• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.3
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• pp.293-304
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• 2011

The purpose of this study was to investigate the displacement and pattern of stress distribution on periodontal ligaments of maxillary first and second molar, and on orthodontic mini-implant (OMI) surface, according to three different insertion angles to the bone surface of OMI using Dragon helix appliance, which is a newly introduced scissors-bite correcting appliance. OMI were placed between second premolar and first molar with three different insertion angles (45, 60, 90 degrees). Displacement and maximum stress distribution area (MSDA) were analyzed by finite element analysis. When the insertion angle to the alveolar bone surface was 90 degrees, maxillary first and second molar both exhibited MSDA at the palatal root apex. Maxillary first molar did not show any significant displacement, while the second molar exhibited intrusive and palatal displacement. On the OMI, as the insertion angle decreased, the MSDA shifted towards the tip, and the amount of displacement had increased. When the OMI was inserted at a 90 degree angle, anchor loss was minimized and scissors-bite correcting effect was maximized.

• The korean journal of orthodontics
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• v.38 no.1
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• pp.5-12
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• 2008

Objective: This study was designed to analyze the primary and secondary stability characteristics of orthodontic mini-screws of tapered design when compared with the cylinder mini-screw. Methods: A total of 48 mini-screws were placed into the buccal alveolar bone of the mandible in 6 male beagle dogs. Comparison was made between tapered and cylinder type mini-screws (Biomaterials Korea, Seoul, Korea). Maximum insertion torque (MIT) was measured using a torque sensor (Mark-10, MGT 50, USA) during installation, and maximum removal torque (MRT) was recorded after 3 and 12 weeks of loading. Results: Taper mini-screws showed a higher MIT value of 22.3 Ncm compared with cylinder mini-screw showing 13.6 Ncm (p < 0.001). The MRT of the taper mini-screw showed a significantly higher value of 9.1 Ncm than those of cylinder mini-screw of 5.7 Ncm at 3-weeks after installation (p < 0.05). However, there was no difference in the MRT value between the taper and cylinder mini-screws at 12 weeks of loading. Conclusions: These results showed that the high insertion torque of the taper mini-screw design increases initial stability until 3 weeks of loading, but does not have any effect on the secondary stability at 12 weeks of loading.

• Journal of Nutrition and Health
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• v.48 no.2
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• pp.157-166
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• 2015

Purpose: The effects of water extract and distillate from the mixture of black goat meat and medicinal herb on MG-63 osteoblast proliferation and mouse bone marrow derived osteoclast formation were investigated. Methods: Proximate composition, volatile basic nitrogen (VBN), mineral content, free amino acid composition and free fatty acid composition in black goat meat were determined. Water extract and distillate were prepared with three groups; goat meat only (BG-E, BG-D), six herbs added group (BG-E6, BG-D6), and eight herbs added group (BG-E8, BG-D8). Osteoblast proliferation, mineralization and calcium uptake activity of MG-63 cells were measured and tartrate resistant acid phosphatase activity of osteoclasts was analyzed. Results: Black goat meat had remarkably low fat and high level of calcium. Glutamic acid was the most abundant amino acid. Herbs added extract groups (BG-E6 and BG-E8) showed increased MG-63 cell proliferation in a concentration dependent manner, while all the distillates did not show the effect. All extracts and distillates showed significantly increased osteoblast mineralization depending on the concentration. In particular, herb added extract, BG-E6, increased 170.3% of control and the distillate of BG-D and BG-D6 increased up to 168.5% and 159.8%, respectively. Calcium uptake activities of all water extracts showed remarkable increase of BG-E6 and BG-E8 up to 615.5% and 628.1% of control, respectively. Ditillates had no effect except BG-D6. All water extracts significantly reduced the activity of tartrate-resistant acid phosphatase (TRAP) in osteoclasts derived from mouse bone marrow. Conclusion: Combination of black goat meat and medicinal herb increased the MG-63 cell proliferation and effectively inhibited osteoclast differentiation in both water extracts and distillate of them, which implies that they could be used as potent functional food materials for bone health.

• Clinics in Shoulder and Elbow
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• v.15 no.1
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• pp.8-15
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• 2012

Purpose: The object of this study was to investigate the difference in torque and pullout strength between the standard anchor insertion (5.0 mm) with a small awl (3.7 mm) and larger anchor insertion (6.5 mm), with a standard awl (5.0 mm) in osteoporotic humeral head. Materials and Methods: The embalmed 24 paired cadaveric shoulders were assigned to either Group A or B. After measuring the bone mineral density (BMD) of the ROI (region of interest) in the humeral head, 5.0 mm suture anchors were inserted using a 3.7 mm awl in Group A1, and the same 5.0 mm anchors were inserted using a 5.0 mm awl in Group A2. The 5.0 mm anchors were inserted using a 5.0 mm awl in Group B1, and 6.5 mm anchors were inserted using a 5.0 mm awl in Group B2. We measured the torques at the time of the anchor insertion and pullout strengths. Results: There was no significant difference in the BMD between the groups. The torque of A1 (20.6 $cN{\cdot}m$) was significantly higher than that of A2 (13.2 $cN{\cdot}m$), and the torque of B2 (20.8 $cN{\cdot}m$) was significantly higher than that of B1(12.1 $cN{\cdot}m$). However, the difference in the increased torque between group A and B was not significant. The pullout strength of A1 (204.2 N) was significantly higher than that of A2 (152.9 N), and the pullout strength of B2 (210.9 N) was significantly higher than that of B1 (149.5 N). However, the difference in the increased pullout strength between Group A and B was not significant. Conclusion: In severe osteoporosis, the use of a larger suture anchor with a standard awl increased the torque and pullout strength significantly, in comparison to the use of the same sized suture anchor and awl. If there is an inadequate interval between the anchors on the greater tuberosity, the use of a 3.7 mm awl and 5.0 mm anchor will be beneficial compared to that of a 5.0 mm awl and 6.5 mm anchor, considering that an increase in the pullout strength does not depend on the awl size.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.2
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• pp.147-161
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• 2012

This study is to assess the effect of horizontal misfit of an implant supported 3-unit fixed prosthodontics on the stress development at the marginal cortical bone surrounding implant neck. Two finite element models consisting of a three unit fixed prosthodontics and an implant/bone complex were constructed on a three dimensional basis. The three unit fixed prosthodontics were designed either shorter (d=17.8mm model) or longer (d=18.0mm model) by 0.1mm than the span of two implants placed at the mandibular second premolar and second molar areas 17.9mm apart. Fitting of the fixed prosthodontics onto the implant abutments was simulated by a total of 6 steps, that is to say, 0.1mm displacement per each step, using DEFORM 3D (ver 6.1, SFTC, Columbus, OH, USA) program. Stresses in the fixed prosthodontics and implants were evaluated using von-Mises stress, maximum compressive stress, and radial stress as necessary. The d=17.8mm model assembled successfully on to the implant abutments while d=18.0mm model did not. Regardless if the fixed prosthodontics fitted onto the abutments or not, excessively higher stresses developed during the course of assembly trial and thereafter. On the marginal cortical bone around implants during the assembly, the peak tensile and compressive stresses were as high as 186.9MPa and 114.1MPa, respectively, even after the final sitting of the fixed prosthodontics (for d=17.8mm model). For this case, the area of marginal bone subject to compressive stresses above 55MPa, equivalent of the $4,000{\mu}{\varepsilon}$, i.e. the reported threshold strain to inhibit physiological remodeling of human cortical bone, extended up to 2mm away from implant during the assembly. Horizontal misfit of 0.1mm can produce excessively high stresses on the marginal cortical bone not only during the fixed prosthodontics assembly but also thereafter.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.23 no.1
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• pp.34-40
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• 2014

There are several treatment options for rehabilitation of partial edentulism including the use of conventional or implant-retained fixed prostheses. However, such prosthetic options cannot always be possible because of compromised general and oral health (i.e. loss of supporting tissues, medical reasons, extensive surgical protocol and osseointegration failure of dental implant) as well as the affordability of patients. In some cases, removable partial denture provides easier access for oral hygiene procedures and the ability to correct discrepancies in dental arch relationships than implant fixed prosthesis. Recently, Implant Supported Removable Partial Denture (ISRPD) where to place dental implant in strategic position has been suggested to improve the limitation and shortcomings of conventional RPD. ISPRD can overcome mechanical limition of conventional RPD by placing implant in a favorable position and can be cost-effective, prosthetic solution for partially edentulous patients who are not immediate candidates for extensive, fixed implant supported restorations. Incorporation of dental implants to improve the RPD support and retention and to enhance patient acceptance should be considered when treatment planning for RPD. In this case, 59 years old male patient who received dental treatment of implant fixed prosthesis on both side of the upper jaw and implant overdenture on lower jaw showed implant abutment screw fracture on #15i and osseointegration failure on multiple number of implants. After removing failed implants, we planned ISRPD using #15i,24i,25i,26i and #23 natural tooth for RPD abutment. We fabricated #23 surveyed crown,#24i=25i=26i surveyed bridge and #15i gold coping for support,retention and stability for RPD. Periodic follow up check for 2years has been performed since the ISRPD delivery to the patient. No sign of screw loosening, fracture or bone resorption around abutment implants were detected.

• The Korean Journal of Cytopathology
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• v.1 no.1
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• pp.93-97
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• 1990

Two cases of giant cell tumor of bone diagnosed by fine needle aspiration cytology are described. Case 1 was a 28-year-old male who had pain sense for one year at the right distal thigh. His radiologic finding revealed a destructive cortical lesion with soft tissue extension at medial side of epiphysis of the distal femur. Case 2 was a 21-year-old female complaining pain at left distal forearm for eight months and showed a well-demarcated expansile osteolytic lesion with multiseptation, and cortical destruction at epiphysis and metaphysis of the left distal radius on the X-ray. Fine needle aspiration of each lesion was performed. The aspirate of the case 1 revealed moderate cellularity, which was composed of scattered giant cells of osteoclastic type and small round to oval monotonous stromal cells in large areas. Giant cells were evenly distributed in single or small groups and had irregular but abundant cytoplasms with 10 to 20 nuclei in the center. The nuclei showed ovoid shape, fine granular chromatin, and a small but conspicuous nucleolus. Stromal cells were dispersed in isolated pattern or sometimes aggregated in clusters and showed the same nuclei as those of giant cells and scanty cytoplasms. Comparing to case 1, case 2 had a more translucent abundant cytoplasm in the giant cells and more spindled stromal cells. All two cases revealed neither nuclear atypism nor increased abnormal mitoses In both giant and stromal cells, suggesting no evidence of malignancy. Thereafter the lesions were treated with excision and curettage, and histologically confirmed as giant cell tumors of the bone.

• Journal of Yeungnam Medical Science
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• v.4 no.2
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• pp.173-178
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• 1987

Osteogenic sarcoma is a malignant primary tumor of bone composed of a malignant connective tissue stroma with evidence of malignant osteoid, bone and/or cartilage formation. A 23year old man was admitted to dental department of Yeungnam University hospital with chief complaint of swelling and pain on alveolar ridge of lower right molar region. It was certain of osteogenic sarcoma through clinical and radiographic features and biopsy. Surgical resection of the lesion was performed by partial mandibulectomy and resin plate insertion. By follow up check of the patient, we made good result of functional reconstruction without any sign of recurrence of the lesion.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.2
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• pp.157-165
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• 2014

Skeletal anchorage is recommended as an orthodontic treatment for an impacted immature permanent tooth. Among these methods, C-tube is relatively safe because it is fixed to the cortical bone of interdental and the lower part of the root with several short miniscrews, which causes less damage to the root in patients of early permanent dentition. As it can be easily bent, the traction direction can be adjusted to favorable bone density sites. However, patient cooperation is important and traction based on physiological force in order to gain root and dentoalveolar tissue development in immature permanent teeth is required. Periodic follow-ups should be mandatory.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.1
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• pp.13-19
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• 2017

The use of ultrasonic surgery units and scalers are steadily increasing in the field of dentistry. Such units and scalers should be evaluated before they are commercialized because the mechanical performance and stability of equipment is crucial for patients. Hence, we created a hand-piece moving system that can test bone cutting and teeth scaling. The purpose of this study was to evaluate the teeth scaling performance of ultrasonic scaler unit. Additionally, we measured the temperature distribution and noise during the test. through an experimental test, we found that a high output of an Ultrasonic NX device can cause serious damage to the teeth surface, and it was not within range in heat generation distribution and noise test.