• The Journal of the Korean dental association
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• v.16 no.1 s.104
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• pp.37-42
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• 1978

A study on the impacted teeth of the anterior segment was carried out. The data for this study were compiled form 1739 outpatients of the Department of Orthodontics, College of Dentistry, Seoul National University. The following conclusions were obtained; 1. The frequency of the impacted teeth of the anterior segment was 2.8% and the frequency of male was 4.0%, that of female was 2.1%., respectively. 2. The order of occurrence of the impacted teeth in the anterior segment was maxillary canine mesiodens, maxillary central incisor, maxillary lateral incisor, mandibular canine. 3. The etiologic factors of the impaction were the space deficiency for eruption, cleft palate, the prolonged retention of deciduous teeth, dentigerous cyst. 4. The favorable results of treatment and prognosis were obtained from the impacted teeth of the normal shape after surgical exposure and adhered the plastic attachment and inducted them into the dental arch.

• Journal of Oral Medicine and Pain
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• v.9 no.1
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• pp.157-167
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• 1984

A human bite-mark shows special feature according to the suspect's dentition. The teeth which most frequently give useful bite-marks are six upper and lower anteriors, while the premolar teeth somtimes give marks it is often difficult to distinguish. The author tried to classify and to analize the anterior dentition which makes the bite-mark directly by means of 672 maxillary and 691 mandibular stone model taken from Korean adult aging from 17 to 40 years old. The results were as follows : 1. There was no particular correlation between the presence of six normal-shaped and correctly positioned upper and lower anteriors and the presence of rotation of teeth. 2. Inter central incisor, inter lateral incisor, inter canine width and angles of adjecent teeth were not identical eath other in studied models. 3. The results of this analysis supported the statement that any bite-mark had no same feature.

• The Journal of the Korean dental association
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• v.54 no.5
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• pp.365-373
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• 2016

Purpose: Cemental tear is a specific type of root surface fracture characterized by a complete separation of a cemental fragment along the cementodentinal junction or a partial split within the cementum along an incremental line. It is suggested to be a factor for periodontal or periapical tissue destruction. The aim of this study is to present a diagnosis and treatment of cemental tear associated with periapical lesion with root canal treatment and regenerative periodontal surgery. Treatments: A 60-year-old male who had a history of sports trauma on the mandibular right central incisor about 10 years ago presented with apical cemental tear. Clinical examination showed a slightly dark yellowish discoloration and sinus tract that was located on the apical labial mucosa. The mobility and percussion were also assessed on the diseased tooth and recorded as $Miller^{\circ}{\phi}s$ Class II and tenderness to percussion. The probing depth was within the normal limit (<3 mm). Radiographic examination revealed a radiolucent lesion at the apical area and extended to distal aspect of the tooth along the fragment of cemental tear. After root canal treatment, periapical surgery was performed. The bony defect was exposed and then the detached root fragment was removed. Apical root resection and retrograde filling with Mineral Trioxide Aggregate (MTA) were accomplished and the bony defect was filled with deproteinized bovine bone mineral (DBBM) and covered with biodegradable collagen membrane. Results: After 9-month follow-up, healing of the mandibular right central incisor was uneventful and no swelling, purulence or pain was revealed in the associated area. Probing pocket depth was favorably stable, and the tooth mobility was decreased to the Miller's Class I. Conclusions: Apical cemental tear associated periapical lesion could be successfully treated with removal of the detached cementum in combination with apical surgery and GTR procedure.

• The korean journal of orthodontics
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• v.31 no.4 s.87
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• pp.439-445
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• 2001

The Purpose of this study was to compare the dento-skeletal characteristics between functional and skeletal anterior cross-bite patients. Twenty-eight functional anterior cross-bite patients and thirty-one skeletal anterior cross-bite patients were selected as a test and a control group. Mean ages of the test and the control group were $9.6{\pm}1.8$ and $9.9{\pm}1.9$, respectively. Lateral cephalograms were taken. Forty-nine cephalometric variables were measured and statistical analysis was performed to find the morphological differences between the groups. Statistically significant differences were found in the cephalometric variables of cranial deflection, maxillary depth, ANB, convexity, NPo-AB, APDI, Mx 1-SN, Mx 1-NA angle, Mx 1-NA, Md 1-NB angle and Md 1-NB. The test group showed more Class III growth potential, more protruded maxilla, lesser maxillo-mandibular difference, more uprighted and retruded maxillary central incisor, more labially tipped and protruded mandibular central incisor.

• The korean journal of orthodontics
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• v.52 no.1
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• pp.53-65
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• 2022

Objective: Planning of incisal position is crucial for optimal orthodontic treatment outcomes due to its consequences on facial esthetics and occlusion. A systematic summary of the proposed parameters is presented. Methods: Studies on Google Scholar^©, PubMed^©, and Cochrane Library, providing quantitative information on optimal central incisor position were included. Results: Upper incisors supero-inferior position (4-5 mm to upper lip, 67-73 mm to axial plane through pupils), antero-posterior position (3-4 mm to Nasion-A, 3-6 mm to A-Pogonion, 9-12 mm to true vertical line, 5 mm to A-projection, 9-10 mm to coronal plane through pupils), bucco-lingual angulation (4-7° to occlusal plane perpendicular on models, 20-22° to Nasion-A, 57-58° to upper occlusal plane, 16-20° to coronal plane through pupils, 108-110° to anterior-posterior nasal spine), mesio-distal angulation (5° to occlusal plane perpendicular on models). Lower incisors supero-inferior position (41-48 mm to soft-tissue mandibular plane), antero-posterior position (3-4 mm to Nasion-B, 1-3 mm to A-Pogonion, 12-15 mm to true vertical line, 6-8 mm to coronal plane through pupils), bucco-lingual angulation (1-4° to occlusal plane perpendicular on models, 87-94° to mandibular plane, 68° to Frankfurt plane, 22-25° to Nasion-B, 105° to occlusal plane, 64° to lower occlusal plane, 21° to A-Pogonion), mesio-distal angulation (2° to occlusal plane perpendicular on models). Conclusions: Although these findings can provide clinical guideline, they derive from heterogeneous studies in terms of subject characteristics and reference methods. Therefore, the optimal incisal position remains debatable.

• Journal of Oral Medicine and Pain
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• v.26 no.2
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• pp.147-156
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• 2001

The purpose of this study was to identify the difference of vertical movement of mandible according to Angle's molar relationship and by skeletal factors affect to vertical movement of mandible. 172(age ranged from 20 to 30) subjects who go to college within territory of Kwangju city without any experience of temporomandibular disorder, extraction and orthodontic treatment. were selected for this study. The subjects were classified into class I(male:30, female:49), class II(male:18, female:24) and class III(male:18, female:33) according to Angle's molar relationship. The distance was measured between incisal edge of maxillary and mandibular central incisor and between bottom of central fossa of maxillary and mandibular 1st molar with ruler. The arch length and width were measured on the diagnostic cast. Cephalometrics were taken and then traced. Landmarks were identified and analyzed. 1. Maximal interincisal opening of male is larger than that of female in class I, class II and class III. Among each group maximal interincisal distance is the largest in class III. Maximal intermolar distance of male is superior to that of female in class I, class II, and class III, but there is no siginficant difference among them. 2. On maximal opening movement of Angle's classification class I and class II, total mandibular length, mandibular ramal length, madibular inferior border length and upper arch width were important variables and facial length, upper arch length and lower arch length had negative relationship to that. On maximal opening movement of Angle's class III, the upper arch length, the lower arch length and anterior facial length were important variables especially when compared with class I and II, and upper arch width had negative relationship. These results suggest that maximal opening movement is affected by facial morphology in all classes, but each group is affected by different facial skeletal variables. Accordingly, facioskeletal variables might be considered as diagnosis and treatment to improve the amount of mouth opening.

• The korean journal of orthodontics
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• v.39 no.2
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• pp.112-119
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• 2009

Objective: To develop a mixed dentition analysis method in consideration of the normal variation of tooth sizes. Methods: According to the tooth-size of the maxillary central incisor, maxillary 1st molar, mandibular central incisor, mandibular lateral incisor, and mandibular 1st molar, 307 normal occlusion subjects were clustered into the smaller and larger tooth-size groups. Multiple regression analyses were then performed to predict the sizes of the canine and premolars for the 2 groups and both genders separately. For a cross validation dataset, 504 malocclusion patients were assigned into the 2 groups. Then multiple regression equations were applied. Results: Our results show that the maximum errors of the predicted space for the canine, 1st and 2nd premolars were 0.71 and 0.82 mm residual standard deviation for the normal occlusion and malocclusion groups, respectively. For malocclusion patients, the prediction errors did not imply a statistically significant difference depending on the types of malocclusion nor the types of tooth-size groups. The frequency of prediction error more than 1 mm and 2 mm were 17.3% and 1.8%, respectively. The overall prediction accuracy was dramatically improved in this study compared to that of previous studies. Conclusions: The computer aided calculation method used in this study appeared to be more efficient.

• The korean journal of orthodontics
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• v.24 no.2
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• pp.247-273
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• 1994

The purpose of this study was to evaluate the dental arch morphology and the occlusal characteristics in the Koreans from the dental-anthropological point of view. The sample consisted of dental stone casts obtained from 120 Korean adults and 142 Japanese adults. Japanese casts and Caucasian data had been preserved at the Dept, of Orthodontics of Tokyo Medical and Dental University. Tooth size and dental arch morphology of the Koreans were compared with that of the Japanese. On the other hand, the variations of 30 crown traits, categorized and quantitatively graded, were compared between two peoples and the frequency distribution of each crown traits were analyzed by means of Chi-square test. The results were summerized as followings ; 1. There was a significant sexual difference in dental arch length and width in the Korean, in which male had a longer and wider dental arch than female. There was a close resemblance for dental arch morphology between the Koreans and the Japanese, except for a little longer mandibular arch of the Japanese. 2. In general, Korean male had wider crown than female, particulary in central incisor,canine,1st molar of maxilla and canine, 1st and 2nd molar of mandible with significance. The Korean had wider maxillary first molar, smaller mandibular first and second molar than the Japanese in both sex. 3. In crown traits of the Korean, shovel-shaped incisor showed lower frequency distribution than in the Japanese, but higher than in the Caucasians. Frequency of incisor reduction was shown higher distribution than in the Japanese and the Caucasians. Carabelli's tubercle showed higher frequency distribution than in Japanese, but remarkably lower than in Caucasians.

• The Korean Journal of Legal Medicine
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• v.42 no.4
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• pp.141-145
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• 2018

There have been many radiographic studies on age estimation that evaluate reduction in size of dental pulp cavity with secondary dentin formation. The Paewinsky method reported high accuracy in estimating ages by measuring the width of the pulp cavity in panoramic radiographs. The aim of this study was to evaluate the application of the Paewinsky method to digital periapical radiographs. This study was conducted on 103 cases that reported to the Section of Human Identification of the National Forensic Service. The age was calculated by applying the Paewinsky method that measures the root and pulp canal width at three points in a tooth. The estimation results were compared with those calculated by the Johanson method. When the Paewinsky models were applied to digital periapical radiographs, the errors were significantly greater as compared to the original study. The errors of the maxillary second premolar and mandibular lateral incisor were greater than those of the maxillary central incisor, lateral incisor, mandibular canine, and first premolar. Furthermore, errors of the age estimation models in level C were greater than those in levels A and B. This study could be a reference for the application of the Paewinsky method to digital periapical radiographs.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.2
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• pp.210-219
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• 2017

This study aimed to investigate the prevalence and distribution of enamel hypomineralization, including molar-incisor hypomineralization (MIH), among adolescents and assess their correlation with esthetic satisfaction. A total of 1371 adolescents between the ages of 14 and 16 years in Yangsan city were evaluated for enamel hypomineralization, including MIH, according to the European Academy of Paediatric Dentistry (EAPD) criteria. In a parallel survey, esthetic satisfaction about anterior teeth and its correlation with incisor enamel hypomineralization were analyzed. The prevalence of MIH was 13.8% (n = 189), while that of hypomineralization in any permanent tooth was 23.2% (n = 318), which was substantially greater compared to the national prevalence of MIH. Mandibular first molars exhibited the highest prevalence of hypomineralization, followed by maxillary central incisors and mandibular second molars. Among anterior teeth, the most frequently affected site was the incisal edge of maxillary central incisors. A high degree of hypomineralization in anterior teeth was associated with a high demand for esthetic treatment.