• The korean journal of orthodontics
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• v.31 no.1 s.84
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• pp.1-13
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• 2001

The extraction lot orthodontic treatment can be adopted for aligning crowded dentition, improving facial esthetics and solving a skeletal discrepancy as alternative for a surgical option. Mandibular second premolar extraction was often selected as treatment plan when there we very little or no space shortage in lower arch or limited retraction of the lower incisors was required. The primary object of this study was evaluate a pretreatment condition and examine the amount of tooth movement ior a mandibular second premolar extraction in growing patients. Pretreatment and posttreatment lateral cephalograms of 14 cases that had their four first premolar extracted (4/4 group), 15 cases with upper first and lower second premolar extraction (4/5 group) were selected. Structural method superimposition was conducted to evaluate a difference of dental change between 4/4 and 4/5 group. The results were as follows, 1. Pretreatment factor for 4/4 extraction or 4/5 extraction choice included maxillary incisor axis to occlusal plane, Class II molar relationship, IMPA and interincisal angle. 2. The amount of molar anterior movement in 4/5 group was greater than that of 4/4 group(p<0.05). 3. There was no significant difference between 4/4 group and 4/5 group in aspects of maxillary tooth movement(p<0.05).

• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.165-181
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• 1999

Treatment mechanics should be individualized to be suitable for each patient's personal teeth and anatomic environment to get a best treatment result with the least harmful effects to teeth and surrounding tissues. Especially, the change of biomechanical reaction associated with that of the centers of resistance of teeth should be considered when crown-to-root ratio changed due to problematic root resorption and/or periodontal disease during adult orthodontic treatment. At the present study, in order to investigate patterns of initial displacements of anterior teeth under certain orthodontic force when crown-to-root ratio changed in not only normal periodontal condition but also abnormal periodontal and/or teeth condition, the changes of the centers of resistance for maxillary and mandibular 6 anterior teeth as a segment were studied using the laser reflection technique, the lever & pulley force applicator and the photodetector with these quantified variables reducing alveolar bone 2mm by 2mm for each of maxillary 6 anterior teeth until the total amount of 8mm and root 2mm by 2mm for each of mandibular 6 anterior ones until the total amount of 6mm. The results were as follows: 1. Under unreduced condition, the center of resistance during initial displacement of maxillary 6 anterior teeth was located at the point of about $42.4\%$ apically from cemento-enamel junction(CEJ) of the averaged tooth of them and kept shifting to about $76.7\%$ with alveolar bone reduction. 2. The distance from the averaged alveolar crest level of maxillary 6 anterior teeth to the center of resistance for the averaged tooth of them kept decreasing with alveolar bone reduction, but the ratio to length of the averaged root embedded in the alveolar bone was stable at around $33\%$ regardless of that. 3. Under unreduced condition, the center of resistance during initial displacement of mandibular 6 anterior teeth was located at the Point of about $43\%$ apically from CEJ of the averaged tooth of them and this ratio kept increasing to about $54\%$ with root reduction. But the distance from CEJ to the center of resistance decreased from around 5.3mm to around 3.3mm, that is to say, the center of resistance kept shifting toward CEJ with the shortening of root length. 4. A unit reduction of alveolar bone had greater effects on the change of the centers of resistance than that of root did during initial Phase of each reduction. But both of them had similar effects at the middle region of whole length of the averaged root.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.26-32
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• 2005

A tooth impaction means a state that a tooth does not erupt out of oral mucosa or alveolar bone for many reasons. The reasons for an impaction of the Maxillary central incisor are an odontoma, supernumerary tooth, space loss, prolonged remaining or early loss of a preceding deciduous tooth, abnormalities of crown or root caused by trauma of a deciduous tooth and an ectopic position of a tooth germ. In the case of the impacted maxillary incisor, a rapid mesial movement of a lateral incisor leads a space loss and a midline deviation can be happened. Furthermore, it can cause a cyst. When we treated a patient with an impacted central incisor early, we could see a better prognosis. It means an early diagnosis and an exact treatment are very important. Generally if the impaction is not severe or it is caused by a keratinized covering tissue, a surgical exposure can induce an eruption easily but an orthodontic force is recommended when an eruption does not happen after a surgical method, when the eruption path is too transpositioned to be corrected spontaneously and when an impacted tooth is located so deeply. In the treatment using an orthodontic force, careful considerations about a root length, pulp, and a periodontal tissue can improve the periodontal and esthetic prognosis for the long follow-up results. This case is using an orthodontic traction following a periodic observation and in no expectation of spontaneous eruption. After treatment of this case, I have got some knowledges, so I report this case.

• The Journal of Korean Academy of Prosthodontics
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• v.8 no.1
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• pp.48-55
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• 1968

1958년(年) Fullmer와 $Lillie^9$에 의(依)하여 최초(最初)로 보고(報告)된 Oxytalan 섬유(纖維)는 산(酸)에 내성(耐性)이 강(强)한 섬유(纖維)로 치근막(齒根膜)에 많이 출현(出現)하고 기계적(機械的) 자극(刺戟)에 의(依)하여 배열(配列), 주행(走行) 및 수적(數的)인 변화(變化)를 가져온다. 저자(著者)는 교정력(矯正力)을 이용(利用)하여 치아(齒牙)를 이동(移動) 시킨후(後) 치근막내(齒根膜內) Oxytalan섬유(纖維)의 수(數), 주행(走行) 및 형태(形態)의 변화(變化)를 실험적(實驗的)으로 관찰(觀察)한바 있어 이를 보고(報告)하는 바이다. 본연구(本硏究)에 사용(使用)된 실험동물(實驗動物)로는 체중(體重) 60gram내외(內外)의 자성백서(雌性白鼠) 15마리를 택(澤)하였다. 각동물(各動物)은 Ether마취후(麻醉後) 교정용(矯正用) 고무줄편(片)을 상악우측(上顎右側) 제1구치(第一臼齒)와 제2구치(第二臼齒) 사이에 삽입(揷入)하여 24, 48, 72시간(時間) 간격(間隔)으로 관찰(觀察)하였다. 동물(動物)을 도살후(屠殺後) 상악골(上顎骨)을 적출(摘出)하여 10%중성(中性) 호루마린에 고정후(固定後) 3%의산(蟻酸)으로 탈회(脫灰)하였다. 파라핀 포매후(包埋後) 근원심적(近遠心的)으로 $4{\sim}6{\mu}$의 절편(切片)을 만들어 Hematoxylin-eosin 및 Aldehyde fuchsin염색(染色)을 시행(施行)하여 경험(鏡險)한 결과(結果)는 하기(下記)와 같다. 1. 치아이동후(齒牙移動後) 교원성섬유(膠原性纖維) 및 Oxytalan섬유(纖維)들의 배열(配列)에 있어 뚜렷한 차이(差異)를 보였다. 2. 치아이동후(齒牙移動後) 사주섬유(斜走纖維)는 염박측(壓迫側)에서는 치아장축(齒牙長軸)에 수직(垂直)되게, 견인측(牽引側)에서는 평행(平行)되게 주행(走行)하고 있었다. 3. 48시간군(時間群)에서 세포증식(細胞增殖)이 심(甚)하였다. 4. Oxytalan섬유(纖維)는 치아(齒牙)들에 교정력(矯正力)을 가(加)한후(後) 견인(牽引) 염박(壓迫) 양측(兩側) 공(共)히 수(數)가 증가(增加)하였다. 5. 염박측(壓迫側)에서 Oxytalan섬유(纖維)는 속(束)을 형성(形成)하며 치아장축(齒牙長軸)에 평행(平行)되게 주행(走行)하였다. 6.견인측(牽引側)에서는 하나 또는 두세개의 섬유(纖維)들이 산발적(散發的)으로 치아장축(齒牙長軸)에 평행(平行)되게 하였다. 7. Oxytalan섬유(纖維)의 수(數)는 염박측(壓迫側)에서 보다 견인측(牽引側)에서 더 변화(變化)가 많았다.

• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.775-782
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• 1998

The purpose of this study is to investigate the change of the EGFR mRNA expression in the rat gingival epithelium by the experimental tooth movement. We applied reciprocal force between the upper anterior teeth using NiTi open coil spring and stainless steel wire for 1, 2 3, 7 days. For the detection of EGFR mRNA, in situ hybridization was done in the tissue samples which were taken from the pressure and tension sides of teeth. The results were as follows ; 1. The expression of EGFR mRNA was increased application-time dependently. a. Day 1 mild expression on the basal and spinous cell layers b. Day 2 . moderate expression on the whole layers c. Day 3 : severe expression on the basal and spinous cell layers 4. Day 7 severe expression on the whole layers 2. The expression level of EGFR mRNA in the pressure and tension sides were similar during the whole Period of experiment except seven day application at which the cornified layer of the tension side showed moderate expression. 3. Removal of the appliance after 7-day force application lowered the level of EGRF mRNA expression. It was returned to the mild and control (rare) level at three and seven days after the removal, respectively. In conclusion, EFGR mRNA was increased by the experimental tooth movement on the rat ginigval epithelium. Up-regulation of EGFR mRNA in the gingival epithelium can be regarded as responses to the possible changes caused by the physical stersses to the oral environment to maintain the homeostatic conditions of the periodontium.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.29 no.1
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• pp.54-61
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• 2020

Forced orthodontic eruption(FOE) is a non-surgical treatment approach that allows augmenting both soft- and hard-tissue profiles of potential implant sites, by forced orthodontic extrusion of "hopeless" teeth and their periodontal apparatus. By stretching the gingival and periodontal ligament fibers during extrusion, tension is imparted to the entire alveolar socket, stimulating osseous apposition at the alveolar crest. FOE increases the width of the attached gingiva, and the mucogingival junction remains stable when the gingival margin migrates coronally. Based on these effects, FOE of non-restorable teeth prior to implant placement is a viable alternative to conventional surgical augmentative procedures in implant site development. The aim of this case report is to describes coronal soft-tissue augmentation around fractured teeth, which was achieved by FOE before implant placement.

• The korean journal of orthodontics
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• v.25 no.2 s.49
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• pp.143-152
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• 1995

This study was performed, by Finite Element Method, to evaluate the stress distribution on the periodontal tissue according to activation of the various closing loops and to predict the pattern of movement of maxillary incisors. At the same time, bull loop, key-hole loop, T-loop, combination loop and asymmetrical T-loop which were used for retraction of maxillary incisors was analysed by Finite Element Method. The following results were obtained 1. Horizontal force was the greatest in bull loop, the followed by key-hole loop, combination loop, T-loop and initial tooth movement exhibited uncontrolled tipping. 2. Horizontal force in asymmetrical T-loop compared to other closing loops was remarkably decreased, and the intrusive force on the incisors occurred. 3. As torque was increased, the moment was increased as a linear increment. 4. As moment was increased, initial movement of tooth changed to root movement from uncontrolled tipping.

• The korean journal of orthodontics
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• v.34 no.1 s.102
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• pp.33-45
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• 2004

The purpose of this experimental study was to determine appropriate magnitude of the Gable bends to produce maximum retraction of the anterior teeth. The Calorific Machine was used to illustrate the tooth movement in three dimension. The experimental teeth except the first premolar were embedded in the artificial alveolar bone part. In a series of experiments, the extraction space was closed using arch wires with bull loops into which the gable bends of $10^{\circ},\;20^{\circ},\;30^{\circ}$ degrees were incorporated. The experiments were repeated three times for each degree of the gable bend. Before and after the space closure, radiographs were taken in the sagittal and occlusal directions using occlusal films. Analysis of variance and Scheffe post hoc test were used to determine significant differences among the three groups. The following results were obtained. 1. As magnitudes of the gable bends increased, more bodily anterior tooth movement was seen and the distance of retraction also increased. 2. As magnitudes of the gable bends increase, the amount of posterior tooth protraction decreased while intrusive and buccal movement increased. 3. The arch was coordinated by distal-in rotation of the canine and mesial-in rotation of the second premolar adjacent to the extraction space.

• The korean journal of orthodontics
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• v.27 no.2
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• pp.335-347
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• 1997

Vitamin D is known to exert its action by activating DNA and RBA within target cells to produce proteins and enzymes that can be used in bone resorption process. Particularly, the active form of vitmain D, 1,25-dihydroxycholecalciferol $[1,25-(OH)_2D_3]$, is considered to be one of the most potent stimulators of osteoclatic acitivity in vitro. The purpose of this study was to evaluate the effect of 1,25-Dihydroxyvitamin $D_3$ on the avtivity of periodotal ligament cells and, the experimental tooth movement. Human periodontal ligament cells were collected from the first premolar tooth extracted for the orthodontic treatment, and were incubated in the environment of $37^{\circ}C$, 5% $CO_2$ and 95% humidity. Microtitration(MIT) assay was done at 10, 25, 50 and 100ng/ml of 1,25-Dihydroxyvitamin $D_3$. 21 Sprague-Daft rats were divided into a control gmup(3), and experimental groups(18) where 100g of force from helical spring was applied across the maxillary incisors 1,25-Dihydroxyvitamin $D_3$ was injected into periodontal ligament at the mesial or distal surface of maxillary incisors so that we can compare the control side and the experimental side. Expreimental groups were sac rifled at 12, 24, 36, 48, 72hours and 7 days after force application, respectively. And the obtained tissues were evaluated histologically. The observed results were as follows. 1. The activity of periodontal ligament cells in l0ng/ml or 25ng/ml of 1,25-Dihydroxyvitamin $D_3$ 1,25-Dihydroxyvitamin $D_3$ was not significantly different to the control at the cultivation of 1, 2 and 3 days. 2. The activity of periodontal ligament cells was significantly increased at 3 days in 50 ng/ml of 1,25-Dihydroxyvitamin $D_3$ and 2, 3 days in 100g/ml of 1,25-Dihydroxyvitamin $D_3$. 3. Up to 7 days after force application, there was no difference in osteoblastic activity, tearing of periodontal ligament and proliferation of capillary at tension side between 1,25-Dihydroxyvitamin $D_3$ injection side and the control side. 4. The osteoclastic activity and the resorption of alveolar bone was greater in 1,25-Dihydroxyvitamin $D_3$ injection side than the control side at 36 hours after force application.

• The korean journal of orthodontics
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• v.39 no.1
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• pp.43-53
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• 2009

Objective: The purpose of this study was to compare the difference in three dimensional tooth movement using three different wire sizes($0.018{\times}0.025-in,\;0.016{\times}0.022-in$ 0.016-in) on a NiTi scissors-bite corrector. Methods: Computed tomography(CT) images of the experimental model before and after tooth movement were taken and reconstructed into three dimensional models for superimposition. The direction and the amount of tooth movement were measured and analyzed statistically. Results: The lingual and intrusive movements of the crown of the maxillary second molar were increased as the size of the NiTi wire increased. The roots of the maxillary second metals moved buccally except for the 0.016-in group. The intrusive movement of the roots of the maxillary second molars was increased as the size of the NiTi wire increased. Due to the use of orthodontic mini-implants, anchorage loss was under 0.2 mm on average. Conclusions: The $0.018{\times}0.025-in$ NiTi wire was most effective in lingual and intrusive movement of the maxillary second molar which was in scissors-bite position. Indirect skeletal anchorage with a single orthodontic mini-implant was rigid enough to prevent anchorage loss.