• 대한치과교정학회지
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• 제24권4호
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• pp.897-916
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• 1994

The biologic potential, which is different from the piezoelectric signals, relates tooth movement at least in part to changes in bone metaboliosm in bioelectric theory. The purpose of this experiment was to determine wheather the application of half sine-wave pulsed electromagnetic fields (HSPEMF) could increase both the rate and amount of orthodontic tooth movement. Forty-three male Hartley guinea pigs, weighting approximately 255g, were utilized in this study. The animals were 35 days old at the start of the study. Laterally directed orthodontic force was applied to the maxillary central incisors of 40 Hartley guinea pigs (20 experimental, 20 control). According to the amount of orthodontic force (6g, 12g), they were divided into two sub-groups (10 experimental I, 10 experimental II, 10 control I, 10 control II). During the experimental period, experimental animals were placed in plastic animal holders with their heads positioned in an area of uniform electromagnetic field. Control animals were placed in similar plastic holders that did not carry the electric apparatus. The results were as follows : 1. The application of a HSPEMF to the experimental groups significantly increase the final amount of orthodontic tooth movement observed over a 10-day experimental period. 2. The application of a HSPEMF to the experimental groups significantly increase the velocity of orthodontic tooth movement observed over a 10-day experimental period. 3. There was no significant difference in the final amount of orthodontic tooth movement at the fourth day to the eighth day, but there was significant difference in the final amount of orthodontic tooth movement at the nineth, tenth day during a 10-day experimental period. 4. After 10 days of HSPEMF exposure & orthodontic force, the experimental groups demonstrated more osteodasts in the pressure side than control groups.

• 대한치과교정학회지
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• 제38권5호
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• pp.337-346
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• 2008

교정치료 본질인 치아이동을 보다 효과적으로 하기 위한 기계적 힘외의 다른 자극원으로서 전기적 자극에 대한 효용성이 부각되고 있다. 본 연구는 임상에서 초소형 전기장치에 의한 전기 자극이 교정적 치아이동에 미치는 효과를 실증하기 위해 시행되었다. 교정용 미니 스크류를 식립한 성인 여성 교정 환자 7명의 상악 견치 후방 견인 시 실험측에 150 gm의 기계적 교정력 외에 $20{\mu}A$의 직류 전류를 공급하는 초소형 전기 장치를 고안, 제작, 장착하여 견치의 근원심에 1일 5시간씩 4주간 전류 자극을 흘리고, 대조측에는 기계적 자극만을 가한 후, 매 주간 치아 이동량을 측정하여 치아이동에 있어서 전기자극의 효과를 검증하였다. 실험기간 동안 치아이동률에 있어서 실험군에서 대조군에 비해 1, 2째주에서 33%, 3, 4째주에서 21,4% 증가된 치아이동을 보였다. 실험군의 평균 치아 이동량은 1, 2째주가 3, 4째주에 비하여 컸으며, 그 차이는 각각 47%, 24% 증가된 치아 이동량을 보였다. 실험을 통하여 미세 전류가 적용되어 치아이동을 촉진할 수 있다는 것이 임상적으로 실증되었다. 생물학적으로 최적의 치아이동을 계획하여 치료계획을 단축시킬 수 있는 방법은 기계적 교정력과 전기자극을 동시에 가하는 것이라고 제안한다.

• 대한치과교정학회지
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• 제24권3호
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• pp.673-693
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• 1994

Most adults, unlike growing children, have some periodontal problems which can influence the outcome of the orthodontic treatment. In cases where periodontal disease progression resulted in marked reduction of periodontium, orthodontic treatment could result in the worsening of the periodontal conditions, and therefore orthodontic treatment planning in such adult patients requires special considerations for the periodontal problems. This study investigates the effects of horizontal orthodontic tooth movement on the changes in the mesial, distal and furcation areas of the disease affected periodontium of adult dogs with advanced bone loss. Six adult dogs with healthy periodontium were selected, and mandibular 2nd premolars were extracted. In the mandibular 3rd premolars, angular bony defects in the mesial and distal sides, and horizontal bony defects in the furcation areas were created. Those that received the flap operation and plaque control were designated as the control, those that had horizontal tooth movement without plaque control after the flap operation as Experimental group I, those that had horizontal tooth movement under plaque control without the flap operation as Experimental group II, and those that had horizontal tooth movement under plaque control after the flap operation as Experimental group III. The control group was sacrificed 2 months postoperatively, and the experimental groups were sacrificed 5 months after the initiation of tooth movement. Specimens were histologically analyzed under light microscope. The results were as follows; 1. After the horizontal tooth movements, Experimental group I and II showed angular bony defects in the mesial sides of the roots and the distal side of the furcation areas, which correspond to the pressure sides. 2. After the horizontal tooth movements, Experimental group I and II showed decreased level of alveolar bone crest in the distal sides of the roots, which correspond to the tension sides. 3. Long junctional epithelium in the control group has not been replaced by periodontal connective tissue after the horizontal tooth movements. 4. Limited formation of new bone was observed in the angular bony defects in the mesial and distal aspects of the roots in the control group. 5. Inflammatory cell infiltration in the connective tissue was most severe in the Experimental group I, followed by Experimental group II, III, and the control group in that order. These results seem to indicate that plaque control was the most influencing factor in the alteration of the periodontal tissue after the horizontal tooth movements in the periodontal tissue with alveolar bone defects.

• 대한치과교정학회지
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• 제42권3호
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• pp.118-128
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• 2012

Objective: The aim of this study was to investigate and compare the in vivo effects of prostaglandin E2 (PGE2) administered by different methods on orthodontic tooth movement and bone metabolism macroscopically, histopatologically, and biochemically. Methods: Forty-five young adult New Zealand rabbits were randomly divided into 3 experimental groups (n = 10/group), 1 positive control group (n = 10), and 1 negative control group (n = 5). The experimental rabbits were fitted with springs exerting 20-g reciprocal force on the maxillary incisors and PGE2 (10 ${\mu}g/mL$) was administered by the intravenous, submucosal, or intra ligamentous route aft er appliance insertion and on days 1, 3, 7, and 14 thereafter. All rabbits were sacrificed on day 21 and their premaxillae were resected for histologic evaluation. Results: Tooth movement was observed in the experimental and positive control groups, but the intraligamentous PGE2 group had the highest values of all analyzed parameters, including serum calcium and phosphorus levels and osteoclastic and osteoblastic populations (p < 0.001). Conclusions: Sub mucosal and intraligamentous PGE2 administration significantly increases orthodontic tooth movement and bone metabolism, but the intraligamentous route seems to be more effective.

• Journal of Korean Dental Science
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• 제5권1호
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• pp.37-44
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• 2012

Purpose: Among the facilitation of tooth movement in adult orthodontic treatment methods, surgical approaches are gaining popularity but complications following mechanical bone reduction are a problem. In this study, tooth movement was observed after alveolar bone was chemically demineralized to verify whether tooth movement had been facilitated. Materials and Methods: Twelve rabbits were used. In the experimental group, the alveolar bone of the left first molar area was exposed and demineralized. Thirty seven percents phosphoric acid was applied for 5 minutes for demineralization. The opposite first molar area was used as control. Two teeth were pulled with 200 g force and 4 rabbits each were sacrificed at 3, 7, and 14 days after the force was applied. Histologic examination was done with hematoxylin and eosin and tartrate-resistant acid phosphatase staining. Result: The histologic examination results revealed more bone resorption in the demineralized area. As time passed, the number of osteoclasts increased in the compressed area. The amount of tooth movement was larger in the experimental group compared to the control group but the difference was not statistically significant. Conclusion: The demineralization with etchant resulted in limited bone resorption, more tooth movement and less damage of the cementum after applied orthodontic force.

• 대한치과교정학회지
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• 제44권6호
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• pp.320-329
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• 2014

Objective: To investigate the involvement of ephrinB2 in periodontal tissue remodeling in compression areas during orthodontic tooth movement and the effects of compressive force on EphB4 and ephrinB2 expression in osteoblasts and osteoclasts. Methods: A rat model of experimental tooth movement was established to examine the histological changes and the localization of ephrinB2 in compressed periodontal tissues during experimental tooth movement. RAW264.7 cells and ST2 cells, used as precursor cells of osteoclasts and osteoblasts, respectively, were subjected to compressive force in vitro. The gene expression of EphB4 and ephrinB2, as well as bone-associated factors including Runx2, Sp7, NFATc1, and calcitonin receptor, were examined by quantitative real-time polymerase chain reaction (PCR). Results: Histological examination of the compression areas of alveolar bone from experimental rats showed that osteoclastogenic activities were promoted while osteogenic activities were inhibited. Immunohistochemistry revealed that ephrinB2 was strongly expressed in osteoclasts in these areas. Quantitative real-time PCR showed that mRNA levels of NFATc1, calcitonin receptor, and ephrinB2 were increased significantly in compressed RAW264.7 cells, and the expression of ephrinB2, EphB4, Sp7, and Runx2 was decreased significantly in compressed ST2 cells. Conclusions: Our results indicate that compressive force can regulate EphB4 and ephrinB2 expression in osteoblasts and osteoclasts, which might contribute to alveolar bone resorption in compression areas during orthodontic tooth movement.

• International Journal of Oral Biology
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• 제41권2호
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• pp.63-68
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• 2016

The aim of this study was to investigate the effect of n-3 polyunsaturated fatty acids (PUFAs) on eruptive movement during tooth development. Sprague-Dawley (SD) rat pups were randomly divided into two groups; control group and experimental group. The experimental group was administered daily with n-3 PUFA by intraperitoneal (IP) injection. After 10 days postpartum, rat pups were sacrificed to evaluate the effect of n-3 PUFA on eruptive tooth movement. Histological analyses were by hematoxylin-eosin (H&E) staining. Tartrate-resistant acid phosphatase (TRAP) assay was performed to compare the osteoclast distribution in the bone matrix above the developing molar teeth. Incisor teeth eruptions were noticeably observed in IP group, as compared to control group. Rat pups in IP group showed faster tooth eruption on day 8 after birth. Through histological analyses, IP group showed thinner bone matrix and more osteoclasts above the $1^{st}$ molar teeth, as compared to control group. TRAP assay showed significantly stronger stained pattern that the osteoclast above the $1^{st}$ molar teeth in IP group, as compared to control group. The results suggested that n-3 PUFA could affect osteoclastic activity involved in bony remodeling during eruptive tooth movement.

• 대한치과교정학회지
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• 제13권2호
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• pp.165-176
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• 1983

The hyalinized zone in compressed periodontal ligament seems to be an unavoidable aspect during certain phases of orthodontically produced tooth movement. And these hyalinized zones leads to a standstill of tooth movement. But when hyalinized zones disappears after a certain period of time and tooth movement is established. In the basic aspect of clinical science of orthodontics, it is very important, to study about the process involved and to establish whether a difference of periodontal response by the amount of the applied experimental force exists. The 35 Guineapigs were divided into the control group (5 animals) and the experimental group (Group I-Group VI 30 animals). The experimental tooth movement of Guineapig's maxillary incisors were carried out by rendering continuous force, 5g (Group I, Group II) 35g (Group III, Group IV), 100g (Group V, Group VI) respectively. 15 animals (Group I, Group III, Group V) were sacrificed one week after this experiment. Another 15 animals (Group II, Group IV, Group VI) were sacrificed one week after the removal of active appliences. At the end of the experimental periods, specimens containing tooth and adjacent periodontal structure were obtained and processed for light and electron microscopy. The results were as follows: 1. In Group I, cellular changes of pressured zones showed swollen mitochondria, dilation of rough surfaced endoplasmic reticulum (RER), vesicles and pyknosis of nucleus. 2. In Group III and Group V, the hyalinized tissues showed cell necrosis accompaning ruptures of cytoplasmic membrane and perinuclear envelope, large cytoplasmic vacuoles and many necrotic cell debris. 3. In Group IV and Group VI, hyalinized tissue were eliminated and the primitive mesenchymal cells and blood capillaries were proliferated. 4. In group V, the destruction of the collagenous fibers were observed, while in group I and group III were not observed. 5. In Croup IV and Group VI, the hyalinized zones were still remained partly.

• 대한치과교정학회지
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• 제46권4호
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• pp.228-241
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• 2016

Objective: Root mobility due to reciprocating movement of the tooth (jiggling) may exacerbate orthodontic root resorption (ORR). "Jiggling" describes mesiodistal or buccolingual movement of the roots of the teeth during orthodontic treatment. In the present study, buccolingual movement is described as "jiggling." We aimed to investigate the relationship between ORR and jiggling and to test for positive cell expression in odontoclasts in resorbed roots during experimental tooth movement (jiggling) in vivo. Methods: Male Wistar rats were divided into control, heavy force (HF), optimal force (OF), and jiggling force (JF) groups. The expression levels of cathepsin K, matrix metalloproteinase (MMP)-9 protein, interleukin (IL)-6, cytokine-induced neutrophil chemoattractant 1 (CINC-1; an IL-8-related protein in rodents), receptor activator of nuclear factor ${\kappa}B$ ligand (RANKL), and osteoprotegerin protein in the dental root were determined using immunohistochemistry. Results: On day 21, a greater number of root resorption lacunae, which contained multinucleated odontoclasts, were observed in the palatal roots of rats in the JF group than in rats from other groups. Furthermore, there was a significant increase in the numbers of cathepsin K-positive and MMP-9-positive odontoclasts in the JF group on day 21. Immunoreactivities for IL-6, CINC-1, and RANKL were stronger in resorbed roots exposed to jiggling than in the other groups on day 21. Negative reactivity was observed in the controls. Conclusions: These results suggest that jiggling may induce ORR via inflammatory cytokine production during orthodontic tooth movement, and that jiggling may be a risk factor for ORR.

• 대한치과교정학회지
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• 제38권3호
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• pp.159-174
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• 2008

치아이동 시 피질골 천공이 치조골 재형성에 미치는 영향을 알아보기 위해서 생후 15주된 자성백서를 사용하여 피질골 천공 후 치아이동을 실시한 실험군(Tooth movement with cortical punching: TMC group, n = 16)과 교정적 치아이동만 실시한 대조군(Tooth movement only group: TM group, n = 16)의 치아주위조직을 면역조직화학염색을 통하여 관찰하였다. 실험군과 대조군의 실험동물에 20 gm의 힘으로 상악 전치부 사이를 이개시키는 치아이동을 시행하였으며 실험군에서는 상악 전치부 구개부위에 피질골 천공을 실시하였다. 치아이동 후 1, 4, 7, 14일째에 실험군과 대조군의 실험동물을 희생시켰다. 면역조직화학염색법으로 OPG, RANK, RANKI의 발현을 비교한 결과, OPG의 발현은 양 군 모두에서 미처치 대조군에 비하여 감소되었으나, 실험군에서의 발현이 대조군보다 컸으며, RANK, RANKL은 피질골 천공을 시행한 경우에 더 강한 발현을 보이는 것이 관찰되었다. 따라서 피질골 천공이 치주조직의 OPG, RANK, RANKL의 발현에 영향을 미치며 치조골의 재형성을 향상시키는 것을 알 수 있었다.