caucasians. Because there are clear racial differences in teeth size, the objectives of this study were to produce correlation coefficients between the combined mesiodistal widths of the permanent mandibular incisors and those of the canines and premolars for each quadrant, and prediction tables with regression equations, specifically for Korean. 178 young adults (70 women, 108 men, mean age 21.63 years) were selected from the College of Dentistry, Yonsei University, Seoul, Korea. The mesiodistal crown diameters of the permanent teeth were measured with calipers. Significant sexual dimorphism was found in tooth sizes. The correlation coefficients between the total mesiodistal width of the mandibular permanent incisors and those of the maxillary and mandibular canines and premolars were found to be between 0.52 and 0.64. The standard error of the estimatation was better (0.60) for women and the ${\gamma}^2$ values ranged from 0.27 to 0.41 for both sexes Prediction tables were prepared for Korean. This study showed larger canine and premolar diameters than Tanaka and Johnston's and Moyers' studies which might be due to the racial differences. Further investigations with a larger sample size will be needed for more representative data on the Korean population.

• Journal of Digital Convergence
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• v.11 no.4
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• pp.303-309
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• 2013

TRAINER for Kids ($T4K^{TM}$, Myofunctional. Research Co, Australia) is a prefabricated myofunctional orthodontic appliance recommended to ClassII division1 malocclusion patients who have bad oral habits such as mouth breathing, tongue thrusting, inappropriate tongue position, thumb sucking and so on. Trainer has a soft texture and a small volume so that those advantages lead to an increase in the agreement rate of young patients of its use. This presentation is to analyze clinical efficacy of Trainer. The analysis is based on a result of regular follow-up on Class II division1 malocclusion patients who has been completely treated by Trainer in the Sanbon Dental Hospital of Wonkwang university. This case report is to present the satisfactory results gained by using Trainer on Class II patients. First, Trainer was applied in Class II malocclusion patients of mixed dentition with expected space insufficient to gain facial improvement. Second, excessive overjet, overbite were improved. Third, main effects are regarded to have been achieved by development of lingual slant of upper jaw, labial slant of lower jaw, and lower part of jaw bone.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.1
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• pp.21-31
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• 2018

This study aimed to investigate the correlation between the inclinations of the incisors and lips in mixed dentition aged 7 - 11 years. Lateral cephalometric radiographs of 353 children were analyzed to measure the upper incisor inclination, lower incisor inclination, lower-nasolabial angle, and mentolabial angle in relation to the skeletal malocclusion classification. The measurements were then assessed using the Kruskal-Wallis test, Pearson correlation, and multiple regression analysis. There were significant negative correlations between the inclination of the upper incisors and lower-nasolabial angle in all classes of skeletal malocclusion. There was a negative correlation between the inclination of the lower incisors and mentolabial angle; however, class II malocclusion had a significant positive correlation. This study identified the factors that affect lip inclination and verified their associations.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.3
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• pp.329-339
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• 2022

The purpose of this study was to compare the palatal dimensions (volume, width, length, and height) in different malocclusions (Class I, II, and III) in mixed dentition using a three-dimensional digital scanner. The study was performed on 30 selected casts from 1400 casts that were taken at the Department of Pediatric Dentistry at Dankook University. Casts consisted of Class I, II, and III malocclusion groups in Hellman's dental age IIIA. The mean age was 8 years and 6 months ± 11 months. Each cast was scanned by three-dimensional digital scanner, Medit T710 (Medit, Seoul, Korea), and shaped into the three-dimensional image and calculated palatal dimensions using the Plan T program (SMD solution, Seoul, Korea). The values were statistically compared and evaluated by Kruskal-Wallis followed by the Mann-Whitney test. According to our results, subjects with Class II malocclusion showed lower palatal width and longer palatal length compared to those with Class I and Class III. For palatal height, Class III malocclusion subjects in mixed dentition exhibited a larger number than Class II and Class I. Lastly, for palatal volume, compared to other malocclusions, Class III showed higher results; however, there were no significant differences. The form of the palate differs in types of malocclusions and understanding of these differences is important in clinical significance. Based on this study, the understanding of the relationship between the shape of the palate and the skeletal pattern provides useful information about orthodontic treatment plans, early diagnosis of malocclusion, and morphological integration mechanisms. Orthopedic treatment in the maxilla should be performed during early and intermediate mixed dentition to enhance treatment efficiency.