• Restorative Dentistry and Endodontics
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• v.15 no.2
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• pp.58-76
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• 1990

This study was designed to elucidate the distribution of the immunoglobulins in the experimentally induced rat periapical lesions. The pulp exposure was performed in 80 molars from 40 rats and the animals were sacrificed at 15, 30, 60 and 90 days after the operation and examined and radiographed. Of the 80 samples, 56 samples were routinely sectioned ($4-6{\mu}$ in thickness) and stained with Hematoxylin-Eosin for the light microscopic examination and 50 samples were stained with toluidin blue for mast cells and 50 samples were stained using the Avidin-Biotin horseradish peroxidase for detecting the presence of Ig A, Ig E, Ig M and Ig G containing cells. The following results were obtained : 1. The periapical lesions could be observed in all of 80 teeth by radiogragh (100%) and the periapical lesions were detected in 50 samples of 51 samples by light microscopy (98%). The size of lesions increased with time lapse both by radiograph and by light microscopy(p<0.05). 2. Of the 50 samples, 19 samples were diagnosed as periapical abscesses, 18 as periapical granulomas, 10 as fibrous scar tissues and 3 cysts. 3. After pulp exposure, periapical granulomas were developed mostly in the 15 day group, with time lapse periapical abscesses and fibrous scar tissues increased. 4. In the 50 periapical lesions, the numbers of Ig G containing cell (57.2%) were prominent and the percentage of Ig A, Ig E and Ig M containing cells were 16.4%, 14.7% and 11.8% respectively. The numbers of all classes of immunoglobulin containing cell were highest in the periapical granulomas and lowest in the cysts(p<0.05). 5. The number of the mast cell and immunoglobulin containing cells decreased generally with time lapse after the pulp exposure and Ig A, Ig E, Ig M and Ig G containing cells and mast cells had the high correlation one another(>0.6).

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.3
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• pp.583-597
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• 1998

The purpose of this study was to evaluate temperature change occurred in enamel, dentin and pulp due to the heat from cavity prepration with laser. We made three models had different cavity depth: cavity depth of model A was 3.52mm, model B was 2.32mm, model C was 1.16mm. We irradiated cavity base with thermal capacity of $30J,100J,300J/cm^2s$ during few seconds and studied the change of temperature in tooth during 10 seconds, and estimated change of thermal capacity by different irradiated site and exposure time. At $300J/cm^2$ irradiation for 2 seconds, the temperature of irradiated surface was elevated fast according to irradiated thermal energy during 1 second. In proportion to continuous exposure time, temperature elevated slowly. The surface temperature was $1370^{\circ}C$. After discontinue of thermal irradiation, the heat of irradiated surface was diffused in dentin and pulp and the greatest temperature was made. The greatest temperature was disappeared within 10 seconds The greatest temperature of the inner part of model brought about very severe change by different depth. Temperature in pulp was raised by the greater irradiated energy density and exposure time.

• 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.40 no.2
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• pp.120-126
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• 2013

Preserving the pulp is important in the treatment of carious pulp exposure in young permanent teeth. Pulpotomy is a vital pulp therapy in which a portion of the coronal pulp tissue is surgically removed, and the remaining radicular tissue is covered with suitable material that protects the pulp from further injury and permits and promotes healing. It is important to develop biocompatible treatment directed at maintaining pulp vitality and increasing tooth longevity. Platelet-rich fibrin (PRF) has been referred to as a second-generation platelet concentrate. Two clinical cases in which PRF was applied as a medicament after pulpotomy of an immature permanent tooth are presented. After isolation, caries removal and pulpotomy with PRF was performed. A layer of mineral trioxide aggregate (MTA) was placed over the PRF, and the final restoration was performed. Postoperatively, the patient had no pain or discomfort, and follow-up radiographs revealed normal periodontal ligament space and trabecular bone pattern.

• Toxicological Research
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• v.23 no.4
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• pp.391-403
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• 2007

The study was conducted to assess the repeated dose and reproduction and developmental toxicities of acetanilide, an intermediate for drug production, as a part of OECD Screening Information Data Set (SIDS) program. The test agent was administered by gavage at dose levels of 0, 22, 67, 200 and 600 mg/kg to Sprague-Dawley rats (12/group/sex) during pre-mating and mating period for males(up to 30 days) and females and pregnancy and early lactation period for females (up to 39-50 days). At 22 mg/kg, decreases in HGB, HCT (males) and MCHC (females), hyperplasia of spleen red pulp, hyperplasia of femur bone marrow (both sexes) were observed. At 67 mg/kg, salivation (males), reduced food consumption (both sexes), decreases in RBC, HGB, HCT and MCHC (males), increases in MCV (males) and spleen weight (males), hyperplasia of spleen red pulp and femur bone marrow (both sexes) were observed. At 200 mg/kg, decreases in locomotor activity and salivation (both sexes), reduced food consumption (both sexes), decreases in RBC, HGB, HCT and increases in MCV, MCH, BUN, T-BIL (males), enlargement of spleen (both sexes), increased weight of spleen (males), hyperplasia of spleen red pulp and femur bone marrow and extramedullary hematopoiesis of liver (both sexes), atrophy of thymus and corpus luteum hyperplasia of ovary (females) were observed. At 600 mg/kg, decreases in locomotor activity, cyanosis (both sexes), reddish tear, and salivation (males), mortality (4 out of 12 females), decreased body weight (females), reduced food consumption (both sexes), decreases in RBC, HGB, HCT and MCHC and increases in WBC, MCV, MCH, reticulocyte, neutrophil, lymphocyte, monocyte, AST, ALT, BUN, T-BIL, ALB, Ca and A/G ratio (males), enlargement of spleen, increased weights of spleen (both sexes), liver (males), kidney and ovary, decreased weights of thymus (females), hyperplasia of spleen red pulp, hyperplasia of femur bone marrow and extramedullary hematopoiesis of liver (both sexes), and atrophy of thymus and corpus luteum hyperplasia of ovary (females) were observed. Regarding the reproduction and development toxicities, there were no treatment-related changes in precoital time, mating index, fertility index and pregnancy index at all doses tested. At 22 and 67 mg/kg, there were no adverse effects on all the parameters observed. At 200 mg/ kg, decreased body weight of pups (day 4 p.p.) were observed. At 600 mg/kg, decreased body weight of pups (day 0 and 4 p.p.) and viability index (day 4 p.p.), increased incidence of newborns dead or with abnormal clinical signs were observed. The results suggest that the NOAELs for general toxicity are < 22 mg/kg, LOAELs are 22 mg/kg and the NOAELs for reproductive toxicity are 67 mg/kg.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.6
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• pp.15-20
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• 2012

The effects of sulfur dioxide on paper were investigated since these sulfur compounds could cause damages on cellulose and organic materials in papers. For the reason, exposure ageing tests were performed on traditional Korean paper (Hanji) and two different types of modern paper (acid-free and acid paper) to determine the damage with regard to the optical as well as physicochemical properties according to the varying $SO_2$ concentration. As a result, optical properties were not changed while physical and chemical peoperties were remarkably changed with the exposure period. In the case of pH, $SO_2$ had little impact on the pH of the Hanji and acid-free paper while the pH of acid paper was remarkably decreased. The decrease of the folding endurance of the Hanji was relatively smaller than those of the acid-free and acid paper. The results prove Hanji was more resistant to $SO_2$ than the modern paper in terms of optical, physical and chemical properties. In addition, it was also suggested that $SO_2$ concentration should be kept below 0.01 ppm for the preservation of paper objects.

• Imaging Science in Dentistry
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• v.39 no.1
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• pp.41-49
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• 2009

Purpose: To detect the progression of experimentally induced periapical lesions on periapical radiograph and cone beam computed tomograph (CBCT) by quantitative analysis. Materials and Methods: After the removal of coronal pulps from premolars of two Beagle dogs, the root canals of premolars were exposed to oral environment during one week and then sealed for 70 days. Digital periapical radiographs and CBCTs were taken at baseline and every 7 days for 77 days after pulp exposure. We examined occurrence and areas of periapical bone resorption. Three comparative groups of CBCT radiographs were prepared by average projection of thin slabs with different bucco-lingual thicknesses (0.1, 3.0, and 8.0 mm) using a 3D visualization software. Radiographic densities were compensated by image normalization. Digital images were processed with mathematical morphology operations. The radiographic density and morphological features of periapical lesions were compared among three groups of CBCT in different time points. Results: In the CBCT group with 0.1 mm thickness, radiographic density (p<0.05) and trabecular bone area (p<0.01) were significantly decreased at the fifth week. However, in the CBCT groups with 3 mm and 8 mm thickness and periapical radiographs, none of densitometric and morphological features showed any significant differences in different time points. Radiographic density of periapical lesion showed increasing tendency at the eleventh week after pulp exposure. Conclusion: Radiographic detection of periapical lesions was possible at the fifth week after pulp contamination by quantitative method and was affected by buccolingual bone thickness.

• Restorative Dentistry and Endodontics
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• v.46 no.2
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• pp.26.1-26.15
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• 2021

Objectives: The aim of the present systematic review was to investigate the cryopreservation process of dental pulp mesenchymal stromal cells and whether cryopreservation is effective in promoting cell viability and recovery. Materials and Methods: This systematic review was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and the research question was determined using the population, exposure, comparison, and outcomes strategy. Electronic searches were conducted in the PubMed, Cochrane Library, Science Direct, LILACS, and SciELO databases and in the gray literature (dissertations and thesis databases and Google Scholar) for relevant articles published up to March 2019. Clinical trial studies performed with dental pulp of human permanent or primary teeth, containing concrete information regarding the cryopreservation stages, and with cryopreservation performed for a period of at least 1 week were included in this study. Results: The search strategy resulted in the retrieval of 185 publications. After the application of the eligibility criteria, 21 articles were selected for a qualitative analysis. Conclusions: The cryopreservation process must be carried out in 6 stages: tooth disinfection, pulp extraction, cell isolation, cell proliferation, cryopreservation, and thawing. In addition, it can be inferred that the use of dimethyl sulfoxide, programmable freezing, and storage in liquid nitrogen are associated with a high rate of cell viability after thawing and a high rate of cell proliferation in both primary and permanent teeth.

• Restorative Dentistry and Endodontics
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• v.48 no.4
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• pp.39.1-39.23
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• 2023

Objectives: This study aimed to investigate the effectiveness of different topical/systemic agents in reducing the damage caused by bleaching gel to pulp tissue or cells. Materials and Methods: Electronic searches were performed in July 2023. In vivo and in vitro studies evaluating the effects of different topical or systemic agents on pulp inflammation or cytotoxicity after exposure to bleaching agents were included. The risk of bias was assessed. Results: Out of 1,112 articles, 27 were included. Nine animal studies evaluated remineralizing/anti-inflammatories agents in rat molars subjected to bleaching with 35%-38% hydrogen peroxide (HP). Five of these studies demonstrated a significant reduction in inflammation caused by HP when combined with bioglass or MI Paste Plus (GC America), or following KF-desensitizing or Otosporin treatment (n = 3). However, orally administered drugs did not reduce pulp inflammation (n = 4). Cytotoxicity (n = 17) was primarily assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on human dental pulp cells and mouse dental papilla Cell-23 cells. Certain substances, including sodium ascorbate, butein, manganese chloride, and peroxidase, were found to reduce cytotoxicity, particularly when applied prior to bleaching. The risk of bias was high in animal studies and low in laboratory studies. Conclusions: Few in vivo studies have evaluated agents to reduce the damage caused by bleaching gel to pulp tissue. Within the limitations of these studies, it was found that topical agents were effective in reducing pulp inflammation in animals and cytotoxicity. Further analyses with human pulp are required to substantiate these findings.

• Journal of Veterinary Clinics
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• v.17 no.1
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• pp.298-298
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• 2000

Seven years old male lion in Everland Zoo has three fractured canine tooth. To avoid the risk of a possible fracture with pulp exposure after restroration of largest abration defects, endodontic therapy was performed. The pulp chamber was filled with calcium hydroxide, zinc oxide cement and gutta percha. We also installed the Crown prosthesis was installed in fractured canine tooth to protect the tooth and to improve the cosmetics and function of the tooth. The lion could eat in one day and there were no any signs of dental problem. It is the obvious prophylactic procedure for wild animal is the inclusion of an oral examination at every opportunity to handle the animal. It is considered that crown prosthesis after endodontic therapy was useful for maintaining normal physiological function and for provention of additional fracture or complication.