No abstract available.
Pemetrexed

This study was done to present a criterion in selection of the most proper light sources and materials by measuring metamerism index(MI) of the light curing composite resins with spectrocolorimeter. Metamerism is defined when two objects appear to be the same color in one illuminant but different in another. This is due to the fact that they have different spectral curves that fail to match under the second illuminant. In this study, A1 & A3 shade of five light curing composite resins (Esthet-X, Filteck Z250, Filteck A110, Charisma, Vitalescence) were chosen based on Vita shade. Five samples were made for shade of each product with Teflon mold (diameter: 15mm, thickness: 2mm). Metamerism index of each samples on a Barium sulfate plate (L*=96.54, a*=0.19, b*=0.01) prepared for sample fixation were measured with spectrocolorimeter(Miniscan XE plus, Model 4000s, Hunter Lab, USA) by applying standard light source D65, C, Fcw, TL84 and A. Standardization was done with reference standard (X=80.8, Y=85.7, Z=90.8) and light trap. The results were as follows. 1. Different resins with same Vita shade showed recognizable color difference(DeltaE*>2). 2. All composites had MI below accepted value 0.5 between standard illuminant(D65, C, & A) and below 1.5 under fluorescent condition (Fcw & TL84). 3. MI value between D65 and A showed higher value than MI value between other source of light(p<0.01). 4. All resins except Z250 showed MI value that A3 is higher than A1 between D65 and A(p<0.05).
Barium Sulfate ; Composite Resins* ; Fungi ; Polytetrafluoroethylene

No abstract available.

The purpose of this study was to evaluate the effect of increasing application time of single bottle adhesives (SBA) to microtensile bond strength (MTBS) of dried dentin. To expose the superficial dentin surfaces, human molars were sectioned perpendicular to the long axis of tooth. 32% phosphoric acid gels were applied for 15s and rinsed. The teeth were randomly assigned to 3 groups ; S group (Single Bond), O group (One-Step), P group (Prime & Bond NT). Each group was divided to 3 subgroups (W: dentin wipe with wet gauge and light cured immediately, D: dentin dried for 30s and light cured immediately, 30: dentin dried for 30s and light cured after applying SBA for 30s). Composite resin was built up on the dentin surface and sectioned to obtain 20 specimens with 1 mm2 cross sectional area and the MTBS was measured. For Single Bond, the mean MTBS of S-W and S-30 group were higher than that of S-D group statistically (P < 0.05). For One-Step, the mean MTBS of O-D group was statistically lower than that of O-W group (P < 0.05). For Prime & Bond NT, the mean MTBS of P-30 group was statistically lower than that of P-D group (P < 0.05).
Adhesives* ; Axis, Cervical Vertebra ; Dentin* ; Gels ; Humans ; Molar ; Tooth

This study was conducted in order to assess whether the form of the shade guide affects in deciding the color of the teeth using the shade guide. Eight shade light cured composite resins (Esthet-X, Dentsply, Milford, USA) were used in this study. Shade guides including the model of maxillary central incisors, teeth-form shade guide, doughnut form shade guide, and shade guide with perforated gray shield were prepared with eight shade composite resins and provided the codes randomly. After arranging the models of teeth, 19 dentists working at the clinic of the Dentistry of Chonnam University Hospital and 65 students of college of dentistry, Chonnnam University selected the shade guides corresponding to the color of each tooth on the gray board under the D65 standard illuminant. B1 shade showed highest accuracy of about 95% among all shade guides of 3 forms applied to the test and regardless of observer, tooth form shade guide showed the highest accuracy (p < 0.05), and the doughnut form showed the lowest accuracy (p < 0.05). At the time of deciding on the color of the teeth using the shade guides as a result of above, the forms of the shade guides can affect the accuracy, and it suggests that the development of the diversified forms of shade guides, which may obtain more accurate results, is required.
Composite Resins ; Dentistry ; Dentists ; Humans ; Incisor ; Jeollanam-do ; Tooth

This study was done to evaluate the shear bond strength between light-cured glass ionomer cement (GIC) base and resin cement for luting indirect resin inlay and to observe bonding aspects which is produced at the interface between them by SEM. Two types of light cured GIC (Fuji II LC Improved, GC Co. Tokyo, Japan and Vitrebond(TM), 3M, Paul, Minnesota, U.S.A) were used in this study. For shear bond test, GIC specimens were made and immersed in 37degrees C distilled water for 1 hour, 24 hours, 1 week and 2 weeks. Eighty resin inlays were prepared with Artglass(R) (Heraeus Kultzer, Germany) and luted with Variolink(R) II (Ivoclar Vivadent, Liechtenstein). Shear bond strength of each specimen was measured and fractured surface were examined. Statistical analysis was done with one-way ANOVA. Twenty four extracted human third molars were selected and Class II cavities were prepared and GIC based at axiopulpal lineangle. The specimens were immersed in 37degrees C distilled water for 1 hour, 24 hours, 1 week and 2 weeks. And then the resin inlays were luted to prepared teeth. The specimens were sectioned vertically with low speed saw. The bonding aspect of the specimens were observed by SEM (JSM-5400(R), Jeol, Tokyo, Japan). There was no significant difference between the shear bond strength according to storage periods of light cured GIC base. And cohesive failure was mostly appeared in GIC. On scanning electron micrograph, about 30 - 120 microm of the gaps were observed on the interface between GIC base and dentin. No gaps were observed on the interface between GIC and resin inlay.
Dentin* ; Glass Ionomer Cements ; Glass* ; Humans ; Inlays* ; Japan ; Minnesota ; Molar, Third ; Resin Cements ; Tooth ; Water

This study was performed to assess the radiopacity of a variety of canal filling and retrograde root-end filling materials according to the specification concerning root canal obturation materials. Ten materials including Gutta-percha pellets, amalgam, Fuji II LC, Dyract(R) AP, Super EBA(R), IRM(R), AH 26(R), Sealapex(TM), Tubli-Seal(TM) and dentin were evaluated in this study. In the first part, densitometric reading of an each step of aluminum step wedge on occlusal film were performed at 60 kVp (0.2, 0.3, 0.4 s), 70 kVp (0.2, 0.3, 0.33 s) to decide appropriate voltage and exposure time. In the second part, ten specimens which are 5 mm in diameter and 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 mm in thickness, were fabricated from each material studied. The specimens were radiographed simultaneously with an aluminum step wedge under decided condition (60 kVp, 0.2 s). The mean radiographic density values of the materials were transformed into radiopacity expressed equivalent thickness of aluminum (mm Al). The following results were obtained. 1. Among the various conditions including 0.2 s, 0.3 s, 0.4 s at 60 kVp and 0.2 s, 0.3 s, 0.33 s at 70 kVp, the appropriate voltage and exposure time that meet the requirement of density from 0.5 to 2.0 was 0.2 s at 60 kVp. 2. All of the materials in this study had greater radiopacity than the minimun level recommended by ISO No. 4049 standards. 3. Most of the materials had greater radiopacity than 3 mm Al requirement of ANSI/ADA specification No. 57 (2000) and ISO No. 6876 (2001) standards except for Fuji II LC and Dyract. It suggests that all experimental canal filling and retrograde root-end filling materials have a sufficient radiopacity that meet the requirement concerning root canal obturation materials except for Fuji II LC and Dyract.
Aluminum ; Compomers ; Dentin ; Glass Ionomer Cements ; Gutta-Percha ; Resins, Synthetic ; Root Canal Obturation

The purpose of this study was to evaluate whether intracanal irrigation method could affect the adhesion between intracanal dentin and root canal filling materials (Gutta-percha/AH 26 sealer and Resilon/Epiphany sealer). Thirty extracted human incisor teeth were prepared. Canals were irrigated with three different irrigation methods as a final rinse and obturated with two different canal filling materials (G groups : Gutta-percha/AH 26 sealer, R groups : Resilon/Epiphany sealer) respectively. Group G1, R1 - irrigated with 5.25% NaOCl. Group G2, R2 - irrigated with 5.25% NaOCl, sterile saline. Group G3, R3 - irrigated with 5.25% NaOCl, 17% EDTA, sterile saline. Thirty obturated roots were horizontally sliced and push-out bond strength test was performed in the universal testing machine. After test, the failure patterns of the specimens were observed using Image-analyzing microscope. The results were as follows. 1. Gutta-percha/AH 26 sealer groups had significantly higher push-out bond strength compared with the Resilon/Epiphany sealer groups (p < 0.05). 2. Push-out bond strength was higher when using 17% EDTA followed by sterile saline than using NaOCl as a final irrigation solution in the Resilon/Epiphany sealer groups (p < 0.05). 3. In the failure pattern analysis, there was no cohesive failure in Group G1, G2, and R1. Gutta-percha/AH 26 sealer groups appeared to exhibit predominantly adhesive and mixed failure patterns, whereas Resilon/Epiphany sealer groups exhibited mixed failures with the cohesive failure occurred within the Resilon substrate.
Adhesives ; Collodion ; Dentin ; Edetic Acid ; Humans ; Incisor ; Root Canal Filling Materials ; Tooth

The purpose of this study was to compare the canal configuration after shaping by ProTaper rotary files and ProTaper hand files in resin simulated canals. Forty resin simulated canals with a curvature of J-shape and S-shape were divided into four groups by 10 blocks each. Simulated root canals in resin block were prepared by ProTaper rotary files and ProTaper hand files using a crown-down pressureless technique. All simulated canals were prepared up to size #25 file at end-point of preparation. Pre- and post-instrumentation images were recorded with color scanner. Assessment of canal shape was completed with an image analysis program. Measurements were made at 0, 1, 2, 3, 4, 5, 6 and 7 mm from the apex. At each level, outer canal width, inner canal width, total canal width, and amount of transportation from original axis were recorded. Instrumentation time was recorded. The data were analyzed statistically using independent t-test. The result was that ProTaper hand files cause significantly less canal transportation from original axis of canal body and maintain original canal configuration better than ProTaper rotary files, however ProTaper hand files take more shaping time.
Axis, Cervical Vertebra ; Dental Pulp Cavity ; Hand* ; Transportation

The purpose of this study was to assess the background color-interceptive ability and opacity of opaque shade composites (Universal composite, Filtek Z350, Charisma, Clearfil ST, Palpaque Estelite, Esthet-X, and Metafil Flo). Twenty four background specimens (diameter 5.5 mm, thickness 3.0 mm) with Root dentin Mustard (Bisco, Schaumburg, IL, USA) were made. The CIE L*a*b* value of background specimens was measured by a spectrophotometer (Spectrolino, GretagMacbeth, Regensdorf, Switzerland). Three specimens in every group were filled on the background specimens. The surface color of samples was measured by a spectrophotometer in 3.0 mm and every thickness to 0.5 mm while grinding. The color difference in the background color along with 3.0 mm specimen gauged the masking effect in each thickness while grinding and polishing. The opacity was calculated in 1 mm thick specimens. The opacity was in the decreasing order of Clearfil ST, Metafil Flo, Filtek Z350, Palpaque Estelite, Universal composite, Charisma, and Esthet-X (p < 0.05). As the thickness get reduced, L* value showed decreasing, a* increasing tendency. The surface color difference between pair of the 3.0 mm thick specimen and after grinding in same opaque resin was above 3.3 except Clearfil ST and Metafil Flo. The color difference (DeltaE*) between pair of background specimen and opaque resin builtup specimen showed more than 10.0 regardless kinds and thickness. The variance in opacity characteristics and color of the opaque composites is dependent upon manufacturer. When using the opaque resin, the optical properties of each material must be considered as well as cavity.
Composite Resins* ; Dentin ; Masks* ; Mustard Plant