• Journal of Periodontal and Implant Science
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• v.37 no.3
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• pp.511-522
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• 2007

Introduction : The purpose of this study was to evaluate the possibility of the acellular dermal matrix (ADM) as a barrier membrane for bone regeneration, and to evaluate the osteogenic effect of ADM as a carrier system for rhBMP-2 in the rat calvarial defect model. Materials and Methods: An 8-mm, calvarial, critical-size osteotomy defect was created in each of 60 male Spraque-Dawley rats(weight $250{\sim}300g$). Three groups of 20 animals, each received either rhBMP-2(0.025mg/ml) in an ADM carrier, ADM only, or negative surgical control. And each group was divided into 2- and 8-weeks healing intervals. The groups were evaluated by histologic and histomorphometric parameters(10 animals/group/healing intervals). Data were expressed as $means{\pm}standard$ deviations($m{\pm}SD$). Comparisons between experimental and control groups were made using two-way ANOVA and post hoc t-test. Comparisons between 2 weeks and 8 weeks were made using paired t-test. The level of statistical difference was defined as P< 0.05. Results : The ADM group and rhBMP-2/ADM group results in enhanced local bone formation in the rat calvarial defect at both 2 and 8 weeks. The amount of defect closure and new bone formation were significantly greater in the rhBMP-2/ADM group relative to ADM group(P<0.05). At 8 weeks, the majority of ADM in the defect was contracted, and integrated with surrounding host tissues. In addition, host cell infiltration and neovascularization of the ADM in the absence of an inflammatory response were observed, and the newly formed bone around ADM showed a continuous remodeling and consolidation. Conclusion : The results of the present study indicated that ADM may be used as a barrier membrane for bone regeneration and that may be employed as a delivery system for BMPs.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.703-719
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• 1995

The purpose of this study was to observe the effects of the periodontal ligament on the healing and the formation of alveolar bone in the extraction socket, when this ligament had artificially remained in the socket during the tooth removal. Twenty rats aged 4 weeks were used and devided into the control groups (10) and the experimental groups (10) in this study. The maxillary right and left first molars were extracted in both groups. In the experimental groups the periodontal ligament was remained in the extraction sockets using 0.4% ${\beta}-aminopropionitrile$, and in the control the periodontal ligament was completely removed by curettage. At 1, 3, 5, 7 and 14 days after the tooth extraction, rats in both groups were serially sacrificed. And the specimens were prepared with Hematoxylin-Eosin stain for the light microscopic evaluation. The results of this study were as follows ; 1. On 1 day, the periodontal ligament was only found in the extraction socket walls of the experimental groups, and there was not the distinguishable difference between the control and the experimental groups. 2. On 3 days, there were more collagen fibers and the appearance of higher cellular density in the experimental groups than in the control. And the cells and collagen of the periodontal ligament were so actively proliferated and synthesized that invaded into the connective tissue of the extraction sockets in the experimental groups. 3. In the experimental groups, the trabecular bone was formed on the basal and lateral bone surface on 5 days. However, there was not the new bone forming appearance in the control groups at this time. 4. On 7 days, the trabecular bone was formed in the control groups. 5. On 14 days, the extraction sockets were almost entirely filled with the bony trabeculae in both groups. But, compared to the control group, the experimental groups showed the prominent differences in the amount & the density of the new bone formed. In conclusion, it was suggested that the residual periodontal ligament tissue in the extraction socket will play a major role as the important cell source in the healing and the new bone formation of the extraction socket.

• 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.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.345-359
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• 2006

Loss of maxillary molar teeth leads to rapid loss of crestal bone and inferior expansion of the maxillary sinus floor (secondary pneumatization). Rehabilitation of the site with osseointegrated dental implants often represents a clinical challenge because of the insufficient bone volume resulted from this phenomenon. Boyne & James proposed the classic procedure for maxillary sinus floor elevation entails preparation of a trap door including the Schneiderian membrane in the lateral sinus wall. Summers proposed another non-invasive method using a set of osteotome and the osteotome sinus floor elevation (OSFE) was proposed for implant sites with at least 5-6mm of bone between the alveolar crest and the maxillary sinus floor. The change of grafted material in maxillary sinus is important for implant survival and the evaluation of graft height after maxillary sinus floor elevation is composed of histologic evaluation and radiomorphometric evaluation. The aim of the present study was radiographically evaluate the graft height change after maxillary sinus floor elevation and the influence of the graft material type in height change and the bone remodeling of grafts in sinus. A total of 59 patients (28 in lateral approach and 31 in crestal approach) who underwent maxillary sinus floor elevation composed of lateral approach and crestal approach were radiographically followed for up to about 48 months. Change in sinusgraft height were calculated with respect to implant length (IL) and grafted sinus height(BL). It was evaluated the change of the graft height according to time, the influence of the approach technique (staged approach and simultaneous approach) in lateral approach to change of the graft height, and the influence of the type of graft materials to change of the graft height. Patients were divided into three class based on the height of the grafted sinus floor relative to the implant apex and evaluated the proportion change of that class (Class I, in which the grafted sinus floor was above the implant apex; Class II, in which the implant apex was level with the grafted sinus floor; and Class III, in which the grafted sinus floor was below the implant apex). And it was evaluated th bone remodeling in sinus during 12 months using SGRl(by $Br\ddot{a}gger$ et al). The result was like that; Sinus graft height decreased significantly in both lateral approach and crestal approach in first 12 months (p$MBCP^{TM}$ had minimum height loss. Class III and Class II was increased by time in both lateral and crestal approach and Class I was decreased by time. SGRI was increased statistically significantly from baseline to 3 months and 3 months(p<0.05) to 12 months(p$ICB^{(R)}$ single use, more reduction of sinusgraft height was appeared. Therefore we speculated that the mixture of graft materials is preferable as a reduction of graft materials. Increasing of the SGRI as time goes by explains the stability of implant, but additional histologic or computed tomographic study will be needed for accurate conclusion. From the radiographic evaluation, we come to know that placement of dental implant with sinus floor elevation is an effective procedure in atrophic maxillary reconstruction.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.6
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• pp.417-424
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• 2009

Osteoclasts, derived from multipotent myeloid progenitor cells, play homeostatic roles in skeletal modeling and remodeling, but may also destroy bone in pathological conditions such as osteoporosis and rheumatoid arthritis. Osteoclast development depends critically on a differentiation factor, the receptor activator of NF-${\kappa}B$ ligand (RANKL). In this study, we found that the hexane soluble fraction of the common fig Ficus carica (HF6-FC) is a potent inhibitor of osteoclastogenesis in RANKL-stimulated RAW264.7 cells and in bone marrow-derived macrophages (BMMs). HF6-FC exerts its inhibitory effects by suppression of p38 and NF-${\kappa}B$ but activation of ERK. In addition, HF6-FC significantly decreased the expression of NFATc1 and c-Fos, the master regulator of osteoclast differentiation. The data indicate that components of HF6-FC may have therapeutic effects on bone-destructive processes such as osteoporosis, rheumatoid arthritis, and periodontal bone resorption.

• Journal of Korean society of Dental Hygiene
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• v.23 no.4
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• pp.219-226
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• 2023

Objectives: This study aimed to investigate the effects of rhubarb extract on osteoclast differentiation in bone marrow-derived macrophages (BMMs). Osteoclasts are vital for bone resorption and remodeling. Osteoclast dysregulation can contribute to various bone-related disorders that directly affect oral health. Rhubarb, a medicinal plant with anti-inflammatory properties, has been shown to modulate bone metabolism. Methods: BMMs were isolated from the femurs and tibias of 5-week-old C57BL/6 mice and cultured in the presence of mouse macrophage colony-stimulating factor (M-CSF) for 3 days. Subsequently, BMMs were treated with M-CSF and receptor activator of nuclear factor-κB ligand (RANKL) to induce osteoclast differentiation. Results: Rhubarb extract effectively suppressed osteoclast differentiation in BMMs. Furthermore, rhubarb extract inhibited the mRNA expression of tartrate-resistant acid phosphatase (TRAP) and cathepsin K (CTSK), which are essential for osteoclastogenesis. Moreover, it inhibited the RANKL-induced expression of nuclear factor of activated T cell c1 (NFATc1), a crucial transcription factor in osteoclast differentiation. Conclusions: These results suggest that rhubarb extract promotes oral health by inhibiting osteoclastogenesis in BMMs. Thus, rhubarb extract shows promise as a therapeutic agent for bone-related disorders that directly affect oral health, particularly those associated with abnormal osteoclast activity. Further research and exploration of the underlying mechanisms are warranted to fully understand their potential clinical applications.

• Korean Journal of Oriental Medicine
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• v.13 no.2 s.20
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• pp.157-164
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• 2007

An imbalance in bone remodeling that is caused by increased bone resorption over bone formation leads to most adult skeletal diseases including osteoporosis. Since the development of anti-resorptive agents from natural substances has recently gained more interest in the treatment of osteoporosis, we evaluated the effects of 222 natural compounds on receptor activator of $NF-{\kappa}B$ ligand (RANKL)-induced of tartrate-resistance acid phosphatase (TRAP) activity in RAW264.7 murine macrophage cell, and found that berberine chloride is one of compounds inhibiting RANKL-induced TRAP activity. Berberine chloride significantly inhibited the RANKL-induced TRAP activity and the formation of multinucleated osteoclasts in a dose-dependent manner. In addition, berberine chloride prevented the RANKL-induced mRNA expression of TRAP, matrix metalloproteinase 9 and c-Src, which have been known to be highly expressed in the process of osteoclastogenesis. Interestingly, berberine chloride prevented the RANKL-induced activation of extracellular signal-regulated kinase (ERK) which is one of mitogen-activated protein (MAP) kinases. In conclusion, berberine chloride could inhibit the osteoclastogenesis via preventing the activation of ERK/MAP kinase signaling pathway.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.1
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• pp.80-86
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• 2006

Cleidocranial dysplasia is rare inherited skeletal dysplasia. It was first reported by Martin in 1765. Subsequently, Marie and Sainton independently documented the criteria of the disease. Cleidocranial dysplasia is a bone disorder caused by a defect in the CBFA1 gene of chromosome 6p21. This gene guides osteoblastic differentiation and appropriate bone formation. Patient with cleidocranial dysplasia has maxillary deficiency, high and narrow palate, prolonged retention of primary teeth, unerupted permanent teeth and supernumerary teeth. Therapeutic options in these patients include of autotransplantation of selected impacted teeth, forced eruption of permanent teeth, full denture, overdenture and implant-supported prosthesis. We report a patient with cleidocranial dysplasia. This patient was treated with implant supported bar overdenture. Despite of gene defect that affects osteoblastic activity, bone remodeling and osseointegration occurred in our patient. So, we report this case with review of literature.

• International Journal of Oral Biology
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• v.34 no.2
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• pp.53-59
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• 2009

Periodontal ligament (PDL) tissue is a connective tissue that is interposed between the roots of the teeth and the inner wall of the alveolar bone socket. PDL is always exposed to physiologic mechanical force such as masticatory force and PDL cells play important roles during orthodontic tooth movement by synthesizing and secreting different mediators involved in bone remodeling. The Wnt/${\beta}$-catenin signaling pathway was recently shown to play a significant role in the control of bone formation. In the present study, we applied cyclic tensile stress of 20% elongation to cultured human PDL cells and assessed its impact after six days upon components of the Wnt/${\beta}$-catenin signaling pathway. RTPCR analysis showed that Wnt1a, Wnt3a, Wnt10b and the Wnt receptor LRP5 were down-regulated, whereas the Wnt inhibitor DKK1 was up-regulated in response to these stress conditions. In contrast, little change was detected in the mRNA expression of Wnt5a, Wnt7b, Fz1, and LRP6. By western blotting we found decreased expression of the ${\beta}$-catenin and p-GSK-3${\beta}$ proteins. Our results thus show that mechanical stress suppresses the canonical Wnt/${\beta}$-catenin signaling pathway in PDL cells.

• Animal cells and systems
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• v.4 no.3
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• pp.273-278
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• 2000

Transforming growth factor-$\beta$ (IGF-$\beta$)s are multifunctional small polypeptides synthesized in most cell types. TGF-$\beta$ exerts pivotal effects on both bone formation and resorption. In addition, increasing lines of evidence implicate TGF-$\beta$ as a potential coupling factor between these two processes during bone remodeling. In the present study, the expression form and the activation mechanism of latent-TGF-$\beta$ were investigated using specific antibodies for each isoform. TGF-$\beta$s were observed to be synthesized and accumulated in a large amount in cultured osteoblastic cells. The estimated molecular weights of intracellular TGF-$\beta$2 and -$\beta$3 were 49 and 55 kDa, respectively. Based on proteolytic digestion study and immunofluorescence observation, these precursor forms seemed to be accumulated in distinct intracellular compartments. To examine whether the internal pool of TGF-$\beta$ was possiblely regulated by external signals, their biological activites were examined in a conditioned media of this cell. Although the intact conditioned media did not contain detectable TGF-$\beta$ activity, heat-treatment or acid-activation of the conditioned media revealed significant TGF-$\beta$ activity. Furthermore, in the presence of estrogen, this activity was dramatically diminished. It is known that activation of latent TGF-$\beta$ can be achieved by different chemical and enzymatic treatments, or by incubation with certain cell types. This extracellular activation was suggested as a key step in the regulation of TGF-$\beta$ activity. In addition to these extracellular activation, this study suggests that the synthesis and intracellular processing are important regulation steps for TGF-$\beta$ action. In addition, this regulation Is specific for TGF-$\beta$ type 2, because the change was not observed in TGF-$\beta$3 in osteoblastic cell line.