• The Journal of Advanced Prosthodontics
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• v.7 no.1
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• pp.51-55
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• 2015

PURPOSE. Bone density at implant placement site is a key factor to obtain the primary stability of the fixture, which, in turn, is a prognostic factor for osseointegration and long-term success of an implant supported rehabilitation. Recently, an implant motor with a bone density measurement probe has been introduced. The aim of the present study was to test the objectiveness of the bone densities registered by the implant motor regardless of the operator performing them. MATERIALS AND METHODS. A total of 3704 bone density measurements, performed by means of the implant motor, were registered by 39 operators at different implant sites during routine activity. Bone density measurements were grouped according to their distribution across the jaws. Specifically, four different areas were distinguished: a pre-antral (between teeth from first right maxillary premolar to first left maxillary premolar) and a sub-antral (more distally) zone in the maxilla, and an interforaminal (between and including teeth from first left mandibular premolar to first right mandibular premolar) and a retroforaminal (more distally) zone in the lower one. A statistical comparison was performed to check the inter-operators variability of the collected data. RESULTS. The device produced consistent and operator-independent bone density values at each tooth position, showing a reliable bone-density measurement. CONCLUSION. The implant motor demonstrated to be a helpful tool to properly plan implant placement and loading irrespective of the operator using it.

• Journal of Periodontal and Implant Science
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• v.34 no.2
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• pp.317-332
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• 2004

Osteoblasts from alveolar bone may have an important role in the bone regeneration for periodontium, but their culture and characterization are not determined yet. The purpose of this study was to investigate the biological characteristics of primary explant cultured osteoblasts(PECO) from alveolar bone. Osteoblasts were isolated and cultured from alveolar socket of extracted tooth in children. To compare the characteristics, osteoblasts and gingival fibroblasts were cultured with DMEM at $37^{\circ}C$, 5% $CO_2$, l00% humidity incubator, and human fetal osteoblasts cell line(hFOB1) were cultured with DMEM at $34^{\circ}C$, 5%, $CO_2$ 100% humidity incubator. To characterize the isolated bone cells, morphologic change, cell proliferation and differentiation were measured. Morphology of PECO was small round body or cuboidal shape on inverted microscope and was similar with hFOB1. PECO became polygonal shape with stellate and had an amorphous shape at 9th passage in culture. PECO had significantly higher activity than that of gingival fibroblasts and hFOB1 in alkaline phosphatase activity. The expression of osteocalcin and bone sialoprotein in PECO was notably increased when compared with hFOB1 and gingival fibroblasts. These result indicated that PECO from alveolar bone in children has an obvious characteristics of osteoblast, maybe applied for the regeneration of bone.

• Journal of Dental Rehabilitation and Applied Science
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• v.19 no.1
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• pp.7-15
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• 2003

This study used FEM(Finite Element method) based on micro-CT images to see the effects of occlusal force distribution with varying bone density and structure. the mandibular premolar region from human cadaver, thickness of 10mm was imaged using micro-CT. the cross sectional images were taken every $10{\mu}m$. these were reconstructed and the longitudinal image at the mid point of mesiodistal of the speciman was obtained for the specimen for the FEM. The stress disribution produced by a vertical force at 100N and 100N horizontal were analyzed by MSC Nastran FEM Package. according to the result of this study the occlusal force distribution depends on the structure of cancellus bone and for further information on the occlusal force distribution on the tooth and the surrounding structure requires further studies on cancellus bone structure. CEJ of all model show the highest peak and region whice meet teeth and bone show second high peak. Original model and cortical bone add model show different stress distribution. Stress distribution changed according to bone structures and densities.

• The korean journal of orthodontics
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• v.33 no.4 s.99
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• pp.279-291
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• 2003

Electric current is a highly probable way as a clinical tool for tooth movement. The purposes of this study were to determine the usefulness of exogenous electric currents in accelerating orthodontic tooth movement and to investigate the effects of electric-orthodontic treatment on the remodeling of the periodontal tissue histologically The study was performed with six male cats weighing around 3kg. The electric device wich is providing the direct electric current of $20{\mu}A$ was inserted to the removable appliance. The right and left maxillary canines were assigned as control and experimental sides respectively. The control canine was Provided with orthodontic force (75gm) oかy and the experimental side was given the same amount of force and electricity. The lingual buttons were bonded to the maxillary canines and both sides of canines were retracted with NiTi coil spring. The electric device was adjusted to provide 20uh direct current to the experimental canines S hours a day The amount of the canine movement was measured with electronic caliper every week. After 4 weeks of tooth movement, the animals were sacrificed and the histologic study was performed. The results of this study were as follows. 1. The application of a direct current to the experimental tooth significantly increased the final amount of orthodontic tooth movement. The amount of tooth movement after 28-day was 37% more in the experimental side. 2. The electrically stimulated tooth showed histologic evidence of significant increases in the amount of bones and matrix deposition in the area of tension. 3. In the compression side, the electric-orthodontic treatment stimulated bone resorption more extensively in the experimental canines. 4. After 28 days of electricity exposure and orthodontic force, the experimental side demonstrated significantly more osteoblasts, osteoclasts, capillaries and osteoid tissues, reflectinr an increase in the local tissue's cellular activity. 5. Intermittent electrical stimulation (five hours a day) had effects to enhance orthodontic tooth movement and tissue remodeling. These results suggested that the low-intensity exogenous electric current by the miniature electric device might accelerate orthodontic tooth movement and bone remodeling in vivo and have the possibility to reduce the orthodontic treatment duration.

• The korean journal of orthodontics
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• v.38 no.5
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• pp.337-346
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• 2008

Objective: The purpose of this study was to determine whether an exogenous electric current to the alveolar bone surrounding a tooth being orthodontically treated can enhance tooth movement in human and to verify the effect of electric currents on tooth movement in a clinical aspect. Methods: This study was performed on 7 female orthodontic patients. The electric appliance was set in the maxilla to provide a direct electric current of $20{\mu}A$. The maxillary canine on one side was assigned as the experimental side, and the other as control. The experimental canine was provided with orthodontic force and electric current. The control side was given orthodontic force only. Electrical current was applied to experimental canines for 5 hours a day. The amount of canine movement was measured with an electronic caliper every week. Results: The amount of orthodontic tooth movement in the experimental side during 4 weeks was greater by 30% compared to that of the control side. The amount of increase in tooth movement in the experimental side was statistically significant. The amount of tooth movement in the experimental side during the first two weeks was !Bleater than that in the following two weeks. The amount of weekly tooth movement in the control side was decreased gradually. Conclusions: These results suggested that the exogenous electric current from the miniature electric device might accelerate orthodontic tooth movement by one third and have the potential to reduce orthodontic treatment duration.

• Journal of Korean Dental Science
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• v.5 no.2
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• pp.77-87
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• 2012

Purpose: This study examined the scanning electron microscopic feature, protein marker expression and osteoinductive activity of demineralized dentin matrix (DDM) from human for nude mice. Materials and Methods: Twenty healthy nude mice, weighing about 20 g were used for study. DDM from Human was prepared and implanted into the dorsal portion of nude mouse. Before implantation, DDM was examined by scanning electron microscopy (SEM). Nude mice were sacrificed at 2 weeks, 4 weeks and 8 weeks after DDM grafting and evaluated histologically by H-E, MT staining. And also immunohistochemistry analysis (ostecalcin, osteopontin) was performed. Result: Dentinal tubules and collagen fibers were observed by SEM of dentin surface of DDM. The DDM induced bone and cartilage independently in soft tissues. And, the histological findings showed bone forming cells like osteoblasts, fibroblasts at 2, 4 and 8 weeks. On immunohistochemistry analysis, osteocalcin and osteopontin positive bone forming cells were observed. Conclusion: This results showed that the DDM from human has osteoinductive ability and is a good alternative to autogenous bone graft materials.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.1
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• pp.23-26
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• 2010

The vascular changes in periodontal tissues cause local hypoxia which seems to affect the periodontal tissue cells. Abrupt changes in oxygen availability within the periodontium have been suggested to have a regulatory role in alveolar bone remodeling during tooth movement, bone growth or fracture healing. The purpose of this study was to study the effects of hypoxia on formation of osteoclast responsible for bone resorption, in vitro. Primary mouse bone marrow cells were cultured in normoxic (20% $O_2$) and hypoxic (1% $O_2$) conditions and assayed for cellular proliferation. The results obtained were as follows : 1. Reducing oxygen tension increased the formation of multinucleated osteoclasts. 2. Hypoxic stimulus increased the size of mature osteoclasts.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.4
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• pp.712-717
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• 1996

The term osteomyelitis literally means inflammation of bone marrow. It is described as an inflammatory condition of bone primarily engaging the medullary cavity extending to the periosteum. Following circulatory collapse and ischemia, the involved portions of the bone become necrotic. Cellulitis and osteomyelitis are the most frequent complications of fractures of the mandible and maxilla, because there is an abscessed tooth in the line of fracture. Since most fractures are compound fractures, infection may develop because of contact with oral secretions or outside air. The treatment of chronic osteomyelitis is still under debate. Some authors rely on antibiotics alone, while others advocate combination with surgery. But when infection occurs, establish proper drainage and administer antibiotics. Author treated a case of infected mandibular fracture with mandibular osteotomy, sequestrectomy, iliac bone graft and hyperbaric oxygen therapy, who had suffered suppurative osteomyelitis and mandibular nonunion following the open reduction of the mandibular fracture.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.19 no.1
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• pp.45-54
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• 1997

The purpose of this investigation was to determine the biomechanical property of calvarial defects reconstructed using toothash, plaster and tooth-plaster mixture. Full-thickness bony defects were made on the rat calvaria with size of $10mm{\times}10mm$. Group 1 was filled with toothash only, group 2 : toothash-plaster mixture, and group 3 : plaster only. The defects were allowed to heal for 12 and 20 weeks before killing the animals. Light microscopic examinations vas taken after 12 week after operation. The hardness was evaluated for test of mechanical property. The following results were obtained : 1. In light microscopic examination 12 week after operation, there were no inflammatory and foreign body reaction. Implanted particles were resorbed gradually or united directly with newly formed bone. 2. In hardness test, the hardness of newly formed bone was lower than that of normal bone and there was significant difference(P<0.01). The site of new bone formation has enough hardness to resist the mechanical stress. These results suggest that toothash and plaster are biocompatible and osteoconductive material.

• International Journal of Oral Biology
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• v.36 no.4
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• pp.187-194
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• 2011

Periodontitis is an inflammatory disorder of the periodontium, characterized by destruction of the tooth supporting tissues including alveolar bone and mediated by various pro-inflammatory mediators. Here, we demonstrated that HP08-0106, composed of four crude drugs-Gardenia jasminoides Grandiflora, Angelica gigas Nakai, Rehmannia glutinosa, and Schizonepeta tenuifolia in a weight ratio of 2:2:1:2, perturbs inflammatory responses, osteoclast formation in LPS-induced RAW 264.7 cells and alveolar bone resorption in ligature-induced periodontitis. HP08-0106 decreased the protein level of iNOS and COX2 as well as the secreted level of IL-$1{\beta}$, indicating that HP08-0106 has antiinflammatory effects. HP08-0106 also inhibited the expression of genes associated with osteoclastogenesis including c-Fos, MMP-9 and TRAP. Moreover, HP08-0106 exhibited a protective effect from alveolar bone loss in ligature-induced periodontitis animal models. Our results strongly suggest that HP08-0106 represent an important therapeutic tool to treat inflammatory disorders associated with bone loss such as periodontitis.