This study was done to evaluate transportation of the apical foramen after 0.5 mm overinstrumentation by ProFile, ProTaper and K³ in simulated resin root canal.

Sixty simulated resin root canal with a curvature of J and S-shape were divided into two groups. Each group consisted of three subgroups with 10 blocks according to the instruments used: ProFile®, ProTaper™, and K^3TM. Simulated resin root canal was prepared by ProFile, ProTaper and K³ with 300 rpm by the crown-down preparation technique. Pre- and post-instrumentation apical foramen images were overlapped and recorded with Image-analyzing microscope 100X (Camcope, Sometech Inc, Korea). The amounts of difference in width and dimension on overlapped images were measured after reference points were determined by Image Analysis program (Image-Pro® Express, Media Cybernetic, USA). Data were analyzed using Kruskal-Wallis and Mann-Whitney U-test.

The results suggest that ProFile showed significantly less canal transportation and maintained original apical foramen shape better than K³ and ProTaper.

This study was performed to verify the possibility of MTA and calcium sulfate as a pulp capping agent through comparing the dental pulp response in dogs after capping with MTA, calcium sulfate, and calcium hydroxide.

24 teeth of 2 dogs, 8 month old, were used in this study.

Under general anesthesia, cervical cavities were prepared and pulp was exposed with sterilized #2 round bur in a high speed handpiece.

MTA, calcium hydroxide, and calcium sulfate were applied on the exposed pulp. Then the coronal openings were sealed with IRM and light-cured composite.

Two months after treatment, the animals were sacrificed. The extracted teeth were fixed in 10% neutral-buffered formalin solution and were decalcified in formic acid-sodium citrate. They were prepared for histological examination in the usual manner. The sections were stained with haematoxylin and eosin.

In MTA group, a hard tissue bridges formation and newly formed odontoblasts layer was observed. There was no sign of pulp inflammatory reaction in pulp tissue.

In calcium hydroxide group, there was no odontoblast layer below the dentin bridge. In pulpal tissue, chronic inflammatory reaction with variable intensity and extension occurred in all samples.

In calcium sulfate group, newly formed odontoblast layer was observed below the bridge. Mild chronic inflammation with a few neutrophil infiltrations was observed on pulp tissue.

These results suggest that MTA is more biocompatible on pulp tissue than calcium hydroxide or calcium sulfate.

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• Effects of the exposure site on histological pulpal responses after direct capping with 2 calcium-silicate based cements in a rat model
  Panruethai Trongkij, Supachai Sutimuntanakul, Puangwan Lapthanasupkul, Chitpol Chaimanakarn, Rebecca Wong, Danuchit Banomyong
  Restorative Dentistry & Endodontics.2018;[Epub]     CrossRef
• Conservative approach of a symptomatic carious immature permanent tooth using a tricalcium silicate cement (Biodentine): a case report
  Cyril Villat, Brigitte Grosgogeat, Dominique Seux, Pierre Farge
  Restorative Dentistry & Endodontics.2013; 38(4): 258.     CrossRef
• Comparison of gene expression profiles of human dental pulp cells treated with mineral trioxide aggregate and calcium hydroxide
  Yong-Beom Kim, Won-Jun Shon, Woocheol Lee, Kee-Yeon Kum, Seung-Ho Baek, Kwang-Shik Bae
  Journal of Korean Academy of Conservative Dentistry.2011; 36(5): 397.     CrossRef
• Pulp response of beagle dog to direct pulp capping materials: Histological study
  Ji-Hyun Bae, Young-Gyun Kim, Pil-Young Yoon, Byeong-Hoon Cho, Yong-Hoon Choi
  Journal of Korean Academy of Conservative Dentistry.2010; 35(1): 5.     CrossRef
• Gene expression profiling in human dental pulp cells treated with mineral trioxide aggregate
  Yong-Beom Kim, Won-Jun Shon, WooCheol Lee, Kee-Yeon Kum, Seung-Ho Baek, Kwang-Shik Bae
  Journal of Korean Academy of Conservative Dentistry.2010; 35(3): 152.     CrossRef
• Biocompatibility of experimental mixture of mineral trioxide aggregate and glass ionomer cement
  Min-Jae Oh, Yu-Na Jeong, In-Ho Bae, So-Young Yang, Bum-Jun Park, Jeong-Tae Koh, Yun-Chan Hwang, In-Nam Hwang, Won-Mann Oh
  Journal of Korean Academy of Conservative Dentistry.2010; 35(5): 359.     CrossRef
• Biocompatibility of bioaggregate cement on human pulp and periodontal ligament (PDL) derived cells
  Choo-Ryung Chung, Euiseong Kim, Su-Jung Shin
  Journal of Korean Academy of Conservative Dentistry.2010; 35(6): 473.     CrossRef
• Physical and chemical properties of experimental mixture of mineral trioxide aggregate and glass ionomer cement
  Yu-Na Jeong, So-Young Yang, Bum-Jun Park, Yeong-Joon Park, Yun-Chan Hwang, In-Nam Hwang, Won-Mann Oh
  Journal of Korean Academy of Conservative Dentistry.2010; 35(5): 344.     CrossRef
• The effect of several root-end filling materials on MG63 osteoblast-like cells
  Jeong-Ho Lee, Won-Jun Shon, WooCheol Lee, Seung-Ho Baek
  Journal of Korean Academy of Conservative Dentistry.2010; 35(3): 222.     CrossRef
• Effects of condensation techniques and canal sizes on the microleakage of orthograde MTA apical plug in simulated canals
  Deuk-Lim Nam, Jeong-Kil Park, Bock Hur, Hyeon-Cheol Kim
  Journal of Korean Academy of Conservative Dentistry.2009; 34(3): 208.     CrossRef
• Comparison of biocompatibility of four root perforation repair materials
  Min-Kyung Kang, In-Ho Bae, Jeong-Tae Koh, Yun-Chan Hwang, In-Nam Hwang, Won-Mann Oh
  Journal of Korean Academy of Conservative Dentistry.2009; 34(3): 192.     CrossRef
• A bioactivity study of Portland cement mixed with β-glycerophosphosphate on human pulp cell
  Young-Hwan Oh, Young-Joo Jang, Yong-Bum Cho
  Journal of Korean Academy of Conservative Dentistry.2009; 34(5): 415.     CrossRef

The purpose of this study was to obtain the basic information for the improvement of dental environment by investigating the presence of methicillin- or vancomycin-resistant Staphylococcus aureus (MRSA or VRSA) isolated from dental health care workers (DHCWs) and environment of the Chosun University Dental Hospital (CUDH) and a private dental clinic (control group). Staphylococcus aureus (S. aureus) was isolated from anterior nares of 42 DHCWs and 38 sites, unit chairs, x-ray devices, computers, etc., at 10 departments of the CUDH and 20 DHCWs and 11 sites at the private dental clinic. S. aureus was isolated on mannitol salt agar plate and confirmed by PCR with S. aureus species-specific primer. Antimicrobial susceptibility test of clinical isolates of S. aureus against several antibiotics including methicillin (oxacillin) was performed by investigating minimum inhibitory concentration (MIC) using broth microdilution assay. In addition, PCR was performed to detect the methicillin- or vancomycin-resistant gene. The data showed that one strain of S. aureus was isolated from DHCWs of the CUDH and three strains of S. aureus was isolated from 3 samples of the private dental clinic, respectively. All of the isolates from the CUDH and the private dental clinic had resistance to penicillin G, amoxicillin and vancomycin and susceptibility to oxacillin and ciprofloxacin. The S. aureus strains were already obtained the resistance to penicillin G and amoxicillin. These results suggest that two dental clinics were under relatively safe environment.

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• Survey of Staphylococcus epidermidis Contamination on the Hands of Dental Hygienists and Equipment Surface of Dental Clinics
  Seol-Hee Kim
  Journal of Dental Hygiene Science.2017; 17(6): 472.     CrossRef
• Antimicrobial susceptibility and pathogenic genes ofStaphylococcus aureusisolated from the oral cavity of patients with periodontitis
  Ga-Yeon Kim, Chong Heon Lee
  Journal of Periodontal & Implant Science.2015; 45(6): 223.     CrossRef
• A Study Regarding Bacterial Contamination of Surfaces in Dental Offices
  Kyoung-Ok Yun, Hye-Young Kim
  Korean Journal of Clinical Laboratory Science.2015; 47(4): 279.     CrossRef
• A Study on Bacterial Concentrations in Dental Offices
  Kyoung-Ok Yun, Hee-Jin Park, Bu-Soon Son
  Korean Journal of Environmental Health Sciences.2014; 40(6): 469.     CrossRef

The purpose of this study is to evaluate the effects of surface treatment and composition of reinforcement material on fracture strength of fiber reinforced composite inlay bridges.

The materials used for this study were I-beam, U-beam TESCERA ATL system and ONE STEP(Bisco, IL, USA). Two kinds of surface treatments were used; the silane and the sandblast. The specimens were divided into 11 groups through the composition of reinforcing materials and the surface treatments.

On the dentiform, supposing the missing of Maxillary second pre-molar and indirect composite inlay bridge cavities on adjacent first pre-molar disto-occlusal cavity, first molar mesio-occlusal cavity was prepared with conventional high-speed inlay bur.The reinforcing materials were placed on the proximal box space and build up the composite inlay bridge consequently. After the curing, specimen was set on the testing die with ZPC. Flexural force was applied with universal testing machine (EZ-tester; Shimadzu, Japan). at a cross-head speed of 1 mm/min until initial crack occurred. The data wasanalyzed using one-way ANOVA/Scheffes' post-hoc test at 95% significance level.

Groups using I-beam showed the highest fracture strengths (p < 0.05) and there were no significant differences between each surface treatment (p > 0.05). Most of the specimens in groups that used reinforcing material showed delamination.

The use of I-beam represented highest fracture strengths (p < 0.05).

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• Esthetic rehabilitation of single anterior edentulous space using fiber-reinforced composite
  Hyeon Kim, Min-Ju Song, Su-Jung Shin, Yoon Lee, Jeong-Won Park
  Restorative Dentistry & Endodontics.2014; 39(3): 220.     CrossRef

The purpose of this study was to assess the antibacterial effect of sodium dichloroisocyanurate (NaDCC), sodium hypochlorite (NaOCl), and chlorhexidine (CHX) on Enterococcus faecalis and to evaluate and to compare the time-dependant antimicrobial effect of NaDCC with NaOCl and CHX in the root canal in vitro before and after instrumentation.

Extracted human single teeth were prepared by serial instrumentation technique. The samples were autoclaved and contaminated for 3 days with E. faecalis monocultures. The teeth were then divided into 4 groups. Each group was irrigated and inserted with 2% NaOCl, 2% NaDCC, 2% CHX and sterilized saline. After 6, 12, 24, 72h, and 1 week incubation, sterilized paper point was inserted into the root canal. Paper points containing root canal contents were then placed on the agar plate. And then each root canal was prepared with #4 and #5 GG (Gates-Glidden) drill. The debris were collected in the sterilized microtube and the plates were incubated at 37℃ in an increased CO₂ atmosphere. After 24h incubation the growth of bacteria around the paper points were measured.

NaOCl and NaDCC solution shows similar antimicrobial effect for E. faecalis at 6, 12, 24, 72h and 1 week. In control group, irrigated with sterilized saline, no antimicrobial effect was observed.

The results are in agreement with other investigators, who have shown the bactericidal property and possibility of NaDCC as a root canal irrigation solution. Thus it seems that NaDCC solutions can be clinically applied into the root canal within 1 week after dilution.

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  Jean Yoo, Haewon Kim, Yeon-Mi Lim, Byung-Il Yoon, Pilje Kim, Ig-Chun Eom, Ilseob Shim
  Human & Experimental Toxicology.2022;[Epub]     CrossRef
• Enterococcus faecium and Enterococcus faecalis in endodontic infections: antibiotic resistance profile and susceptibility to photodynamic therapy
  Ana Carolina Chipoletti Prado, Patrícia Pimentel De Barros, Jéssica Diane Dos Santos, Luciane Dias De Oliveira, Claudio Antônio Talge Carvalho, Marcia Carneiro Valera, Antonio Olavo Cardoso Jorge, Juliana Campos Junqueira
  Lasers in Dental Science.2017; 1(2-4): 91.     CrossRef
• Evaluation of Antimicrobial Activity and Disease Control Efficacy of Sodium Dichloroisocyanurate (NaDCC) Against Major Strawberry Diseases
  Da-Ran Kim, Gun-Hye Gang, Hyun-Ji Cho, Hae-Suk Yoon, Youn-Sig Kwak
  The Korean Journal of Pesticide Science.2015; 19(1): 47.     CrossRef
• Effect of Gamma Irradiation and Its Convergent Treatments on Lily Leaf Blight Pathogen, Botrytis elliptica, and the Disease Development
  Ji-Hoon Kim, Sung-Chul Yun
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• Microorganism penetration in dentinal tubules of instrumented and retreated root canal walls.In vitroSEM study
  Saad Al-Nazhan, Alaa Al-Sulaiman, Fellwa Al-Rasheed, Fatimah Alnajjar, Bander Al-Abdulwahab, Abdulhakeem Al-Badah
  Restorative Dentistry & Endodontics.2014; 39(4): 258.     CrossRef
• Analysis of para-chloroaniline after chemical interaction between alexidine and sodium hypochlorite using mass spectrometry: A preliminary study
  Hyeon-Sik Kim, Seung-Hyun Han, Soram Oh, Sang-Min Lim, Yu Gu, Kee-Yeon Kum
  Journal of Korean Academy of Conservative Dentistry.2010; 35(4): 295.     CrossRef
• The comparison of different canal irrigation methods to prevent reaction precipitate between sodium hypochlorite and chlorhexidine
  Moon-Sun Choi, Se-Hee Park, Kyung-Mo Cho, Jin-Woo Kim
  Journal of Korean Academy of Conservative Dentistry.2010; 35(2): 80.     CrossRef
• Comparison of Antibacterial effect of Listerine® with Various root canal irrigants
  Young Hun Kim, Min-Kyung Kang, Eun-Kyoung Choi, So-Young Yang, Inseok Yang, In-Chol Kang, Yun-Chan Hwang, In-Nam Hwang, Won-Mann Oh
  Journal of Korean Academy of Conservative Dentistry.2009; 34(6): 500.     CrossRef
• Evaluation ofEnterococcus faecalisremoval efficacy of the EndoVac® and EndoActivator® intracanal irrigation methods
  Seung-Gon Song, Se-Hee Park, Kyung-Mo Cho, Jin-Woo Kim
  Journal of Korean Academy of Conservative Dentistry.2009; 34(5): 390.     CrossRef
• The effect of MTAD as a final root canal irrigants on the coronal bacterial leakage of obturated root canals
  Tae Woo Kim, Seok Woo Chang, Dong Sung Park
  Journal of Korean Academy of Conservative Dentistry.2008; 33(4): 397.     CrossRef

This in vitro study examined the effect of surface defects on cutting blades on the extent of the cyclic fatigue fracture of HEROShaper Ni-Ti rotary files using fractographic analysis of the fractured surfaces. A total of 45 HEROShaper (MicroMega) Ni-Ti rotary files with a #30/.04 taper were divided into three groups of 15 each. Group 1 contained new HEROShapers without any surface defects. Group 2 contained HEROShapers with manufacturing defects such as metal rollover and machining marks. Group 3 contained HEROShapers that had been clinically used for the canal preparation of 4-6 molars. A fatigue-testing device was designed to allow cyclic tension and compressive stress on the tip of the instrument whilst maintaining similar conditions to those experienced in a clinic. The level of fatigue fracture time was measured using a computer connected the system. Statistical analysis was performed using a Tukey's test. Scanning electron microscopy (SEM) was used for fractographic analysis of the fractured surfaces. The fatigue fracture time between groups 1 and 2, and between groups 1 and 3 was significantly different (p < 0.05) but there was no significant difference between groups 2 and 3 (p > 0.05). A low magnification SEM views show brittle fracture as the main initial failure mode. At higher magnification, the brittle fracture region showed clusters of fatigue striations and a large number of secondary cracks. These fractures typically led to a central region of catastrophic ductile failure. Qualitatively, the ductile fracture region was characterized by the formation of microvoids and dimpling. The fractured surfaces of the HEROShapers in groups 2 and 3 were always associated with pre-existing surface defects. Typically, the fractured surface in the brittle fracture region showed evidence of cleavage (transgranular) facets across the grains, as well as intergranular facets along the grain boundaries. These results show that surface defects on cutting blades of Ni-Ti rotary files might be the preferred sites for the origin of fatigue fracture under experimental conditions. Furthermore, this work demonstrates the utility of fractography in evaluating the failure of Ni-Ti rotary files.

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• The Effect of Canal Curvature and Different Manufacturing Processes of Five Different NiTi Rotary Files on Cyclic Fatigue Resistance
  Panupat Phumpatrakom, Awiruth Klaisiri, Sukitti Techapatiphandee, Thippawan Saekow, Panuroot Aguilar
  European Journal of General Dentistry.2024;[Epub]     CrossRef
• Effect of internal stress on cyclic fatigue failure in .06 taper ProFile
  Hye-Rim Jung, Jin-Woo Kim, Kyung-Mo Cho, Se-Hee Park
  Restorative Dentistry & Endodontics.2012; 37(2): 79.     CrossRef
• Effect of internal stress on cyclic fatigue failure in K3
  Jun-Young Kim, Jin-Woo Kim, Kyung-Mo Cho, Se-Hee Park
  Restorative Dentistry & Endodontics.2012; 37(2): 74.     CrossRef
• Stress distribution for NiTi files of triangular based and rectangular based cross-sections using 3-dimensional finite element analysis
  Hyun-Ju Kim, Chan-Joo Lee, Byung-Min Kim, Jeong-Kil Park, Bock Hur, Hyeon-Cheol Kim
  Journal of Korean Academy of Conservative Dentistry.2009; 34(1): 1.     CrossRef
• Comparative analysis of various corrosive environmental conditions for NiTi rotary files
  Ji-Wan Yum, Jeong-Kil Park, Bock Hur, Hyeon-Cheol Kim
  Journal of Korean Academy of Conservative Dentistry.2008; 33(4): 377.     CrossRef

The purpose of this study was to evaluate the difference of surface roughness of composite resin according to composite resin type, polishing methods, and use of resin sealant.

Two hundred rectangular specimens, sized 8 × 3 × 2 mm, were made of Micro-new (Bisco, Inc., Schaumburg, IL, U.S.A) and Filtek Supreme (3M ESPE Dental Products, St. Paul, MN, U.S.A.), and divided into two groups; Micronew-M group, Filtek Supreme-S group. Specimens for each composite group were subdivided into five groups by finishing and polishing instruments used; M1 & S1 (polyester strip), M2 & S2 (Sof-Lex disc), M3 & S3 (Enhance disc and polishing paste), M4 & S4 (Astropol), and M5 & S5 (finishing bur). Polished groups were added letter B after the application of resin surface sealant (Biscover), eg, M1B and S1B.

After specimens were stored with distilled water for 24 hr, average surface roughness (Ra) was taken using a surface roughness tester. Representative specimens of each group were examined by FE-SEM (S-4700: Hitachi High Technologies Co., Tokyo, Japan). The data were analysed using paired t-test, ANOVA and Duncan's tests at the 0.05 probability level. The results of this study were as follows;

The lowest Ra was achieved in all groups using polyester strip and the highest Ra was achieved in M5, S5 and M5B groups using finishing bur. On FE-SEM, M1 and S1 groups provided the smoothest surfaces, M5 and S5 groups were presented the roughest surfaces and voids by debonding of filler on the polished specimens.

In conclusion, surface roughness by polishing instruments was different according to type of composite resin. Overall, polyester strip produced the smoothest surface, but finishing bur produced the roughest surface. Application of resin sealant provided the smooth surfaces in specimens polished with Enhance, Astropol and finishing bur, but not provided them in specimens polished with Sof-Lex disc.

Dental caries is the most common disease in the oral cavity. However, the mechanism and treatment of dental caries is not completely understood since many complex factors are involved. Especially the effect of pH on remineralization of early stage of dental caries is still controversial.

In this study, dental caries in dentin was induced by using lactic acidulated buffering solutions and the loss of inorganic substance was measured. Also decalcified specimens were remineralized by three groups of solution with different pH (group of pH 4.3, 5.0, and 5.5). Then, the amount and the area of inorganic substance precipitation was quantitatively analyzed with microradiograph. Also a qualitative comparison of the normal phase, the demineralized phase, and the remineralized phase of hydroxyapatite crystal was made under SEM.

The results were as follows;

In microradiograghic analysis, as the pH increased, the amount of remineralization in decalcified dentin tended to increase significantly. As the pH decreaced, deeper decalcification, however, occurred along with remineralization. The group of pH 5.5 had a tendency to be remineralized without demineralization (p < 0.05).

In according to the results of this experiment, the decalcifying and remineralizing process of dentine is neither simple nor independent, but a dynamic process in which decalcification and remineralization occur simultaneously. The remineralization process occurred from the hydroxyapatite crystal surface.

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  Jihyeon Lee, Hwalim Lee, Jongsoo Kim, Joonhaeng Lee, Jongbin Kim, Jisun Shin, Miran Han
  International Journal of Clinical Preventive Dentistry.2024; 20(1): 19.     CrossRef
• The remineralizing features of pH 5.5 solutions of different degree of saturations on artificially demineralized enamel
  Young-Jun Kwak, Eui-seoug Kim, Sung-Ho Park, Hyung Kyu Gong, Yoon Lee, Chan-Young Lee
  Journal of Korean Academy of Conservative Dentistry.2008; 33(5): 481.     CrossRef