• Molecules and Cells
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• v.41 no.5
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• pp.476-485
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• 2018

Although tectorigenin (TG), a major compound in the rhizome of Belamcanda chinensis, is conventionally used for the treatment of inflammatory diseases, its effects on osteogenesis and osteoclastogenesis have not been reported. The objective of this study was to investigate the effects and possible underlying mechanism of TG on in vitro osteoblastic differentiation and in vivo bone formation, as well as in vitro osteoclast differentiation and in vivo bone resorption. TG promoted the osteogenic differentiation of primary osteoblasts and periodontal ligament cells. Moreover, TG upregulated the expression of the BMP2, BMP4, and Smad-4 genes, and enhanced the expression of Runx2 and Osterix. In vivo studies involving mouse calvarial bone defects with ${\mu}CT$ and histologic analysis revealed that TG significantly increased new bone formation. Furthermore, TG treatment inhibited osteoclast differentiation and the mRNA levels of osteoclast markers. In vivo studies of mice demonstrated that TG caused the marked attenuation of bone resorption. These results collectively demonstrated that TG stimulated osteogenic differentiation in vitro, increased in vivo bone regeneration, inhibited osteoclast differentiation in vitro, and suppressed inflammatory bone loss in vivo. These novel findings suggest that TG may be useful for bone regeneration and treatment of bone diseases.

• The Journal of the Korean dental association
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• v.54 no.5
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• pp.348-355
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• 2016

Ideal autogenous or allogenic bone graft materials should provide 1) stabilization of blood clot, 2) scaffolds for cellular proliferation and differentiation, 3) release of osteogenic growth factors, 4) appropriate resorption profile for remodeling of new bone. Teeth, especially dentin, mostly contain hydroxyapatite and type I collagen which are similar to bone, and could be valuable graft material. Clinically teeth are used as calcined or demineralized forms. Demineralized form of dentin can be more effective as a graft material. But a conventional decalcification method takes time and long treatment time may give negative effects to various osteogenic proteins in dentin. Author used a new clinical method to prepare autogenous teeth, which could be grafted into the removal defects immediately after extraction using vacuum ultrasonic system. The process could be finished within two hours regardless of the form (powder, chip or block). Teeth were processed to graft materials in block, chip, or powder types immediately after extraction. It took 120 minutes to prepare block types and 40 minutes to prepare powder. Clinical cases did not show any adverse response and the healing was favorable. Rapid preparation of autogenous teeth with the vacuum ultrasonic system could make the immediate one-day extraction and graft possible.

• The Journal of Advanced Prosthodontics
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• v.14 no.3
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• pp.182-202
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• 2022

PURPOSE. The aim of this study is to summarize various biomechanical aspects in evaluating the long-term stability of dental implants based on finite element method (FEM). MATERIALS AND METHODS. A comprehensive search was performed among published studies over the last 20 years in three databases; PubMed, Scopus, and Google Scholar. The studies are arranged in a comparative table based on their publication date. Also, the variety of modeling is shown in the form of graphs and tables. Various aspects of the studies conducted were discussed here. RESULTS. By reviewing the titles and abstracts, 9 main categories were extracted and discussed as follows: implant materials, the focus of the study on bone or implant as well as the interface area, type of loading, element shape, parts of the model, boundary conditions, failure criteria, statistical analysis, and experimental tests performed to validate the results. It was found that most of the studied articles contain a model of the jaw bone (cortical and cancellous bone). The material properties were generally derived from the literature. Approximately 43% of the studies attempted to examine the implant and surrounding bone simultaneously. Almost 42% of the studies performed experimental tests to validate the modeling. CONCLUSION. Based on the results of the studies reviewed, there is no "optimal" design guideline, but more reliable design of implant is possible. This review study can be a starting point for more detailed investigations of dental implant longevity.

• 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).

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.567-577
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• 2006

Background Several bone grafting materials have been used in sinus augmentation procedures. Macroporous Biphasic Calcium Phosphate($MBCP^{TM}$) consists of the mixture of 60% HA and 40% ${\beta}-TCP$. Therefore, it can provide good scaffold for the new bone to grow owing to HA, in the other hand, it can have bioactivity for bone remodeling owing to ${\beta}-TCP$. The purpose of this study was to evaluate bone formation following maxillary sinus augmentation using $MBCP^{TM}$ by means of histologic analysis. Material and Method $MBCP^{TM}$ was placed as a primary bone substitute for maxillary sinus augmentation. Three patients were selected after evalaution of their medical dental examination. $MBCP^{TM}$ only, $MBCP^{TM}$ combined with Irradicated cancellous bone and $MBCP^{TM}$ combined with autogenous bone were used for each patient. After about eight months, bone biopsies were harvested for histologic evaluation and fixtures installed. Results Eight months after surgery we observed new vital bone surrounding $MBCP^{TM}$ particle and the amount of new bone was about 30% even though there were discrepancies between specimens. This case report documents that $MBCP^{TM}$ when used as a grafting material for sinus floor augmentation whether combined other bone graft material or not, may lead to the predictable results for dental implants on posterior maxillary area with insufficient vertical height for fixture installation.

• Experimental and Molecular Medicine
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• v.50 no.11
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• pp.2.1-2.16
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• 2018

Supplementation of mesenchymal stem cells (MSCs) at sites of bone resorption is required for bone homeostasis because of the non-proliferation and short lifespan properties of the osteoblasts. Calcium ions ($Ca^{2+}$) are released from the bone surfaces during osteoclast-mediated bone resorption. However, how elevated extracellular $Ca^{2+}$ concentrations would alter MSCs behavior in the proximal sites of bone resorption is largely unknown. In this study, we investigated the effect of extracellular $Ca^{2+}$ on MSCs phenotype depending on $Ca^{2+}$ concentrations. We found that the elevated extracellular $Ca^{2+}$ promoted cell proliferation and matrix mineralization of MSCs. In addition, MSCs induced the expression and secretion of osteopontin (OPN), which enhanced MSCs migration under the elevated extracellular $Ca^{2+}$ conditions. We developed in vitro osteoclast-mediated bone resorption conditions using mouse calvaria bone slices and demonstrated $Ca^{2+}$ is released from bone resorption surfaces. We also showed that the MSCs phenotype, including cell proliferation and migration, changed when the cells were treated with a bone resorption-conditioned medium. These findings suggest that the dynamic changes in $Ca^{2+}$ concentrations in the microenvironments of bone remodeling surfaces modulate MSCs phenotype and thereby contribute to bone regeneration.

• The korean journal of orthodontics
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• v.49 no.4
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• pp.235-245
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• 2019

Objective: This study examined bone microstructure restoration after rapid maxillary expansion (RME) with and without corticotomy over multiple retention periods. Methods: Eighteen male Dorper sheep were randomly distributed into three groups (n = 6 each group): group 1, RME with corticotomy on the buccal and palatal sides; group 2, conventional RME treatment; and group 3, no treatment. Post-RME, trabecular bone microstructure and new bone formation were evaluated by using microcomputed tomography (microCT) and histomorphometry after a 4- or 12-week retention period. Intergroup differences in bone quality and bone remodeling were analyzed by using two-way analysis of variance with Bonferroni post-hoc test. Results: The bone volume fraction (bone volume [BV]/total volume [TV]) values relative to the control in groups 1 and 2 were 54.40% to 69.88% after the 4-week retention period and returned to approximately 80% after the 12-week retention period. The pooled BV/TV values of the banded teeth in groups 1 and 2 were significantly lower than those of the control after the 4-week retention period (p < 0.05). However, after the 12-week retention period, the pooled BV/TV values in group 2 were significantly lower than those in groups 1 and 3 (p < 0.05). Histomorphological analysis showed that the new bone formation area in group 1 was approximately two to three times of those in group 2 and control. Conclusions: Corticotomy significantly enhanced the restoration of bone quality after the retention periods for banded teeth. This benefit might result from the increased new bone formation after corticotomy.

• Imaging Science in Dentistry
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• v.53 no.1
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• pp.1-9
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• 2023

Purpose: The aim of this study was to evaluate 3-dimensional cone-beam computed tomography (CBCT) images of alveolar bone changes in patients who underwent minimally invasive periodontal surgery-namely, the pinhole surgical technique (PST). Materials and Methods: Alveolar bone height was measured and compared on CBCT images of 254 teeth from 23 consecutive patients with Miller class I, II, or III recession who had undergone PST. No patient with active periodontal disease was selected for surgery. Two different methods were used to assess the alveolar bone changes postoperatively. In both methods, the distance between the apex of the tooth and the mid-buccal alveolar crestal bone on pre- and post-surgical CBCT studies was measured. Results: An average alveolar bone gain >0.5 mm following PST was identified using CBCT(P=0.05). None of the demographic variables, including sex, age, and time since surgery, had any significant effect on bone gain during follow-up, which ranged from 8 months to 3 years. Conclusion: PST appears to be a promising treatment modality for recession that results in stable clinical outcomes and may lead to some level of resolution on the bone level. More long-term studies must be done to evaluate the impact of this novel technique on bone remodeling and to assess sustained bone levels within a larger study population.

• The Journal of Advanced Prosthodontics
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• v.12 no.2
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• pp.67-74
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• 2020

PURPOSE. This study evaluated the influence of prosthesis weight and number of implants on the bone tissue microstrain. MATERIALS AND METHODS. Fifteen (15) fixed full-arch implant-supported prosthesis designs were created using a modeling software with different numbers of implants (4, 6, or 8) and prosthesis weights (10, 15, 20, 40, or 60 g). Each solid was imported to the computer aided engineering software and tetrahedral elements formed the mesh. The material properties were assigned to each solid with isotropic and homogeneous behavior. The friction coefficient was set as 0.3 between all the metallic interfaces, 0.65 for the cortical bone-implant interface, and 0.77 for the cancellous bone-implant interface. The standard earth gravity was defined along the Z-axis and the bone was fixed. The resulting equivalent strain was assumed as failure criteria. RESULTS. The prosthesis weight was related to the bone strain. The more implants installed, the less the amount of strain generated in the bone. The most critical situation was the use of a 60 g prosthesis supported by 4 implants with the largest calculated magnitude of 39.9 mm/mm, thereby suggesting that there was no group able to induce bone remodeling simply due to the prosthesis weight. CONCLUSION. Heavier prostheses under the effect of gravity force are related to more strain being generated around the implants. Installing more implants to support the prosthesis enables attenuating the effects observed in the bone. The simulated prostheses were not able to generate harmful values of peri-implant bone strain.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.1
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• pp.13-22
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• 1999

The purpose of this investigation was to evaluate the acceptability of the collagen-based xenograft ($Laddec^{(R)}$). Full thickness bone defects were prepared in the calvaria of the rats. In the experimental groups the bone defects were filled with a kind of collagen based xenograft. And bone defects, which left without filling, were used as control groups. Sequential sacrifice was performed at the 1st, 2nd, 4th, 8th, and 16th weeks of experiment. 1. At the 1st week of experiment, infiltration of chronic inflammatory cell was observed in all groups. In the experimental group, resorption of the xenograft was initiated. 2. At the 2nd week of experiment, infiltration of chronic inflammatory cells was decreased in all groups. In the experimental group, active resorption of xenograft and new bone formation from the periphery of the xenograft was observed. 3. At the 4th and 8th weeks of experiment, more resorption of the xenograft and new bone formation with calcification was observed in the experimental group. 4. At the 16th week of experiment, small bone trabecula was formed partially in the control group but that couldn't fill the whole bone defect. In the experimental group, more advanced resorption of xenograft and more new bone formation was observed. However mid portion of the xenograft was still remained without resorption. 5. From this experiment, we concluded that the collagen-based xenograft had some osteoconductive but no osteoinductive property. So the xenograft would be used for the bone defect filling material where rapid bone remodeling is not required.