• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.3
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• pp.604-612
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• 1998

The majority of Class III malocclusion have maxillary retrusion. Thus, it becomes obvious that management of most skeletal Class III malocclusion cases should include maxillary protraction as major objective. Additionally, in Class III malocclusion with posterior crossbite, RME "disarticulates" the maxilla and initiates cellular response in the sutures, allowing a more positive reaction to protraction forces. Using facemask with RME helped in correction of skeletal Class III malocclusion by the anterior displacement of maxilla and maxillary dentition, and changing the direction of the growth of mandible. Thus, acceptable improvement in the Class III profile was performed.

• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.105-112
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• 1988

To predict duration of orthodontic treatment of malocclusion, 304 male and female patients whose orthodontic treatment was finished in department of orthodontics, Infirmary of dental college, Chosun University were studied. The duration of treatment was studied according to types of malocclusion, beginning ages of treatment, Hellman's dental ages, the determination of tooth extraction, types of tooth extraction and types of orthodontic appliance. The following results were obtained. 1. The duration of treatment was 18 months in Class I malocclusion, 20 months in Class II malocclusion and 24 months in Class III malocclusion. 2. The more early treatment was done, the more duration of treatment was needed according to beginning age of treatment and Hellman's dental ages. 3. Treatment of tooth extraction case was needed for 78 days more than that of non-extraction case. 4. The duration of treatment with unilateral extraction of premolars was the shortest (598 days) and that with single arch extraction of premolars was the longest (685 days) according to types of tooth extraction. 5. The duration of treatment by removable appliance was the shortest (237 days) and the combination of removable appliance, headgear and full banded appliance was the longest (1425 days) according to types of orthodontic appliance. 6. The duration of treatment was 18 months in typical orthodontic treatment with 4 extraction of premolar and full banded appliance.

• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.227-234
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• 1988

To study diagnosis and treatment plan of malocclusion, comparison of race and nation and consideration of treatment technique, 885 orthodontic patients of the department of orthodontics, Infirmary of dental college, Chosun University were evaluated. The frequency and pattern of tooth extraction were studied according to malocclusion types and developmental stages of occlusion and sex. Thefollowingresultswereobtained. 1. Average frequency of tooth extraction for orthodontic treatment was $38.3\%$. 2. The frequency of tooth extraction was $43.7\%$ in class I malocclusion, $34.2\%$ in class II malocclusion and $32.1\%$ in class III malocclusion. 3. The drequency of tooth extraction was the highest in permanent dentition $(49.2\%)$. 4. The frequency of tooth extraction was not different between male and female. 5. The frequency of 3-4 premolars extraction was the highest $(57.5\%)$ and that of lower incisor extraction was the lowest $(2.9\%)$ in patterns of tooth extraction. 6. Both frequency of unilateral and single arch extraction were the highest in class III malocclusion.

• The korean journal of orthodontics
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• v.22 no.2 s.37
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• pp.389-412
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• 1992

Along with form and function relationship of craniofacial growth comes a concern for the masticatory muscles with postnormal occlusion. It is the aim of this study to grope the certain differences upon the electromyographic activities of the masticatory muscles between normal occlusion and class II malocclusion during the varieties of oral functions. 26 persons of normal occlusion whose mean age were 18.9-25.6 years and another 26 persons of class II malocclusion whose mean age were 19.0-28.9 years served for this study. The electromyographic recordings processed by $Medelec^{\circledR}$ MS 25 EMG apparatus were taken from the anterior and posterior temporal, and anterior and posterior masseter muscles of both sides, and suprahyoid muscles as well. Analyses of the data toward such specific activities as mandibular rest, maximal biting, chewing gums and swallowing peanuts turned out the following summary and conclusions. 1. The maximal mean amplitude of the posterior temporalis showed significant augmentation in class II malocclusion, however the anterior temporalis, posterior masseter, and suprahyoid muscles manifested meaningful diminutions. 2. Stronger posterior temporalis and weaker anterior masseter and suprahyoid muscles were arranged in maximal biting with parameters of maximal mean amplitude. 3. The anterior temporalis of working side expressed smaller maximal mean amplitude in class II malocclusion. Significant swelling in duration were shown at anterior and posterior temporalis of working side, and posterior temporalis of balancing side in class II malocclusion, and marked reduction at anterior masseter of balancing side and posterior masseter of working side as well. The lessened latency were expressed at anterior masseter of working side, and anterior and posterior masseter of balancing side. Class II malocclusion group had significant prolongation of silent period duration. Mean silent period duration of 10.75 msec in normal occlusion and 24.37 msec in class II malocclusion were calculated. 4. Significant augmentations of maximal mean amplitude while swallowing peanuts were yielded at right anterior temporalis and posterior temporalis of both sides, however left anterior masseter and right posterior masseter showed diminution. No significant differences in duration showed at every muscle examined in class II malocclusion group.5. Weaker masseter and stronger temporalis were suggested as characteristics of class II malocclusion.

• The korean journal of orthodontics
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• v.10 no.1
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• pp.15-27
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• 1980

This study was undertaken to compare the craniofacial morphology of Class II, Division 1 malocclusion with that of normal occlusion in children, and to investigate the incidence of various Class II, Division 1 craniofacial skeletal patterns. The subjects consist of thirty seven boys and fifty three girls with Class II, Division 1 malocclusion, and forty six boys and eighty one girls 10-15 years with normal occlusion. Measurements were recorded, tabulated and analyzed on the lateral cephalograms by the degree of SNA, SNB and ANB. The following characteristics of the Class II, Division 1 skeletal pattern were observed. 1. The anteroposterior relationship of the maxilla to the cranium in the Class II, Division 1 was very similar to that of normal occlusion. 2, Mandible of the Class II, Division 1 malocclusion was in the posterior position in relation to the cranial anatomy when compared to normal. 3. The chin point as measured by SN Pog and NS Gn showed distal positioning in relation to normal occlusion. 4. SN to mandibular plane angle was large in Class II, Division 1 malocclusion. 5. Mandibular incisor inclination was not significantly different between Class II, Division 1 malocclusion and normal occlusion, but maxillary incisors inclined and positioned labially and consequently overjet was large in Class II, Division 1 malocclusion. 6. Class II, Division 1 malocclusion was divided into four types of craniofacial skeletal pattern. The most common Class II, Division 1 pattern was found to be type C in which SN-Mand. Pl. was above mean range of normal occlusion. The next frequent pattern was found to be type A in which maxilla and mandible were within normal range of protrusion while upper incisors were severly labially inclined.

• The korean journal of orthodontics
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• v.14 no.1
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• pp.151-160
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• 1984

This study was designed to get the informations of the mesiodistal axial inclinations of the posterior teeth and of the relationships between these and other angular measurements of facial bony structures in normal occlusion and malocclusion groups using lateral roentgenocephalograms. The subjects consisted of 73 normal occlusions (31 males 42 females), 38 Class II Division 1 malocclusions (17 males 21 females) and 47 Class III malocclusions (19 males 28 females). The findings of this study are as follows : 1. In mandible, the posterior teeth axes of Class II Division 1 malocclusion group were inclined more mesially and those of Class III malocclusion group were inclined more distally than normal occlusion group. In maxilla, Class II Division 1 malocclusion group showed more distal inclination and Class III malocclusion group showed more mesial inclinaton of 1st, 2nd premolars and more distal inclination of 1st, 2nd molars than those of the normal occlusion group. 2. There was a tendency for teeth axes to maintain nearly the same inclination in relation to occlusal plane irrespective of various OMA and OPA in each group. 3. F M A, P M A and O P A were the largest in Class II Division 1 malocclusion group and O M A, GoA were the largest in Class 111 malocclusion group. 4. There were high correlationships between mandibular teeth inclinations related to mandibular plane and 4 angular measurements except OPA, and between maxillary teeth inclinations related to palatal plane and OPA.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.25.1-25.9
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• 2015

Background: During the orthognathic surgery, it is important to know the exact anatomical location of the mandibular foramen to achieve successful anesthesia of inferior alveolar nerve and to prevent damage to the nerves and vessels supplying the mandible. Methods: Cone-beam computed tomography (CBCT) was used to determine the location of the mandibular foramen in 100 patients: 30 patients with normal occlusion (13 men, 17 women), 40 patients with skeletal class II malocclusion (15 men, 25 women), 30 patients with skeletal class III malocclusion (17 men, 13 women). Results: The distance from the anterior border of the mandibular ramus to mandibular foramen did not differ significantly among the three groups, but in the group with skeletal class III malocclusion, this distance was an average of $1.43{\pm}1.95mm$ longer in the men than in the women (p < 0.05). In the skeletal class III malocclusion group, the mandibular foramen was higher than in the other two groups and was an average of $1.85{\pm}3.23mm$ higher in the men than in the women for all three groups combined (p < 0.05). The diameter of the ramus did not differ significantly among the three groups but was an average of $1.03{\pm}2.58mm$ wider in the men than in the women for all three groups combined (p < 0.05). In the skeletal class III malocclusion group, the ramus was longer than in the other groups and was an average of $7.9{\pm}3.66mm$ longer in the men than women. Conclusions: The location of the mandibular foramen was higher in the skeletal class III malocclusion group than in the other two groups, possibly because the ramus itself was longer in this group. This information should improve the success rate for inferior alveolar nerve anesthesia and decrease the complications that attend orthognathic surgery.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.4
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• pp.221-228
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• 2009

The purpose of the study was to investigate the characteristics of the pronunciation of Korean vowels in patients with class III malocclusion. 11 adult male patients with class III malocclusion(mean ages 22.3 years) and four adult males with normal occlusion(mean ages 26.5 years) were selected for the analysis of eight Korean monophthongs /ㅣ, ㅔ, ㅐ, ㅏ, ㅓ, ㅗ, ㅡ, ㅜ/. The values and relationships of F1, F2 and F3 were derived from the stable section of target vowel in each sentence, and the analysis using formant plots and vowel triangles' distance and area was conducted to find the features of two groups' vowel distributions. Consequently, it was identified that the pronunciation of males patients with class III malocclusion showed high values of F1 in the low vowels, high values of F2 in the back vowels, and remarkably low position of /ㅏ/. The vowel triangle suggested that the triangle areas of male patients with class III malocclusion were shown wider vertically and narrower horizontally than those of males with normal occlusion. These characteristics could reflect the structural features of class III malocclusion such as the prognathic mandible, low tongue position, and advancement of back position of the tongue.

• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.89-104
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• 1988

This study was performed to investigate the relationships between the EMG activity of the masticatory muscles in Angle's Class II div. 1 malocclusion and normal occlusion. This study was ranged from age 12 to 14 year-old for 30 male subjects: 15 subjects were Angle's Class II div. 1 malocclusion, and 15 subjects were normal occlusion with acceptable profile. Their cephalometric measurement were analyzed, and the EMG recordings from the anterior temporal, posterior temporal, masseter, and orbicularis oris muscles were analyzed during rest position, mastication of peanuts, and swallowing. All data was recorded and statistically processed with the VAX-11/780 computer system. The results were as follows: 1. The activity of muscles at rest was highest in the posterior temporal muscle with normal occlusion, as well as in those with Class II div. 1 malocclusion, and the posterior temporal muscle activity of Class II div. 1 malocclusion was higher than that of normal occlusion. 2. During mastication, all muscle activities of Class II div. 1 malocclusion were recorded lower than those of normal occlusion, and the activity of the anterior temporal muscle was higher than that of the posterior temporal muscle in both types of occlusion. 3. As for the activity in orbicularis oris muscle, it was greater in opening phase than in closing phase during chewing cycle with both types of occlusion. 4. During swallowing, the activities of the anterior temporal, masseter, and orbicularis oris muscles of Class II div. 1 malocclusion were recorded lower than those of normal occlusion.

• The korean journal of orthodontics
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• v.35 no.1 s.108
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• pp.60-68
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• 2005

The evaluation of malocclusion has to be done quantitatively and qualitatively. This will be lead toward an analysis of malocclusion severity as well as treatment difficulty. The method of proper evaluation of malocclusion severity and treatment difficulty is necessary to assess treatment effect and efficiency for the orthodontists and to establish fundamentals for planning and executing the health-related policies in private and public institutions. The purposes of this study as the first part of the objective and quantitative analysis of malocclusion were 1) to measure treatment difficulty based on the opinions of several orthodontists. and 2) to investigate the relationships between objective malocclusion severity and subjective treatment difficulty 100 pairs of dental casts that had various types and severity of malocclusion were selected from the orthodontic departments of Kyurghee University and Samsung Medical Center The objective malocclusion severity was measured with the PAR (Peer Assessment Rating) index and the subjective treatment difficulty was evaluated by 8 experienced orthodontists. The relationships between objective malocclusion severity and subjective treatment difficulty were statistically evaluated. There were significant relationships between objective malocclusion severity and subjective treatment difficulty especially in the measurements of the upper anterior alignment, the buccal occlusion. the overjet, the overbite and the midline discrepancy en the malocclusion components. The results of this study can provide the background knowledge to develop a new occlusal index. which contains both the malocclusion severity and treatment difficulty for Korean orthodontists.