• Biomaterials and Biomechanics in Bioengineering
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• v.3 no.2
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• pp.105-114
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• 2016

The purpose of this study is to evaluate the effects of cryopreservation on dental pulp-derived stem cells (DPSC) viability over a period of three years. Dental pulp-derived stem cells were isolated and cultured from thirty-one healthy teeth. DPSC isolates were assessed for doubling-time and baseline viability prior to cryopreservation and were assessed again at three time points; one week (T1), 18 months (T2), and 36 months (T3). DPSC can be grouped based on their observed doubling times; slow (sDT), intermediate (iDT), and rapid (rDT). Viability results demonstrated all three types of DPSC isolates (sDT, iDT and rDT) exhibit time-dependent reductions in viability following cryopreservation, with the greatest reduction observed among sDT-DPSCs and the smallest observed among the rDT-DPSC isolates. Cryopreserved DPSCs demonstrate time-dependent reductions in cellular viability. Although reductions in viability were smallest at the initial time point (T1) and greatest at the final time point (T3), these changes were markedly different among DPSC isolates with similar doubling times (DTs). Furthermore, the analysis of various DPSC biomarkers - including both intracellular and cell surface markers, revealed differential mRNA expression. More specifically, the relative high expression of Sox-2 was only found only among the rDT isolates, which was associated with the smallest reduction in viability over time. The expression of Oct4 and NANOG were also higher among rDT isolates, however, expression was comparatively lower among the sDT isolates that had the highest reduction in cellular viability over the course of this study. These data may suggest that some biomarkers, including Sox-2, Oct4 and NANOG may have some potential for use as biomarkers that may be associated with either higher or lower cellular viability over long-term storage applications although more research will be needed to confirm these findings.

• Restorative Dentistry and Endodontics
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• v.44 no.2
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• pp.20.1-20.8
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• 2019

Objectives: To achieve pulp-dentin complex regeneration with tissue engineering, treatment efficacies and safeties should be evaluated using in vivo orthotopic transplantation in a sufficient number of animals. Mice have been a species of choice in which to study stem cell biology in mammals. However, most pulp-dentin complex regeneration studies have used large animals because the mouse tooth is too small. The purpose of this study was to demonstrate the utility of the mouse tooth as a transplantation model for pulp-dentin complex regeneration research. Materials and Methods: Experiments were performed using 7-week-old male Institute of Cancer Research (ICR) mice; a total of 35 mice had their pulp exposed, and 5 mice each were sacrificed at 1, 2, 4, 7, 9, 12 and 14 days after pulp exposure. After decalcification in 5% ethylenediaminetetraacetic acid, the samples were embedded and cut with a microtome and then stained with hematoxylin and eosin. Slides were observed under a high-magnification light microscope. Results: Until 1 week postoperatively, the tissue below the pulp chamber orifice appeared normal. The remaining coronal portion of the pulp tissue was inflammatory and necrotic. After 1 week postoperatively, inflammation and necrosis were apparent in the root canals inferior to the orifices. The specimens obtained after experimental day 14 showed necrosis of all tissue in the root canals. Conclusions: This study could provide opportunities for researchers performing in vivo orthotopic transplantation experiments with mice.

• Journal of the korean academy of Pediatric Dentistry
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• v.10 no.1
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• pp.139-147
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• 1983

This study was undertaken to evaluate the physiological roles & mechanism of $Ca^{++}$-ATPase & $Mg^{++}$-ATPase in human dental pulp. Each specimen of dental pulp was obtained from the freshly extracted, freeze-dried 242 teeth. $Ca^{++}$-ATPase & $Mg^{++}$-ATPase activity were measured by the release of inorganic phosphate & protein with Spectrophotometer. The results were as follows; 1. The $Ca^{++}$-ATPase & $Mg^{++}$-ATPase activity were significantly increased in developing teeth. 2. The $Ca^{++}$-ATPase & $Mg^{++}$-ATPase activity were significantly decreased in nonvital teeth. 3. The $Ca^{++}$-ATPase & $Mg^{++}$-ATPase activity were significant decreased in deciduous teeth. 4. The $Ca^{++}$-ATPase & $Mg^{++}$-ATPase activity didn't have relation with dental caries. 5. The $Ca^{++}$-ATPase & $Mg^{++}$-ATPase were activated by either $Ca^{++}$ alone or $Mg^{++}$ alone.

• The Journal of the Korean dental association
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• v.57 no.10
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• pp.569-578
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• 2019

The purpose of this retrospective study was to compare outcome of preformed stainless steel crown restorations according to depth of caries in primary molars. The study subjects consisted primary molars having dentin caries extending at least one-fourth of dentin without signs and symptoms of irreversible pulpitis. A total 295 primary molars received preformed stainless steel crown restorations without any base materials were included in this study. Survival rates were compared using a Kaplan-Meier analysis test. There was no significant difference between depth of caries and survival period in primary molars. And also there was no significant difference with or without pulp therapy. The results of this study suggest that neither the amount of caries nor pulp therapy affect the survival period of primary molars significantly. Proper restoration is more important to achieve sealing for stopping caries progression.

• The Journal of the Korean dental association
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• v.4 no.1
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• pp.41-43
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• 1963

A rare case of a fused teeth on the side of upper left third molar was observed from a 28 years old Korean male. The characteristics were as follows: 1)The upper third molar fusrd with the suppernumerary tooth .2)The crown part of the fused teeth were separated and the root were fused. 3)On the x-ray finding. the pulp chamber was two , but it had only one pulp canal.

• The Journal of the Korean dental association
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• v.12 no.3
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• pp.195-198
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• 1974

The purpose of this study is to obtain the histopathological change of dentin and pulp when the prepared cavity is exposed to oral fluid without protection. The results were as follows: 1. Hyperemia of pulp blood vessel and round cell infiltration in odontoblast layer observed on the one week experimental dogs. 2. Marked edematous change, round cell infiltration, fibrotic change and prolif eration of collagenous fiber showed on the 8 week experimental dogs. 3. Prepared cavity should be protected by the biologically accepted lining mater ials regardless of cavity depth.

• Journal of Oral Medicine and Pain
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• v.6 no.1
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• pp.101-110
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• 1981

For the purpose of an estimation of age based on the changes in the human dental cavity caused by increase in age, 1,208 extracted teeth in the parts from central incisors and lateral incisors and lateral incisors to second premolars of upper and lower, right and left side were evaluated and analized all of surface index of pulp cavity. The results are as follows : 1. The surface index of pulp caxities of upper and lower, central and lateral incisors, and tend to decrease regularly as the age increase. So above teeth are more applicable to age estimation than canine and premolars. 2 For the purpose of age estimation by surface index of pulp cavity of central and lateral incisor, linear equations are as follows. Upper central incisor: X=(16.301-Y)/0.12 Upper lateral incisor: X=(16.620-Y)/0.11 Lower central incisor: X=(20.963-Y)/0.16 X=Age Y=Surface index of pulp cavity Correlation coefficient between chronologic age and estimated age is 0.699 3.The least error(3.3 yrs of age)reveals in 41-45 age group, which shows the highest possibility of estimation of age. The highest error(4.1 yrs of age)reveals in 61-65 age group and 56-60 age group.

• Journal of Oral Medicine and Pain
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• v.16 no.1
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• pp.95-102
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• 1991

The purpose of this study carried into the Electric pulp test for having knowledge of the difference of each one's stimulant threshold in normal teeth, the stimulant threshold at 10:00 A.M. and 3:00 P.M. in the same teeth, the differendce of the stimulant threshold between dental caries and normal contralateral teeth. In this study, 27 students aged between 22 and 24 years were selected from a pool of students who are sttending school of dentistry, chosun university who did not possessed dental disease like the dental caries, periodontal disease and restoration etc., and 30 outpatients who possessed dental caries(++). The obtained results were as follows : 1. The stimulant thresholds of the premolars and canine were higher than that of the incisors. 2. The stimulant thresholds of the carious teeth were lower than that normal contralateral teeth. 3. There were no difference stimulant threshold at 10:00 A.M. and 3:00 P.M.

• The Journal of the Korean dental association
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• v.55 no.5
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• pp.352-357
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• 2017

Teeth are made up of three hard tissues, enamel, dentin, and cementum. The dental pulp is the only non-mineralized connective tooth tissue that is surrounded by dentin. The dentin-pulp complex is able to respond to injury by producing hard tissue deposition. However, dentin is considered one of the most difficult tissues to regenerate because of its unique anatomic and physiologic nature. Recently, advances in understanding the applicability of bio-active dentin regenerating proteins are emerging with the development of biological-based therapies using bio-active materials. Dentin defects were regenerated by the deposition of tubular physiologic dentin after application of the bio-active protein in a beagle dog model. Therefore, the bio-active protein may be able to serve as a novel dentin regenerating material and improve symptoms of dentin hypersensitivity.

• Restorative Dentistry and Endodontics
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• v.37 no.2
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• pp.119-122
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• 2012

Regenerative endodontics has a potential to heal a partially necrotic pulp, which can be beneficial for the continued root development and strengthening of immature teeth. For this purpose, triple antibiotic mixture of ciprofloxacin, metronidazole, and minocycline was recommended as intracanal medicament in an attempt to disinfect the root canal system for revascularization of a tooth with a necrotic pulp. However, discoloration of the tooth was reported after applying this. This case shows the idea for preventing the tooth discoloration using a delivery syringe to avoid the contact between the clinical crown and the antibiotics.