• 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.25 no.4
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• pp.453-463
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• 1995

Most commonly used axis for central incisors in lateral cephalometric radiographs is the line connecting root apex and incisor edge. However, crown axis and root axis do not always coincide in cases of malocclusion patients. The angle created by these axis are called the collum angle, which should be considered in orthodontic diagnosis and treatment. In this study, 31 Class I malocclusion, 30 Class II division 1 malocclusion, 31 Class II division 2 malocclusion, and 31 Class m malocclusion patients were selected and their collum angles were measured. Correlation between these angles and malocclusions was investigated, and the correlation analysis with other parameters in cephalometrics was done. The results were as follows ; 1. The mean collum angles according to the types of malocclusions are ; $3.11^{\circ}{\pm}3.54^{\circ}$ for Class I, $1.23^{\circ}{\pm}2.41^{\circ}$ for Class II division 1, $3.77^{\circ}{\pm}4.39^{\circ}$ for Class II division 2, and $3.90^{\circ}{\pm}4.08^{\circ}$ for Class III malocclusion. 2. Statistically significant differences in collum angles were noted between Class II division 1 group and Class II division 2 and Class III group. 3. Significant correlations were found between collum angles and other parameters used in cephalometrics, namely IMPA for Class I, Wits for Class II division 1, Overbite for Class II division 2 and for ClassIII.

• 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.41 no.4
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• pp.237-254
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• 2011

Objective: The purpose of this study was to compare the displacement patterns shown by finite element analysis when the maxillary anterior segment was retracted from different orthodontic miniscrew positions and different lengths of lever arms in lingual continuous and segmented arch techniques. Methods: A three dimensional model was produced, the translation of teeth in both models was measured and individual displacement was calculated. Results: When traction was carried out from miniscrews in the palatal slope, lingual tipping of crowns and extrusion of the maxillary anterior segment were found in both continuous and segmented arches as the lever arms were made shorter. With miniscrews in the midpalatal suture area, the displacement patterns were similar to the palatal slope, but bodily movement of the upper incisors was observed in both continuous and segmented arches with the lever arm at 20 mm. When lever arms were longer, there was less extrusion of the incisors and more buccal displacement of the canines. Such displacement was shown less in the continuous arch than the segmented arch. The second premolar showed crown mesial tipping and intrusion, and the molars showed distal tipping in the continuous arch. The posterior segment was displaced three dimensionally in the segmented arch, but the amount of displacement was less than the continuous arch. Conclusions: It is recommended that lever arms of 20 mm in length be used for bodily movement of the anterior segment. Use of continuous or segmented arches affect the displacement patterns and induce differences in the amount of displacement.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.3
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• pp.250-259
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• 2011

The aim of this study was to suggest a design for an orthodontic miniscrew which may work most favorably in the thin cortical bone of the adolescent. In this study, orthodontic miniscrews with different diameters, lengths, and body types were manufactured and implanted in two artificial bone samples with different cortical bone thickness. Maximum insertion torque, maximum removal torque, and lateral alteration torque were measured. As a result, the bone quality, body type, diameter, and the length all had their effects on the maximum insertion torque, maximum removal torque, and lateral alteration torque. Cortical bone thickness was the most important factor. In initial stability, conical types showed better results than cylindrical types. Increase in the diameter had favorable effects in achieving mechanical stability. Increase in the length did not have as much influence as the other factors did on the initial stability, but there was a statistically significant difference between screws of 6 mm and 8 mm lengths(p<0.05). In conclusion, the conical type screw with a diameter of 1.8 mm is most favorable in the thin cortical bone of the adolescent. In terms of length, the 8 mm screw is expected to perform better than the 6 mm screw.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.421-429
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• 2001

Since Non-Extraction treatment in some orthodontic case shows unstable result and unfavorable profile, extraction is selected as inevitable treatment option for the harmonious profile, facial skeleton, and the stable dentition on both arches. For the achievement of proper goal, premolars, molars, sometimes incisors or canines are selected to be extracted. The first Premolar is usually extracted for relieving the crowded dentition with which the molar relations are class I to gain stable dentition and proper profile, but often results in the depression of profile or the loss of vortical dimension. On the contrary, the extracton of the second molar helps maintaining the fullness of profile and the vertical dimension, prevents additional space closural procedures which often make the procedures complicated, relieves both anterior and posterior crowding, and substitutes the extraction fossae for newly erupting 3rd molars. From the point of recurrence, the second molar extraction procedure, therefore, is more beneficial. This cases showed the good results of second molar extraction procedures in the patients with class I crowding.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.357-366
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• 2008

Posterior cross-bite is a relatively frequent malocclusion in primary and early mixed dentition and the reported prevalence of posterior cross-bite varies from 7% to 23%. It has been defined as a transverse discrepancy in arch relationship which the palatal cusp of the upper posterior teeth do not occlude in the central fossa of the opposing lower teeth, and can be manifested in a single tooth or in a group of teeth. Posterior cross-bite does not often self-correct and therefore immediate treatment is recommended. Occlusal adjustment to eliminate premature contact that causes mandibular deviation, expansion of narrow maxillary arch, arrangement of the individual teeth to treat asymmetry within the dental arch are the methods of treating cross-bite. In the present case, functional posterior cross-bite was observed in the primary and the early mixed dentition children. The children were treated by the slow maxillary expansion and occlusal adjustment. The outcome of periodic examinations after the correction of cross-bite was favorable.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.4
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• pp.335-341
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• 2013

Impacted maxillary canines are the most frequently impacted teeth after the third molars. The exact etiology of impacted maxillary canines is unknown, but several complications may result from impacted maxillary canines. An early detection of ectopically erupting teeth can lead to performing interceptive treatment such as early extraction of primary canine and provide the best long-term results. In the absence of prevention, clinicians should consider orthodontic treatment followed by surgical exposure of the canine to bring it into occlusion. However, in cases when the finding ectopically erupting teeth and severe root resorption of adjacent teeth are found late, malposed canine can replace the injured teeth. In these presented cases, early diagnosis and treatment of ectopic eruption and root resorption were not performed. The maxillary incisor replacement with ectopically erupting canine can be the alternative treatment of choice with successful results. The reconstructed canine is planned to be checked periodically for the condition of composite resin restoration. Orthodontic treatment and dental implant are planned. This report shows that when early diagnosis was not done, maxillary incisor replacement with ectopically erupting canine could prevent uncertain prognosis of the adjacent teeth with root resorption and provide esthetic satisfactory with time saved and cost reduced.

• The korean journal of orthodontics
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• v.35 no.5 s.112
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• pp.361-370
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• 2005

Fiber reinforced composite (FRC) has been widely used in operative and prosthetic fields of dentistry and its use is expanding into the orthodontic field. The purpose of this study was to examine the changes of flexural properties of FRC reinforced with silica glass fiber (FibreKor, Jeneric/Pentron Inc.. Wallingford. U.S.A.) according to the duration of water absorption. Specimens were grouped according to their shape as round and rectangular cross sections, and were immersed in distilled water at room temperature $(23^{\circ}C)$ for 0 hour 1 hour 1 week. 15 days, 1 mouth and 3 mouths. The number of specimens was 5 for each duration and bending test was done using a torque tester The flexural stiffness after 24 hour water immersion was reduced to 59% for round specimens and 25% for rectangular specimens and after 3 mouths of water immersion it was reduced to 29% and 19% stiffness of the 0 hour-specimen respectively Yield flexural moment after 24 hour water immersion was reduced to 45%for round specimens and 76% for rectangular specimens and after 3 months of water immersion it was reduced to 29% and 60% stiffness of the 0 hour-specimen respectively Ultimate flexural moment after 24 hour water immersion was reduced to 35% for round specimens and 76% for rectangular specimens and after 3 mouths of water immersion it was reduced to 25% and 37% stiffness of 0 hour-specimen respectively. Those results suggested that the flexural stiffness of FibreKor decreased greatly after initial water immersion. Consequently, further research for the maintenance of strength against water will be necessary

• The korean journal of orthodontics
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• v.26 no.5 s.58
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• pp.601-611
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• 1996

Craniofacial growth pattern is an important diagnostic data in the course of orthodontic diagnosis and treatment planning ; it also has great influence in the establishment of occlusion as well as shaping and development of face. There have been many studies to classify different craniofacial growth patterns and attempts to predict growth patterns. This study aimed to correlate craniofacial growth pattern and symphysis morphology. 120 adult patients with age from 19 to 39 (mean age : 23.1) were chosen as subjects , using lateral cephalometric films. their anterior to posterior facial height ratios were calculated. They were divided into 3 groups - clockwise growth pattern with $56\%-62\%$(36subjects), counter-clockwise growth pattern group with $65\%$-80\%$(43subjects) and normal growth pattern group with $62\%-65\%$(41subjects). Symphysis morphology and Prominence evaluation in each subject were studied and the following conclusions were drawn : 1. In comparison of symphysis morphology between the sex groups, men showed large symphysis height and prominence. 2. Concerning the symphysis morphology, the clockwise growth pattern group showed larger height, H/D ratio and actual length but smaller depth, angle, effective length and E/A ratio compared to the counter -clockwise growth pattern group. 3. Those with smaller prominance of symphysis showed clockwise growth tendency and those with larger prominance showed counter-clockwise growth tendency.