• Proceedings of the KACD Conference
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• 2007.05a
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• pp.283-283
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• 2007

• Proceedings of the KACD Conference
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• 2006.05a
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• pp.246-246
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• 2006

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.1
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• pp.69-69
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• 2022

• Proceedings of the KACD Conference
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• 2007.11a
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• pp.641-641
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• 2007

• Restorative Dentistry and Endodontics
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• v.49 no.2
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• pp.20.1-20.13
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• 2024

Objectives: This study investigated the nanoleakage of root canal obturations using calcium silicate-based sealer according to different drying methods. Materials and Methods: Fifty-two extracted mandibular premolars with a single root canal and straight root were selected for this study. After canal preparation with a nickel-titanium rotary file system, the specimens were randomly divided into 4 groups according to canal drying methods (1: complete drying, 2: blot drying/distilled water, 3: blot drying/NaOCl, 4: aspiration only). The root canals were obturated using a single-cone filling technique with a calcium silicate-based sealer. Nanoleakage was evaluated using a nanoflow device after 24 hours, 1 week, and 1 month. Data were collected twice per second at the nanoscale and measured in nanoliters per second. Data were statistically analyzed using the Kruskal-Wallis and Mann-Whitney U-tests (p < 0.05). Results: The mean flow rate measured after 24 hours showed the highest value among the time periods in all groups. However, the difference in the flow rate between 1 week and 1 month was not significant. The mean flow rate of the complete drying group was the highest at all time points. After 1 month, the mean flow rate in the blot drying group and the aspiration group was not significantly different. Conclusions: Within the limitations of this study, the canal drying method had a significant effect on leakage and sealing ability in root canal obturations using a calcium silicate-based sealer. Thus, a proper drying procedure is critical in endodontic treatment.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.220-227
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• 1997

The purpose of our study is to evaluate the ability of nickel-titanium(NiTi) files in maintaining the original curvature of a curved root canal during canal preparation. Curved canals on translucent resin blocks were prepared with NiTi and stainless steel files, and they were placed at the platform which can reproduce the same position. The unprepared and prepared canal forms were accurately compared by double exposure technique of photography. By finite element methods we also analyzed stress distributions of NiTi and stainless steel files in a curved canal. The results were as follows : 1. NiTi files were excellent in maintaining the original curvature of a curved canal than stainless steel files after canal preparation. 2. The results of canal preparation with these files were well verified by the analysis of stress distributions using finite element methods.

• 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.27 no.1
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• pp.54-65
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• 2002

Black-pigmented bacteria have been implicated in the endodontic infections. This group of microorganisms includes Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia, and Prevotella nigrescens. The organisms display a wide variety of virulence factors that may be pertinent to acute endodontic infections. The aim of this study was to identify P. endodontalis, P. gingivalis, P. intermedia, and P. nigrescens by using special potency disk test, filter paper spot test, 165 rRNA gene-directed PCR, and API 32A. Microbial samples were collected from root canals of 33 intact teeth with necrotic pulp and/or apical periodontitis. Conventional laboratory methods were used for identification of the strains of black pigmented bacteria. Eighteen of 33 samples were positive for the growth of black-pigmented bacteria Five colonies were cultured from each pure cultured colonies from Brucella agar plate. Seventy seven colonies were positive for the growth of black-pigmented bacteria. Thirty three of 77(42.6%) were identifed as P. nigrescens, 10 of 77(12.9%)were P. gingivalis, 6 of 77(7.8%) were P. endodontalis, 10 of 77(12.9%) were P. intermedia. On the contrary the reference strains of P. nigrescens, experimental strains of P nigrescens was sensitive to kanamycin in special potency disk test. 165 rRNA gene PCR and API test after rapid presumptative identification methods, such as special potency disk test and filter paper spot test, would be accurate detection methods for black-pigemented bacteria.

• Korean Journal of Bronchoesophagology
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• v.9 no.2
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• pp.49-55
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• 2003

Background and Objectives : Traditionally incision and drainage is considered to be standard treatment of deep neck infection. But antibiotics and diagnostic technique are developed recently, there are reports that conservative therapy could be as successful as open surgical drainage. The purposes of this study has been to assess clinical feature between surgical therapy group and conservative therapy group through statistical analysis. Materials and Methods : A retrospective study was performed on 46 cases of deep neck space abscess, which were confirmed CT, in patients admitted from January 1999 to June 2002. Result : About 80% of all are treated with conservative therapy. Erythrocyte sediment rate, volume of abscess and duration of hospitalization of conservative therapy group are decreased than those of surgical therapy group. Conclusions : Conservative therapy is expected to be effective on treatment of early stage, small sized deep neck infection. But its complication can lead to serious condition of patient it should be done under meticulous observation.

• Restorative Dentistry and Endodontics
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• v.37 no.4
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• pp.236-239
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• 2012

Although several methods including composite resin restoration and microabrasion have been used for management of white spot lesion, tooth jewelry can be considered as another noninvasive option. This case report describes the management of white spot lesions by using tooth jewelry. This report also highlights the patients' preference for tooth jewelry as an esthetic concern.