• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.3
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• pp.277-291
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• 2023

This study aimed to compare the effects of applying different types of dentin bonding agents (DBAs) on tooth and on the sealing ability of CSC in regenerative endodontic procedures (REPs). Specimens were made from 120 human first premolars and categorized into the following groups based on the presence and the type of DBA: Group I, no bonding; Group II, One-Step; Group III, Clearfil SE Bond; and Group IV, Single Bond Universal. Subsequently, the groups were categorized into Subgroup a and Subgroup b, in which Endocem MTA^® Premixed Regular and Biodentine were used, respectively. The CIE L^*a^*b^* on the photos taken prior to TAP placement (S0), 1 week after TAP placement (S1), 2 weeks after TAP placement (S2), 4 weeks after TAP placement (S3) and 2 weeks after CSC placement (S4) was used to assess discoloration. The samples were submerged in a 2% methylene blue solution and magnified by 30 times under a stereomicroscope to assess microleakage. The application of DBA during REP reduced crown discoloration, while Biodentine showed minimal discoloration with or without DBA and regardless of the DBA type. Additionally, the application of DBA did not increase microleakage.

• Restorative Dentistry and Endodontics
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• v.41 no.4
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• pp.283-295
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• 2016

Objectives: In this study, we characterized human dental pulp cells (HDPCs) obtained by different culture methods to establish the most suitable methodology for dental tissue engineering and regenerative endodontic applications. Materials and Methods: HDPCs were isolated by the outgrowth method (HDPCs-OG), the enzymatic digestion method (collagenase/dispase/trypsin, HDPCs-ED), or the combination of both methods (HDPCs-Combined). The expression of mesenchymal stem cell markers (CD105, CD90, and CD73) was investigated. In vitro differentiation capacities of HDPCs into adipogenic, osteogenic, and chondrogenic lineages were compared. Differentiation markers were analyzed by quantitative reverse-transcription polymerase chain reaction (RT-PCR) and western blotting. Results: Our data indicated that whole HDPCs-ED, HPDCs-OG, and HDPCs-Combined could be differentiated into adipogenic, chrondrogenic, and osteogenic cell types. However, we found that the methods for isolating and culturing HDPCs influence the differentiation capacities of cells. HDPCs-OG and HDPCs-ED were preferably differentiated into adipogenic and osteogenic cells, respectively. Differentiation markers shown by RT-PCR and western blotting analysis were mostly upregulated in the treated groups compared with the control groups. Conclusions: Our findings confirmed that cell populations formed by two different culture methods and the combined culture method exhibited different properties. The results of this study could provide an insight into regenerative endodontic treatment using HDPCs.

• Restorative Dentistry and Endodontics
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• v.43 no.3
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• pp.18.1-18.12
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• 2018

Objectives: This study compared the retention of BioAggregate (BA; Innovative BioCeramix) and mineral trioxide aggregate (MTA; Angelus) as coronal plugs after applying different intracanal medications (ICMs) used in regenerative endodontic. Materials and Methods: One-hundred human maxillary central incisors were used. The canals were enlarged to a diameter of 1.7 mm. Specimens were divided into 5 groups (n = 20) according to the ICM used: calcium hydroxide (CH), 2% chlorhexidine (CHX), triple-antibiotic paste (TAP), double-antibiotic paste (DAP), and no ICM (control; CON). After 3 weeks of application, ICMs were removed and BA or MTA were placed as the plug material (n = 10). The push-out bond strength and the mode of failure were assessed. The data were analyzed using 2-way analysis of variance, the Tukey's test, and the ${\chi}^2$ test; p values < 0.05 indicated statistical significance. Results: The type of ICM and the type of plug material significantly affected bond strength (p < 0.01). Regardless of the type of ICM, BA showed a lower bond strength than MTA (p < 0.05). For MTA, CH showed a higher bond strength than CON, TAP and DAP; CHX showed a higher bond strength than DAP (p < 0.01). For BA, CH showed a higher bond strength than DAP (p < 0.05). The mode of failure was predominantly cohesive for BA (p < 0.05). Conclusions: MTA may show better retention than BA. The mode of bond failure with BA can be predominantly cohesive. BA retention may be less affected by ICM type than MTA retention.

• Restorative Dentistry and Endodontics
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• v.44 no.3
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• pp.25.1-25.10
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• 2019

Objective: The aim of this study was to evaluate discoloration of teeth undergoing regenerative endodontic procedures (REPs) using blood clot or platelet-rich fibrin (PRF) as the scaffolds and different calcium silicate-based materials as the intracanal coronal barriers in an ex vivo model. Materials and Methods: Forty-eight bovine incisors were prepared and disinfected using 1 mg/mL double antibiotic paste (DAP). The specimens were then randomly divided into 2 groups (n = 24) according to the scaffolds (blood or PRF). After placement of scaffolds each group was divided into 2 subgroups (n = 12) according to the intracanal coronal barriers (ProRoot MTA or Biodentine). The pulp chamber walls were sealed with dentin bonding agent before placement of DAP and before placement of scaffolds. The color changes (${\Delta}E$) were measured at different steps. The data were analyzed using 2-way analysis of variance. Results: Coronal discoloration induced by DAP was not clinically perceptible (${\Delta}E{\leq}3.3$). Regarding the type of the scaffold, coronal discoloration was significantly higher in blood groups compared with PRF groups at the end of REP and after 1 month (p < 0.05). However, no significant difference was found between PRF and blood clot after 6 months (p > 0.05). Considering the type of intracanal coronal barrier, no significant difference existed between ProRoot MTA and Biodentine (p > 0.05). Conclusions: With sealing the dentinal tubules of pulp chamber with a dentin bonding agent and application of DAP as an intracanal medicament, coronal color change of the teeth following the use of PRF and blood sealed with either ProRoot MTA or Biodentine was not different at 6-month follow-up.

• 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.

• Restorative Dentistry and Endodontics
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• v.42 no.1
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• pp.19-26
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• 2017

Objectives: Recently, bioceramic sealers like EndoSequence BC Sealer (BC Sealer) have been introduced and are being used in endodontic practice. However, this sealer has limited research related to its retreatability. Hence, the aim of this study was to evaluate the retreatability of two sealers, BC Sealer as compared with AH Plus using micro-computed tomographic (micro-CT) analysis. Materials and Methods: Fifty-six extracted human maxillary incisors were instrumented and randomly divided into 4 groups of 14 teeth: 1A, gutta-percha, AH Plus retreated with chloroform; 1B, gutta-percha, AH Plus retreated without chloroform; 2A, gutta-percha, EndoSequence BC Sealer retreated with chloroform; 2B, gutta-percha, EndoSequence BC Sealer retreated without chloroform. Micro-CT scans were taken before and after obturation and retreatment and analyzed for the volume of residual material. The specimens were longitudinally sectioned and digitized images were taken with the dental operating microscope. Data was analyzed using an ANOVA and a post-hoc Tukey test. Fisher exact tests were performed to analyze the ability to regain patency. Results: There was significantly less residual root canal filling material in the AH Plus groups retreated with chloroform as compared to the others. The BC Sealer samples retreated with chloroform had better results than those retreated without chloroform. Furthermore, patency could be re-established in only 14% of teeth in the BC Sealer without chloroform group. Conclusion: The results of this study demonstrate that the BC Sealer group had significantly more residual filling material than the AH Plus group regardless of whether or not both sealers were retreated with chloroform.

• Restorative Dentistry and Endodontics
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• v.39 no.3
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• pp.230-234
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• 2014

This study describes the treatment of an immature permanent tooth with periapical lesion which was treated with regenerative approach using platelet rich plasma (PRP). The root canal of immature human permanent tooth with periapical lesion was gently debrided of necrotic tissue and disinfected with 2.5% NaOCl, and then medicated with triple antibiotic paste comprised of ciprofloxacin, metronidazole, and tetracycline. When the tooth was asymptomatic, PRP and mineral trioxide aggregate (MTA) were placed into the root canal. Six months after PRP treatment, radiographical examination revealed resolution of the radiolucency and progressive thickening of the root wall and apical closure. Our findings suggest that PRP can be used for the treatment of immature permanent teeth with periapical lesion, as part of a regenerative endodontic treatment procedure.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.2
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• pp.197-202
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• 2015

Numerous challenges in treating permanent dentition are encountered, especially in treating immature teeth with pulp necrosis. Historically, calcium hydroxide application during long periods of time was used to induce the formation of a calcific barrier across the open apex. In 2004, a new treatment modality for the management of the open apex was introduced. This treatment was named as 'revascularization' and gained acceptance among dentists. The protocol was different from the traditional apexification techniques in that the canal was irrigated and disinfected with a combination of three antibiotics (ciprofloxacin, metronidazole and minocycline). At the next appointment, bleeding was induced and the canal was sealed with MTA. Successful regenerative endodontic treatment of necrotic immature permanent teeth can provide continued root development, increased thickness in the dentinal walls and apical closure. These developments of a functional pulp-dentin complex have a promising impact on retaining the natural teeth, the goal of the dental health care.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.277-292
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• 2020

The pulp treatment of primary and immature teeth in the children and adolescents is affected by the environment of the patients, clinical careers and dentists performing the techniques, as well as clinical modalities and pulpal diagnosis. The purpose of this study was to investigate the current status of pulp treatment performed in real clinical practice, as well as the reasons behind the choice of treatment methods. The study was conducted on a total of 153 members of the Korean Academy of Pediatric Dentistry, and statistical data from the Health Insurance Review and Assessment Service (HIRA) from 2010 to 2018 were analyzed together. Both the survey results and the statistics from the HIRA showed that 1-visit pulpectomies of primary teeth were most common, and the frequency of the use of the Ni-Ti file was increased in children with primary or mixed-dentition. In the treatment of immature permanent teeth, regenerative endodontic treatment by individual dentists was found to be less frequent than in university hospitals.

• The Journal of the Korean dental association
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• v.54 no.3
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• pp.206-216
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• 2016

Objectives The aim of this study was to evaluate the antibacterial effect of xanthorrhizol (XTZ) on E. faecalis, compared with 2% chlorhexidine (CHX). Materials and Methods Normal physiological state (NS), starvation state (SS), and alkalization state (AS) of E. faecalis were used. A solution containing 1% XTZ in 30% ethanol, 1% dimethyl sulfoxide (DMSO), and 100 mg/ml sodium methyl cocoyl taurate was used and is referred to as Xan in this study. To determine the minimal bactericidal concentration (MBC) of Xan and CHX, $500{\mu}l$ of E. faecalis (NS and two stress states) was added to a microtube containing $500{\mu}l$ of serial 2-fold dilutions of 1% Xan and 2% CHX (1:2-1:128). The MBC of each antimicrobial was determined by the plate count method. Results The antibacterial effect of Xan was more effective on E. faecalis in AS than in the other states (NS, SS) at 0.125% Xan and 0.03325% Xan (P<0.05). In contrast, the antibacterial effect of CHX was more effective against E. faecalis in SS than the other states (NS, AS) at 0.0625% CHX (P<0.05). In SS, the antibacterial effect of CHX was more effective than that of Xan at 0.125% and 0.0625% (P<0.05). However, in AS, the antibacterial effect of Xan was more effective than that of CHX at 0.0625% and 0.03325% (P<0.05). Conclusions In endodontic retreatment cases in which it is important to effectively remove E. faecalis from the infected root canal, Xan may be more suitable when combined with NaOCl than CHX.