• The korean journal of orthodontics
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• v.36 no.2 s.115
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• pp.103-113
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• 2006

Most elderly women experience a decrease in their bone density due to a deficiency of calcium intake, ovariectomy, or menopause. This study evaluated the usability of the microscrew as a skeletal anchorage system in these orthodontic treatment cases, using rats as a research group. The 4 month old sprague-dawley species rats were divided into two groups, the OS (Ovariectomy Screw), and the SS (Sham operation Screw) group. In both the OS and SS groups, microscrews were implanted into the palatal bone between the upper molar teeth and two upper incisors were retracted using NETE coil spring with 75 g of force. After 3days, the again after 7 days, 7 rats in each group were sacrificed. Three days before they were sacrificed, Alizarin red S was intraperitoneally injected, and their maxillary bone, tibia and blood from their hearts were taken. The components of the extracted blood were biochemically analyzed and non-decalcified grinding resin sections for maxillary bone and tibia were made. The sections were examined with a polarization microscope, and fluorescent microscope. Smaller concentrations of Ca and P, the inorganic substances closely related to bone density, were found in the extracted blood of the OS group. Both OS and SS groups showed a possibility of bone remodeling with a high concentration of ALP after 7 days. An increase in bone density on the tension and compression sides of the microscrew and the tension side of the tooth for both OS and SS groups was confirmed with a polarization microscope. However, the bone density of the pressure side of the tooth and apical side was decreased. More deposits of Alizarin red S in the bone after 7 days rather than 3 days seen with a fluorescent microscope suggested the existence of new bone formation.

• The korean journal of orthodontics
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• v.36 no.6
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• pp.412-421
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• 2006

Objective: The result of finite element analysis depends on material properties, structural expression, density of element, and boundar or loading conditions. To represent proper elastic behavior, a finite element model was made using Hounsfield unit (HU) values in CT images. Methods: A 13 year 6 month old male was used as the subject. A 3 dimensional visualizing program, Mimics, was used to build a 3D object from the DICOM file which was acquired from the CT images. Model 1 was established by giving 24 material properties according to HU. Model 2 was constructed by the conventional method which provides 2 material properties. Protraction force of 500g was applied at a 45 degree downward angle from Frankfort horizontal (FH) plane. Results: Model 1 showed a more flexible response on the first premolar region which had more forward and downward movement of the maxillary anterior segment. Maxilla was bent on the sagittal plane and frontal plane. Model 2 revealed less movement in all directions. It moved downward on the anterior part and upward on the posterior part, which is clockwise rotation of the maxilla. Conclusion: These results signify that different outcomes of finite element analysis can occur according to the given material properties and it is recommended to use HU values for more accurate results.

• The korean journal of orthodontics
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• v.38 no.3
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• pp.187-201
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• 2008

Objective: The aim of this study was to determine whether cortical punching stimulates the expression of matrix metalloproteinase-1, -8, and -13 in orthodontic tooth movement in rats. Methods: A total of 32 male sprague-dawley rats at 15 weeks old were divided into two groups of 16 rats each, to form the tooth movement with cortical punching (TMC) group and tooth movement only (TM) group. A total of 20 gm of orthodontic force was applied to rat incisors to cause experimental tooth movement. Cortical punching was performed on the palatal side near the central incisor with a 1.0 mm width microscrew in the TMC group. The duration of tooth movement was 1, 4, 7, and 14 days. Results: Measurements of the mRNA expression were selected as the means to determine the identification of expression of MMP-1, -8, and -13. In the TMC group, the expression of collagen type I was greater than that of the TM group from day 4 to day 14. Expression of TIMP-1 in the TM group was greater than that of the TMC group in the pressure side of PDL and alveolar bone cell at day 4. In the TMC group, TIMP-1 was expressed at the osteoclast, but not at the tooth surface of the TM group at day 14, Maximum induction of the mRNA of MMP-1 was observed on day 4 in the TMC group, but it was observed on day 7 in the TM group. MMP-8 mRNA of the TMC group was twice greater than that of the TM group at f days. In the TMC group, maximum induction of MMP-13 mRNA was observed on day 1. Conclusions: These findings suggested that cortical punching can stimulate remodeling of PDL and alveolar bone connective tissues during experimental orthodontic tooth movement in rats.

• The korean journal of orthodontics
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• v.38 no.3
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• pp.159-174
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• 2008

Objective: The purpose of this study was to investigate whether cortical punching could stimulate the expression of OPG, RANK, and RANKL during tooth movement by immunohistochemistry. Methods: 34 sprague-dawley rats (15 weeks old) were allocated into 3 groups: TMC group (experimental group; Tooth Movement with Corticotomy, n = 16), TM group (control group; Tooth Movement only group, n = 16), and non-treatment group (n = 2). 20 gm of orthodontic force was applied to rat incisors by inserting elastic bands. The duration of force application was 1, 4, 7 and 14 days. A microscrew (diameter 1.2 mm) was used for cortical punching of the palatal side of the upper incisors in the TMC group. Results: Distributions of OPG, RANK, and RANKL were evaluated by immunohistochemistry. OPG, RANK and RANKL were observed on experimental and control groups. On the compression side, the degree of the expression of OPG decreased in both groups. The expression of RANK was most prominent in the experimental group of day 4. The expression of RANKL was most intensive and extensive in the experimental group of day 7. However, the expression of OPG was decreased in the experimental and control groups compared to the non treatment group. The expression of OPG, RANK and RANKL after force application were decreased at day 14. Conclusions: These findings suggested that cortical punching might stimulate remodeling of alveolar bone during a 2 week period of tooth movement without any pathologic change.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.2
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• pp.112-119
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• 2011

Purpose: Collagen membranes are used extensively as bioabsorbable barriers in guided bone regeneration. However, collagen has different effects on tissue restoration depending on the type, structure, degree of cross-linking and chemical treatment. The purpose of this study was to evaluate the inflammatory reaction, bone formation, and degradation of dehydrothermal treated porcine type I atelocollagen (CollaGuide$^{(R)}$) compared to of the non-crosslinked porcine type I, III collagen (BioGide$^{(R)}$) and the glutaldehyde cross-linked bovine type I collagen (BioMend$^{(R)}$) in surgically created bone defects in rat mandible. Methods: Bone defect model was based upon 3 mm sized full-thickness transcortical bone defects in the mandibular ramus of Sprague-Dawley rats. The defects were covered bucolingually with CollaGuide$^{(R)}$, BioMend$^{(R)}$, or BioGide$^{(R)}$ (n=12). For control, the defects were not covered by any membrane. Lymphocyte, multinucleated giant cell infiltration, bone formation over the defect area and membrane absorption were evaluated at 4 weeks postimplantation. For comparison of the membrane effect over the bone augmentation, rats received a bone graft plus different covering of membrane. A $3{\times}4$ mm sized block graft was harvested from the mandibular angle and was laid and stabilized with a microscrew on the naturally existing curvature of mandibular inferior border. After 10 weeks postimplantation, same histologic analysis were done. Results: In the defect model at 4 weeks post-implantation, the amount of new bone formed in defects was similar for all types of membrane. Bio-Gide$^{(R)}$ membranes induced significantly greater inflammatory response and membrane resorption than other two membranes; characterized by lymphocytes and multinucleated giant cells. At 10 weeks postoperatively, all membranes were completely resorbed. Conclusion: Dehydrotheramal treated cross-linked collagen was safe and effective in guiding bone regeneration in alveolar ridge defects and bone augmentation in rats, similar to BioGide$^{(R)}$ and BioMend$^{(R)}$, thus, could be clinically useful.

• The korean journal of orthodontics
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• v.30 no.6 s.83
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• pp.677-685
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• 2000

Anchorage plays an important role in orthodontic treatment. Because of limited anchorage Potential and acceptance problems of intra- or extraoral anchorage aids, endosseous implants have been suggested and used. However, clinicians have hesitated to use endosseous implants as orthodontic anchorage because of limited implantation space, high cost, and long waiting period for osseointegration. Titanium miniscrews and microscrews were introduced as orthodontic anchorage due to their many advantages such as ease of insertion and removal, low cost, immediate loading, and their ability to be placed in any area of the alveolar bone. In this study, a skeletal Class II Patient was treated with sliding mechanics using M.I.A.(micro-implant anchorage). The maxillary micro-implants provide anchorage for retraction of the upper anterior teeth. The mandibular micro-implants induced uprighting and intrusion of the lower molars. The upward and forward movement of the chin followed. This resulted in an increase of the SNB angle, and a decrease of the ANB angle. The micro-implants remained firm and stable throughout treatment. This new approach to the treatment of skeletal Class II malocclusion has the following characteristics . Independent of Patient cooperation. . Shorter treatment time due to the simultaneous retraction of the six anterior teeth . Early change of facial Profile motivating greater cooperation from patients These results indicate that the M.I.A. can be used as anchorage for orthodontic treatment. The use of M.I.A. with sliding mechanics in the treatment of skeletal Class II malocclusion increases the treatment simplicity and efficiency.

• The korean journal of orthodontics
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• v.34 no.2 s.103
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• pp.197-203
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• 2004

Tweed-Merrifield directional force technology is a very useful concept, especially for the treatment of Glass II malocclusion. It has contributed to treating a favorable counter-clockwise skeletal change and balanced face, while head gear force using high pull J-hook (HPJH) in an appropriate direction is also essential to influence such results. Clinicians have encountered some problems concerning patients' compliance; however skeletal anchorage has been used widely of late because it does not necessitate patients' compliance, yet produces absolute anchorage. In this case, a good facial balance was obtained by Tweed-Merrifield directional force technology using HPJH together with skeletal anchorage, which provided anchorage control in the maxillary posterior area, torque control in the maxillary anterior area, and mandibular response. This indicates 4hat skeletal anchorage can be used to reinforce sagittal and vortical anchorage in the maxillary posterior area during the retraction of anterior teeth. The author used HPJH for torque control, Intrusion, and the bodily movement of maxillary anterior teeth during on masse movement. However, it is thought that such a result nay also be achieved by substituting mini- or microscrews for HPJH. Consequently, Tweed-Merrifield directional force technology using skeletal anchorage for the treatment of Class II malocclusion not only maximiaes the result of treatment but can also minimize patients' compliance.