• The korean journal of orthodontics
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• v.16 no.1
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• pp.167-177
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• 1986

This study was undertaken to compare the main differences and its effects of the 4 first bicuspid extraction on the face and dental arch of the class II div 1 malocclusion. The subjects consisted of twenty two class II div 1 malocclusion, four males, eighteen females, were 14 Years 2 Months old at the stan of the treatment 16 Year 3 Months old at the end of the treatment. (mean age) Twenty one variables were observed by comparing the statistical data of the pretreatment records with postteratment records, which were consited of eight varibles on the study model digitation, thirteen variables on the tracing of the lateral cephalogram. The following results were obtained. 1. No significant change was observed in the intercanine width. 2. Intercuspal widths of the 1st. premolar and 2nd. premolar were decreased. 3. Change of the overjet was dependant upon upper anterior rather than lower anterior. 4. No significant changes were observed in facial plane angle and ANB angle. 5. Uprighting of the lower 1st. molar had an effect on the increase of the facial height.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.496-503
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• 2001

Maxilla overgrowth who diagnosis with skeletal Class II division 1 have transverse and also sagittal problem. If maxillary growth vector is direction to anterior inferior, mandible is rotation to clockwise pattern and it disturbance it's anterior growth. At this time, treatment goal is restrict of maxillary growth to accomplish ideal intermaxillary relation and one of treatment choice is the application of extraoral force. This report is 3 case treated by activator and headgear combination therapy, who diagnosed with skeletal Class II div. 1 malocclusion.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.95-111
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• 1997

The human speech organ consists of respiration system (lung, larynx), phonation system (vocal cord), articulation system (esophagus, pharynx, uvula, teeth, gingiva, palate, tongue, lip) and resonating system(oral cavity, nasal cavity, paranasal sinus). Because teeth are components of the articulation system, it has been reported that the persons with abnormally positioned teeth generally have abnormal occlusion and pronunciation. In this study, using /ㅅ(s)/, the most commonly mispronunced consonant in children with malocclusion, and the seven single vowels, /사(sa), 서($s\delta$), 소(so), 수(su), 스($s\omega$), 시(si), 세(se)/ and / ㅏ(a), ㅓ($\delta$), ㅗ(o), ㅜ(u), ㅡ($\omega$), 1(i), ㅔ(e)/ were recorded and analyzed using speech analysis program on computer by measuring formants and compared them for investigating the differences in pronunciation in children with Angle's class I occlusions and those with Angle's class II div.1 malocclusion. The result were as follows: 1. In the Angle's Class II div.1 group, there were no significant differences in F1 of all recorded sounds as compared with Angle's Class I group(p>0.05). 2. In the consonants, there were significant differences in F2 of /스($s\omega$)/ and F2/F1 ratio of /사(sa), 서($s\delta$), 시(si)/ between the two group(p<0.05). 3. In the vowels, there were significant differences F2/F1 ratio of /ㅓ($\delta$)/(p<0.05) and no significant differences in F2/F1 ratio between two group(p>0.05). 4. In the consonants, there were significant differences in F2 and F2/F1 ratio when succeeding vowels were high or low, and F2/F1 ratio when front in accordance with tongue position (p<0.05). 5. In the vowels, there were no significant differences in formant in accordance with tongue position(p>0.05)

• The korean journal of orthodontics
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• v.19 no.3
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• pp.35-48
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• 1989

1795 patients who visited orthodontic department from 1979 to 1987, were surveyed on the yearly tendency of patient distribution and state of Angle's classification. The results were as follows; 1. There was increased visiting rate of patient per year and higher visiting rate in female than in male. 2. 8-15 age group was 70.3% in total visiting patients and over 20 age group was 10.8%, under 7 age group was 7.3%. 3. Class I malocclusion was 26.3%, Class II div 1 was 31.0%, Class II div 2 was 1.6% and Class III was 41.1% in total visiting patient. 4. There was increased tendency to be received preventive treatment than fixed treatment and increased extracting rate per year in fixed treatment. 5. There was increased tendency for the number of the patient to be received orthognathic surgery.

• The korean journal of orthodontics
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• v.2 no.1
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• pp.35-40
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• 1971

Since malocclusion affects a large segment of the population, it is by definition a public health problem. The etiology ana treatment of malocclusions have been studied by clinicians; however epidemioloic aspect of tile problem have been neglected. This study was undertaken using Angle's classification to obtain and to evaluate epidemiologic data on the prevalence of malocclusion in a group of 2,378 Yonsei University students, 17 to 23 years of age. All freshmen were selected, except for those students receiving orthodontic treatment and those few with too many missing teeth which prohibits classification by Angle's method. The following results were obtained: 1) Almost $91\%$ of students had malocclusion of the teeth severe enough to require correction. 2) There was a statistically significant difference in malocclusion between males and females($93.66\%$ malocclusion in males, $79.13\%$ malocclusioa in females). 3) Crowding was most pravalent in class I malocclusion. 4) There appeared to be a specific association between the number of lost first molars and Angle's classification. 5) In this study, more class II, Div.2 malocclusion appeared than in Massier's and Frankel's study of Caucasians, which used similar criteria. Class III malocclusion was more prevalent than normal occlusion in the Korean students studied, but in Caucasians' normal occlusion was more prevalent.

• The korean journal of orthodontics
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• v.39 no.1
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• pp.36-42
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• 2009

Objective: The purposes of this study were to provide an epidemiologic data base related to the orthodontic treatment need and to know the changing trends about treatment modality of private orthodontic clinics. Methods: Distribution, trends and orthodontic treatment plan of malocclusion patients were investigated in 1,620 consecutive patients who had been visited and examined in 4 private orthodontic clinics located in Seoul from 2003-2006. Results: Percentage of male and female patients was 26.9% and 73.1% respectively Age distribution had shown that percentage of the patients above 13 years was 78.9%, and above 19 years was 59.0%. Average age of whole patients was 20.5 years. With regard to Angle classification, each percentage of Class I, Class II division 1, Class II division 2 and Class III malocclusion was 38.9%, 34.8%, 2.3% and 24.0%. The percentage of extraction cases(00.9%) outnumbered nonextraction cases(39.1%) and 46% of extraction cases were upper and lower 1st premolar extraction cases. Patients who had chose treatment with fixed appliance and orthognathic surgery was 10.2%. Conclusions: Because the high percentage of adult, Class II malocclusion and orthognathic surgery cases in patients of private orthodontic clinics were shown in this study, orthodontic education program and national health policy in Korea need reformation.

• The korean journal of orthodontics
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• v.25 no.1 s.48
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• pp.87-100
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• 1995

Distributions and trends were examined in 2155 malocclusion patients who had been examined and diagnosed at Deparment of Orthodontics in Youngdong Severance Hospital over a 10 year-period from 1984 to 1993. The results were as follows ; 1. The number of patients per you had nearly quadrupled during the 10 year-period, with females($58.3\%$) outnumbering males ($41.7\%$). 2. Age distribution had shown 7-12 year-old group being the largest($53.3\%$), but percentages of 7-12 year-old and 13-18 year-old groups had been decreasing while that of above-19 patients had gradually incresed. 3. Distributions in the types of malocclusion according to the Angle's Classification had shown $27.8\%$ for Class I, $22.6\%$ for Class II division 1, $7.9\%$ for Class II division 2, and $41.6\%$ for Class III. Percentages of Class I patients had decreased while percentages of Class II and III patients had increased. 4. Non-extraction cases ($75.4\%$) had outnumbered extraction cases ($24.6\%$), with a general trend toward fewer extraction cases over the 10 year period. 5. Patients who had orthognathic surgery had been increasing, with Class I, II, and III cases comprising $8.8\%,\;16.9\%\;and\;74.3\%$, respectively. There had been three times as newly 2-jaw operations as 1-jaw operations. 6. Nearly $4\%$ of the subjects had facial asymmetries, with Class III cases being the most frequent. 7. Patients with TMD symptoms comprised $4.6\%$, with an increasing trend. The symptoms had occurred more frequently in older patients and in females. 8. Geograpic distributions showed majority (3/4) of patients from the nearby areas, namely Gangnam-gu, Seocho-gu and Songpa-gu.

• The korean journal of orthodontics
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• v.26 no.1 s.54
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• pp.113-124
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• 1996

The purpose of this report is to present the successful improvement of occlusal relationship and facial estherics in Class II div.1 malocclusion by orthodontic treatment with upper first premolars and lower second premolars extracted. Before treatment, the patients showed Class II div. 1 relation with severe overjet. deep overbite, large ANB angle, retrusive mandible and a convex soft tissue profile. After treatment, normal canine and molar relationships were obtained. Facial esthetics were improved. There were no mesial tipping of lower first molars and root resorptions. With the adequate diagnosis and treatment plan and biomechanics, the application of upper first and lower second premolar extraction may be one of good strategies in some Class II cases treatment.

• The korean journal of orthodontics
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• v.42 no.6
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• pp.280-290
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• 2012

Objective: This study aimed to compare the effects of conventional and orthodontic mini-implant (OMI) anchorage on tooth movement and arch-dimension changes in the maxillary dentition in Class II division 1 (CII div.1) patients. Methods: CII div.1 patients treated with extraction of the maxillary first and mandibular second premolars and sliding mechanics were allotted to conventional anchorage group (CA, n = 12) or OMI anchorage group (OA, n = 12). Pre- and post-treatment three-dimensional virtual maxillary models were superimposed using the best-fit method. Linear, angular, and arch-dimension variables were measured with software program. Mann-Whitney U-test and Wilcoxon signed-rank test were performed for statistical analysis. Results: Compared to the CA group, the OMI group showed more backward movement of the maxillary central and lateral incisors and canine (MXCI, MXLI, MXC, respectively; 1.6 mm, p < 0.001; 0.9 mm, p < 0.05; 1.2 mm, p < 0.001); more intrusion of the MXCI and MXC (1.3 mm, 0.5 mm, all p < 0.01); less forward movement of the maxillary second premolar, first, and second molars (MXP2, MXM1, MXM2, respectively; all 1.0 mm, all p < 0.05); less contraction of the MXP2 and MXM1 (0.7 mm, p < 0.05; 0.9 mm, p < 0.001); less mesial-in rotation of the MXM1 and MXM2 ($2.6^{\circ}$, $2.5^{\circ}$, all p < 0.05); and less decrease of the inter-MXP2, MXM1, and MXM2 widths (1.8 mm, 1.5 mm, 2.0 mm, all p < 0.05). Conclusions: In treatment of CII div.1 malocclusion, OA provided better anchorage and less arch-dimension change in the maxillary posterior teeth than CA during en-masse retraction of the maxillary anterior teeth.

• The korean journal of orthodontics
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• v.15 no.2
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• pp.229-237
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• 1985

The Purpose of this study was to investigate the differences in soft tissue characteristics according to the dental or skeletal dysplasia. For this purpose, lateral cephalogram of 153 children (Hellman dental age IIIB: control group 32, Angle CIII. div. 1 malocclusion group 55, Angle Cl III group 66) were traced and measured. For these measurements, following conclusions were made. 1. FH A, FH Sn, FH UL, AA' of the Class III group were thicker than those of the normal and Class II group, but FH B, FH LL, BB' of the Class III group were not significantly different from those of the normal group. 2. FH B, FH LL, BB' of the Class II group were thicker than those of the normal and Class III group, but FH A, FH Sn, FH UL, AA' of the Class II group were not significantly different from those of the noraml group. 3. Ans-Sn, FH P were not significantly different in three groups, while PP' of the Class III group was thicker than those of the other groups. 4. The lower lips of the Class II group were more anterioly everted with respect to the lower incisor inclination than those of the other groups. 5. The severity of skeletal dysplasia was partly camouflaged by the soft tissue.