• International Journal of Oral Biology
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• v.35 no.1
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• pp.1-5
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• 2010

Human fibroblasts that maintain the structural integrity of connective tissues by secreting precursors of the extracellular matrix are typically cultured with serum. However, there are potential disadvantages of the use of serum including unnatural interactions between the cells and the potential for exposure to animal pathogens. To prevent the possible influence of serum on fibroblast cultures, we devised a serum-free growth method and present in vitro data that demonstrate its suitability for growing porcine fetal fibroblasts. These cells were grown under four different culture conditions: no serum (negative control), 10% fetal bovine serum (FBS, positive control), 10% knockout serum replacement (KSR) and 20% KSR in the medium. The proliferation rates and viabilities of the cells were investigated by counting the number of cells and trypan blue staining, respectively. The 10% FBS group showed the largest increase in the total number of cells ($1.09\;{\times}\;10^5\;cells/ml$). In terms of the rate of viable cells, the results from the KSR supplementation groups (20% KSR:64.7%; 10% KSR: 80.6%) were similar to those from the 10% FBS group (68.5%). Moreover, supplementation with either 10% ($3.0\;{\times}\;10^4\;cells/ml$) or 20% KSR ($4.8\;{\times}\;10^4\;cells/ml$) produced similar cell growth rates. In conclusion, although KSR supplementation produces a lower cell proliferation rate than FBS, this growth condition is more effective for obtaining an appropriate number of viable porcine fetal fibroblasts in culture. Using KSR in fibroblast culture medium is thus a viable alternative to FBS.

• Reproductive and Developmental Biology
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• v.29 no.3
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• pp.145-147
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• 2005

Autocrine or paracrine mediators released by the early embryo are implicated in the support of embryonic development. Their mechanisms and optimal embryo density in the medium, however, are uncertain. This study was conducted to establish the optimal embryo density and culture medium volume in mouse parthenogenetic embryo culture. In experiment 1, culture of parthenogenetirally activated oocytes at a concentration of $2{\~}4$ embryos/${\mu}L$ significantly improved development to the blastoryst stage ($72{\%}{\leq}$) compared with culture at the lower ($0.2{\~}1$e mbryos/${\mu}L,\;0\~37.5\%$) and the higher ($5{\~}6$ embryos/${\mu}L,\;30\~53\%$) concentration for 120 h when the oocytes were cultured in a 5 ${\mu}L$ drop under mineral oil In experiment 2, the embryos cultured at a concentration of $2{\~}4$ embryos/${\mu}L$ in a 10 ${\mu}L$ drop ($81.1{\%}$) showed significantly higher blastocyst rates than those in a 5 ${\mu}L$ drop ($68.5{\%}$). This study optimizes in vitro culture condition by modifying embryo density and the volume of culture medium It may give appropriate level of autocrine and/or paracrine factors to enhance viability and subsequent normal development of mouse parthenogenetic embryos in vitro.

• Journal of dental hygiene science
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• v.3 no.1
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• pp.39-44
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• 2003

This study was to investigate the antibacterial effect of Schizandrae fructus and Evodiae fructus extracts on S. mutans growth. The antibacterial effect of these extracts on S. mutans was good at Schizandrae fructus extract than the Evodiae fructus extract. The antibacterial activities of these extracts were measured 8.5 mm and 6.5 mm at 20 mg/ml concentration, respectively. The growth of S. mutans in control medium was the highest at 8 hrs, while the media of Schizandrae fructus and Evodiae fructus extracts added-medium(2 mg/ml) showed maximum growth at 16hrs. The pH values of the control medium was 5.08 at 8 hrs, but the media supplemented with Schizandrae fructus and Evodiae fructus extracts were 6.00, and 5.36 at 8 hrs, respectively. The amounts of total carbohydrate for the control media was 0.81 mg/ml at 8 hrs, but the media supplemented with Schizandrae and Evodiae fructus extracts were 1.32 mg/ml and 1.88 mg/ml at 8 hrs, respectively. In the change of culture medium proteins, the control culture broth and cultures supplemented with Schizandrae fructus and Evodiae fructus extracts were 8.39 mg/ml, 8.59 mg/ml and 9.97 mg/ml at 8 hrs, respectively. The S. mutans polysaccharide contents of the control medium and the media supplemented with Schizandrae and Evodiae fructus extracts were 300 mg/100 ml, 240 mg/100 ml and 280 mg/100 ml at 8 hrs, respectively.

• Restorative Dentistry and Endodontics
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• v.41 no.3
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• pp.167-175
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• 2016

Objectives: Endodontically treated teeth with insufficient tooth structure are often restored with esthetic restorations. This study evaluated the cytotoxicity and biological effects of yttria partially stabilized zirconia (Y-TZP) blocks in combination with several dental cements. Materials and Methods: Pairs of zirconia cylinders with medium alone or cemented with three types of dental cement including RelyX U200 (3M ESPE), FujiCEM 2 (GC), and Panavia F 2.0 (Kuraray) were incubated in medium for 14 days. The cytotoxicity of each supernatant was determined using 3-(4,5-dimethylthiazole- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays on L929 fibroblasts and MC3T3-E1 osteoblasts. The levels of interleukin-6 (IL-6) mRNA were evaluated by reverse transcription polymerase chain reaction (RT-PCR), and IL-6 protein was evaluated by enzyme-linked immunosorbent assays (ELISA). The data were analyzed using one-way ANOVA and Tukey post-hoc tests. A p < 0.05 was considered statistically significant. Results: The MTT assays showed that MC3T3-E1 osteoblasts were more susceptible to dental cements than L929 fibroblasts. The resin based dental cements increased IL-6 expression in L929 cells, but reduced IL-6 expression in MC3T3-E1 cells. Conclusions: Zirconia alone or blocks cemented with dental cement showed acceptable biocompatibilities. The results showed resin-modified glass-ionomer based cement less produced inflammatory cytokines than other self-adhesive resin-based cements. Furthermore, osteoblasts were more susceptible than fibroblasts to the biological effects of dental cement.

• Korean Journal of Materials Research
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• v.33 no.4
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• pp.130-134
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• 2023

This study evaluated cell viability and cytokine release in immortalized human oral fibroblasts (hTERT-hNOFs) and keratinocytes (IHOK) exposed to a dental-impregnated gingival retraction cord. To prepare the extracts, dental gingival retraction cords impregnated with aluminum chloride hexahydrate were immersed in a cell culture medium for 24 h at 37 ℃. hTERT-hNOFs and IHOK were cultured for 24 h. The cell culture medium was removed and extracts of the dental gingival retraction cords were added. After incubation with the extract solution, cell viability was evaluated using an MTT assay. The levels of the cytokines IL-1α and IL-8 were measured in the supernatants of each cell type. The cell viability after exposure to the extract solution for 10 min exceeded 70 % in both cell types. The ET50 values for hTERT-hNOF and IHOK were 35.75 and 28.98 min, respectively. For IHOK, the IL-1α level was (5.35 ± 5.22) pg/mL at 10 min, (3.58 ± 5.38) pg/mL at 20 min, and (2.85 ± 4.28) pg/mL at 60 min of exposure (p > 0.05). The IL-8 level in IHOK was (67.16 ± 18.70) pg/mL at 10 min, (78.36 ± 7.50) pg/mL at 20 min, and (111.9 ± 26.10) pg/mL at 60 min of exposure (p > 0.05). Cytokine release was not observed from hTERT-hNOFs. Based on these results, cell viability and cytokine release were confirmed in cells exposed to the impregnated gingival retraction cord. In addition, the application of the extracts to hTERT-hNOF and IHOK during the actual contact time and determination of ET50 may be beneficial for evaluating the biocompatibility of dental-impregnated gingival retraction cords.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2005.10a
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• pp.126-127
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• 2005

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2005.10a
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• pp.126-127
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• 2005

• Journal of Korean society of Dental Hygiene
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• v.10 no.1
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• pp.65-79
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• 2010

Objectives : This study was designed to present how to reduce the fear associated with dental treatment by analyzing the fear levels for dental treatment, the influential factors for the fear, the general characteristics of patients and the correlations between trust in dental care professionals and satisfaction with dental treatment. Methods : The subjects were 400 workers at 5 industrial sites, which got health management conducted by health management agencies, among small and medium industrial sites located in the Gyeongbuk region of South Korea during a period of February to March, 2009. Results & Conclusion : 1. Of the subjects, 134 (30.7%) and 303 (69.3%) persons had high and low fear levels of dental treatment respectively. 2. The fear levels of dental treatment were higher in women than men, and significantly high in proportion to the patients' subjective bad health levels and past dental care fear frequencies. 3. The fear associated with dental treatment was significantly correlated to the trust in dentists.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.4
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• pp.279-288
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• 2007

In the present study, we focused on stem cells in the dental papilla of the tooth germ. The tooth germ, sometimes called the tooth bud, is the primordial structure from which a tooth is formed. The tooth germ consists of the enamel organ, the dental papilla, and the dental follicle. The dental papilla lies below a cellular aggregation of the enamel organ. Mesenchymal cells within the dental papilla are responsible for formation of dentin and pulp of a tooth. Tooth germ disappears as a tooth is formed, but that of a third molar stays in the jawbone of a human until the age of 10 to 16, because third molars grow slowly. Impacted third molar tooth germs from young adults are sometimes extracted for orthodontic treatment. In the present study, we evaluated the osteogenic activity and mineralization of cultured human dental papilla-derived cells. Dental papillas were harvested from mandible during surgical extraction of lower impacted third molar from 3 patients aged 13-15 years. After passage 3, the dental papilla-derived cells were trypsinized and subsequently suspended in the osteogenic induction DMEM medium supplemented with 10% fetal bovine serum, 50 g/ml L-ascorbic acid 2-phosphate, 10 nM dexamethasone and 10 mM -glycerophosphate at a density of $1\;{\times}10^6\;cells/dish$ in a 100-mm culture dish. The dental papilla-derived cells were then cultured for 6 weeks and the medium was changes every 3 days during the incubation period. Dental papilla-derived cells showed positive alkaline phosphatase (ALP) staining during 42 days of culture period. The formation of ALP stain showed its maximal manifestation at day 7 of culture period, then decreased in intensity during the culture period. ALP mRNA level was largely elevated at 1 weeks and gradually decreased with culture time. Osteocalcin mRNA expression appeared at day 14 in culture, after that its expression continuously increased in a time-dependent manner up to day 28. The expression remained constant thereafter. Runx2 expression appeared at day 7 with no detection thereafter. Von Kossa-positive mineralization nodules were first present at day 14 in culture followed by an increased number of positive nodules during the entire duration of the culture period. Osteocalcin secretion was detectable in the culture medium from 1 week. The secretion of osteocalcin from dental papilla-derived cells into the medium greatly increased after 3 weeks although it showed a shallow increase by then. In conclusion, our study showed that cultured human dental papilla-derived cells differentiated into active osteoblastic cells that were involved in synthesis of bone matrix and the subsequent mineralization of the matrix.

• Journal of Technologic Dentistry
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• v.23 no.2
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• pp.61-74
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• 2002

This experiment was to find out the complacency of wearing dentures and the linkage to the quality of life style of oldsters 60 years old and over. 122 numbers of oldsters who came to aid to the health center were put to survey. This was taken place within the areas of Deajun, Koonsan, Mooju and Jinahn, thus procured the following result. 1. The length of edentulous period of 1-6years of oldsters aged around 60s showed 26.0%. The oldsters with edentulous period of over 7years aged in the 70s showed 26.1 % and 56.0% on oldsters aged in the 80s. This shows that as the age increases the edentulous period lengthens. (P<0.05) The length of time of using the denture shows. llyears or over on women 41.9%, less than 6years on men 71.4% as the highest rate. 11 years or over on towns/subcounty show 57.5%, small and medium cities more than 1 year 63.6%, less than six years also 63.6% and Kwangyuk city 47.6%. 2. The complacency on medical treatment of dentures was highest in Kwangyuk city of 61.3%, compared to towns/subcounty of 50.8% and small and medium cities of 33.3%. (P<0.05) 3. The complacency on mastication and pronunciation appears, 2.74% in Kwangyuk city, 3.10% in towns/ subcounty which is higher than the small and medium cities showing 1.09% on average. Satisfaction rate tends to be higher as the length of time of using the denture is longer. 4. Inconvenience on eating habits caused by dentures were felt by women. Wanting to get a new denture was 25.6% by women showing much higher rate than that of men which is 2.8% by men. (P<0.05) 5. The complacency of change in their life style after wearing the dentures were higher in Kwangyuk city of 64.5% whereas it showed 27.0% in towns! subcounty and 16.7%in small and medium cities. (P<0.05)