• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.343-351
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• 1998

The purpose of this study was to investigate the pretreatment and posttreatment dentofacial characteristics of non-extraction patients with Class I malocclusion. And to compare this result with matched non-orthodontic normal occlusion and Class I premolar extraction patients. Such comparison might help identify morphologic characteristics of the non-extraction patients. Initial and final cephalometric evaluation were compared in a sample of 22 patients with Class I malocclusions treated in non-extraction manner with edgewise appliance and MEAW The mean age of the total population was 14 years 9 months and the average treatment time was 2 years 8 months. 32 landmarks were located and digitized on each cephalogram. From these landmarks, 24 linear and angular dimension were obtained. Student's t-test were used to compare the pretreatment - posttreatment results, Nonextraction - Normal groups, and nonextraction Extraction groups. Significance was predetermined at $p{\leq}0.05$. The results were as follows. 1. Before treatment, the mean value of the $ODI\;was\;69.9^{\circ},\;APDI\;was\;82.1^{\circ},\;CF\;was\;152^{\circ},\;EI\;was\;152^{\circ}$ in the non-extraction groups. 2. The skeletal pattern of the non-extraction groups were similar with non-orthodontic normal groupsr, but the non-extraction groups had larger interincisal angle. 3. Comparison between groups treated with and without extraction indicated at pretreatment, the extraction groups had more protrusive lips, smaller interincisal angle, and EI. 4. After treatment, there was no significant changes in the skeletal pattern of the non-extraction groups, but uprighting of the maxillary and mandibular first molar and decrease of the interincisal angle were seen.

• The korean journal of orthodontics
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• v.23 no.4 s.43
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• pp.607-618
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• 1993

If the centric prematurity occurs after orthodontic treatment, it creates centric slide regarded as a possible factor in the cause of temporomandibular disorder and/or postorthodontic relapse. The purpose of this study was to investigate the manner of centric prematurity and centric slide in postorthodantic patients. The 36 orthodontic patients who had been treated with edgewise appliance at least 3 mouths previously were used in this study. After recording centric relation by the leaf gauge technique, the centric prematurity and centric slide were studied using SAM2 articulator and mandibular position indicator. The results were as follows : 1. The highest percentage of centric prematurities were found on the second molars. 2. The buccal incline of the palatal cusp was the most frequent area of centric prematurities in the maxilla, while the lingual incline of the buccal cusp was the most frequent area in the mandible. 3. There were no trends in the direction of centric slide on the mandibular position indicator. 4. There were no significant differences in centric discrepancies between the premolar extraction and nonextraction group.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.547-552
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• 2001

Extracting mandibular incisors for orthodontic treatment may adversely affect the occlusion. However, when properly used, extraction of mandibular inciors is a selection for the correction of the malocclusion. Generally, treatment for crowding needs to select between nonextraction and four premolar extraction. Approaches for crowded mandibular incisors include distal movement of posterior teeth, lateral movement of canines, labial movement of incisors, interproximal enamel reduction, removal of premolars, removal of one or two incisors, and various combinations of the above. Extraction of incisors is used in case of crowding, anterior tooth size discrepancy, absent of maxillary lateral incisors, and ectopic eruption. But severe overjet. overbite, and space are the contraindication of it. A patient had severe crowding on upper anterior teeth, impacted upper left lateral incisor, palatal ectopic eruption of upper right incisor and severe crowding on lower anterior teeth. Lower lateral incisors are extracted for space availability and facial esthetics. We report the case of orthodontic treatment of upper and lower anterior crowding through extraction of lateral incisor.

• The korean journal of orthodontics
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• v.31 no.2 s.85
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• pp.283-300
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• 2001

With socioeconomic development and change of esthetic recognition, the demand for orthodontic treatment and number of orthodontic patients has been increasing so rapidly. And frequency of malocclusion was changed. So this study was done in an attempt to provide an epidemiologic study so that we can accomodate their orthodontic needs adequately and to obtain the reliable quantitative information regarding the characteristics of orthodontic patients. Distribution and trends were examined in 3,070 malocclusion patients who had been examined and diagnosed at Department of Orthodontics, Dental Hospital, Chosun University over 10 year-period from 1990 to 1999. The results were as follows : 1. The number of patients per year was increasing trend and higher visiting rate in female(56.5%) than in male(43.5%). 2. Age distribution had shown 7${\sim}$ 12 year-old group being the largest(37.9%) and each percentage of 13${\sim}$18, 19${\sim}$24, above-19, 0${\sim}$6 year${\sim}$old group was 32.0%, 19.6%, 7.1%, 3.4%. 3. Hellman dental age IVa which is completion of the permanent dentition showed the highest percentage in male and female. 4. Geographic distribution showed a majority of patients in Kwang Ju(71.0%). Group within the distance 10km from Chosun Dental Hospital was 56.3% and group within 20km was 14.7%. 5. Anterior cross bite showed the highest percentage in chief complaints and percentage of Mn. prognathism and protrusion of Mx. teeth was 12.6%, 12.2%. 6. Distribution in the types of malocclusion according to the Angle's classification had shown; 38.9% for Class I, 20.7% for Class II division 1, 2.0% for Class III division 2, 38.4% for Class III. 7. In the dental vertical dysplasia according to the Angle's classification, deep bite was the most frequent in Class II div.1 and div. 2(24.3%, 56.7%) and open bite in Class III(21.4%). 8. In the skeletal sagittal dysplasia, 39.3% of skeletal Class II was due to the undergrowth of the mandible and 46.3% of skeletal Class III was due to the overgrowth of the mandible. 9. Distribution in orthodontic treatment acceding to the extraction and nonextraction had shown 66.9% for nonextraction case, 33.1% for extraction case, and four first bicuspids have been extracted in the highest percentage(38.6%). 10. Patients who had orthognathic surgery comprised 7.9%, with an increasing trend.

• The korean journal of orthodontics
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• v.27 no.6 s.65
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• pp.905-916
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• 1997

The purpose of this investigation were to evaluate facial vortical changes occurring in patients treated orthodontically with first premolar, second remolar and second molar extractions : to compare these changes with those occurring in patients treated orthodontically without extractions : and finally, to evaluate the effects of extractions in facial vortical changes. Cephalometric records of 50 male & female nonextraction patients and 88 male & female extraction patients were obtained from the department of orthodontics at Chosun University, College of Dentistry. The second molar fully erupted pPatients to have little variation according to growth were chosen as the sample for this investigation. For comparisons, the samples of 88 male & female extraction patients were subdivided into 42 first premolar extraction, 24 second premolar extraction, and 22 second molar extraction patients. Fourteen cephalometric measurements were selected to examine whether orthodontic extraction treatment led to vertical changes or not. The pretreatment and posttreatment lateral cephalographs were taken on the same radiographic unit. $SPSS/PC^+$ statistical program was used to compare and to analyze the changes between 'before & after' orthodontic treatment. The results of this study were as follows. 1. There were no statistical significances in any cephalometric measurements between 'before & after' orthodontic treatment regardless of orthodontic extractions for each group. 2. On average, the upper 6 to palatal Plane and the lower 6 to mandibular plane after orthodontic treatment were increased in all group. This means most of orthodontic mechanics are extrusive in nature. Especially, in orthodontic extraction. cases, it may be caused by orthodontic mechanics for space closure and alignments. 3. On average, in the second molar extraction group, the facial vertical dimension was increased after orthodontic treatment. It nay be induced as a result of moving the molars distally to gain enough space to correct the molar relationship and to simultaneously improve the deep bite. 4. There was no statistical significance between orthodontic extractions and facial vertical changes. This means that orthodontic extractions have no influence on facial vortical changes. 5. The cephalometric measurements with statistical significance in ficial vertical changes for each group were PP-MP, Op-MP, $\underline{1}$ to PP and $\overline{1}$ to MP.

• The korean journal of orthodontics
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• v.41 no.4
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• pp.297-306
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• 2011

Nonextraction camouflage treatment in mild Class III malocclusion is achieved by backward movement of the lower dentition and forward movement of the upper dentition. Many camouflage treatment modalities have been used for distal tipping and distal movement of mandibular posterior teeth. The amount of distal movement of mandibular dentition can be improved in cases of severe crowding, even without the patient's cooperation, by using miniscrews for anchorage. However, miniscrew insertion may be unsuccessful, and it may contact the adjacent root because of the distal movement of dentition. Distal tipping of mandibular dentition can be achieved using multiloop edgewise archwires and intermaxillary elastics. However, the complexity of this wire design causes discomfort to patients. Recently, a new treatment using improved superelastic NiTi wires (ISWs) and intermaxillary elastics has been introduced. ISWs can deliver orthodontic force more effectively, and their use with molar tip-back treatment has several advantages-this approach is effective, simple, and easy to use and reduces patient discomfort. The aim of this study was to report a case of camouflage treatment using ISW with tip-back and intermaxillary elastics for distal tipping of mandibular posterior dentition and to evaluate the effectiveness of this treatment in a clinical setting.

• The korean journal of orthodontics
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• v.23 no.4 s.43
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• pp.565-606
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• 1993

The purpose of this study was to evaluate the change of before and after treatment of anterior openbite malocclusions treated by Multiloop Edgewise Archwire technique. The openbite sample consisted of 4 male and 12 female adults, treated with nonextraction or third molar extraction. The normal sample consisted of 58 subjects, which have pleasing facial profile and normal occlusion and no experience of orthodontic or prosthodontic treatment. The 58 subjects of normal sample were subdivided by cephalemetric vertical relationship of face. The 40 subjects, cephalometric vertical relationship of face was in normal range, classified as Normal Sample group 1. The 18 subjects, increased cephalometric vertical relationship of face, classified as Normal Sample group 2. The computerized cephalometric analysis was accomplished with 50 reference points for 22 skeletal measurements, 46 dentoalveolar measurements, 8 soft tissue measurements. Statistical analysis of the data was carried out with paired t-test, Student's t-test, and DUNCAN test using SAS(PC version), The results were as follows : 1. There were no statistically significant differences in skeletal measurement between before and after treatment. The major changes were in dentoalveolar region. 2. After treatment, the long axis of maxillary and mandibular posterior teeth were distally tipped-back, and uprighted to bisected occlusal plane. The interincisal angle was increased. 3. There were no statistically significant increase in the upper posterior dental height and statistically significant decrease in the lower posterior dental height. The upper anterior dental height was increased, but there was no statistically significant increase in the absolute upper anterior dental hight. The lower anterior dental height was increased. 4. After treatment, the maxillary occlusal plane to palatal plane angle and the mandibular occlusal plane to mandibular plane angle were statistically significant increased. Then, there were no statistically significant difference between after treatment group and normal sample group 2. 5. After treatment, the percentage of upper lip length to upper anterior dental height was decreased. Then, There were no statistically significant difference between after treatment group and normal sample group 2.

• The korean journal of orthodontics
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• v.25 no.3 s.50
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• pp.299-310
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• 1995

The purpose of this study is to know about the positional change of second molar when orthodontic treatment is performed. To know about it, we andlysed cephalogram pre. and post treatment for 54 adult patients who werefinished orthodontic treatment by banding to the first molar and classify them into 4 groups Class I extraction group 15, Class I nonextraction group 12, Class II group 13, class Class III group 14. The following conclusions were obtained : 1. In the extraction group of Class I , mandibular second molar showed less extrusion and mon distal inclination than first moarl. But maxillary second molar showed more or less extrusive and mesial inclination to much the same degree of first molar. 2. Inthe non-extractio group of Class I, mandibular second molar in intrusive to first molar, it showed smilar distal inclination to first molar. But maxillary second molar is extrusive similarly to first molar. 3. In the group of Class II , mandibular second molar is less extrusive than first molar and maxillary second molar is more extrusive than first molar. 4. In the group of Class III, mandibular second molar showed similar extrusion to first molar and more distal inclination than first molar. But maxillary second molar showed less extrusion than first molar. 5. A comparision of the positional change of second molar among groups : The change of distance from FH plane to funcation point of maxillary second molar is the difference between Class I extraction group and Class II group, Class I extraction group and Class III group. The change of maxillary second molar to palatal plane and occlusal plane is the difference between Class I extraction group and Class III group. And the change of distance from mandibular plan to furcation point of mandibular second molar is difference between Class I extraction group and non-extraction group, Class I non-extraction group and Class II group, Class I non-extraction group and Class III group. But the change of angle of mandibular second molar to mandibular plane and occlusal plane is make no difference in among groups.