• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.5
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• pp.571-577
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• 2008

Introduction: Possible etiologic factors associated with bone loss around implants after implantation are surgical trauma, occlusal overload, periimplantitis, presence of micro gap and the formation of biologic distances. Tarnow et al. observed that the crestal bone loss was greater when the distance between the implants was <3mm than when the implants were ${\geq}\;3mm$ apart. The aim of this study was to evaluate the influence of different interimplant distance on marginal bone and crestal bone resorption in the beagle dogs. Materials and methods: The mandibular premolars of 5 dogs were extracted bilaterally. After 12 weeks of healing, each dog received 7 implants. On each side, implants were separated by 2mm (Group 1) and by 5mm (Group 2). After 16 weeks of healing, the dogs were sacrificed. Marginal bone loss was determined through linear measurements made between the implant-abutment junctions and the most coronal portions of the bone in contact with the implant surface. A line was drawn uniting the implant-abutment junctions of the adjacent implants, and a linear measurement was made at the midpoint in the direction of the most coronal peak of the interimplant bone crest to determine the crestal bone loss. Both of them was measured radiologically and histologically. Result and conclusion: In radiological analysis, the mean of marginal bone loss was $1.26{\pm}0.14mm$ for group 1 and $1.23{\pm}0.34mm$ for group 2, the mean of crestal bone loss was $1.10{\pm}0.14mm$ for group 1 and $1.02{\pm}0.30mm$ for group 2. The results were not statistically significant between 2 groups. In histological analysis, the mean of marginal bone loss was $1.63{\pm}0.48mm$ for group 1 and $1.62{\pm}0.50mm$ for group 2, the mean of crestal bone loss was $1.23{\pm}0.35mm$ for group 1 and $1.15{\pm}0.39mm$ for group 2. The differences were also not statistically significant. The clinical significance of this result is that the increase in the crestal bone loss results in the increase in the distance between the base of the interproximal contact of the crowns and the bone crest, and this determines if papilla will be present or absent between implants. Considering this fact, keeping up sufficient interimplant distance is important to minimize crestal bone loss.

• The korean journal of orthodontics
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• v.50 no.3
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• pp.157-169
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• 2020

Objective: The aim of this retrospective study was to evaluate the pre- and postsurgical bone densities at alveolar and extra-alveolar sites following two-jaw orthognathic surgery. Methods: The sample consisted of 10 patients (mean age, 23.2 years; range, 18.0-27.8 years; 8 males, 2 females) who underwent two-jaw orthognathic surgery. A three-dimensional imaging program (Invivo 5) was used with multidetector computed tomography images taken pre- and postoperatively (obtained 32.3 ± 6.0 days before surgery and 5.8 ± 2.6 days after surgery, respectively) for the measurement of bone densities at the following sites: (1) alveolar bone in the maxilla and mandible, (2) extra-alveolar sites, such as the top of the head, menton (Me), condyle, and the fourth cervical vertebrae (C4). Results: When pre- and postsurgical bone densities were compared, an overall tendency of decrease in bone density was noted. Statistically significant reductions were observed in the densities of cancellous bone at several areas of the maxillary alveolar bone; cortical and cancellous bone in most areas of the mandibular alveolar bone; cortical bone in Me; and cancellous bone in C4. There was no statistically significant difference in bone density in relation to the depth of the alveolar bone. In a comparison of the bone densities between groups with and without genioplasty, there was almost no statistically significant difference. Conclusions: Accelerated tooth movement following orthognathic surgery may be confirmed with reduced bone density. In addition, this study could offer insights into bone metabolism changes following orthognathic surgery, providing direction for further investigations in this field.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.3
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• pp.314-324
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• 2006

Statement of problem. Osseointegration is important mechanism of dental implant but it is not easy to evaluate. Indirect measurement is non-invasive and clinically applicable but they need more study about correlation between indirect values and degree of osseointegration. Purpose. The aims of this study were to evaluate the coefficient of correlation between indirect measurement and direct measurement under different healing time, and assessment of effect of initial insertion torque to the implant stability. Material and Methods. 20 rabbits received 3 implants on each side of tibia. Three kinds of implants (machined surface implant, Sandblasted with Large grit and Acid etched implant, Resorbable Blast Media treated implant) were used. During the surgery implant insertion torque were measured with $Osseocare^{TM}$. After the 1, 4, 8, 12 weeks of healing time, animals were sacrificed and stability values (Implant Stability Quotient with $Osstell^{TM}$, removal torque with torque gauge) were measured. Results. The Bone quality of rabbit tibia was classified into 2 groups according to the insertion torque. Resonance frequency analysis (ISQ) and removal torque showed positive correlation until $4^{th}$ week (r=0.555, p=0.040). After $8^{th}$ week (r=0.011, p=0.970) the correlation became weak and it turned negative at $12^{th}$ week (r=-0.074, p=0.801). Insertion torque and ISQ showed changing correlation upon the healing time ($1^{st}$ week: r=0.301, p=0.033, $4^{th}$ week: r=-0.429, p=0.018, $8^{th}$ week: r=0.032, p=0.865, $12^{th}$ week: r=-0.398, p=0.029). Insertion torque and removal torque has positive correlation but it was not statistically significant ($1^{st}$ week: r=0.410, p=0.129, $4^{th}$ week: r=0.156, p=0.578, $8^{th}$ week: r=0.236, p=0.398, $12^{th}$ week: r=0.260, p=0.350). Conclusion. In this study, bone quality may affect the degree of osseointegration positively during healing time and correlation between ISQ and degree of osseointegration can be different according to the healing time and bone quality.

• Safety and Health at Work
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• v.2 no.2
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• pp.87-96
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• 2011

In 1967, the problem of occupational lead exposure came to public attention in Korea. Since then, regular progress has been made in lowering workplace lead exposures, instituting new workplace controls, and implementing health examinations of exposed workers. Past serious lead poisoning episodes made it possible to introduce biological monitoring programs on a voluntary basis in high-lead-exposure facilities in Korea. Industry-specific occupational health services for lead workers in Korea during the last 22 years can be categorized into three phases. During the first phase (1988-1993), efforts were directed at increasing awareness among workers about the hazards of lead exposure, biological monitoring of blood zinc protoporphyrin began, and a respiratory protection program was introduced. During the second phase (1994-1997), a computerized health management system for lead workers was developed, blood-lead measurement was added to biologic monitoring, and engineering controls were introduced in the workplace to lower air-lead levels to comply with air-lead regulations. Finally, during the third phase (1998-present), a new biomarker, bone-lead measurement by X-ray fluorescence, was introduced. Bone-lead measurement proved to be useful for assessing body burden and to demonstrate past lead exposure in retired workers. Occupational health service practice for lead workers, including the industry-specific group occupational health system, has brought considerable success in the prevention of lead poisoning and in reducing the lead burden in Korean lead workers during the last several decades. The successful achievement of prevention of lead poisoning in Korea was a result of the combined efforts of lead workers, employers, relevant government agencies, and academic institutes.

• Korean Journal of Acupuncture
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• v.35 no.4
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• pp.210-225
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• 2018

Objective : This research is aimed to compare the three sets of Dongin(K-1, K-2, K-3) to Chosun and Chinese acupuncture bronze men, and through literature review of acupuncture points and meridians to see how acupuncture of Chosun affected the Japan's acupuncture bronze men. Methods : Using 3D scanning, we compared the location of acupoints by the proportional bone measurement method of the three sets of Dongin to those of Chosun and China. We also compared the meridians and acupuncture points of the three sets of Dongin to Doningyosodo. Results : Dongin K-1 and K-2 have all the unique characteristics of ChimGuemDongIn. Their heads were made about 30% larger than the location of points by the proportional bone measurement method and their necks were shortened to get the right proportion. Their gender was not specified. Their hands were sticking forward, and knees were slightly bent, and the arms and legs were carefully crafted to record acupuncture points. Dongin K-1 and K-2 marked the meridians and acupuncture points according to Doningyosodo. In particular, BL39 in Dongin K-1 and K-2 has been marked as in ChimGeumDongIn, which is considered to have come from DongUiBoGam. These characteristics do not exist in Chinese acupuncture bronze men. The location of points by the proportional bone measurement method was marked on the right side of the Dongin K-3, while the eight extra meridians were marked on the left side. Conclusions : In summary, Dongin K-1 and K-2 indicate the Japanese history of acupuncture which may have influenced from Chosun.

• Imaging Science in Dentistry
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• v.30 no.2
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• pp.101-108
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• 2000

Purpose : The effects of step numbers of copper wedge and exposure on the coefficient of determination (r²) of the conversion equation to Cu-equivalent image and on the Cu-equivalent value (mmCu) and it's coefficient of variation measured at each copper step and the mandibular premolar area were evaluated. Method: Digital image analyzing system consisted of scanner, personal computer, and a stepwedge with 10 steps of 0.03 mm copper in thickness as reference material was prepared for quantitative assessment of the bone mineral density. NIH image program was used for analyzing images. Results : The film having moderately high film density showed the discrepancy between the real thickness and the measured Cu-equivalent value of each copper step. The Cu-equivalent image was dependent on the determinational coefficient of the conversion equation than the coefficient of variance of the measured value. Conclusion : Obtaining conversion equation with high coefficient of determination and proper film exposure are supposed to be neccessary for quantitative assessment of bone density. Multiple steps in the range of the corresponding copper thickness to the bone density of the area to be measured should be prepared.

• Journal of Nutrition and Health
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• v.29 no.7
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• pp.778-787
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• 1996

The purpose of present study was to assess the change of bone mineral density(BMD) and the influences of anthroopometric indices and body composition on BMD in Korean women in Taegu. Subjects were 242 healthy female in the range of 7-67 years old, were divided into 4 age groups in order to assess the influence o factors on BMD according to age. Body composition and BMD measurements of lumbar spine, femur(neck, ward's triangle, trochanter) and total body were performed by dual energy X-ray absorptiometry. The analysis indicated that BMD of most region was positively related to body weight, BMI in all groups 4(50-67years), and closely related to femurs than lumbar spine. This study found correlations between BMD and both total fat body mass and total lean body mass in group 1, 2, 3, and correlations between BMD and only total fat body mass and in group 4. But on regression models the most significant prediction of BMD throughout the skeleton was total lean body mass in group 1(7-16years)and 2(17-34years, and total fat body mass in group 3 and 4. It is concluded that the our data can be used to screen early women of low bone mass. This study confirms that one of the most effective way to prevent osteoporosis and the fractures is to maximize peak bone mass in early life and to minimize bone loss through maintaining adequate weight.

• Women's Health Nursing
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• v.14 no.1
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• pp.12-19
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• 2008

Purpose: This study was to identify the influencing factors in postmenopausal women's bone mineral density (BMD). Method: The sample for the study was 107 postmenopausal women who took the BMD test. For BMD measurement, lumbar spine BMD(L2-5) was measured by Dual-energy X-ray absorptiometry(DEXA). Data was collected by questionnaires on the selected variables such as reproductive factors and life style factors. Result: In reproductive factors, parity shows significant differences with BMD (F=4.16, p=.02). In life style factors, diet (F=3.01, p=.05) and exercise (F=7.39, p=.00) show significant differences with BMD. Excercise, diet and parity accounted for 42.0% of the influencing factors in Postmenopausal Women's Bone Mineral Density. Conclusion: The influencing factors in postmenopausal women's bone mineral density were excercise, diet and parity. In this paper, it is suggested that the influence of reproductive and life style factors in postmenopausal women's BMD should be studied by long term and needs repeated research. This study can be used as foundation material for nursing education program development for osteoporosis prevention and improvement.

• Korean Journal of Community Nutrition
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• v.13 no.1
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• pp.125-133
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• 2008

This study was carried out to compare bone density risk factors affecting women's BMD, and to examine the relationship age, lifestyle and dietary habits for bone health by physical measurement and questionnaires. The subjects of this study were 194 women living in the Seoul area. When the subjects were divided into normal and risk groups, BMD, height, weight, BMI, total body water, soft lean mass, fat free mass, protein, mineral, body-fat of normal group were much higher than those of the risk group. The breakfast eating rate of the normal group was much higher than that of the risk group, walking time was significantly longer and exercise was more (p < 0.05). The normal group had more frequent intakes of tunas, squid, radishes, the green parts of radish, cucumbers, carrots and Iucchinis, tomatoes, and grapes than the risk group (p < 0.01 or p < 0.05). In conclusion, breakfast eating, exercise, intakes of some foods such as anchovies, radishes, carrots, zucchinis and tomatoes were significantly important factor to prevent bone density risk.

• Applied Microscopy
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• v.29 no.3
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• pp.377-382
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• 1999

Osteoporosis means a deficiency in the amount of bone tissue in the skeleton or part of the skeleton. Osteoporosis is a lesion, not a specific disease. 'Osteoporotic' describes the slate of a bone or skeleton at a given time. Osteoporosis may be diagnosed subjectively by visual appraisal, or objectively by measurement of radiographs, sawn bones, or microscopic sections. This study was carried out to make clear of the influence of ovariectomy on time course of fibular osteoporosis in rats. Seven weeks after ovariectomy, osteoporosis was evident, when the size of the bone marrow cavities significantly increased and the width from the bone marrow cavity and cortex significantly decreased than normal.