• Restorative Dentistry and Endodontics
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• v.48 no.2
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• pp.20.1-20.13
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• 2023

This mini-review was conducted to present an overview of the use of exosomes in regenerating the dentin-pulp complex (DPC). The PubMed and Scopus databases were searched for relevant articles published between January 1, 2013 and January 1, 2023. The findings of basic in vitro studies indicated that exosomes enhance the proliferation and migration of mesenchymal cells, as human dental pulp stem cells, via mitogen-activated protein kinases and Wingless-Int signaling pathways. In addition, they possess proangiogenic potential and contribute to neovascularization and capillary tube formation by promoting endothelial cell proliferation and migration of human umbilical vein endothelial cells. Likewise, they regulate the migration and differentiation of Schwann cells, facilitate the conversion of M1 pro-inflammatory macrophages to M2 anti-inflammatory phenotypes, and mediate immune suppression as they promote regulatory T cell conversion. Basic in vivo studies have indicated that exosomes triggered the regeneration of dentin-pulp-like tissue, and exosomes isolated under odontogenic circumstances are particularly strong inducers of tissue regeneration and stem cell differentiation. Exosomes are a promising regenerative tool for DPC in cases of small pulp exposure or for whole-pulp tissue regeneration.

• Restorative Dentistry and Endodontics
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• v.12 no.2
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• pp.73-80
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• 1987

The present study was designed to help elucidate the effect of glass ionomer cements on the exposed dental pulp by means of histologic examination. A total of 40 cavities of class V were prepared on the teeth of 4 dogs with exposure of 1mm in diameter on the bases of them. 20 cavities were filled with glass ionomer cement as the experimental group and the other 20 cavities were filled with zinc oxide eugenol cement as the control group. The dogs were sacrificed at one, two, three, and four weeks after filling, and the specimens were routinely prepared and stained with Hematoxylin-Eosin. The obtained microscopic findings were as follows: Inflammatory cell infiltrations were observed in control in 1 week, which decreased markedly with time. In all control groups, hemorrhage around exposed pulp tissue and coagulation change of pulp were observed. Secondary dentin formation and thickened predentin were observed in 4 week cases, and the recovery of pulp tissue was favorable on the whole. Inflammatory cell infiltration was observed in all GIC groups. Proliferation of blood vessel and congestion were observed with coagulation changes around the exposed pulp tissue. Secondary dentin formation and thickened predentin were observed in 3 weeks. In the experimental 4 week case, secondary dentin formation was evident. On the whole, pulpal irritation of glass ionomer cement was relatively severe. Recovery of pulp tissue in GIC groups was less favorable compared with that of ZOE groups.

• Restorative Dentistry and Endodontics
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• v.13 no.2
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• pp.265-282
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• 1988

The pulp response of posterior composite resins in relation to the thickness of remaining dentin was studied with 120 teeth from 6 dogs, Class V. cavities were prepared on the cervical area of facial surfaces. The thickness of remaining dentin was controlled with Caries Meter$^{(R)}$. The cavities of group A were prepared to show the electrical impedance of 22-26$K{\Omega}$(thickness of remaining dentin:0.4-0.5mm). The cavities of group B, 50-55$K{\Omega}$(thickness of remaining dentin: 0.8-0.9mm). Zinc - Oxide Eugenol cement, Estilux$^{(R)}$ posterior, Heliomolar$^{(R)}$ radiopaque, P-30$^{(R)}$ and Scotchbond$^{(R)}$+P-30$^{(R)}$ were filled in each cavity. After 3days, 1 week, 2 weeks, 4 weeks, 9 weeks and 13 weeks, the teeth and pulp tissue were processed routinely and stained with Hematoxylin and Eosin. Pathological tissue changes were observed with light microscope. The following results were obtained. I. The pulp response of group A cavties was severer than that of group B cavities. 2. In the pulp of group A cavities which were filled with Zinc-Oxide Eugenol Cement, only vascular changes were observed after 3 days and 1 week, severe acute inflammation after 4 weeks, moderate acute inflammation after 9 weeks, and chronic inflammation and formation of granulation tissue after 13 weeks. 3. In the pulp of group A cavities which were filled with Estilux$^{(R)}$ posterior, only vascular changes were observed after 3 days and 1 week. But the inflammatory response has became much severer with the elapsed experimental period. 4. In the pulp of group A cavities which were filled with Heliomolar$^{(R)}$ radiopaque, the inflammatory response with the elapsed experimental period was not severer than that of the pulp of group A cavities which were filled with other materials. 5. In the group B cavities, the difference of pulp response by filling materials was not recognizable. In the group A cavities, the pulp response of Estilux$^{(R)}$ posterior was severest and in order P-30$^{(R)}$, Heliomolar$^{(R)}$ radiopaque was slighter.

• 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.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.

• The Journal of the Korean dental association
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• v.9 no.4
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• pp.157-160
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• 1971

To compare the effects of various pulp capping agents that are usually applied to human pulp tissue, adult dogs were bred for a certain period and each capping agent was applied experimentally to pulp tissue after vital pulpotomy. Histological observations are as follows. 1) In comparison between methods of vital pulpotomy, one and two appointment method, different courses of healing were observed. In one appointment method, the granulation tissue formation at the amputation sur face of pulp tissue had a tendency to be transformed to scar tissue formation. In two appointment method, more transformation than that of one appointment method from scar tissue to dentin matrix formation were observed. 2) Histologic changes that have appeared in pulp tissue are a) fixation at outer layer b) degeneration at middle layer c) hyperemia and round cell infiltration at inner layer 3) With use of formocresol mixed zinc oxide powder in two appointment method complete formation of dentin matrix were observed. 4) Among the methods and aagents described above formocresol mixed zinc oxide powder in two appointment method appeared to be relatively effective.

• Restorative Dentistry and Endodontics
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• v.12 no.2
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• pp.101-108
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• 1987

The purpose of this study was to investigate the pulpal responses of dental adhesive resins. A total of 40 cavities of the permanent healthy teeth from 4 dogs were prepared. In the experimental group, the cavities were etched for 1 minute with citric acid and filled with experimental resins (ie. Super-Bond C & B$^{(R)}$). In the control group, the cavities were filled with calcium hydroxide base materials (ie. Dycal$^{(R)}$) without etching. The dogs were sacrificed at one, two, three and four weeks after the time of filling and the specimens were routinely prepared and stained with Hematoxylin-Eosin. The microscopic findings were as follows: Infiltration of inflammatory cells was not observed in both experimental and control groups. Change in the odontoblastic layer was not observed in all control groups but severe swelling was observed in deep dental pulp tissue of the control two and three week cases. Pulp tissue was recovered with plenty of fibrous component in the control four week case and reparative dentin formation was not occurred in all cases. Slight changes of the odontoblastic layer beneath the cavity were observed in the experimental one week case. In experimental two and three week cases, swelling of deep pulp tissue was increased and localized reparative dentin formation was observed. In the experimental four week case, odontoblastic layer was recovered with regular appearance and fibrous component of the pulp was increased, but reparative dentin formation was not evident.

• Restorative Dentistry and Endodontics
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• v.20 no.1
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• pp.342-350
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• 1995

To determine the factors which affect the flow of dentinal fluid through cat dentinal tubules in vivo, the flow of fluid was measured by observing the movement of the fat droplets of dilute milk in a glass capillary with a microscope connected to the monitor. After measuring the exposed area of dentin, hydraulic conductances of dentin were calculated. The mean pressure which stoped the outward flow of dentinal fluid was 9.5mmHg. The hydraulic conductance of dentin under the condition of pulp exposed was increased by 21 % from that under the condition of dentin exposed. Under the conditions of pulp cut and pulp removed, the hydraulic conductances of dentin were increased by 22 % and 31 % respectively from that under the condition of dentin exposed. These results show that the direction and rate of dentinal fluid flow in cat dentin is affected mainly by the hydrostatic pressure of interstitial fluid of pulp tissue in the state of low compliance. Both of the osmotic effect produced by the protein constituents of interstitial fluid across the odontoblast tell layer and the change of interstitial fluid pressure produced by the state of the microcirculation of the pulp also affect the direction and rate of dentinal fluid in some degree.

• Journal of the korean academy of Pediatric Dentistry
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• v.8 no.1
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• pp.37-46
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• 1981

This study was undertaken to evaluate the pulpal responses to the pulp-capping materials such as glutaraldehyde and formocresol in pulpotomy technique, especially in the primary dentition. Mandibular primary canines and molars of 5 dogs (aged about 8-9 weeks)were selected for this study. The intervals of observation for histologic study of pulpotomized primary teeth with 2% glutaraldehyde, formocresol and calcium hydroxide in the usual manner ranged from 2 hours, 1 week, 2 weeks, 3 weeks and 5 weeks after experiments respectively. Each specimens were fixed with 10% formalin and decalcified in 5% nitric acid. All slides were stained with Hematorylin-Eosin and examined histopathologically. The results were as follows; 1. In calcium hydroxide groups, formation of dentin bridge was initiated in 1 week after experiments and completed in 5 weeks after experiments. 2. Formation of dentin bridge was not seen, whereas necrosis of pulp tissue was noted, in formocresol and glutaraldehyde groups. 3. Duration of tissue reactions and tissue changes were similar, in formocresol and glutaraldehyde groups. 4. In formocresol and glutaraldehyde groups, amputation surfaces of the pulp were covered with blood clots, beneath which coagulation necrois was noted, but inflammatory cells were not prominent, in 2 hours and 1 week after experiments. But coagulation necrosis was proceeded to the apical portion, accompanied by infiltration of inflammatory cells, since 2 weeks after experiments. And suppuration or gangrene of the pulp tissue were noted in 3 weeks and 5 weeks groups. 5. Suppuration or gangrene of pulp seemed to provoke the resorption of dentin wall, and inflammatory changes and resorption of roots were noted in the periodontal membrane near the periapical region. 6. As compared with calcium hydroxide groups, resorption of the root was pronounced in form or cresol and glutaraldehyde groups. Effects of medicaments to the succedaneous tooth germ were not seen.

• Restorative Dentistry and Endodontics
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• v.6 no.1
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• pp.27-35
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• 1980

This study was to evaluate the effectiveness of a few disinfectant on amputated pulps of domestic dogs. The materials employed for the purpose were zinc oxide eugenol paste, calcium hydroxide as control groups and guaiacol (1%, 5%, 10% by weight) added zinc oxide eugenol paste and formaldehyde (1%, 5%, 10% by weight) added calcium hydroxide as experimental groups. Following were the results obtained throngh histo-pathological examination. 1) In calcium hydroxide-formaldehyde groups, secondary dentin formation was observed in the 2 weeks, but the remaining pulp tissue was severely atrophied according to the concentration of formaldehyde and the time increased. 2) In zinc oxide eugenol-guaiacol groups, the first evidence of secondary dentin formation was observed in the 3 weeks. It seems that the concentration variety of guaiacol influenced very little to the potential ability of dentin formation. 3) Except 1% formaldehyde containing calcium hydroxide group, every group showed severe pulp degeneration. In all groups of zinc oxide eugenol-guaiacol cases revealed the tendency of recovery.