• The korean journal of orthodontics
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• v.36 no.6
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• pp.465-473
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• 2006

Objective: This study evaluated the effects of nitric oxide (NO) on the proliferation and differentiation of human periodontal ligament cells involved in orthodontic tooth movement. Methods: A range of concentrations of sodium nitroprusside (SNP), a NO donor, were administered to samples of human periodontal ligament cells, followed by measurement of cell viability, alkaline phosphatase (ALP) activity, and expression of osteonectin and bone sialoprotein. Results: Cell viability, ALP activity and the expression of osteonectin and bone sialoprotein were increased in human periodontal ligament cells treated with SNP concentrations of < 0.2 mM compared with controls, but were decreased with SNP concentrations of > 1.0 mM. Conclusion: NO has a biphasic effect on proliferation and differentiation in human periodontal ligament cells, with a stimulatory effect at low concentrations and an inhibitory effect at high concentrations.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.203-209
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• 2016

Purpose: Stimulating the proliferation and migration of periodontal ligament cells (PDLCs) has become the main goal of periodontal regeneration. To accomplish this goal, regeneration procedures have been developed, but results have not been predictable. Recently, tissue engineering using enamel matrix derivatives (EMDs) and growth factors has been applied to periodontal regeneration; however, the mechanism of EMDs is largely unknown. The aim of this study was to investigate the effects of EMDs on the proliferation and release of growth factors from PDLCs. Materials and methods: Human PDLCs were removed from individually extracted 3rd molars of healthy young adults, and cultured in the media containing EMDs (Emdogain, Biora, Malmo, Sweden) at concentration of 0, 12.5, 25, 50, 100, and $200{\mu}g/mL$ each. Cell proliferation and ALP (alkaline phosphatase) activity were measured. The evaluation of growth factors released by PDLCs was also performed by one-way analysis of variance (ANOVA) and Bonferroni's multiple comparison test. Results: Significantly increased proliferation and ALP activity were observed in PDLCs treated with over $25{\mu}g/mL$ and $50{\mu}g/mL$ EMDs, respectively. Additionally, treatment of PDLCs with $50{\mu}g/mL$ resulted in significantly increased release of vascular endothelial growth factor (VEGF) and transforming growth factor $(TGF)-{\beta}$ after 24 h and 48 h, respectively. Conclusion: EMDs enhance the proliferation and ALP activity of PDLCs, and promote the release of growth factors, including VEGF and $TGF-{\beta}$, from PDLCs. Therefore EMDs could be one of the effective methods for periodontal regeneration.

• The korean journal of orthodontics
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• v.26 no.1 s.54
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• pp.83-94
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• 1996

Substance P is one of the neuropeptide which presents highly in tension site of periodontal ligament during the orthodontic tooth movement. It has bnn also hon as one of the neuropeptides which cause neurogenic inflammation in various tissues and organs. However, there is no report about the effect of substance P on major extracellular matrix protein, collagen production. The purpose of this study was to evaluate the collagen production by substance P in human periodontal ligament cell. The collagenase-digestion method was used to evaluate collagen production and also used Northern blot hybridization for the evaluation of collagen mRNA level. This study also Included in terms of prostanglandins and gelatinase production with respect to collagen production. For the collagen degradation, zymography was used to estimate denatured collagen degradation. Dose-dependent effect of substance P on noncollagen protein, collagen, and percent collagen was that substance P increased noncollagen protein synthesis, but decreased collagen sytnsis. So the percent collagen, which determined by relative collagen production against total protein production, w3s decreased from $7\%\;to\;3.6\%$. This inhibitory effect of substance P on collagen production was disappeared when cells were treated concomitantly with indomethacin. It means that substance P-induced inhibitory effect on collagen production was due at least in part to the production of prostaglandins. To evaluate whether substance P-induced inhibitory effect on collagen production is correspond to the steady-state levels of procollagen mRNA, Northern blot hybridization was performed and it showed that substance P has no effect on the steady-slate level of ${\alpha}1(I)$ procollagen mRNA. It means that the inhibitory effect of substance P on collagen production was due to the change of a certain mechanism after posttranscription. In this context, gelatinase production by substance P in periodontal ligament cells was evaluated by zymography. Zymogram showed that substance P has no effect on gelatinase production in periodontal ligament cells. To explore wheter substance P-induced inhibitory effect on collagen production is selevtive in periodontal ligament cells or not, MC3T3-E1 cells which originated from mouse calvaria was used. It showed that substance P has no effect on collagen production in MC3T3-E1 cells. Taken together, substance P inhibits collagen production in human periodontal ligament cells. This effect was not due to the change of the steady-state level of procollagen mRNA and gelatinase production, but due at least in part to the change of prostaglandins production.

• Restorative Dentistry and Endodontics
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• v.35 no.6
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• pp.473-478
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• 2010

Objectives: This study was performed to investigate the biocompatibility of newly introduced Bioaggregate on human pulp and PDL cells. Materials and Methods: Cells were collected from human pulp and PDL tissue of extracted premolars. Cell culture plate was coated either with Bioaggregate or white MTA, then the same number of cells were poured to cell culture dishes. Cell attachment and growth was examined under a phase microscope after 1,3 and 7 days of seeding. Cell viability was measured and the data was analyzed using Student t-test and one way ANOVA. Results: Both types of cells used in this study were well attached and grew healthy on Bioaggregate and MTA coated culture dishes. No cell inhibition zone was observed in Bioaggregate group. There was no statistical difference of viable cells between bioaggreagte and MTA groups. Conclusions: Bioaggregate appeared to be biocompatible compared with white MTA on human pulp and PDL cells.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.5
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• pp.455-463
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• 2007

The present study was designed to evaluate effects of the commonly used NSAIDs(acetaminophen, aspirin, and ibuprofen) on human periodontal ligament cells. Human periodontal ligament cells were grown from a cell line provided by Kyungpook National University. Effects of NSAIDs on the proliferation of human periodontal ligament cells were assessed using MTT assays. And then $PGE_2$ concentrations were determined by ELISA and the changes of cellular configuration were found by electron micrograph. The results were as follows; 1. The MTT assay demonstrated that the commonly used NSAIDs(acetaminophen, aspirin, and ibuprofen) had not significant cytotoxic effect on human periodontal ligament cells. 2. NSAIDs inhibited the $PGE_2$ synthesis of human periodontal ligament cells compared with the control group. These inhibitory effects had no significant differences with NSAID type and concentration. 3. Electron micrographs of human periodontal ligament cells treated with NSAIDs showed more narrow and irregular shape.

• 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.

• Restorative Dentistry and Endodontics
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• v.32 no.5
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• pp.419-425
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• 2007

The aim of this study was to evaluate the radiopacity and cytotoxicity of three resin-based (AH 26, EZ fill and AD Seal), a zinc oxide-eugenol-based (ZOB Seal), and a calcium hydroxide-based (Sealapex) root canal sealers. Specimens, 10 mm in diameter and 1 mm in thickness, were radiographed simultaneously with an aluminum step wedge using occlusal films, according to ISO 6876/2001 standards. Radiographs were digitized, and the radiopacity of sealers was compared to the different thicknesses of the aluminum step wedge, using the Scion image software. Using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the cytotoxicity of each material was determined in immortalized human periodontal ligament (IPDL) cells. The results demonstrated that EZ fill was the most radiopaque sealer, while Sealapex was the least radiopaque (p < 0.05). AH 26, AD Seal and ZOB Seal presented intermediate radiopacity values. All the materials evaluated, except for Sealapex, presented the minimum radiopacity required by ISO standards. The cell viabilities of resin-based root canal sealers were statistically higher than that of other type of root canal sealers through the all experimental time. Further, EZ fill showed statistically lower cell viability in 24 and 48 hours compared to AD Seal and in 72 hours compared to all other resin-based root canal sealers. However, there was no correlation between the radiopacity and cytotoxicity of three resin-based root canals sealers (p > 0.05). These results indicate that resin-based root canal sealer is more biocompatible and has advantage in terms of radiopacity.

• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.421-430
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• 1997

Alveolar bone grows with development of tooth germs and roots; bone deposition occurs with tooth eruption. Bone components undergoes processes of resorption and deposition, and when the balance between them is disrupted, decrease in alveolar bone height or excessive bone deposition result. It has been hon that repositioning of teeth through orthodontic treatment can cause alveolar bone resorption which result in decreased alveolar bone height, and there have been many studies to evaluate such effects. X-ray films that could be replicated and standardized were chosen in clinical studies, and among them, bitewing films were used for objective evaluation of changes in alveolar bone level. Twenty subjects, 10 to 13-year- old (average 12.2) children with Cl I molar key, healthy oral condition, no congenital missing, no periodontal disease, and pre-and post-orthodontic bitewing films, were randomly selected for comparison of alveolar bone heights. Amounts of tooth and changes in alveolar bone heights were analyzed. The following results were obtained: 1. Amount of tooth movement in canine, premolar, and molar regions, changes in tooth axis, and changes in alveolar bone heights were measured, and the mean and median values were obtained. 2. When pre-and post-orthodontic alveolar bone levels were compared, larger changes were noticed in maxilla than mandible. 3. When mesio-distally compared, larger changes were observed in the distal sides of 3D3 and 4M3, mesial sides of 4M3 and 4D3, distal sides of 4D3 and 5M3, mesial sides of 5M3 and 5D3, md distal sides of 5D3 and 6M3. 4. When the amounts of tooth movements(TX, TY)and changes in tooth axis(A) were compared,34TX, 34TY, 34A of both sides in maxilla were greater, iud changes in alveolar bone level were greater than any other region.