• Restorative Dentistry and Endodontics
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• v.39 no.2
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• pp.89-94
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• 2014

Objectives: The aim of this study was to evaluate the cytotoxicity, setting time and compressive strength of MTA and two novel tricalcium silicate-based endodontic materials, Bioaggregate (BA) and Biodentine (BD). Materials and Methods: Cytotoxicity was evaluated by using a 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-((phenylamino)carbonyl)-2H-tetrazolium hydroxide (XTT) assay. Measurements of 9 heavy metals (arsenic, cadmium, chromium, copper, iron, lead, manganese, nickel, and zinc) were performed by inductively coupled plasma-mass spectrometry (ICP-MS) of leachates obtained by soaking the materials in distilled water. Setting time and compressive strength tests were performed following ISO requirements. Results: BA had comparable cell viability to MTA, whereas the cell viability of BD was significantly lower than that of MTA. The ICP-MS analysis revealed that BD released significantly higher amount of 5 heavy metals (arsenic, copper, iron, manganese, and zinc) than MTA and BA. The setting time of BD was significantly shorter than that of MTA and BA, and the compressive strength of BA was significantly lower than that of MTA and BD. Conclusions: BA and BD were biocompatible, and they did not show any cytotoxic effects on human periodontal ligament fibroblasts. BA showed comparable cytotoxicity to MTA but inferior physical properties. BD had somewhat higher cytotoxicity but superior physical properties than MTA.

• The korean journal of orthodontics
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• v.27 no.6 s.65
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• pp.955-961
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• 1997

Nicotine is one of the major components of cigarette smoking which causes various systemic and local diseases to human body. Mitogenic effects of nicotine to systemic disease are interesting factors in the results of cellular Proliferation especially to vascular and pulmonary tissue or cells. The study of local effects concerns with destruction of tissue and delayed healing rate after various surgical treatment. Platelet-Derived Growth factor(PDGF) and Insulin-like growth factor(IGF) are blown as major mitogens to human PDL cells. The purpose of this study was to investgate the mitogenic effects of nicotine to human PDL cells. We studied the expression of PDGF-$\alpha$ receptor, PDGF-$\beta$receptor, and IGF-l receptor mRNA from the nicotine treated human PDL cells by northern analysis. The experimental groups were divided into different serum($1\%,\;10\%$) and nicotine (100ng/m1,1000ng/m1) concentrations and each group was studied by time course. The results of this study showed upregulation of PDGF-${\alpha},\;{\beta}$ receptor and IGF-l receptor mRNA at 100ng/ml nicotine concentration and $10\%$ serum group to the time course. These results suggest that physiologically attainable nicotine concentrations may stimulate the mitogenic gene synthesis to human PDL cells in vitro.

• The korean journal of orthodontics
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• v.39 no.4
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• pp.248-256
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• 2009

Objective: The aim of this study was to determine if human PDL cells can produce osteoclastogenic mRNA and examine how compressive stress affects the expression of osteoclastogenic mRNA in human PDL cells. Methods: Human PDL cells were obtained from biscupids extracted for orthodontic treatment. The compressive force was adjusted by increasing the number of cover glasses. PDL cells were subjected to a compressive force of 0.5, 1.0, 2.0, 3.0 or $4.0\;g/cm^2$ for 0.5, 1.5, 6, 24 or 48 hours. Reverse transcription polymerase chain reaction (RT-PCR) analysis was performed to examine levels of M-CSF, IL-$1{\beta}$, RANKL, OPG mRNA expression. Results: Human PDL cells could produce M-CSF mRNA. Human PDL cells under compressive stress showed increased M-CSF, IL-$1{\beta}$ and RANKL mRNAs expression in a force (up to $2\;g/cm^2$) and time-dependent manner. However, OPG mRNA expression was constant regardless of the level and duration of stress. Conclusions: Continuous compressive stress induced the mRNA expression of osteoclastogenic cytokines including M-CSF, RANKL, IL-$1{\beta}$ in PDL cells. Together with an unchanged OPG mRNA level, these results suggest that compressive stress-induced osteoclastogenesis in vivo is partly controlled by M-CSF, RANKL and IL-$1{\beta}$ expression in PDL cells.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.3
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• pp.198-206
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• 2015

Purpose: We aimed to investigate the effect of combined various microgrooves and thermal oxidation on the titanium (Ti) and to evaluate various in vitro responses of human periodontal ligament cells (PLCs). Materials and methods: Grade II titanium disks were fabricated. Microgrooves were applied on titanium discs to have $0/0{{\mu}m}$, $15/3.5{{\mu}m}$, $30/10{{\mu}m}$, and $60/10{{\mu}m}$ of respective width/depth by photolithography. Thermal oxidation was performed on the microgrooves of Ti substrata for 3 h at $700^{\circ}C$ in air. The experiments were divided into 3 groups: control group (ST), thermal oxidation group (ST/TO), and combined microgrooves and thermal oxidation group (Gr15-TO, Gr30-TO, Gr60-TO). Surface characterization was performed by field-emission scanning microscopy. Cell adhesion, osteoblastic differentiation, and mineralization were analyzed using the bromodeoxyurdine (BrdU), Alkaline phosphatase (ALP) activity, and extracellular calcium deposition assays, respectively. Statistical analysis was performed using the oneway analysis of variance and Pearson's bivariate correlation analysis (SPSS Version 17.0). Results: In general, the combined microgrooves and thermal oxidation group (Gr15-TO, Gr30-TO, Gr60-TO) showed significantly higher levels compared with the control (ST) or thermal oxidation (ST-TO) groups in the BrdU expression, ALP activity, and extracellular calcium deposition. Gr60-TO group induced highest levels of cell adhesion and osteoblastic differentiation. Conclusion: Within the limitation of this study, we conclude that the Ti surface treatment using combined microgrooves and thermal oxidation is highly effective in inducing the cell adhesion andosteoblastic differentiation. The propose surface is also expected to be effective in inducing rapid and strong osseointegration of Ti oral implants.

• The korean journal of orthodontics
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• v.38 no.3
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• pp.187-201
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• 2008

Objective: The aim of this study was to determine whether cortical punching stimulates the expression of matrix metalloproteinase-1, -8, and -13 in orthodontic tooth movement in rats. Methods: A total of 32 male sprague-dawley rats at 15 weeks old were divided into two groups of 16 rats each, to form the tooth movement with cortical punching (TMC) group and tooth movement only (TM) group. A total of 20 gm of orthodontic force was applied to rat incisors to cause experimental tooth movement. Cortical punching was performed on the palatal side near the central incisor with a 1.0 mm width microscrew in the TMC group. The duration of tooth movement was 1, 4, 7, and 14 days. Results: Measurements of the mRNA expression were selected as the means to determine the identification of expression of MMP-1, -8, and -13. In the TMC group, the expression of collagen type I was greater than that of the TM group from day 4 to day 14. Expression of TIMP-1 in the TM group was greater than that of the TMC group in the pressure side of PDL and alveolar bone cell at day 4. In the TMC group, TIMP-1 was expressed at the osteoclast, but not at the tooth surface of the TM group at day 14, Maximum induction of the mRNA of MMP-1 was observed on day 4 in the TMC group, but it was observed on day 7 in the TM group. MMP-8 mRNA of the TMC group was twice greater than that of the TM group at f days. In the TMC group, maximum induction of MMP-13 mRNA was observed on day 1. Conclusions: These findings suggested that cortical punching can stimulate remodeling of PDL and alveolar bone connective tissues during experimental orthodontic tooth movement in rats.