• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.3
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• pp.216-222
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• 2013

Paradigm shift in management of infected immature permanent teeth has occurred. The new concept of the treatment includes minimal or no intracanal instrumentation, disinfection with triple antibiotic paste and sealing with mineral trioxide aggregate. This regenerative endodontic treatment promotes differentiation of periradicular stem cells that induce regeneration of vital tissue and continuation of root formation. Thorough disinfection and three-dimensional scaffold are important in this new concept of the treatment. Platelet-rich fibrin has been reported as 'new scaffold' instead of blood clot, which had been used in the past. Triple antibiotics can be used to disinfect the tooth but may lead to complications including discoloration. Three cases of infected immature permanent tooth caused by dens evaginatus fracture are presented. After removal of necrotic pulp and thorough intracanal irrigation, only platelet-rich fibrin was applied to the root canal in the first case. In the other cases, topical antibiotics was used for disinfection and platelet-rich fibrin for scaffold. In all the cases, the opening was sealed with mineral trioxide aggregate. All the cases showed proper healing of inrabony lesion and some lengthening of root. According to these cases, regenerating vital tissue of the infected immature permanent tooth can be achieved with disinfection and application of platelet-rich fibrin.

• International Journal of Oral Biology
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• v.36 no.3
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• pp.117-122
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• 2011

Endothelial cells are a vital constituent of most mammalian organs and are required to maintain the integrity of these tissues. These cells also play a major role in angiogenesis, inflammatory reactions, and in the regulation of thrombosis. Angiogenesis facilitates pulp formation and produces the vessels which are essential for the maintenance of tooth homeostasis. These vessels can also be used in bone and tissue regeneration, and in surgical procedures to place implants or to remove cancerous tissue. Furthermore, endothelial cell regeneration is the most critical component of the tooth generation process. The aim of the present study was to stimulate endothelial regeneration at a site of acute cyclophosphamide (CP)-induced endothelial injury by treatment with human umbilical cord-derived endothelial/mesenchymal stem cells (hEPCs). We randomly assigned 16 to 20-week-old female NOD/SCID mice into three separate groups, a hEPC ($1{\times}10^5$ cells) transplanted, 300mg/kg CP treated and saline (control) group. The mice were sacrificed on days 5 and 10 and blood was collected via the abdominal aorta for analysis. The alanine transaminase (ALT), aspartate aminotransferase (AST), serum alkaline phosphatase (s-ALP), and albumin (ALB) levels were then evaluated. Tissue sections from the livers and kidneys were stained with hematoxylin and eosin (HE) for microscopic analysis and were subjected to immunohistochemistry to evaluate any changes in the endothelial layer. CP treatment caused a weight reduction after one day. The kidney/body weight ratio increased in the hEPC treated animals compared with the CP only group at 10 days. Moreover, hEPC treatment resulted in reduced s-ALP, AST, ALT levels compared with the CP only group at 10 days. The CP only animals further showed endothelial injuries at five days which were recovered by hEPC treatment at 10 days. The number of CD31-positive cells was increased by hEPC treatment at both 5 and 10 days. In conclusion, the CP-induced disruption of endothelial cells is recovered by hEPC treatment, indicating that hEPC transplantation has potential benefits in the treatment of endothelial damage.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.174-180
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• 2012

In case of an immature tooth with necrotic pulp, regeneration of pulp tissue into a canal would be the ideal outcome. It may be capable of promoting the continuation of normal root development. Platelet-rich fibrin has been suggested as a potentially ideal scaffold for regenerative endodontic treatment. Immature permanent teeth of young children were diagnosed with pulp necrosis and apical abscess as the result of clinical and radiographic examination. After removal of necrotic pulp, canal was irrigated with 5.25% NaOCl and dried with paper point. A triple antibiotic mixture was placed in canal space in 3 weeks. After removal of the antibiotic mixture, the platelet-rich fibrin was injected into the canal space with MTA placed directly over the platelet-rich fibrin clot. The coronal region was restored by composite resin. On the basis of short-term results of the present 3 cases, regeneration of vital tissues appears to be possible in a tooth with necrotic pulp and a periapical lesion. Also, platelet-rich fibrin proves to be potentially an ideal scaffold for this procedure. Therefore, long-term clinical observation and examination about this treatment using platelet-rich fibrin in immature permanent teeth of young children are considered to be necessary.

• Restorative Dentistry and Endodontics
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• v.40 no.4
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• pp.314-321
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• 2015

Tooth related factors such as palatoradicular groove can be one of the causes for localized periodontal destruction. Such pathological process may result in apicomarginal defect along with inflammation of pulp. This creates challenging situation which clinician must be capable of performing advanced periodontal regenerative procedures for the successful management. This case report discusses clinical management of apicomarginal defect associated with extensive periradicular destruction in a maxillary lateral incisor, along with histopathologic aspect of the lesion.

• Restorative Dentistry and Endodontics
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• v.13 no.1
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• pp.7-19
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• 1988

The object of this paper was to investigate the histopatological changes on dog's pulp under cavitation by irradiation of the $CO_2$ laser. The subjects were derived from four dogs, and irradiated 113.23 J/$mm^2$, 283.09 J/$mm^2$, 566.08 J/$mm^2$ in Group I, II, and III respectively. The dogs were sacrificed immediately, 24 hour, 72 hour and 1 week after $CO_2$ laser treatment. For light microscopic examination, routine H-E and PAS stains were employed. For electron microscopic observation, the teeth were fixed in 1% paraformaldehyde and 1% glutaraldehyde, decalcified teeth in 10% EDTA were stained by uranyl acetate and lead citrate. The observation was made with a Hitachi H-500 model electron microscope. The following results were obtained in this study: 1. At the early stage of the experimental sub-groups-immediately, 24 hour, 72 hour samples of Group I, II and III-coagulation necrosis and hyperemia were observed in odontoblastic and subodontoblastic pulpal layer. 2. At the 1 week sub-group of Group I, II, regenerative hyperplasia of the odontoblasts without coagulation necrosis were revealed, in addition to thickened predentin. On he other hand coagulation necrosis and atrophic change accompanying with hyperplasia were found at the 1 week sub-group of Group III. 3. Ultrastructurally, the odontoblasts appeared nuclear degeneration, vacuolar change of cytoplasmic organelles and rupture of plasma membrane at the early stage of the experimental period of all groups. 4. Under spectrohelioscopic examination, regenerative odontobalsts were seen at the 1 week specimens of Group I, II and III. 5. The pulpal response occured at 113-566 J/$mm^2$. The pathologic change of pulp tissue occured at the early experimental period but regeneration of odontoblasts could be seen after 1 week.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.640-646
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• 2009

In case of luxation injuries, loss of tooth vitality is common. And in case of trauma in the immature permanent teeth, precise diagnosis of pulp necrosis is very difficult. That is because limitation in distinguishing between normal dental papilla in immature permanent teeth, transient apical breakdown(TAB), which is part of normal healing process, and apical radiolucency in pulp necrosis. Especially in non-vital immature permanent tooth, the treatment is complex and requires long time. This clinical case report shows that severely infected immature teeth with periradicular periodontitis can undergo healing and apexogenesis or maturogenesis with no definative treatment or after conservative treatment. In the cases reported, we emphasize the considerable power of regeneration of the tooth, probably due to its large number of undifferentiated mesenchymal cells in the dental papilla, pulp tissue, periodontal ligament tissues. Thus, when endodontic treatment in immature permanent teeth, over instrumentation is not recommend for preserve the apical vital stem cells.

• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.2
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• pp.149-164
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• 2024

This study compared the solubility, water absorption, dimensional stability, release of various ions (hydroxyl, calcium, sulfur, strontium, and silicon), and cytotoxicity of light-cured resin-modified pulp-capping materials. Resin-modified calcium hydroxide (Ultra-blend^TM plus, UBP), light-cured resin-modified calcium silicate (TheraCal LC^TM, TLC), and dual-cure resin-modified calcium silicate (TheraCal PT^TM, TPT) were used. Each material was polymerized; solubility, 24-hour water absorption, and 30- day dimensional stability experiments were conducted to test its physical properties. Solubility was assessed according to the ISO 6876 standard, and 24 hours of water absorption, 30 days of dimensional stability were assessed by referring to the previous protocol respectively. Eluates at 3 and 24 hours and on 7, 14, and 28 days were analyzed according to the ISO 10993-12 standard. And the pH, Ion-releasing ability, cell proliferation rate, and cell viability were assessed using the eluates to evaluate biochemical characteristics. pH was measured with a pH meter and Ion-releasing ability was assessed using inductively coupled plasma atomic emission spectrometry (ICP-AES). Cell proliferation rate and cell viability were assessed using human dental pulp cells (hDPCs). The former was assessed by an absorbance assay using the CCK-8 solution, and the latter was assessed by Live and Dead staining. TPT exhibited lower solubility and water absorption than TLC. UBP and TPT demonstrated higher stability than TLC. The release of sulfur, strontium, calcium, and hydroxyl ions was higher for TLC and TPT than for UBP. The 28-day release of hydroxyl and silicon ions was similar for TLC and TPT. TLC alone exhibited a lower cell proliferation rate compared to the control group at a dilution ratio of 1 : 2 in cell proliferation and dead cells from Live and Dead assay evaluation. Thus, when using light-cure resin-modified pulp-capping materials, calcium silicate-based materials can be considered alternatives to calcium hydroxide-based materials. Moreover, when comparing physical and biochemical properties, TPT could be prioritized over TLC as the first choice.

• International Journal of Stem Cells
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• v.16 no.2
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• pp.180-190
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• 2023

Background and Objectives: Regenerative endodontic procedures (REPs) are a research hotspot in the endodontic field. One of the biggest problems of REPs is that it is difficult to realize regeneration of pulp-dentin complex and functional reconstruction. The reason is still not clear. We hypothesize that the migration may be different in different dental stem cells. Periodontal ligament stem cells (PDLSCs) may migrate faster than stem cells of apical papilla (SCAPs), differentiating into cementum-like tissue, bone-like tissue and periodontal ligament-like tissue and, finally affecting the outcomes of REPs. Hence, this study aimed to explore the mechanism that regulates the migration of PDLSCs. Methods and Results: After isolating and culturing PDLSCs and SCAPs from human third molars, we compared the migration of PDLSCs and SCAPs. Then we investigated the role of SDF-1𝛼-CXCR4/CXCR7 axis in PDLSC migration. We further investigated the impact of Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS) on PDLSC migration and the potential mechanism. PDLSCs showed better migration under both noninflammatory and inflammatory conditions than SCAPs. SDF-1𝛼 can promote the migration of PDLSCs by elevating the expression of CXCR4 and CXCR7, increasing the interaction between them, promoting expression of 𝛽-arrestin1 and activating the ERK signaling pathway. P. gingivalis LPS can promote the migration of PDLSCs toward SDF-1𝛼 through increasing the expression of CXCR4 via the NF-𝜅B signaling pathway, promoting the expression of 𝛽-arrestin1, and activating the ERK signaling pathway. Conclusions: This study helped elucidate the potential reason for the difficulty in forming pulp-dentin complex.

• Journal of Periodontal and Implant Science
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• v.43 no.3
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• pp.136-140
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• 2013

Purpose: The aim of this study was to identify a role for endodontic intervention in enhancing the regenerative potential of the periodontal ligament when combined with periodontal treatment in seriously involved teeth with a secondary endodontic component. Methods: Patients who exhibited radiolucency extending to the periapical region, abnormal electric pulp testing values, and deep probing depth derived from primary periodontal disease with secondary endodontic involvement were included. Intentional root canal treatment was applied to those teeth in which the apical lesions were presumed to communicate with those of the periodontal lesion of the teeth that remained vital. In all three selected cases, regenerative periodontal therapy incorporating either bone graft or guided tissue regeneration was instituted 3 months after the endodontic intervention. Results: Remarkable enhancement in radiographic density was noticeable around the affected teeth as evidenced by changes in radiopacity. There was a significant reduction in the probing pocket depth and gain in the clinical attachment level. Chewing discomfort gradually disappeared from the commencement of the combined treatment. Conclusions: An intentional endodontic intervention may be a worthwhile approach for the sophisticated management of teeth suffering from serious attachment loss and alveolar bone destruction with concomitant secondary endodontic involvement.

• Journal of dental hygiene science
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• v.13 no.3
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• pp.296-303
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• 2013

Lysyl oxidase (LOX), extracellular matrix enzyme, is catalyzing lysine-derived crosslinks in collagen and elastin. Recently, several LOX-like proteins (LOXL, LOXL2, LOXL3 and LOXL4) have been identified in human but their specific functions are still largely unknown. The purpose of this study was to evaluate the function of the LOX family genes during odontoblastic differentiation of human dental pulp (HDP) cells induced with odontogenic supplement (OS). The messenger RNA (mRNA) expression of LOX family genes and differentiation markers was assessed by reverse transcriptase polymerase chain reaction analysis (RT-PCR). The formation of mineralization nodules was evaluated by alrizarin red S staining. Amine oxidase activity of HDP cells was measured by peroxidase-coupled fluormetric assay. The expressions of differentiation markers, such as alkaline phosphatase (ALP), osteopontin (OPN), osteocalcin (OCN), dentin matrix protein1 (DMP1), dentin sialophosphoprotein (DSPP) in HDP cells were increased after treatment with OS media. The LOX and LOXL mRNA expression were gradually increased in OS media, whereas LOX enzyme activities were markedly detected on day 7. The mRNA expression and LOX enzyme activity of collagen type I was very similar to the pattern of LOX gene. In this study, the expression of LOX and its isoforms, and activity of LOX were highly regulated during odontoblastic differentiation. Thus, these results suggest that LOX plays a key role in odontoblastic differentiation of HDP cells.