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Effect of sonicated extracts of Enterococcus faecalis on the production of matrix metalloproteinase-8 by human polymorphonuclear neutrophils.

Sung Kyung PARK ; Won Jun SHON ; Sung Sam LIM

Journal of Korean Academy of Conservative Dentistry.2005;30(2):138-144. doi:10.5395/JKACD.2005.30.2.138

This in vitro study monitored MMP-8 production on PMN by stimulated with the following three groups; Sonicated extracts of E. faecalis (SEF), SEF treated with Ca(OH)2 (12.5mg/ml) for 7 days, and lipopolysaccharides (LPS) of E. coli. The level of MMP-8 in each group was immediately measured by ELISA. The data were analyzed with Kruskal-Wallis test and Mann-Whitney U test. In the SEF group, the level of production of MMP-8 was higher than the negative control group in low concentration (0.05microg/ml) of SEF (p < 0.05), but it decreased with an increase in the concentration of SEF (p < 0.05). In the case of SEF treated with Ca(OH)2, all of the MMP levels were higher than negative control group (p < 0.05), but no statistical difference was found among the different SEF concentrations (p > 0.05). All of the levels in E. coli LPS were increased with increasing concentrations (p < 0.05). According to this study we could summarize as follows: 1. MMP-8 was expressed at low level in untreated PMN group and the levels of MMP-8 were upregulated in PMN stimulated by E. coli LPS groups. 2. In the SEF groups, the level of production of MMP-8 decreased with an increase in the concentration of SEF (p < 0.05). So E. faecalis may have suppressive effect on the production of MMP-8 by PMN. 3. In the case of SEF treated with Ca(OH)2, all of the MMP levels at different SEF concentrations were higher than untreated PMN group (p < 0.05), but no statistical difference was found among the different SEF concentrations (p > 0.05).
Calcium Hydroxide ; Enterococcus faecalis* ; Enterococcus* ; Enzyme-Linked Immunosorbent Assay ; Humans* ; Lipopolysaccharides ; Matrix Metalloproteinase 8* ; Neutrophils*

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Surface hardness of the dental composite cured by light that penetrate tooth structure according to thickness of tooth structure, light intensity and curing time.

Soo Kyung CHO ; Dong Jun KIM ; Yun Chan HWANG ; Won Mann OH ; In Nam HWANG

Journal of Korean Academy of Conservative Dentistry.2005;30(2):128-137. doi:10.5395/JKACD.2005.30.2.128

In this study we measured the amount of light energy that was projected through the tooth material and analyzed the degree of polymerization by measuring the surface hardness of composites. For polymerization, Optilux 501 (Demetron, USA) with two types of light guide was used: a 12 mm diameter light guide with 840 mW/cm2 light intensity and a 7 mm diameter turbo light guide with 1100 mW/cm2. Specimens were divided into three groups according to thickness of penetrating tooth (1 mm, 2 mm, 0 mm). Each group was further divided into four subgroups according to type of light guide and curing time (20 seconds, 40 seconds). Vickers'hardness was measured by using a microhardness tester. In 0 mm and 1 mm penetrating tooth group, which were polymerized by a turbo light guide for 40 seconds, showed the highest hardness values. The specimens from 2 mm penetrating tooth group, which were polymerized for 20 seconds, demonstrated the lowest hardness regardless of the types of light guides (p < 0.05). The results of this study suggest that, when projecting tooth material over a specified thickness, the increase of polymerization will be limited even if light intensity or curing time is increased.
Hardness* ; Polymerization ; Polymers ; Tooth*

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The effect of NaOCl treatment and sterilization procedures on the corrosion of endodontic files.

Won Kyung YANG ; Yoon Sik RA ; Young Kyoo LEE ; Ho Hyun SON ; Mi Ri KIM

Journal of Korean Academy of Conservative Dentistry.2005;30(2):121-127. doi:10.5395/JKACD.2005.30.2.121

A variety files made of stainless steel (S-S) or nickel-titanium (Ni-Ti) are used during endodontic treatment. The purpose of this study was to evaluate the corrosion susceptibility of S-S and Ni-Ti endodontic files. Three brands of files were used for this study: K-flex(R) S-S files (Maillefer, USA), Profile(R) Ni-Ti files (Maillefer, USA), K-3(R) Ni-Ti files (SybronEndo, USA). 120 files of each brands (21mm, ISO size #20) were divided into 12 groups according to 1) sterilization methods using Autoclave or Ethylene Oxide (E-O) gas, 2) Irrigation solutions using 5.25 % NaOCl or Saline, 3) the number of sterilization (1, 5, 10 times). After above procedures, each of the files was inspected by three examiners with a light microscope and camera at X25. Each file was judged and ranked according to the following criteria: 0; no corrosion, 1; mild corrosion, 2; moderate corrosion, and 3; severe corrosion. The files of high score were examined under the Scanning Electron Microscope. Data were statistically analyzed with the Kruskal-Wallis test (p < 0.05). Most of the ten time-autoclaved files had showed mild to moderate corrosion. But, one or five time-autoclaved files did not show corrosive surface. NaOCl treatment and E-O gas sterilization did not influence on corrosion. There was a significant difference in corrosion susceptibility between sterilization methods and the number of autoclaving. However, there was no significant difference between brands and file materials.
Corrosion* ; Ethylene Oxide ; Stainless Steel ; Sterilization*

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Microleakage of the class V cavity according to restoration site and cavity size using SEM and three-dimensional reconstruction techniques.

In Seo YANG ; Dong Hoon SHIN

Journal of Korean Academy of Conservative Dentistry.2005;30(2):112-120. doi:10.5395/JKACD.2005.30.2.112

This study was done to evaluate whether there were any differences in microleakage of class V composite restorations according to restoration site and cavity size. Total sixty-four restorations were made in molar teeth using Esthet-X. Small (2 x 2 x 1.5 mm) and large (4 x 2 x 1.5 mm) restorations were made at the buccal/lingual surface and the proximal surface each. After 1,000 times of thermocycling (5degrees C - 55degrees C), resin replica was made and the percentage of marginal gap to the whole periphery of the restoration was estimated from SEM evaluation. Thermocycled tooth was dye penetrated with 50% silver nitrate solution. After imbedding in an auto-curing resin, it was serially ground with a thickness of 0.25 mm. Volumetric microleakage was estimated after reconstructing three dimensionally. Two-way ANOVA and independent T-test for dye volume, Mann-Whitney U test for the percentage of marginal gap, Spearman's rho test for the relationship between two techniques were used. The results were as follows: 1. The site and size of the restoration affected on the microleakage of restoration. Namely, much more leakage was seen in the proximal and the large restorations rather than the buccal/lingual and the small restorations. 2. Close relationship was found between two techniques (Correlation coefficient = 0.614 / P = 0.000). Within the limits of this study, it was noted that proximal and the large restorations leaked more than buccal/lingual and the small restorations. Therefore, it should be strictly recommended large exposure of margins should be avoided by reducing unnecessary tooth reduction.
Molar ; Silver Nitrate ; Tooth

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Endodontic flare-ups incidence and related factors.

Hye Young JUNG ; Sang Hyuk PARK ; Gi Woon CHOI

Journal of Korean Academy of Conservative Dentistry.2005;30(2):102-111. doi:10.5395/JKACD.2005.30.2.102

The purpose of this study was to assess the incidence of flare-ups among patients who received endodontic treatment and to examine the correlation with pre-operative and operative variables. Analysis was in two aspects (a) overall incidence of flare-ups as expressed by a percentage of all patients visits and (b) percentage of flare-ups that occurred as related to various factors such as patient demographics, diagnosis, and treatment procedures. 1. From the 840 teeth which were examined in this study, the total number of flare-ups was 13. 2. As to gender of patients, there was no significant difference in flare-ups. 3. As to tooth groups, there was no significant difference in flare-ups. 4. In the teeth with pre-operative symptom, there was a statistically significant higher incidence of flare-ups than the teeth without it. 5. In the teeth with apical periodontitis, there was a statistically significant higher incidence of flare-ups. 6. As to pulp and periapical status, non-vital teeth had a higher incidence as compared with vital teeth, irreversible pulpitis. 7. Multi-visit treatment resulted in the higher incidence of flare-ups than one visit treatment. 8. Re-treatment procedures had a statistically significant higher incidence of flare-ups than root canal treatment. In this study, overall percentages of flare-ups was 1.55%. It showed a statistically significant higher incidence related to pre-operative symptom, apical periodontitis, and re-treatment. There was no significant difference in flare-ups related to gender, tooth groups, and fistula.
Demography ; Dental Pulp Cavity ; Diagnosis ; Fistula ; Humans ; Incidence* ; Periapical Periodontitis ; Pulpitis ; Tooth

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Effect of canal tapering in teeth of various apical size & cross-sectional configuration on microleakage.

Jung Hee KIM ; Kyung Ha LEE ; Se Joon LEE ; Mi Kyung YU ; Kwang Won LEE

Journal of Korean Academy of Conservative Dentistry.2005;30(2):95-101. doi:10.5395/JKACD.2005.30.2.095

The aim of this study was to evaluate the microleakage of teeth according to root canal preparation with & without apical enlargement in various size of apical foramen. 60 extracted one canal roots were cross-cutted at 5 mm from root apex and divided into two groups according to their apical foramen size of large (L) and small (S). Each group was subdivided into two groups accordance with their cross-sectional configuration at 5 mm from apex, round (R) and ovoid (O); SR Group, SO Group, LR Group, LO Group. Each group was shaped in .02 taper by Quantec series Nickel-Titanium (NiTi) rotary file, obturated by lateral condensation method. Leakage was measured using a fluid transport model under 40 cmH2O pressure. After the leakage test, blocks which had showed the leakage retreated with .04 taper and .06 taper and evaluated the degree of fluid filtration in each group. The data was analysed statistically using chi-square test and fisher's exact test. The results obtained were as follows: 1. Significant difference in leakage was found in groups which had different apical foramen size in .02 taper instrumentation (p < 0.05), but not in .04 taper instrumentation (p > 0.05). 2. The difference in microleakage according to the shape of canal was not evident at 5 mm from apex (p > 0.05). 3. There was correlation between .02 taper instrumentation and .04 taper instrumentation in LR group , LO group (p < 0.05).
Filtration ; Root Canal Preparation ; Tooth Apex ; Tooth*

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The effect of environment on the physical properties of core materials.

Yoo Sook HWANG ; Kyoung Kyu CHOI ; Sang Jin PARK

Journal of Korean Academy of Conservative Dentistry.2005;30(2):86-94. doi:10.5395/JKACD.2005.30.2.086

The purpose of this study was to measure the flexural strength and hardness of four core materials in 4 different medias and to evaluate the relationship between the physical properties. For the flexural strength, the specimens were prepared from each of the following materials: Bisfil Core, Core Max, Fuji IX GP, Miracle Mix and randomly divided into four groups and stored at 37 degree C in the following medias: distilled water for 24 hours (DW/1), distilled water for 30 days (DW/30). 2% NaF for 30 days (NF/30), 0.02N lactic acid for 30 days (LA/30). After storage, the specimens were subjected to flexural strength testing and calculated to flexural modulus. For hardness testing, specimens were prepared from four materials and storaged in the uniform way. After storage, the specimens were subjected to Vicker's hardness testing. 1. The flexural strength of Core Max were the highest, and the flexural strength of Miracle Mix were the lowest. 2. The hardness of Bisfil Core were the highest. 3. The hardness of Core Max were the highest. 4. The hardness of Miracle Mix were the lowest. 5. 2% NaF and 0.02N lactic acid negatively affected the flexural strength and hardness of four core materials.
Hardness ; Hardness Tests ; Lactic Acid ; Water

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Stress analysis of maxillary premolars with composite resin restoration of notch-shaped class V cavity and access cavity; Three-dimensional finite element study.

Seon Hwa LEE ; Hyeon Cheol KIM ; Bock HUR ; Kwang Hoon KIM ; Kwon SON ; Jeong Kil PARK

Journal of Korean Academy of Conservative Dentistry.2008;33(6):570-579. doi:10.5395/JKACD.2008.33.6.570

The purpose of this study was to investigate the distribution of tensile stress of canal obturated maxillary second premolar with access cavity and notch-shaped class V cavity restored with composite resin using a 3D finite element analysis. The tested groups were classified as 8 situations by only access cavity or access cavity with notch-shaped class VS cavity (S or N), loading condition (L1 or L2), and with or without glass ionomer cement base (R1 or R2). A static load of 500 N was applied at buccal and palatal cusps. Notch-shaped cavity and access cavity were filled microhybrid composite resin (Z100) with or without GIC base (Fuji II LC). The tensile stresses presented in the buccal cervical area, palatal cervical area and occlusal surface were analyzed using ANSYS. Tensile stress distributions were similar regardless of base. When the load was applied on the buccal cusp, excessive high tensile stress was concentrated around the loading point and along the central groove of occlusal surface. The tensile stress values of the tooth with class V cavity were slightly higher than that of the tooth without class V cavity. When the load was applied the palatal cusp, excessive high tensile stress was concentrated around the loading point and along the central groove of occlusal surface. The tensile stress values of the tooth without class V cavity were slightly higher than that of the tooth with class V cavity.
Acrylic Resins ; Bicuspid ; Finite Element Analysis ; Glass Ionomer Cements ; Morpholines ; Oxazolidinones ; Silicon Dioxide ; Tooth

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Reconsideration of treatment protocol on the reduction of Enterococcus faecalis associated with failed root canal treatment.

Woo Cheol LEE ; Seong Tae HONG ; Wonjun SHON

Journal of Korean Academy of Conservative Dentistry.2008;33(6):560-569. doi:10.5395/JKACD.2008.33.6.560

Microorganism survived in the root canal after root canal cleaning and shaping procedure is a main cause of root canal treatment failure. There are several mechanisms for the bacteria to survive in the root canal after chemomechanical preparation and root canal irrigation. Bacteria organized as biofilm has been suggested as an etiology of persistent periapical lesion. Recent studies were focus on removal of Enterococcus faecalis biofilm due to the report that the persistence of this bacteria after root canal treatment may be associated with its ability to form biofilm. Several investigations demonstrated that current root canal treatment protocol including use of NaOCl, EDTA and Chlorhexidine as irrigants is quite effective in eliminating E. faecalis biofilm. However, this microorganism still can survive in inaccessible areas of root canal system and evade host immune response, suppress immune activity and produce biofilm. Up to date, there is no possible clinical method to completely get rid of bacteria from the root canal. Once the root canal treatment failure occurred, and conventional treatment incorporating current therapeutic protocol has failed, periapical surgery or extraction should be considered rather than prolong the ineffected retreatment procedure.
Bacteria ; Biofilms ; Chlorhexidine ; Clinical Protocols ; Dental Pulp Cavity ; Drug Combinations ; Edetic Acid ; Enterococcus ; Enterococcus faecalis ; Piperonyl Butoxide ; Pyrethrins ; Retreatment ; Treatment Failure

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The Effect of Temporary Filling Materials on The Adhesion between Dentin Adhesive-coated Surface and Resin Inlay.

Tae Gun KIM ; Kwang Won LEE ; Mi Kyung YU

Journal of Korean Academy of Conservative Dentistry.2008;33(6):553-559. doi:10.5395/JKACD.2008.33.6.553

The purpose of this research was to compare the microtensile bond strength of resin coated surface and resin inlay according temporary filling materials prior to applying self-adhesive resin cement. Caviton(GC, Japan), Provifil(Promedica, Neumunster, Germany), Provifil(Promedica, Neumunster, Germany) & petrolatum, and Eugenol-based cement, Tembond(Kerr, Orange CA, USA) were used as temporary filling materials. After fabrication of Tescera(Bisco, Schamburg IL, USA), it was bonded with a self-adhesive resin cement, Rely X unicem(3M, St. Paul. Minn, USA). After this procedure, the microtensile bond strength was measured and it was analyzed through one-way ANOVA and Duncan test(p<0.05). Caviton(GC, Tokyo, Japan) showed statistical difference except for the control(group I) and the saliva(group II)(p<0.05). Provifil(group IV), Provifil & petroneum(group V), Tembond(group VI) had lower microtensile bond strength.
Analysis of Variance ; Calcium Sulfate ; Citrus sinensis ; Dental Cements ; Dentin ; Inlays ; Petrolatum ; Resin Cements ; Root Canal Filling Materials ; Tokyo ; Vinyl Compounds ; Zinc Oxide

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