• Journal of Periodontal and Implant Science
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• v.37 no.sup2
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• pp.353-369
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• 2007

Gingival tissue samples were obtained during periodontal surgery or tooth extraction. According to the patient's systemic condition & clinical criteria of gingiva, each gingival sample was divided into three groups. Group 1 (n=8) is clinically healthy gingiva without bleeding and no evidence of bone resorption or periodontal pockets, obtained from systemically healthy 8 patients. Group 2 (n=8) is inflamed gingiva from patients with chronic periodontitis. Group 3 (n=8) is inflamed gingiva from patients with chronic periodontitis associated with type 2 diabetes. Tissue samples were prepared and analyzed by Western blotting. The quantification of $IL-1{\beta}$, MMP-13 and TIMP-1 were performed using a densitometer and statistically analyzed by one-way ANOVA followed by Tukey test. 1. The expressions of MMP-13 and TIMP-1 showed increasing tendency in group 2 & 3 compared to group 1. 2. The expressions of $IL-1{\beta}$ & MMP-13 were showed increasing tendency in group 3 compared to group 2. 3. As $IL-1{\beta}$ levels were increasing, MMP-13 showed increasing tendency in group 3, and although $IL-1{\beta}$ , MMP-13 levels were increasing, TIMP-1 levels were similar expressed comparing to group 2. In conclusion, this study demonstrated that the expression levels of MMP-13 and TIMP-1 had increasing tendency in inflamed tissue. It can be assumed that $IL-1{\beta}$ and MMP-13 may be partly involved in the progression of periodontal inflammation associated to type 2 DM.

• Journal of Periodontal and Implant Science
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• v.37 no.sup2
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• pp.325-338
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• 2007

The purposes of this study were to compare and quantify the expression of IL-6, e1stase and ${\alpha}_1-PI$ in the gingival tissues of patients with type 2 diabetes mellitus and healthy adults with chronic periodontitis. Gingival tissue samples were obtained during periodontal surgery or tooth extraction. According to the patient's systemic condition & clinical criteria of gingiva, each gingival sample was devided into three groups. Group 1 (n=8) is clinically healthy gingiva without bleeding and no evidence of bone resorption or periodontal pockets, obtained from systemically healthy 8 patients. Group 2 (n=8) is inflammed gingiva from patients with chronic periodontitis. Group 3 (n=8) is inflammed gingiva from patients with chronic periodontitis associated with type 2 diabetes. Tissue samples were prepared and analyzed by Western blotting. The quantification of IL-6, elastase and ${\alpha}_1-PI$ were performed using a densitometer and statistically analyzed by one-way ANOVA followed by Tukey test. 1. The expression levels of IL-6 showed increasing tendency in group 2 and 3, and It was highest in group 3. 2. The expression of elastase showed increasing tendency in group 2 and 3, and It was highest in group 3. 3. The expression of ${\alpha}_1-PI$ showed increasing tendency in group 3 compared to group 1. 4. The ${\alpha}_1-PI$/elastase ratio was decreased in group 2 and 3 compared to group 1, especially most decreased in group 3. 5. As IL-6 levels were increasing, elastase showed increasing tendency in group 3, and although IL-6 and elastase levels were increasing, ${\alpha}_1-PI$ level in group 3 showed slightly increasing pattern comparing to group 1. In conclusion, this study demonstrated that the expression levels of IL-6 and elastase will be inflammatory markers of periodontal inflammed tissue and DM. The ${\alpha}_1-PI$/elastase ratio also may be important measuring inflmmatory factors in the progression of periodontal inflammation associated to type 2DM.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.309-317
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• 2000

Bisphosphonates inhibit bone resorption in vivo and in vitro. Currently proposed mechanism of action of bisphosphonates involves both direct effect on osteoclasts and indirect effect through the mediation of osteoblasts. Recent understanding of molecular mechanism of osteoclastogenesis indicates that osteoclast differentiation is quite tightly regulated by signaling molecules from differentiating osteoblasts. Therefore this investigation was designed to elucidate the effect of bisphosphonate on osteoblast differentation. For this purpose, in vitro effects of etidronate and alendronate on the expression of Cbfa1 a master control gene of osteoblast differentiation, several bone marker genes, and formation of calcified nodules were evaluated. To evaluate the effect of bisphosphonate on calcified nodule formation, osteoblasts isolated from rat calvaria were cultured in a-MEM containing $10^{-4},\;10^{-5},\;10^{-6}M$ of etidronate or $10^{-6},\;10^{-7},\;10^{-8}M$ of alendronate for 15 days, and then stained by alizarin red to determine mineralization. To evaluate the effect of bisphosphonate on osteoblast differentiation, osteoblast cells were cultured in a-MEM containing $10^{-4},\;10^{-5},\;10^{-6}M$ of etidronate or $10^{-6}$ M of alendronate for 8 days. And then total RNA was extracted and northern blot analysis was done to examine the expression of Cbfa1, type I collagen, alkaline phosphatase, osteopontin and osteocalcin. The results were as follows: 1. Etidronate suppressed the calcification of bone nodule in dose dependent manner, while alendronate didn't. 2. The expression of Cbfa1 was decreased dose dependently by etidronate, but increased by alendronate. 3. Etidronate suppressed the expression of type I collagen, osteopontin and osteocalcin in dose dependent manner however alendronate promote the expression of osteoblast marker gene. 4. The expression of alkaline phosphatase was not affected either etidronate nor alendronate. These results suggest that etidronate suppressed the expression of Cbfa1 in dose dependent manner, and consequently the expression of osteoblast marker genes, such as type I collagen, osteopontin and osteocalcin were also suppressed in similar manner. And finally this decreased expression of osteoblastic marker gene prevent calcined bone nodule formation.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.4
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• pp.405-417
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• 2010

Previous studies have already shown that mouthguard is effective in protecting jaw bone, teeth and oral tissue against sports trauma. However, other than severe trauma, repetitive force, such as disorders like clenching, cause teeth or oral tissue damage. These kinds of disorders usually present pathologic attrition in the posterior teeth, resorption in alveolar bone, loss of teeth and destruction of occlusion. Wearing a mouthguard is believed to be effective in preventing these disorders. But its effect is not examined thoroughly enough. The purpose of this study is to identify whether mouthguard is effective in reducing strain caused by clenching. Mandibular first molars in the normal occlusal relationship without any history of dental treatment were chosen. Biaxial type strain gauge was placed on the buccal surface of the tooth. Having maximum occlusal force, measured by load cell, as a standard, clenching intensity were divided into three stages; moment of slightly tooth contact, medium bite force (50% of maximum bite force), maximum bite force. Strain occurring in dentition in each stage with and without mouthguard was measured. Changes in strain (on dentition) between each stage and difference in strain, between with or without mouthguard were recorded by PCD-300 analyzer and PCD-30 soft ware. The data was statistically analyzed by Wilcoxon signed rank test. The following results were drawn; Without mouthguard, strain given on dentition increased as the clenching force increased. With mouthguard, strain given on dentition also increased as the clenching force increased. With mouthguard, strain decreased, in all cases of clenching force stages. Data on the moment of slightly tooth contact stage, had no statistical significance. However, with mouthguard, 50-90% of decrease in strain could be obtained in maximum occlusal force, compared to the group without mouthguard. Mouthguard decreased the strain on the dentition, caused by clenching. Therefore, mouthguard seems to be effective in preventing damage on dentition, by acting against clenching, which occurs both consciously and unconsciously during sports activities.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.20 no.4
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• pp.305-315
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• 1998

The fibrous layer of mandibular condyle of the neonatal, 1-, 7-, 14-, 27-, 55-days and 1 year old rats were examined in the electron microscope with particular attention to the ultrastructure and diameter of collagen fibrils. In the 1-day rats, most of the cells of the fibrous layer were undifferentiated mesenchymal cells and fibroblasts with rough a little developed rough endoplasmic reticulum(RER) and golgi apparatus(GA). In 7-, 17 and 27-days old rats, most of the fibroblast showed well developed GA and RER with widely distended cisternae containing granular materials. In many of these cells contained intracytoplasmic filaments among the cytoplamic organelle. In 55-day and 1-year old rats, three types of cells were observed, ie, cells containing well developed cytoplasmic organelle presumed to be involved in the collagen fibril synthesis, cells showing well developed lysosomes, golgi apparatus, mitochondria and short cytoplasmic process presumed to be involved in the active resorption of the injured collagen fibrils or cellular debris, cells containing many intracytoplasmic filaments and a little organelle presumed to be cells of inactive state. The average diameters of collagen fibrils were similar in 1- and 7-day old rats as $38.48{\pm}3.81nm$, $38.06{\pm}3.86nm$. That was thickest in 14 days old rats as $50.21{\pm}3.93nm$ among experimental groups. They were gradually thinner in 27-, 55-day rats as $40.05{\pm}2.52nm$, $43.63{\pm}1.20nm$ and thinnest in 1-year old rats as $37.38{\pm}2.17nm$. The distribution pattern of diameters of collagen fibrils were unimordal with peak of 30-60nm in rats from 1-day to 17-day old. With aging from 27-day to 1 year old rats, collagen fibril diameters showed wide distribution pattern and percentage of thin collagen fibrils increased. These results may show the functional adaptation of fibrous layer of mandibular condyle to the increased mechanical forces with aging.

• The korean journal of orthodontics
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• v.33 no.3 s.98
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• pp.199-210
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• 2003

Tooth movement is the result of bone metabolism in the periodontium, where various cytokines take important roles. Interleukin-6(II-6) and nitrous oxide (NO) were reported to be secreted from osteoblasts in the process of bone resorption. The mechanism of the process has not been clearly understood, but the activation of mitogen-activated protein kinase (MAPK) was known to be an important process in the release of the inflammatory cytotines in macrophages. In this regard, to prove the role of MAPK in the release of IL-6 and NO in MC3T3E-1 osteoblasts, Northern blot analysis, Western blot analysis and immune complex kinase assay were used. As a result, the treatment of MC3T3E-1 osteoblast cultures with combined $interferon-\gamma(IFN-\gamma)$, lipopolysaccharide (LPS) and tumor necrosis $factor-\alpha(TNF-\alpha)$ induces expressions of inducible nitric oxide synthase (iNOS) and IL-6, resulting in sustained releases of large amounts of NO and IL-6. However, $IFN-\gamma,\;LPS,\;and\;TNF-\alpha$ individually induce a non-detectable or small amount of NO and IL-6 in MC3T3E-1 osteoblasts. The role of MAPK activation in the early intracellular signal transduction involved in iNOS and IL-6 transcription in the combined agents-stimulated osteoblasts has been investigated. The p38 MAPK pathway is specifically involved in the combined agents-induced NO and IL-6 release, since NO and IL-6 release in the presence of a specific inhibitor of p38 MAPK, 4-(4-fluorophenyl)-2-(4-metylsulfinylphenyl)-5-(4-metylsulfinylphenyl)-5-(4-pyridyl)imidazole) (SB203580), were significantly diminished. In contrast, PD98059, a specific inhibitor of MEK1, had no effect on NO and IL-6 release. Northern blot analysis showed that the p3a MAPK pathway controlled the iNOS and IL-6 transcription level. These data suggest that p38 MAPK play an important role in the secretion of NO and IL-6 in $LPS/IFN{\gamma}-or\;TNF-\gamma-treated\;MC3T3E-1$ osteoblasts.

• 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.

• Korean Journal of Community Nutrition
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• v.7 no.1
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• pp.121-129
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• 2002

Osteoporosis, the typical metabolic bone disease of the elderly, is characterized by a reduction in bone mineral density (BMD) and increased fracture risk. Genetic and environmental factors are known to play a key role in bone metabolism, and diet is also considered to be one of the important factors. The purpose of the present study was to investigate the relationship among the factors affecting BMD, including stature, body weight, age, time period since onset of menopause, and biochemical markers of bone turnover in postmenopausal women. Seventy-eight postmenopausal women who visited health promotion center for health examinations volunteered to participate in this study and they were divided into two groups according to the time period since onset of menopause : women with a time period since onset of menopause of less than 5 years (Group 1) and women with a time period since onset of menopause of 5 years or more (Group 2). The demographic characteristics and dietary intake were surveyed using a questionnaire. BMDs of the lumbar spine and femoral neck of subjects were measured by dual energy X-ray absorptiometry. Serum levels of 25-hydroxy-vitamin D and parathyroid hormone (PTH), known to be indicators of bone related hormone status, were anlyzed. Serum samples were measured for calcium, phosphorus, alkaline phosphatase, and osteocalcin as bone formation indicators, and urine was analysed for deoxypyridinoline, creatinine, calcium, and sodium as bone resorption indicators. The results are as follow : The mean BMDs of the lumbar spin and femoral neck were $1.02 \pm 0.02 g/cm^2 and 0.81 \pm 0.02 g/cm^2 respectively, and the BMD level of Group 2 was significantly lower than tat of Group 1 (p<0.01, p<0.05, respectively). The mean daily intake of energy was 1838 $\pm$ 55 kcal. When nutrient intake was compared with the recommended dietary allowances (RDA) of the subjects, only calcium, vitamin A and riboflavin intake showed means lower than the RDA. The nutrient intake did not show any significant differences between Group 1 and 2 Serum and urine levels of biochemical markers of bone turnover did not show any significant differences between Group 1 and 2, and all were within the normal range. However, the PTH and deoxypyridinoline levels showed a tendency to be higher, and the osteocalcin level to be lower in Group 2 than in Group 1. Although age and years after menopause (YAM) showed negative correlations with lumbar spine bone mineral density (LBMD) (r= -0.38, p<0.001, and r= -0.26, p< 0.05, respectively), no correlation was found with femoral neck bone mineral density (NBMD). While height, body weight and body mass index (BMI) showed a positive correlation with LBMD (r= 0.32, p<0.001, r= 0.38, p<0.001, r= 0.22, p= 0.05, respectively), only body weight and BMI showed a positive correlation with NBMD (r= 0.30, p<0.01, and r= 0.27, p<0.05, respectivley). There was no significant corealtion between BMDs and the nutrient intake of subjects, except in the case of carbohydrates (r= 0.22, p<0.05). Also, serum and urine levels of bone turnover markers showed no significant correlation with nutrient intake. On the other hand, serum osteocalcin had a positive correlation with vitamin C intake (r= 0.22, p= 0.05), and urine deoxypyridinolin showed a negative correlation with niacin intake (r= -0.22, p= 0.05). Urinary na was negatively correlated with protein intake(r= -0.23, p= 0.05). The results suggested that it is difficult to prevent the decrease in bone mass among postmenopausal women eating the usual Korean diet. However, the BMDs of the lumbar spine and femoral neck were positively related to body weight ad BMI in postmenopausal women. Therefore, this study confirmed that one of the most effective ways to minimize bone loss in postmenopausal women would be to maintain an adequate body weight with balanced nutrient intake and activity in the pre-and postmenopausal periods.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.1
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• pp.59-72
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• 2000

In this study, the rate of bone formation and the pattern of bone to implant contact surface around HA coated implant and pure Ti implant inserted into the irradiated tibia of rabbit were compared. Sixteen mongrel mature male rabbits were used as experimental animal. Each rabbit received 15 Gy of irradiation. Four weeks after irradiation, two holes were prepared on the tibia of each rabbit for placement of HA coated type and pure Ti type implants. Prior to implant placement, one group received steroid irrigation and the control group was similarly irrigated with normal saline. This was immediately followed by placement of the two different types of implants. Postoperatively, tetracycline was injected intramuscularly for 3 days. For fluorescent labelling, 3 days of intramuscular alizarine red injection was given. 2 weeks before sacrifice, followed by intramuscular calcein green on the last 3 days before specimen collection. Each rabbit was sacrificed on the second, fourth, sixth and eighth week after the implantation. The specimens were observed by the light microscope and the fluorescent microscope. The results were as follows; 1. All implants inserted into the irradiated tibia of rabbit were free from clinical mobility and no signs of bony resorption were noted around the site of implant placement. 2. Under the light microscope, new bone formation proceeded faster around implants that received steroid irrigation compared to the control group irrigated with saline. Bone to implant contact surface was greater in the steroid irrigated group than the saline irrigated group. Therefore, better initial stabilization was observed in the group pretreated with steroid irrigation. 3. Under the light microscope. HA coated implants showed broader bone to implant contact surface than pure Ti implants, and HA coated implants had better bone healing pattern than pure Ti implants. 4. In the steroid pretreated group, acceleration of bone formation was demonstrated by fluorescent microscopy around the 2, 4 weeks group and the 6 weeks HA coated implant group. The difference in the rate of bone formation proved to be statistically significant(P<0.05). Faster bone formation was noted in the saline irrigated group in the 6 weeks pure Ti implants and 8 weeks group. The difference was not statistically significant(P<0.05). 5. For the rabbits that were sacrificed on the second and fourth week after the implant placements, the rates of bone formation around HA coated implants proceeded faster than those around pure Ti implants under the fluorescent microscopy. For the rabbits that were sacrificed on the sixth week after the implant placements, the rates of bone formation around pure Ti implants proceeded faster than those around HA coated implants under the fluorescent microscopy. But this result did not show statistical significance (P<0.05) For the rabbits that were sacrificed on the eighth week after the implant placements, the rates of bone formation around HA coated implants proceeded faster than those around pure Ti implants under the fluorescent microscopy. This result was statistically significant (P<0.05).

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.404-416
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• 2001

Purpose : Traditionally, the treatement of choice has been a bone grafting procedure to increase the length of bone in case of actual length discrepancy. But, bone grafting procedure has many disadvantages, for example, graft resorption, donor site morbidity, and so on. So, many trials have been performed to avert the use of autogenous bone graft via introducing new materials or methods. And, one of those trials has been realized by the development of a technique inducing bone lengthening by osteotomy (or corticotomy) and slow gradual distraction of the osteotomized segments. This new technique of bone lengthening dates back to the early 20th century. But, the majority of information concerning the biology of new bone formation during bone lengthening and technical details of the procedure were produced by extensive clinical and experimental studies performed by Ilizarov, a Russian surgeon. According to Ilizarov, with adequate blood supply, preservation of periosteum, rigid fixation of the osteotomized segments, and proper rate and rhythm of distraction, intramembranous bone rapidly develops within the distraction gap in the limb lengthening procedure. In the limb lengthening, many orthopedic surgeons try to observe the biologic and clinical principles recommended by Ilizarov. In the oral and maxillofacial region, however, not a few studies must be performed to apply this surgical technique in the clinical cases. Besides, the mechanism of bone formation in the distraction gap is not clear, yet. The purpose of this experiment was to scrutinize serially the histological changes in the elongated bone affected by osteodistraction of the mandibular body in an adult canine model. In addition, it was performed to confirm the presence of specific region(s) which was important in the bone formation in the gap through the observation of the expression pattern of osteocalcin and osteonectin with the immunohistochemical examination. Materials and Methods : The experimental and control specimens were obtained from seven adult male mongrel dogs weighing over 20kg. The distractors were custom-made linear extraoral devices and bicortical fixation screws were 2.3mm in diameter, 50mm in total length, 15mm in screw length. The distractors were devised to produce a linear gap of 0.75mm between two bony segments every $360^{\circ}$ turn of the rotation rod of the device. The mandibular body of the right side of each animal was corticotomized perpendicular to the occlusal plane and then two bony segments were separated completely by careful manipulation of the segments with bone forceps. The left side of each animal was left intact. This side was served as control. At sixth day after osteotomy and fixation of the segments were performed, distraction of the segments was commenced with a rate of 1.1mm/day and a rhythm of two/day for ensuing 7 days. The animals were euthanized at the 16th. 29th, and 44th day after the osteotomy. The bony specimens were decalcified, embedded in paraffin, sectioned $5{\mu}m$ thick and stained with H&E. The prepared specimens were examined under the light microscope. And, immunohistochemical examinations using anti-osteocalcin antibody (OC1, Biodesign, USA) and anti-osteonectin antibody (Haematologic Technologies Inc., Essex, VT) to locate the expressions of osteocalcin and osteonectin, respectively, were performed. Results : 1. New bone was observed already at the 16th. day after osteotomy. This suggests that new bone formation in osteodistraction was commenced at an early stage of the regenerative process. But, radiologically and microscopically, bony union was not completed in the distraction gap at the 44th. day after osteotomy. Therefore, rigid fixation must be maintained between the bony fragments till the complete bony union is confirmed clinically rather than one month or so after the completion of distraction.