Kee-Yeon Kum - Academia.edu (original) (raw)

Papers by Kee-Yeon Kum

Research paper thumbnail of THE INFLUENCE OF pH ON THE FORMATION OF ARTIFICIAL ROOT CARIES IN ACID BUFFER SOLUTION

Restorative Dentistry and Endodontics, 1999

산완충용액의pH가인공치근우식의형성에미치는영향 오현석∙금기연∙노병덕∙이찬영연세대학교치과대학치과보존학교실 THE INFLUENCE OF pH ON THE FORMATION OF ... more 산완충용액의pH가인공치근우식의형성에미치는영향 오현석∙금기연∙노병덕∙이찬영연세대학교치과대학치과보존학교실 THE INFLUENCE OF pH ON THE FORMATION OF ARTIFICIAL ROOT CARIES IN ACID BUFFER SOLUTION Hyun-Suk Oh, Kee-Yeon Kum, Byeng-Duck Ro, Chan-Young Lee Department of Conservative Dentistry, College of Dentistry, Yonsei University Recently root caries is reported as an increasing oral disease. Many researchers studied in vivo and in vit-ro enamel lesions but due to its peculiar structure and different chemical composition compared to theenamel, little effort has been made to root caries study.The purpose of this study is to compare and to evaluate the eff ect of pH on the progression of artificialroot caries lesion. Under the constant degree of saturation, the specimens were divided into 4 groups(pH4.3, 5.0, 5.5, 6.0). Each group was immersed in acid buffer sol ution for 1, 3, 5, 7 days and examined usingthe polarizing microscope.The results were as follows:1. The body of the lesion in the dentin showed higher degree of positive birefr...

Research paper thumbnail of The Inhibitory Effect of Taurine and Alendronate on the Osteoclast Differentiation Mediated by Sonicated Extracts of Porphyromonas Gingivalis in Vitro

Restorative Dentistry and Endodontics, 2001

The objective of this study was to investigate the inhibitory effect of taurine and alendronate o... more The objective of this study was to investigate the inhibitory effect of taurine and alendronate on the osteoclast differentiation. Osteoblasts and bone marrow cells from 1-2 day old mouse were co-cultured in 10% fetal bovine serum - minimal essential media (FBS-MEM). Osteoclast differentiation was induced by adding the sonicated extracts of Porphyromonas gingivalis (P.gingivalis). Osteoclasts were identified using tartrate resistant acid phosphotase staining (TRAP). Alendronate of 10, 10, 10M and taurine of 500, 1000, 1500/ml were added respectively. The cytotoxic effects of alendronate and taurine were examined using MTT(3-(4,5-dimethylthiazol -2-yl-2,5-diphenyltetrazo- lium bromide) method. After culturing with the sonicated extracts of P.gingivalis, the amounts of IL-6 in the culture supernatant were measured and compared using the ELISA method. The results were as follows : 1. Osteoclasts were differentiated at the concentration of 0.01~0.1/ml sonicated extracts of P.gingivalis....

Research paper thumbnail of Mandibular molar C-shaped root canals in 5th millennium BC China

Archives of Oral Biology, 2020

Research paper thumbnail of Molecular Epidemiology and Association of Putative Pathogens in Root Canal Infection

Journal of Endodontics, 2000

The purpose of this study was to investigate the epidemiology of putative pathogens in root canal... more The purpose of this study was to investigate the epidemiology of putative pathogens in root canals with apical periodontitis and to determine the associations among the putative pathogens. Eighteen symptomatic and 20 asymptomatic teeth from 36 subjects were studied. This research was performed with polymerase chain reaction and hybridization using rRNA-based oligonucleotide probes. The most frequently found species was Fusobacterium sp. (68.4%), followed by Peptostreptococcus micros (44.7%) and Porphyromonas gingivalis (26.3%). Sixteen teeth (42.1%) contained one or more species of the selected black-pigmented bacteria. Bacteroides forsythus and Treponema sp. were detected in 8 teeth and 6 teeth, respectively. Among the analyzed bacteria, significant relationships were shown in the combination of B. forsythus/P. gingivalis and Treponema sp./P. gingivalis. There was no significant association between any bacteria and any symptoms.

Research paper thumbnail of Effect of Autoclave Sterilization on the Cyclic Fatigue of Three Nickel-Titanium Instruments

Ain Shams Dental Journal, 2015

The purpose of this study is to assess the effect of autoclave sterilization on the cyclic fatigu... more The purpose of this study is to assess the effect of autoclave sterilization on the cyclic fatigue and torsional fracture resistance of ProTaper Universal (PTU), K3XF, HyFlex EDM (EDM), and TF adaptive (TFA). Sixty instruments from each file type were divided into two categories for cyclic fatigue group (CGr) and torsional fracture group (TGr). CGr and TGr were divided into three subgroups, respectively, consisting of ten instruments from each file type. Cyclic fatigue fracture test was performed using artificial canal made of stainless steel, and the mean number of cycles to failure (NCF) were determined. CGr1, the files were tested to establish baseline for NCF; CGr2, the files were tested cyclic fatigue after 10 cycles of autoclave; CGr3, instruments were autoclaved after being cycled to 25, 50, and 75% of corresponding NCF determined in CGr1, followed by cyclic fatigue test. The torsional fracture test was performed without autoclave (TGr1), after 3-cycle autoclave (TGr2), and 7-cycle autoclave (TGr3), respectively, which evaluated maximum torque and angular deflection. NCF, maximum torque and angular deflection were compared using one-way ANOVA with Bonferroni test. Two-way ANOVA was performed to determine the interaction between 'autoclave treatment' and 'type of NiTi file'. EDM showed highest NCF within the same autoclave treatment. TFA presented the lowest maximum torque and the highest angular deflection, and PTU presented the lowest angular deflection. Within the same NiTi file systems, most of NCF, maximum torque and angular deflection of tested files were not significantly influenced by autoclave condition.

Research paper thumbnail of Effect of preheating on the viscoelastic properties of dental composite under different deformation conditions

Dental materials journal, 2015

Preheating of dental composites improves their flowability, facilitating successful restorations.... more Preheating of dental composites improves their flowability, facilitating successful restorations. However, the flowability of dental composites is affected not only by temperature but also by the deformation conditions. In the present work, the effects of various deformation conditions upon the viscoelastic properties of a preheated dental composite were studied. The rheological properties of Z350 dental composites at 25, 45, and 60°C were measured by a strain-controlled rheometer. When a low strain (0.03%) was applied, the preheated composite exhibited greater shear storage modulus (G') and complex viscosity (η*) than a room-temperature composite. Oppositely, when a high strain (50%) was applied, G' and η* of a preheated composite were lower than those of a room-temperature composite. Preheating of dental composites might be helpful in clinical practice both to increase the slumping resistance when minimal manipulation is used (e.g., during the build-up of a missing cusp ti...

Research paper thumbnail of PCR-based Identification of Eubacteirum species in endodontic infection

Journal of Korean Academy of Conservative Dentistry, 2003

Research paper thumbnail of Gene-expression analysis of cementoblasts and osteoblasts

Journal of Periodontal Research, 2015

Research paper thumbnail of Apical prepration size in infected root canals

Journal of Korean Academy of Conservative Dentistry, 2010

Research paper thumbnail of In vitro evaluation of cleaning efficacy of various irrigation methods in mandibular molars

Journal of Korean Academy of Conservative Dentistry, 2009

Research paper thumbnail of Odontoblastic Differentiation, Inflammatory Response, and Angiogenic Potential of 4 Calcium Silicate–based Cements: Micromega MTA, ProRoot MTA, RetroMTA, and Experimental Calcium Silicate Cement

Journal of Endodontics, 2015

Introudction: The aim of this study was to analyze the effects of different calcium silicate-base... more Introudction: The aim of this study was to analyze the effects of different calcium silicate-based cements (CSCs) for pulp capping materials including MicroMega MTA (MMTA; MicroMega, Besanchon, France), Retro MTA (RMTA; BioMTA, Seoul, Korea), ProRoot MTA (PMTA; Dentsply, Tulsa, OK), and experimental CSC (ECSC) on odontoblastic differentiation, in vitro angiogenesis, and the inflammatory response in human dental pulp cells. Methods: Differentiation was evaluated by alkaline phosphatase activity, alizarin red staining, and reverse-transcriptase polymerase chain reaction (RT-PCR) for the marker genes. The levels of inflammatory mediators and cytokines were measured by RT-PCR and an enzyme-linked immunosorbent assay. In vitro angiogenesis was assessed by RT-PCR for angiogenic genes and an endothelial tube formation assay. Results: PMTA, MMTA, and ECSC increased the alkaline phosphatase activity and mineralization nodule formation and up-regulated messenger RNA (mRNA) expression of odontoblastic markers compared with RMTA. In addition, PMTA, MMTA, and ECSC upregulated the mRNA of angiogenic genes in human dental pulp cells and increased the capillary tube formation of endothelial cells compared with RMTA. However, all CSCs showed similar expression levels of inducible nitric oxide synthase and cyclooxygenase-2 protein as well as proinflammatory mediators such as nitric oxide, prostaglandin E2, tumor necrosis factor alpha, interleukin (IL)-1b, IL-6, and IL-8 mRNA. Conclusions: Taken together, our experimental results suggest that all CSCs are favorable materials for pulp capping, but PMTA, MMTA, and ECSC may be recommended over RMTA.

Research paper thumbnail of Effects of calcium silicate endodontic cements on biocompatibility and mineralization-inducing potentials in human dental pulp cells

Journal of endodontics, 2014

The objective of this study was to evaluate the biocompatibility, inflammatory response, and odon... more The objective of this study was to evaluate the biocompatibility, inflammatory response, and odontoblastic potential of Biodentine (Septodont, Saint Maur des Fosses, France), Ortho-MTA (OMTA; BioMTA, Seoul, Korea), Angelus-MTA (AMTA; Angelus, Londrina, Brazil), and IRM (Dentsply Tulsa Dental, Tulsa, OK) in human dental pulp cells. The underlying signaling mechanisms were also investigated. Biocompatibilities were examined by the 3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide assay. Differentiation was assessed by alkaline phosphatase activity, alizarin red S staining, and reverse-transcription polymerase chain reaction for marker genes. The levels of inflammatory mediators and cytokines were measured by reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assay. Signal transduction analysis was performed by Western blotting. Biodentine, OMTA, and AMTA showed favorable cell proliferation, alkaline phosphatase activity, formation of mineraliz...

Research paper thumbnail of Lifespan of one nickel-titanium rotary file with reciprocating motion in curved root canals

Journal of endodontics, 2010

The purpose of this study was to examine the lifespan of one nickel-titanium (NiTi) rotary file w... more The purpose of this study was to examine the lifespan of one nickel-titanium (NiTi) rotary file when used in reciprocating motion and to compare the time required for its preparation of a curved root canal using both reciprocating and continuous motion. One hundred twenty curved canals from 60 extracted maxillary and mandibular molars were selected for measuring the mean number of uses. Each canal was prepared with reciprocating motion until the ProTaper F2 single file (Dentsply Maillefer, Ballaigues, Switzerland) reached the working length. One file was used until it was fractured. Another 60 canals were divided into two groups. 30 canals in the continuous rotation motion (CM) group were prepared using continuous rotation following the sequence of ProTaper files, whereas the canals in the reciprocating motion (RM) group (n = 30) were prepared with reciprocating motion with the sole use of the ProTaper F2. The total root canal preparation time was measured until the F2 file finally ...

Research paper thumbnail of Clinical study of shade improvement and safety of polymer-based pen type BlancTic Forte whitening agent containing 8.3% Carbamide peroxide

Journal of Korean Academy of Conservative Dentistry, 2009

Research paper thumbnail of Clinical assessment of whitening efficacy and safety of in-office tooth whitening system containing 15% hydrogen peroxide with or without light activation

Journal of Korean Academy of Conservative Dentistry, 2011

Research paper thumbnail of Scanning electron microscopic study on the efficacy of root canal wall debridement of rotary Ni-Ti instruments with different cutting angle

Journal of Korean Academy of Conservative Dentistry, 2002

Research paper thumbnail of 상아질 지각과민증과 치주 처치에서 레이저의 이용

Journal of Dental Rehabilitation and Applied Science, 2014

Research paper thumbnail of In vitro evaluation of accuracy and consistency of four different electronic apex locators

Journal of Korean Academy of Conservative Dentistry, 2006

Research paper thumbnail of Lipoteichoic Acid Partially Contributes to the Inflammatory Responses to Enterococcus faecalis

Journal of Endodontics, 2008

Research paper thumbnail of Chlorhexidine Gluconate Attenuates the Ability of Lipoteichoic Acid from Enterococcus faecalis to Stimulate Toll-like Receptor 2

Journal of Endodontics, 2009

Chlorhexidine gluconate (CHX) has been widely used as a canal irrigant or an intracanal medicamen... more Chlorhexidine gluconate (CHX) has been widely used as a canal irrigant or an intracanal medicament on account of its antibacterial substantivity. This in vitro study aimed to determine if CHX attenuates the inflammatory activity of Enterococcus faecalis and its major virulence factor, lipoteichoic acid (LTA). An enzymelinked immunosorbent assay showed that CHX-killed E. faecalis was less potent than heat-killed E. faecalis in the production of tumor necrosis factor ␣ (TNF-␣) by a murine macrophage cell line, RAW 264.7 (p Ͻ 0.05). Interestingly, pretreatment of LTA with 2% CHX for 6 hours or with 0.2% CHX for 24 hours almost eliminated the TNF-␣ inducibility (p Ͻ 0.05). Furthermore, CHX abrogated the ability of LTA to stimulate Toll-like receptor 2, resulting in the attenuated induction of TNF-␣ expression. Collectively, our results suggest that CHX can inactivate LTA of E. faecalis leading to the alleviation of inflammatory responses induced by E. faecalis and its LTA.

Research paper thumbnail of THE INFLUENCE OF pH ON THE FORMATION OF ARTIFICIAL ROOT CARIES IN ACID BUFFER SOLUTION

Restorative Dentistry and Endodontics, 1999

산완충용액의pH가인공치근우식의형성에미치는영향 오현석∙금기연∙노병덕∙이찬영연세대학교치과대학치과보존학교실 THE INFLUENCE OF pH ON THE FORMATION OF ... more 산완충용액의pH가인공치근우식의형성에미치는영향 오현석∙금기연∙노병덕∙이찬영연세대학교치과대학치과보존학교실 THE INFLUENCE OF pH ON THE FORMATION OF ARTIFICIAL ROOT CARIES IN ACID BUFFER SOLUTION Hyun-Suk Oh, Kee-Yeon Kum, Byeng-Duck Ro, Chan-Young Lee Department of Conservative Dentistry, College of Dentistry, Yonsei University Recently root caries is reported as an increasing oral disease. Many researchers studied in vivo and in vit-ro enamel lesions but due to its peculiar structure and different chemical composition compared to theenamel, little effort has been made to root caries study.The purpose of this study is to compare and to evaluate the eff ect of pH on the progression of artificialroot caries lesion. Under the constant degree of saturation, the specimens were divided into 4 groups(pH4.3, 5.0, 5.5, 6.0). Each group was immersed in acid buffer sol ution for 1, 3, 5, 7 days and examined usingthe polarizing microscope.The results were as follows:1. The body of the lesion in the dentin showed higher degree of positive birefr...

Research paper thumbnail of The Inhibitory Effect of Taurine and Alendronate on the Osteoclast Differentiation Mediated by Sonicated Extracts of Porphyromonas Gingivalis in Vitro

Restorative Dentistry and Endodontics, 2001

The objective of this study was to investigate the inhibitory effect of taurine and alendronate o... more The objective of this study was to investigate the inhibitory effect of taurine and alendronate on the osteoclast differentiation. Osteoblasts and bone marrow cells from 1-2 day old mouse were co-cultured in 10% fetal bovine serum - minimal essential media (FBS-MEM). Osteoclast differentiation was induced by adding the sonicated extracts of Porphyromonas gingivalis (P.gingivalis). Osteoclasts were identified using tartrate resistant acid phosphotase staining (TRAP). Alendronate of 10, 10, 10M and taurine of 500, 1000, 1500/ml were added respectively. The cytotoxic effects of alendronate and taurine were examined using MTT(3-(4,5-dimethylthiazol -2-yl-2,5-diphenyltetrazo- lium bromide) method. After culturing with the sonicated extracts of P.gingivalis, the amounts of IL-6 in the culture supernatant were measured and compared using the ELISA method. The results were as follows : 1. Osteoclasts were differentiated at the concentration of 0.01~0.1/ml sonicated extracts of P.gingivalis....

Research paper thumbnail of Mandibular molar C-shaped root canals in 5th millennium BC China

Archives of Oral Biology, 2020

Research paper thumbnail of Molecular Epidemiology and Association of Putative Pathogens in Root Canal Infection

Journal of Endodontics, 2000

The purpose of this study was to investigate the epidemiology of putative pathogens in root canal... more The purpose of this study was to investigate the epidemiology of putative pathogens in root canals with apical periodontitis and to determine the associations among the putative pathogens. Eighteen symptomatic and 20 asymptomatic teeth from 36 subjects were studied. This research was performed with polymerase chain reaction and hybridization using rRNA-based oligonucleotide probes. The most frequently found species was Fusobacterium sp. (68.4%), followed by Peptostreptococcus micros (44.7%) and Porphyromonas gingivalis (26.3%). Sixteen teeth (42.1%) contained one or more species of the selected black-pigmented bacteria. Bacteroides forsythus and Treponema sp. were detected in 8 teeth and 6 teeth, respectively. Among the analyzed bacteria, significant relationships were shown in the combination of B. forsythus/P. gingivalis and Treponema sp./P. gingivalis. There was no significant association between any bacteria and any symptoms.

Research paper thumbnail of Effect of Autoclave Sterilization on the Cyclic Fatigue of Three Nickel-Titanium Instruments

Ain Shams Dental Journal, 2015

The purpose of this study is to assess the effect of autoclave sterilization on the cyclic fatigu... more The purpose of this study is to assess the effect of autoclave sterilization on the cyclic fatigue and torsional fracture resistance of ProTaper Universal (PTU), K3XF, HyFlex EDM (EDM), and TF adaptive (TFA). Sixty instruments from each file type were divided into two categories for cyclic fatigue group (CGr) and torsional fracture group (TGr). CGr and TGr were divided into three subgroups, respectively, consisting of ten instruments from each file type. Cyclic fatigue fracture test was performed using artificial canal made of stainless steel, and the mean number of cycles to failure (NCF) were determined. CGr1, the files were tested to establish baseline for NCF; CGr2, the files were tested cyclic fatigue after 10 cycles of autoclave; CGr3, instruments were autoclaved after being cycled to 25, 50, and 75% of corresponding NCF determined in CGr1, followed by cyclic fatigue test. The torsional fracture test was performed without autoclave (TGr1), after 3-cycle autoclave (TGr2), and 7-cycle autoclave (TGr3), respectively, which evaluated maximum torque and angular deflection. NCF, maximum torque and angular deflection were compared using one-way ANOVA with Bonferroni test. Two-way ANOVA was performed to determine the interaction between 'autoclave treatment' and 'type of NiTi file'. EDM showed highest NCF within the same autoclave treatment. TFA presented the lowest maximum torque and the highest angular deflection, and PTU presented the lowest angular deflection. Within the same NiTi file systems, most of NCF, maximum torque and angular deflection of tested files were not significantly influenced by autoclave condition.

Research paper thumbnail of Effect of preheating on the viscoelastic properties of dental composite under different deformation conditions

Dental materials journal, 2015

Preheating of dental composites improves their flowability, facilitating successful restorations.... more Preheating of dental composites improves their flowability, facilitating successful restorations. However, the flowability of dental composites is affected not only by temperature but also by the deformation conditions. In the present work, the effects of various deformation conditions upon the viscoelastic properties of a preheated dental composite were studied. The rheological properties of Z350 dental composites at 25, 45, and 60°C were measured by a strain-controlled rheometer. When a low strain (0.03%) was applied, the preheated composite exhibited greater shear storage modulus (G') and complex viscosity (η*) than a room-temperature composite. Oppositely, when a high strain (50%) was applied, G' and η* of a preheated composite were lower than those of a room-temperature composite. Preheating of dental composites might be helpful in clinical practice both to increase the slumping resistance when minimal manipulation is used (e.g., during the build-up of a missing cusp ti...

Research paper thumbnail of PCR-based Identification of Eubacteirum species in endodontic infection

Journal of Korean Academy of Conservative Dentistry, 2003

Research paper thumbnail of Gene-expression analysis of cementoblasts and osteoblasts

Journal of Periodontal Research, 2015

Research paper thumbnail of Apical prepration size in infected root canals

Journal of Korean Academy of Conservative Dentistry, 2010

Research paper thumbnail of In vitro evaluation of cleaning efficacy of various irrigation methods in mandibular molars

Journal of Korean Academy of Conservative Dentistry, 2009

Research paper thumbnail of Odontoblastic Differentiation, Inflammatory Response, and Angiogenic Potential of 4 Calcium Silicate–based Cements: Micromega MTA, ProRoot MTA, RetroMTA, and Experimental Calcium Silicate Cement

Journal of Endodontics, 2015

Introudction: The aim of this study was to analyze the effects of different calcium silicate-base... more Introudction: The aim of this study was to analyze the effects of different calcium silicate-based cements (CSCs) for pulp capping materials including MicroMega MTA (MMTA; MicroMega, Besanchon, France), Retro MTA (RMTA; BioMTA, Seoul, Korea), ProRoot MTA (PMTA; Dentsply, Tulsa, OK), and experimental CSC (ECSC) on odontoblastic differentiation, in vitro angiogenesis, and the inflammatory response in human dental pulp cells. Methods: Differentiation was evaluated by alkaline phosphatase activity, alizarin red staining, and reverse-transcriptase polymerase chain reaction (RT-PCR) for the marker genes. The levels of inflammatory mediators and cytokines were measured by RT-PCR and an enzyme-linked immunosorbent assay. In vitro angiogenesis was assessed by RT-PCR for angiogenic genes and an endothelial tube formation assay. Results: PMTA, MMTA, and ECSC increased the alkaline phosphatase activity and mineralization nodule formation and up-regulated messenger RNA (mRNA) expression of odontoblastic markers compared with RMTA. In addition, PMTA, MMTA, and ECSC upregulated the mRNA of angiogenic genes in human dental pulp cells and increased the capillary tube formation of endothelial cells compared with RMTA. However, all CSCs showed similar expression levels of inducible nitric oxide synthase and cyclooxygenase-2 protein as well as proinflammatory mediators such as nitric oxide, prostaglandin E2, tumor necrosis factor alpha, interleukin (IL)-1b, IL-6, and IL-8 mRNA. Conclusions: Taken together, our experimental results suggest that all CSCs are favorable materials for pulp capping, but PMTA, MMTA, and ECSC may be recommended over RMTA.

Research paper thumbnail of Effects of calcium silicate endodontic cements on biocompatibility and mineralization-inducing potentials in human dental pulp cells

Journal of endodontics, 2014

The objective of this study was to evaluate the biocompatibility, inflammatory response, and odon... more The objective of this study was to evaluate the biocompatibility, inflammatory response, and odontoblastic potential of Biodentine (Septodont, Saint Maur des Fosses, France), Ortho-MTA (OMTA; BioMTA, Seoul, Korea), Angelus-MTA (AMTA; Angelus, Londrina, Brazil), and IRM (Dentsply Tulsa Dental, Tulsa, OK) in human dental pulp cells. The underlying signaling mechanisms were also investigated. Biocompatibilities were examined by the 3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide assay. Differentiation was assessed by alkaline phosphatase activity, alizarin red S staining, and reverse-transcription polymerase chain reaction for marker genes. The levels of inflammatory mediators and cytokines were measured by reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assay. Signal transduction analysis was performed by Western blotting. Biodentine, OMTA, and AMTA showed favorable cell proliferation, alkaline phosphatase activity, formation of mineraliz...

Research paper thumbnail of Lifespan of one nickel-titanium rotary file with reciprocating motion in curved root canals

Journal of endodontics, 2010

The purpose of this study was to examine the lifespan of one nickel-titanium (NiTi) rotary file w... more The purpose of this study was to examine the lifespan of one nickel-titanium (NiTi) rotary file when used in reciprocating motion and to compare the time required for its preparation of a curved root canal using both reciprocating and continuous motion. One hundred twenty curved canals from 60 extracted maxillary and mandibular molars were selected for measuring the mean number of uses. Each canal was prepared with reciprocating motion until the ProTaper F2 single file (Dentsply Maillefer, Ballaigues, Switzerland) reached the working length. One file was used until it was fractured. Another 60 canals were divided into two groups. 30 canals in the continuous rotation motion (CM) group were prepared using continuous rotation following the sequence of ProTaper files, whereas the canals in the reciprocating motion (RM) group (n = 30) were prepared with reciprocating motion with the sole use of the ProTaper F2. The total root canal preparation time was measured until the F2 file finally ...

Research paper thumbnail of Clinical study of shade improvement and safety of polymer-based pen type BlancTic Forte whitening agent containing 8.3% Carbamide peroxide

Journal of Korean Academy of Conservative Dentistry, 2009

Research paper thumbnail of Clinical assessment of whitening efficacy and safety of in-office tooth whitening system containing 15% hydrogen peroxide with or without light activation

Journal of Korean Academy of Conservative Dentistry, 2011

Research paper thumbnail of Scanning electron microscopic study on the efficacy of root canal wall debridement of rotary Ni-Ti instruments with different cutting angle

Journal of Korean Academy of Conservative Dentistry, 2002

Research paper thumbnail of 상아질 지각과민증과 치주 처치에서 레이저의 이용

Journal of Dental Rehabilitation and Applied Science, 2014

Research paper thumbnail of In vitro evaluation of accuracy and consistency of four different electronic apex locators

Journal of Korean Academy of Conservative Dentistry, 2006

Research paper thumbnail of Lipoteichoic Acid Partially Contributes to the Inflammatory Responses to Enterococcus faecalis

Journal of Endodontics, 2008

Research paper thumbnail of Chlorhexidine Gluconate Attenuates the Ability of Lipoteichoic Acid from Enterococcus faecalis to Stimulate Toll-like Receptor 2

Journal of Endodontics, 2009

Chlorhexidine gluconate (CHX) has been widely used as a canal irrigant or an intracanal medicamen... more Chlorhexidine gluconate (CHX) has been widely used as a canal irrigant or an intracanal medicament on account of its antibacterial substantivity. This in vitro study aimed to determine if CHX attenuates the inflammatory activity of Enterococcus faecalis and its major virulence factor, lipoteichoic acid (LTA). An enzymelinked immunosorbent assay showed that CHX-killed E. faecalis was less potent than heat-killed E. faecalis in the production of tumor necrosis factor ␣ (TNF-␣) by a murine macrophage cell line, RAW 264.7 (p Ͻ 0.05). Interestingly, pretreatment of LTA with 2% CHX for 6 hours or with 0.2% CHX for 24 hours almost eliminated the TNF-␣ inducibility (p Ͻ 0.05). Furthermore, CHX abrogated the ability of LTA to stimulate Toll-like receptor 2, resulting in the attenuated induction of TNF-␣ expression. Collectively, our results suggest that CHX can inactivate LTA of E. faecalis leading to the alleviation of inflammatory responses induced by E. faecalis and its LTA.