• The Journal of the Korean dental association
• /
• v.51 no.3
• /
• pp.138-147
• /
• 2013

Orthodontic tooth movement is a unique process which tooth, solid material is moving into hard tissue, bone. Orthodontic force in general provides the strain to the PDL and alveolar bone, which in turn generates the interstitial fluid flow(in detail, fluid flow in PDL and canaliculi). As a results of matrix strain, periodontal ligament cells and bone cells are deformed, releasing variety of cytokines, chemokines, and growth factors. These molecules lead to the orthodontic tooth movement(OTM). In these inflammation and tissue remodeling sites, all of the cells could closely communicate with one another, flowing the information for tissue remodeling. To accelerate the rate of OTM in future, local injection of single growth factor(GF) or a combination of multiple GFs in the periodontal tissues might intervene to stimulate the rate of OTM. Corticotomy is effective and safe to accelerate OTM.

• Imaging Science in Dentistry
• /
• v.46 no.4
• /
• pp.229-237
• /
• 2016

Purpose: The aim of this article is to review a group of lesions associated with periodontal ligament (PDL) widening. Materials and Methods: An electronic search was performed using specialized databases such as Google Scholar, PubMed, PubMed Central, Science Direct, and Scopus to find relevant studies by using keywords such as "periodontium", "periodontal ligament", "periodontal ligament space", "widened periodontal ligament", and "periodontal ligament widening". Results: Out of nearly 200 articles, about 60 were broadly relevant to the topic. Ultimately, 47 articles closely related to the topic of interest were reviewed. When the relevant data were compiled, the following 10 entities were identified: occlusal/orthodontic trauma, periodontal disease/periodontitis, pulpo-periapical lesions, osteosarcoma, chondrosarcoma, non-Hodgkin lymphoma, progressive systemic sclerosis, radiation-induced bone defect, bisphosphonate-related osteonecrosis, and osteomyelitis. Conclusion: Although PDL widening may be encountered by many dentists during their routine daily procedures, the clinician should consider some serious related conditions as well.

• International Journal of Oral Biology
• /
• v.41 no.2
• /
• pp.83-88
• /
• 2016

Periodontitis is an inflammatory disease, which destroys the connective tissue and the alveolar bone. Recently, it has been suggested that the effect of natural substances could be induced into an anti-inflammatory environment. However, the effect of Safflower seed extract (SAF-M) associated with periodontitis has not been investigated yet. Therefore, the purpose of this study was to assess the anti-inflammatory effects of SAF-M. Cytotoxicity was assessed through MTS analysis using hGF and hPDL cells. Periodontitis was induced by injecting LPS into gingival tissue on the maxillary molars of rats ($45{\mu}g$ LPS/one time, 3 times a week for 3 weeks). SAF-M was administered daily at 30 mg/kg and 100 mg/kg. Alveolar bone resorption was evaluated through the micro-CT. hGF and hPDL cells showed differential cytotoxicity in response to SAF-M at 5 mg/ml and 1 mg/ml concentrations. Micro-CT showed reduction of the alveolar bone resorption in the SAF-M treatment group. These results suggested that SAF-M is a potential therapeutic agent for periodontitis.

• Journal of electromagnetic engineering and science
• /
• v.4 no.1
• /
• pp.17-22
• /
• 2004

In this paper, we implement an efficient MLC/PDL system for AWGN channels. In terms of the tradeoff between the hardware implementation and system performance, proposed algebra LDPC codes are optimized by the Gaussian approximation(GA) according to the rate of each level assigned by the capacity rule and chosen as the component code. System performance with Ungerboeck Partitioning(UP), Miked Partitioning(MP) and Gray Mapping(GM) of 8PSK are evaluated, respectively. Many results are presented in this paper; they can indicate that the proposed MLC/PDL system using optimized algebra LDPC codes with different code rate, capacity rule and Gray mapping(GM) can achieve the best performance.

• Proceedings of the Optical Society of Korea Conference
• /
• 2002.11a
• /
• pp.42-43
• /
• 2002

• KSBB Journal
• /
• v.11 no.2
• /
• pp.254-261
• /
• 1996

Attenuated varicella-zoster virus (VZV) was propagated in human lung fibroblast (HLF) cells Among media tested in this work, DMEM was the best medium for the growth of HLF cells. Because HLF was a normal finite cell line, cell growth late was dependent on the age of HLF cells. When the population doubling level (PDL) was higher than 46, apoptosis of HLF cells started and cell growth rate decreased. The optimum temperature for the cell growth and virus propagation in the T-flask culture was $37^{\circ}C$. In a microcarrier culture system in which Cytodex-3 was used for the VZV propagation in spinner vessels, the yield of plaque forming cells was lower than that in the T-flask culture. The relatively high shear environment near microcarriers was thought to cause the low yield of VZV in the microcarrier culture system.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.32 no.3
• /
• pp.272-278
• /
• 2006

Purpose: This study is designed to evaluate biocompatibility of three types of absorbable collagen GBR membrane in vitro. Material and Method: The human PDL fibroblasts culture was obtained through typical way and the cells used in the experiment was forth passage. The membranes examined were Experimental group A, B, C. All the 3-experimental groups were made of bovine pericardium and the membranes were excised into 5$\times$5mm respectively. The samples of the membranes were fixed on the 24-well plate with the double-sided adhesive tape. Then, 2ml of cell suspension which included $2{\times}10^4$cells was inoculated into the 24-well plate, and the cells were cultured for 1 week. Cellular viability and the alkaline phosphatase activity were measured with ELISA. The membranes in the culture were processed to examine with SEM. Results: The survival rate was highest in control and Experimental group A is the next, group B and group C in order of the value. The values are analyzed for statistical difference using Wilcoxon test. All the values of experimental groups are significantly lower than those of control, and the vaules among the experimental groups significantly differ from each other. Alkaline phosphatase level was identical order with the viable cell rate. SEM examination revealed that the PDL fibroblasts adherent on culture dish (control) and group A were spindle-shaped, but on group B and C, the cells were round-shaped without processes.

• Journal of Periodontal and Implant Science
• /
• v.28 no.1
• /
• pp.103-120
• /
• 1998

Prokaryotic and eukaryotic cells respond to heat stress and other environmental abuses by synthesizing a small set of stress proteins and by inhibiting post-transcription synthesis of normal proteins. The purpose of the present study was to document the stress response produced by inflamed gingival tissue in vivo, and cytokine inducted human periodontal ligament cells. Human PDL cells were exposed to TNF-$\alpha$(1ng/ml), INF-$\gamma$(200 U/ml), LPS(100ug/ml), combination of cytokine, and SDS-PAGE gels running and Western blotting analysis was done. In vivo studies, the healthy gingival tissusse of a control group and inflamed gingival tissue of adult periodontitis were studied by immunohistochemistry and histology. The results were as follows 1. HSP 47 was distributed on basal layer in healthy gingiva, but stronger stained in basal, suprabasal, and spinous layer of inflamed gingiva. 2. HSP 47 was rare on endothelial cells and mononuclear cells in healthy gingiva, but stronger expressed in inflamed gingiva. 3. HSP 70 expression was rare on epihelium and inflammatory cells hi both healthy & inflamed gingiva. 4. HSP 70 was actively expressed on endothelial cells and inflammatory cells of capillary lumen in moderately & mild inflamend gingiva. 5. PDL cells showed low level of HSP 47 protein expression which was significantly induced by cytokine stimulation (LSP only and combination). 6. Maximum HSP 70 protein induction was seen with stimulation by a combination of the cytokine, Combination of TNF-$\alpha$, INF-$\gamma$, LPS have been shown to synergistically effects of HSP 70 expression. On the above findings, HSP Is influenced by cytokine and chronic inflammation in vivo, and may be involved in protection of tissue during periodontal inflammatiom.

• Restorative Dentistry and Endodontics
• /
• v.43 no.3
• /
• pp.24.1-24.12
• /
• 2018

Objectives: The aim of this in vitro study was to evaluate the biocompatibility of newly proposed root-end filling materials, Biodentine, Micro-Mega mineral trioxide aggregate (MM-MTA), polymethylmethacrylate (PMMA) bone cement, and Smart Dentin Replacement (SDR), in comparison with contemporary root-end filling materials, intermediate restorative material (IRM), Dyract compomer, ProRoot MTA (PMTA), and Vitrebond, using human periodontal ligament (hPDL) fibroblasts. Materials and Methods: Ten discs from each material were fabricated in sterile Teflon molds and 24-hour eluates were obtained from each root-end filling material in cell culture media after 1- or 3-day setting. hPDL fibroblasts were plated at a density of $5{\times}10^3/well$, and were incubated for 24 hours with 1:1, 1:2, 1:4, and 1:8 dilutions of eluates. Cell viability was evaluated by XTT assay. Data was statistically analysed. Apoptotic/necrotic activity of PDL cells exposed to material eluates was established by flow cytometry. Results: The Vitrebond and IRM were significantly more cytotoxic than the other root-end filling materials (p < 0.05). Those cells exposed to the Biodentine and Dyract compomer eluates showed the highest survival rates (p < 0.05), while the PMTA, MM-MTA, SDR, and PMMA groups exhibited similar cell viabilities. Three-day samples were more cytotoxic than 1-day samples (p < 0.05). Eluates from the cements at 1:1 dilution were significantly more cytotoxic (p < 0.05). Vitrebond induced cell necrosis as indicated by flow cytometry. Conclusions: This in vitro study demonstrated that Biodentine and Compomer were more biocompatible than the other root-end filling materials. Vitrebond eluate caused necrotic cell death.

• Journal of Periodontal and Implant Science
• /
• v.28 no.4
• /
• pp.545-559
• /
• 1998

Magnoliae cortex has been used as a drug for treatment of fractures in Chinese medicine and safflower(Carthamus tinctorius $Linn{\acute{e}}$) has been traditionally used for treatment of blood stasis. The purpose of present study was to examine the biologic effects of magnoliae cortex extract and safflower extract mixture(MSM) on human periodontal ligament cells and fetal rat calvarial osteoblasts and on healing of rat calvarial defects. The ethanolic extracts of magnoliae cortex(MCE), safflower seed(SSE), Zea May L(ZML) were prepared as positive control group. MSM mixed to the ratios of 1 : 1, 1 : 2, 1 : 5 and 1 : 10 were used as test group. The effects of each agents on the growth and survival, ALPase activity, cell proliferation and tissue regenerative effect of each extracts was evaluated by histomorphometric measuring of newly formed bone on the 8 mm defect in rat calvaria after oral administration of 2 ratio groups(1 : 5 and 1 : 10) at 3 different doses (0.1, 0.25 and 0.5g/kg per day). MSM stimulated the growth and survival rate of osteoblasts and PDL cells more than any other agents. The growth and survival rate were increased as the proportion of safflower seed extract was increased. MCE, SSE, ZML stimulated the ALPase activity of osteoblast and PDL cell in comparison to the negative control group. But all groups of MSM regardless of ratio of safflower seed extract stimulated the ALPase activity than any other agent. The ALPase activity was also increased as the proportion of safflower seed extract was increased. Although MCE, SSE, ZML stimulated the proliferation of osteoblasts. 1 : 5 and 1 : 10 ratio MSM showed significant increase in stimulation of proliferation of osteoblasts. No agent significantly increased proliferation of PDL cells. Significant new bone formation were seen where 1 : 5 ratio, 0.5g/kg group and 1 : 10 ratio, 0.25, 0.5g/kg groups were used. These results show that magnoliae cortex extract and safflower seed extract mixture can potentially increase bone regeneration ability.