• The korean journal of orthodontics
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• v.24 no.4 s.47
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• pp.773-785
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• 1994

It has been generally believed that the impaction or eruption of mandibular third molars has significant correlations with the growth of the mandible, size of mandibular arch and size of teeth. The purpose of this study was to examine if there is any correlation between the status of eruption of mandibular third molars and the amount of mandibular crowding. The effect of missing of third moalrs to mandibular crowding was studied as well. 140 adult students of Yonsei University were selected and divided into three groups according to the status of mandibular third molars, Group 1) congenital missing group, Group 2) eruption group, and Group 3) impaction group. The tooth size, dimensions of the mandibular dental arch, and the amount of crowding were measured and compared. Results were as follows ; 1. There was no statistically significant difference in tooth size between the missing group and the eruption group(p<0.05). Impaction group showed larger total tooth material, inci- sal tooth material, and individual tooth size except central incisors compared to missing group (p<0.05). Impaction group showed larger total tooth material, incisal tooth material compared to eruption group as well(p<0.05). When individual tooth size was compared, impaction group had larger central incisors, canines, and second premolars than eruption group(p<0.05). 2. Missing group showed larger intermolar width than impaction group and it was stati- stically significant(p<0.05). 3. When compared the amount of total crowding, impaction group showed the largest am- ount of crowding, then eruption group, and missing group showed the least amount of crowding respectively(p<0.05). There was no statistically significant difference between missing stoup and eruption group in the amount of incisal crowding(p<0.05). Impaction group show- ed the largest amount of incisal crowding among all three groups(p<0.05).

• The korean journal of orthodontics
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• v.28 no.6 s.71
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• pp.981-989
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• 1998

Positions, angulation and mesiodistal dimension of lower incisors are important in esthetics, occlusion and post-treatment stability of tower arch. When lower incisor is congenitally missing, problems such as increased overjet and overbite, closing in of adjacent teeth and size/space discrepancies may occur. When creating treatment plans, incisor position and angulation, lip support, anteroposterior skeletal relationship canine-molar relationship, overjet overbite, remaining growth potential, crowding and anterior tooth ratio have to be considered. For an accurate analysis of incisal size discrepancy, diagnostic model set-up may be helpful. The two patients in this presentation both had two lower incisor missing, but the degree of crowding, skeletal relationship, lip support, molar relationship are different and therefore treatment plan was different as well. Long term follow-up may be necessary for stability and retention.

• The Journal of the Korean dental association
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• v.55 no.4
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• pp.296-302
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• 2017

The traditional orthognathic surgery treatment consists of three steps: preoperative orthodontic treatment, orthognathic surgery, and postoperative orthodontic treatment, and the average treatment period is usually two years. Also, patients with Class III malocclusion should spend more time getting their facial features worse during the decompensation process. However, most of the patients who want orthognathic surgery visit the chief complaints of appearance improvement, and resolve this address as soon as possible. The concept of $^{\circ}{\AE}$Surgery - First 'does not cause a facial imbalance caused by decompensation for the pre - operative correction period, and the patient can obtain an improved facial profile immediately after the operation. In addition, the correction period is shortened by Regional Acceleratory Phenomenon (RAP) after surgery. However, it is not applicable to all patients. Patients with severe crowding, severe curve of spee or reverse curve of spee, severe transverse discrepancy of the maxilla and mandibular arch, and severe incisal angles are less likely to apply the technique. Although it is not yet possible to apply this technique to all patients, it has many advantages over the conventional method. Especially, the patients' preference is increasing due to the rapid appearance improvement and the shortening of the total treatment period.

• The korean journal of orthodontics
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• v.32 no.3 s.92
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• pp.165-174
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• 2002

The purpose of this study was to compare on masse retraction of six anterior teeth with separate canine retraction in the amount of the anchorage loss and the retraction of the anterior teeth. The subjects consisted of 30 adult female patients with Angle Class 1 malocclusions who were treated by .022' straight wire appliance with 4 first permolar extraction. They were composed of two groups. Group 1 consisted of 15 subjects, whose six anterior teeth were retracted by on masse retraction. Group 2 consisted of 15 subjects, whose canines were retracted separately. Pre-treatment and post-treatment lateral cephalometric radiographs were analyzed. All data were processed statistically with independent samples t-test, and the conclusions were as follows. 1. There was no significant difference in the amount of the anchorage loss between two groups(p>0.05). 2. There was no significant difference in the amount of the retraction of the anterior teeth between two groups(p>0.05). 3. There was a significant difference in the amount of the inclinational change of the upper incisors between two groups. It was greater in Group 2. 4. There was a significant difference in the vertical positional change of the upper incisal edges between two groups. The upper incisal edges in Group 2 were more extruded than Group 1 by about 1mm. 5. There was no significant difference in the vertical positional change of the root apex of the upper incisors between two groups(p>0.05). And there was no significant difference in the vertical positional change of the upper molar(p>0.05).

• The korean journal of orthodontics
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• v.34 no.1 s.102
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• pp.1-11
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• 2004

Predicting the arch length discrepancy by simply comparing the available arch perimeter with tooth materials is merely a 2-dimensional analysis of the teeth movement. However, the real teeth movement takes place 3-dimensionally and is affected by various factors such as, the arch fen the curve of Spee and the axis of the incisors. The purpose of this study is to clarify the relationship between the decrease in the arch perimeter and the horizontal positional change of the incisors after extraction of the 1st bicuspids, for more analytic evaluation of the arch length discrepancy at pre-treatment model analysis stage. In addition to that to evaluate the effect of the curve of Spee, teeth axis to the basal plane, and the incisional crowding to the treatment outcome. All patients were treated at the department of orthodontics, dental hospital, Yonsei university. Inclusion criteria for patients selection were as follows. $\cdot$ Angle classification I malocclusion with bialveolar protrusion $\cdot$ Extraction of 4 1st bicuspids $\cdot$ No tooth anomaly or prosthesis $\cdot$ No abnormal attrition $\cdot$ No ectopically erupted teeth $\cdot$ Angle classification I canine and molar relationship $\cdot$ Less than 3mm of crowding Model analysis of the above patients was performed and the following conclusions were obtained. 1. When the intercanine distance was maintained, the available space for the distal movement of the mandibular incisors after the extraction of the 4 1st bicuspids was larger than the space provided by the extraction of the 4 1st bicuspids. However the difference was less than 1mm. The more tapered the anterior arch form, the larger the difference. 2. Compared to the situation in which the intercanine distance was maintained, when the intercanine distance was expanded to meet the width of the Posterior teeth, the incisors could move about 3mm more distally. 3. The positional difference of the incisal tip was insignificant whether the central incisors were moved by tipping or bodily movement. 4. When the anterior crowding was solved without changing the intercanine distance, the larger the anterior arch length was, the more the anterior movement of the incisors. 5. When the curve of Spee was levelled, the increase in the arch perimeter was less than half of the deepest curve of Spee.

• The korean journal of orthodontics
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• v.27 no.6 s.65
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• pp.871-880
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• 1997

Multiple features of occlusion have been combined by epidemiologists in attempts to objectively to determine malocclusion severity and treatment priority. Jenny et al were developed DAI(Dental Aesthetic Index), which is an orthodontic index based on socially defined aesthetic standards. This study aimed to evaluate association between 10 occlusal components of DAI and individual measures of skeletal morphology by use of univariate and multivariate analysis. In addition the relationship between a Dental Aesthetic Index score and skeletal morphology was evaluated. The data for this study were obtained from cephalometric radiographs and dental casts of 182 Korean patients(79 men, 103 women) with permanent dentition who had been accepted for the orthodontic treatment at Department of Orthodontics, Chonbuk National University. The results are as follows: 1. Several occlusal components of DAI(missing, crowding and spacing in the incisal segment, diastema, largest anterior irregularity on upper and lower arch) were not associated with individual measures of craniofacial morphology. 2. Sagittal occlusal components of DAI were associated with anteroposterior skeletal measures. 3. The relation between vertical occlusal components of DAI and vertical skeletal measures was low magnitude. 4. A Dental Aesthetic Index, which is based on several aspects of occlusion, did not identify craniofacial morphology. We can conclude that combination of certain occlusal components of the DAI may be related with specific skeletal morphology; but, this concept could not be accepted generally.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.3
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• pp.147-152
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• 2013

Purpose: The aim of this study was to propose the position of maxillary anterior teeth and intercanine width measurements based on the incisive papilla in accordance with the cephalic type and gender of dentate Korean adult with normal teeth alignment. Materials and methods: 42 students with Class I normal occlusion, without crowding or spacing, were selected from the Chonnam National University School of Dentistry. The lateral skull radiographs of the subjects were taken and were classified as different cephalic types, based on their PFH / AFH ratios. 42 casts of their maxilla were prepared and both the distance between the upper central incisors and the middle of the incisor papilla was measured with a vernier caliper (A) and the distance between the maxillary canine cusp tips (B) were measured. Statistical analysis was performed using SPSS version 15 and their significance was investigated. Results: For dolichocephalic group, the mean values for A and B were 8.43 (SD: 0.61) and 36.73 (SD: 2.17), respectively. The mean value for A was 8.51 (SD: 1.27) for the mesocephalic group and 8.76 (SD 1.03) for the brachycephalic group. The mean value for B was 35.91 (SD: 1.86) for the mesocephalic group and 37.34 (SD: 2.23) for the brachycephalic group. For the male group, the mean A value was 8.86 (SD: 1.04) and the mean B value was 37.60 (SD: 0.24). For the female group, the mean A value was 8.41 (SD: 0.93) and the mean B value was 36.18 (SD: 2.01). The difference between male and female group in A values were not statistically significant (P>.05). The B values of the male subjects were greater than those of the female subjects and was statistically significant (P<.05). Conclusion: 42 students with normal dentition and occlusion in korea, the distance from the incisive papilla and the incisal edge of maxillary central incisors had no difference in cephalic type or gender. However, the distance between the cusp tip of both canines had significant difference in gender where the male showed higher values than the female, while having no difference in cephalic types.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.3
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• pp.207-217
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• 2014

The purpose of the present study was to evaluate the relationship between the malocclusion and dental caries in adolescents with permanent dentition. The subjects of the study were 385 adolescents aged 12 to 15 years. Dental Aesthetic Index (DAI) and DMFT index were recorded as clinical indicators of malocclusion and dental caries. The mean Dental Aesthetic Index (DAI) score of the subjects was 12.42 and the mean DMFT index of the subjects was 2.89. Four students (1.04%) were included in the group of orthodontic treatment mandatory, which signifies the handicapping malocclusion. Moreover, the result of gender-specific analysis of the DAI components observed that the prevalence of midline diastema and mandibular overjet were significantly higher among boys (p < 0.05). In 7 components (missing teeth, incisal segment crowding, maxillary anterior irregularity, mandibular anterior irregularity, mandibular overjet, anterior openbite, antero-posterior molar relationship) among the 10 DAI components, abnormal groups showed significantly higher DMFT index than normal groups (p < 0.05). The subjects in the group of definite to handicapping malocclusion (DAI ${\geq}$ 26) showed significantly higher DMFT index than the subjects in the group of minor or no malocclusion (p < 0.01). In addition, the DAI score had significant positive linear correlation with the DMFT index (r = 0.584, p < 0.01). Consequently, the current findings suggested a positive relationship between the malocclusion and caries prevalence. And several specific types of malocclusion were supposed to be significantly correlated with dental caries.