• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.2
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• pp.144-150
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• 2015

Early treatment is recommended for class III malocclusion in the primary dentition, though it is difficult to diagnose correctly. It was recommended dental maturation can possibly be used to make a differential diagnosis of skeletal class III malocclusion. This study aimed to compare dental maturation of first molars in children with skeletal or non-skeletal class III malocclusion in the primary dentition and to determine if dental maturation could be used to make a differential diagnosis of class III malocclusion. Among the children visiting the department of pediatric dentistry in Pusan National University Dental Hospital for anterior crossbite in the primary dentition, 18 were categorized into the non-skeletal class III malocclusion and 34 into the skeletal class III malocclusion. Panoramic radiographs were used to make comparative analysis of dental age and the eruption rate of the first molars. The following results were obtained. No difference was found between chronologic and dental age by the skeletal features or gender, with the latter being older than the former (p < 0.05). The discrepancies in eruption rate of first molars were significantly different between skeletal (18.91%) and non-skeletal groups (16.53%) (p < 0.05). This result implies that maturation of the first molars might be used to make a differential diagnosis of class III malocclusion.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.2
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• pp.209-218
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• 2019

This study was aimed to evaluate orofacial morphologies on the cases of developmental disorders of maxillary first molars. Panoramic radiographs, lateral cephalographs, and clinical photos of 2983 children who attended the Pediatric Dental Clinic of Pusan National University Dental Hospital from 2006 to August 2017 were assessed retrospectively. 34 patients were selected whose maxillary first molars were missed or developmentally delayed unilaterally or bilaterally. Demirjian's method was used for estimating dental age, then which was compared to chronologic age of children. Parameters expressing skeletal and dentoalveolar disharmony were checked and compared with control. Additionally, occlusion relationship was evaluated. Maxillary dental age was significantly delayed compared to chronologic age. Several parameters which show skeletal open-bite tendency and skeletal class III malocclusion with maxillary retrusion were statistically significant. Anterior crossbite and edge-bite were expected in most of these cases, but compensation by occlusion and soft tissue was also verified which might mask skeletal class III tendency. Congenital missed or developmentally delayed maxillary first molars might be related with declined growth of maxilla. If developmental disorders of maxillary first molars were verified during clinical examination, careful monitoring of orofacial growth was necessary during puberty and timed orthopedic and orthodontic intervention were considered.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.366-372
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• 2018

The purpose of this study was to investigate the effects of educational evaluation with the application of flipped learning on undergraduate students' self-directed learning ability (cognitive domains, motive domains, conductive domains) and cognitive learning competency (knowledge and thought, creation, problem solving). An educational evaluation class, which applied flipped learning designed on the basis of pre-class, in-class, and post-class, was taught to 57 undergraduate students for twelve of the sixteen weeks of a semester. It was held each week on Thursdays for two (Ed- I don't understand 'for two'). The study results showed that, applying the flipped learning educational education class for undergraduate students improved self-directed learning ability (motivation domains, behavior domains) and cognitive learning competence (higher order thinking, metacognition, creativity tendency, problem-solving process). This study provides meaningful suggestions on exploring instructional design and effective teaching and learning methods applied to flipped learning.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.3
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• pp.359-366
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• 2010

It was easy to find that children of a skeletal anterior crossbite in the early mixed dentition period showed a stark difference in the dental maturity between their maxillary and mandibular teeth, if they have stronger physical characteristics. If the difference of dental age between maxillary and mandibular teeth which can be identified via panoramic radiographs may serve as an early sign of class III malocclusion, this is considered valuable as a tool of early detection diagnosis. We obtained lateral cephalometric radiographs, panoramic radiographs, working model and clinical images of patients of Hellman dental age IIA and IIC who visited the department of pediatric dentistry, Pusan National University Dental Hospital and examined them to select 50 patents for normal occlusion group and skeletal anterior crossbite group, respectively. Their panoramic radiographs were used for the Demirjian's method to figure out dental ages of maxillary and mandibular teeth of each group and the eruption rate of the first molars. Their differences are as follows: 1. In both groups, the dental ages from Demirjian's method were advanced than the chronological ages. No sexual dimorphism was detected for the chronological or dental age in either group (p>0.05). 2. The difference of dental age of maxillary and mandibular teeth between the normal occlusion group and crossbite group was 0.22 and 0.69 years, respectively, with a higher difference in crossbite group(p<0.05). 3. Compared to the normal occlusion group, the crossbite group showed a higher difference in the eruption rate between maxillary and mandibular first molar(p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.3
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• pp.225-232
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• 2014

The purpose of this study was to compare skeletal maturity index and dental developmental stages based on skeletal malocclusion. A total of 192 patients (89 male and 103 female) between 6 to 14 years old were selected for this study and underwent cephalograms, panorama radiographs, and hand-wrist radiographs. Any syndromic cases were excluded. Selected clinical parameters were dichotomised for statistical analysis. Chi-square, logistic regression analysis, and independent t-tests were used for the statistical evaluation. Canine, first molar, and second molar calcification were significantly associated with skeletal maturity in the logistic regression model (p < 0.05). In addition, patients who had higher skeletal maturity index were 11.43 times more likely to be female than those who had lower skeletal maturity index (p < 0.001). The patients with skeletal class II malocclusion displayed significantly higher dental developmental stage in canines, first premolars, first molars, and second molars than the patients with class III malocclusion (p < 0.05). The dental developmental stage of the patients was significantly associated with skeletal maturity. In addition, there was a significant difference between class II and class III malocclusion with some types of tooth calcification.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.1
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• pp.57-64
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• 2010

The purpose of this investigation was to study the relationship between vertical facial pattern and dental maturation in children in pubertal and pre-pubertal periods. The material consisted of lateral head films and panoramic radiographs of 1306 patients. The subjects were selected according to Ricketts's VERT index and other including criteria. These subjects were divided by VERT index to brachyfacial group and dolichofacial group. In each selected subject, dental age was determined according to Demirjian's dental maturity score. All subjects were distributed according to age, vertical facial type and sex, mean and standard deviation of chronological age, dental age and age difference were determined in each group. And the data were analysed to find the difference of tooth maturation by facial pattern. Findings of this study include: 1. In all groups, dental age was determined higher than chronological age in statistically significant level. 2. Compared by vertical facial pattern, in pubertal age groups, it seems that subjects with brachyfacial type presented the tendency to have an advanced dental maturation, only in female group. 3. Compared by pubertal period, brachyfacial groups presented more advanced dental maturation in pubertal groups than pre-pubertal groups.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.2
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• pp.119-128
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• 2011

In the process of assessing the children with anterior crossbite in early mixed dentition, it has frequently been detected that the stronger the skeletal pattern of the malocclusion is, the more markedly delayed the development and eruption of maxillary teeth are. If the anteroposterior characteristics of craniofacial skeleton has any relationship with dental maturation, the evaluation of dental development and eruption was thought to be able to contribute to early diagnosis of crossbite in children. This study was performed for the purpose of elucidating the relationship between dental maturation of maxillary teeth and some cephalometric values in children with anterior crossbite of maxillary undergrowth type in early mixed dentition. Among the children in Hellman dental age IIA and IIC who attended the Pediatric Dental Clinic of Pusan National University Hospital with orthodontic problems, cases with Class III malocclusion were classified and 50 cases of maxillary undergrowth type and type with normal maxilla respectively were randomly selected and studied as subjects. From their lateral cephalographs and panoramic radiographs, their anteroposterior skeletal features, the dental maturity and eruption rate were obtained of each group and data were analyzed to yield the results as follows: 1. Comparing the maturity of maxillary teeth of both groups, only the first molars of maxillary undergrowth group showed significantly slower development and eruption (p<0.05). 2. There was high correlation between maturation of maxillary 1st molar and chronological age(p<0.05). 3. Among the parameters of anteroposterior relationship of skeletal pattern in maxilla and mandible. Wits was revealed as a useful index to predict both the calcification and eruption rate of the 1st molars whereas SNA was to eruption rate(p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.2
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• pp.215-221
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• 2007

The aim of this study was to test whether metric measurements of crown length, root length and apex width during tooth development could be a better basis for correlation with age than the classical methods based on subjective estimations of various stages of tooth development. Panoramic radiographs of 120 children, aged 7 to 9 years, were collected from the department of the pediatric dentistry of Chonnam National University Hospital, Korea. The methods of Mornstad was used to estimate age. The structures measured were crown length root length and apex width in panoramic radiographic. The results were as follows : 1. In the boys, it showed higher correlation between lower 2nd molar crown length, lower 1st molar root length or lower 1st permolar apical width and age. In the girls, it showed higher correlation between lower 2nd premolar crown length, lower 2nd molar root length or lower 1st molar apical width and age. 2. With the aid of a multiple regression model, a linear relationship between some of these distances and age was shown. Boy(months) = 43.958 + lower 2nd molar crown length ${\times}$ 4.392 + lower 1st molar root length ${\times}$ 2.255 - lower 1st permolar apical width ${\times}$ 2.046, Girl(months) = 75.213 + lower 2nd premolar crown length ${\times}$ 3.910 lower 2nd molar root length ${\times}$ 2.280 - lower 1st molar apical width ${\times}$ 6.217 Age was estimated in boys and girls using the mathematic model ; the mean difference between chronological and estimated ages was $-2.1{\pm}6.8$ months for boys and $6.1{\pm}6.2$ months for girls. Therefore, it seems to be more accurate and easier than the earlier methods.