• The korean journal of orthodontics
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• v.46 no.3
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• pp.155-162
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• 2016

Objective: The aim of this study was to investigate whether labial tooth inclination and alveolar bone loss affect the moment per unit of force ($M_t/F$) in controlled tipping and consequent stresses on the periodontal ligament (PDL). Methods: Three-dimensional models (n = 20) of maxillary central incisors were created with different labial inclinations ($5^{\circ}$, $10^{\circ}$, $15^{\circ}$, and $20^{\circ}$) and different amounts of alveolar bone loss (0, 2, 4, and 6 mm). The $M_t/F$ necessary for controlled tipping ($M_t/F_{cont}$) and the principal stresses on the PDL were calculated for each model separately in a finite element analysis. Results: As labial inclination increased, $M_t/F_{cont}$ and the length of the moment arm decreased. In contrast, increased alveolar bone loss caused increases in $M_t/F_{cont}$ and the length of the moment arm. When $M_t/F$ was near $M_t/F_{cont}$, increases in Mt/F caused compressive stresses to move from a predominantly labial apical region to a palatal apical position, and tensile stresses in the labial area moved from a cervical position to a mid-root position. Although controlled tipping was applied to the incisors, increases in alveolar bone loss and labial tooth inclination caused increases in maximum compressive and tensile stresses at the root apices. Conclusions: Increases in alveolar bone loss and labial tooth inclination caused increases in stresses that might cause root resorption at the root apex, despite the application of controlled tipping to the incisors.

• Journal of Periodontal and Implant Science
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• v.39 no.2
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• pp.129-138
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• 2009

Purpose: This study was designed to compare the bond regeneratiom effects of treatment using silk fibroin membrane ( Nanogide-S$^{(R)}$ ) resorbable barrier with control group treated by polyactic acid / polylacticglycolic acid membrane(Biomesh$^{(R)}$ ) Methods: 44 severe bone loss on extraction socket from 44 patients were used in this study. In experimental group 22 sites of them were treated by silk fibrin membrane as and the other 22 sites were treated by polyactic acid/ polylacticglycolic acid membrane as a control group. Clinical parameters including recovered bone width, length and radiographic parameter of vertical length were evlauated at base line and 3 months after surgery. Results: 1) Severe bone width, length was significantlly decreased in two group. 2) Bone width, length was significantlly decreased in two group. 3) Decreased bone width, length and radiographic examination differences between group. Conclusions: On the basis of these results, silk fibrin resorbable membrane has similar bone regeneration ability to polyactic acid / polylacticglycolic acid membrane in guided bone regeneration for severe bone loss defect on extraction socket.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.2
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• pp.241-268
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• 1995

Splint therapy, the immobilization of teeth, has been done for patient's masticatory comforts and an adjunctive aid in periodontal therapy. Mandibular premolars are frequently splinted in many distal extension removable partial denture cases. But splinting is an extensive restoration that may not be conservative of tooth structure and may prove to be quite costly to the patient. The two dimensional finite element analysis method was used to determine the magnitude and mode of distribution of the stresses of the periodontal ligament and supporting alveolar bone when abutments with different periodontal supports were splinted and distal-extension removable partial denture was subjected to different loading schemes. The results were as follows : 1. When abutments were splinted, stresses moved from apico-distal to apico-mesial of terminal abutment on a vertical force and from disto-alveolar crest to apex on a distally directed force. But stresses were generally diminished on a mesially directed force. 2. As vertical bone loss was proceeding, most of stresses were transmitted to residual ridge and the rest of stresses were concentrated on apex of distal abutment. But these apical stresses were minimized when abutments were splinted. 3. As mesially inclined bone loss was proceeding, it seemed to be dangerous that many stresses were concentrated on the distal alveolar crest, especially in the distally directed load case. Abutments splinting decreased the alveolar crestal stresses but not enough. 4. For all vertical stresses were effectively decreased on splinting, stresses were concentrated as highly on apico-mesial area of distal abutment in distally directed load cases as the distal inclination of bone level was severe. 5. The directions and magnitudes of abutment movements were decreased with teeth splinting.

• Physical Therapy Korea
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• v.8 no.1
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• pp.51-58
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• 2001

In children with cerebral palsy, bone density is decreased by disturbance of bone remodelling due to lack of normal weight bearing and muscle contraction through physical activity. Loss of bone density cause fracture, delays treatment with immobilization, and leads to functional limitation. The purpose of this study was to investigate bone mineral density of lumbar spine in children with spastic quadriplegia and diplegia. Six spastic quadriplegia and 14 spastic diplegia were evaluated in this study. QDR 4500 X-ray densitometer was used to measure bone density at lumbar spine (L1~L4). Children with cerebral palsy showed lower bone density than that of normal children. Bone density in children with spastic quadriplegia and diplegia was $-1.812{\pm}.962$, $-1.519{\pm}.935$, respectively. However, there was no significant differences in bone density between children with spastic quadriplegia and diplegia. There was no significant difference in bone density relation to motor development level, height, and weight. Further study is needed to find the appropriate interventions for preventing loss of bone density in children with cerebral palsy.

• BMB Reports
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• v.51 no.9
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• pp.468-473
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• 2018

Purinergic receptor signaling is increasingly recognized as an important regulator of inflammation. The P2X family purinergic receptors P2X5 and P2X7 have both been implicated in bone biology, and it has been suggested recently that P2X5 may be a significant regulator of inflammatory bone loss. However, a role for P2X5 in periodontitis is unknown. The present study aimed to evaluate the functional role of P2X5 in ligature-induced periodontitis in mice. Five days after placement of ligature, analysis of alveolar bone revealed decreased bone loss in $P2rx5^{-/-}$ mice compared to $P2rx7^{-/-}$ and WT control mice. Gene expression analysis of the gingival tissue of ligated mice showed that IL1b, IL6, IL17a and Tnfsf11 expression levels were significantly reduced in $P2rx5^{-/-}$ compared to WT mice. These results suggest the P2X5 receptor may regulate bone loss related to periodontitis and it may thus be a novel therapeutic target in this oral disease.

• International Journal of Oral Biology
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• v.35 no.4
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• pp.145-151
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• 2010

Periodontitis is an inflammatory disorder of the periodontium and is characterized by destruction of the tooth supporting tissues, mediated by the upregulation of synthesis and release of a variety of pro-inflammatory factors. Inflammatory cytokines and prostaglandins upregulate RANKL and its subsequent binding to RANK stimulates osteoclast formation, resorption activity, and survival. In our present study, we investigated the effects of HP08-0111, composed of Coptis japonica (Thunb.) Makino, vitamin C and vitamin E, upon inflammatory responses, osteoclastogenesis and alveolar bone loss. HP08-0111 decreased the expression of IL-1$\beta$ and COX2 on LPS-induced RAW 264.7 cells and inhibited osteoclast-specific genes such as c-Fos, MMP-9, and TRAP. HP08-0111 also exhibited protective effects against alveolar bone loss in rats with ligature-induced periodontitis. Our results suggest that HP08-0111 is potentially an important therapeutic tool for the treatment of disorders associated with bone loss such as periodontitis.

• Journal of the East Asian Society of Dietary Life
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• v.6 no.3
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• pp.295-305
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• 1996

This study was done to evaluate the effectiveness of dietary calcium level(a diet which met 100% or twice the calcium level in AIN-76 diet) on preventing bone loss in ovariectomized rats. Forty female Sprauge-Dawley rats(body weight 200$\pm$5g) were divided into two groups. One group were ovariectomized(Ovx) while the others received sham operation(Sham). Thereafter, each rat group was further divided into normal calcium diet(NCD, 0.52%) and high calcium diet(HCD, 1.04%) sub-groups. All rats were fed on experimental diet and deionized water ad libitum for 8 weeks. Urinary pyridinoline & creatinine and serum estradiol, luteinizing hormone, calcium, phosphate, total protein, albumin, alkaline phosphatase and osteocalcin were determined. There were no significant differences in serum calcium. total protein and albumin in the two groups(Ovx vs Sham) of rats. Ovariectomized rats had significantly lower estradiol than sham operated rats. There was a highly significant correlation between total bone mineral density(TBMD) and overall level of esteradiol(r=0.59, p<0.05). Total bone mineral density did not correlate significantly with ALP or osteocalcin, although a negative trend was evident. However, the rats fed high calcium diet had a lower crosslinks value and osteocalcine than the rats fed normal calcium diet. An increased rate of bone turnover is usually associated with a decrease in bone mass bexause bone formation at each remodeling site is never as great as resorption. Ovariectomized rats fed high calcium diet had a lower crosslink value and osteocalcin; it means high cacium diet decreased bone turnover rate. The findings from the present study demonstrated that bone loss due to ovarian hormonal deficiency can be partially prevented by a high calcium diet. Futhermore, these findings support the strategy of the use of a high calcium diet in the prevention of estrogen depletion bone loss (postmenopausal osteoporosis).

• Clinical and Experimental Reproductive Medicine
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• v.19 no.1
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• pp.49-56
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• 1992

Bone mineral density was measured to assess whether the patients with premonopausal hypogonadism, comprised of 19 patients with hypogonadotropic hypogonadism(HH), 55 with premature ovarian failure(POF), 23 with hyperprolactinemia(HPLN), and 8 with Sheehan's syndrome. All aged from 20 to 39, were associated with some decrease in regional bone mass compared with that of 63 normal-associated with some decrease in regional bone mass compared with that of 63 normal-cycling control women matched with age and sex. Measurement of bone mineral density was carried out using Dual photon absorptiometry at four sites; femur neck, ward's triangle, trochanter and spine(L2-L4). Bone mineral density at all four sites were significantly decreased in patients with HH(p<0.01), POF(p<0.01). In hyperprolactinemic patients, the decrease in bone mass was significant at femur neck and Ward's triangle(p<0.05). The patients with POF were noted to be associated with significant bone loss when their duration of amenorrhea exceeded one year. In this study, the degree of loss of bone mass and the affected sites seemed to be different depending on the various types of hypogonadism and POF was noted have caused the appearance of loss of bone mass earlier than other thpes of hypogondism we experienced.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.5
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• pp.1325-1329
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• 2003

The preventive effect of Salvia miltiorrhiza extracts (SMEs) on the progress of bone loss induced by ovariectomy (OVX) was studied in rats. We measured body weight and bone histomorphometry in sham, OVX or SMEs-administered OVX rats. From light microscopic analyses, a porous or erosive appearances were observed on the surface of trabecular bone of tibia in OVX rats, whereas those of the same bone in sham rats and in SMEs-administered rats were composed of fine particles. The trabecular bone area and trabecular thickness in OVX rats decreased by 50% from those in sham rats, these decreases were completely inhibited by administration of SMEs for 7 weeks. In this study, the mechanical strength in femur neck was significantly enhanced by the treatment of SMEs for 7 weeks. In OVX rats, free T3 was normal in all cases, whereas free T4 was significantly increased. Although there was no difference between OVX and SMEs-administered rats in T3 level, we have found significant difference between them in T4 level. These results strongly suggest that SMEs are effective in preventing the development of bone loss induced by OVX in rats.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.3
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• pp.233-242
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• 2004

The purpose of this study was to investigated the possibility of Meles meles as an edible functional resource. To assess the effects of Meles meles fermented liquid(ML) with medicinal plants in postmenopausal women, the menopause symptoms, hematological and serum chemical variables and bone health indices were examined. Twenty five postmenopausal women participated in the study. As a result, in postmenopausal women, ML supplements were effective in reducing the incidence of menopause symptoms, such as insomnia(44.0%), sensitivity(40.0%), headache(34.0%), hot flush and decreased vaginal lubrication(20.0%) after 12 weeks. Also serum estradiol and calcitonin and calcium levels were 23.27 pg/mL, 14.88 pg/mL and 8.86 mg/dL before the ML intake. Levels were significantly increased of estradiol and calcitonin and calcium after ML intake during 12 weeks to 30.36 pg/mL, 21.61 pg/mL and 10.01 mg/dL. Osteocalcin and bone alkaline phosphatase activity were 14.36 ng/mL, 21.55 U/L before the ML intake, but according to ML intake, the levels were significantly decreased. In conclusion, ML play benefical roles in the prevention of bone loss and menopause symptoms. Howere current data are not sufficient to determine the effective doses for benefical effect as well as harmful effect and support dietary recommendation level for ML. Therefore, our results should be viewed with caution. But Meles meles fermented liquid with medicinal plants can be used as possible food resources and functional food materials, more studies are needed to identify the proper mechanism of ML.