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Öğe Effect of EDTA and citric acid solutions on the microhardness and the roughness of human root canal dentin(ELSEVIER SCIENCE INC, 2005) Eldeniz, AU; Erdemir, A; Belli, SThe purpose of this study was to evaluate the effect of citric acid and EDTA solutions on the microhardness and the roughness of human root canal dentin. Forty-five human teeth sectioned longitudinally were used. Specimens were randomly divided into three groups of 30 teeth each and were treated as follows: (a) one molar (19%) citric acid (C6H8O7) for 150 s followed by 5.25% NaOCl; (b) 17% EDTA for 150 s and rinsed with 5.25% NaOCl; (c) rinsed with distilled water and served as control. Three groups were then divided into two subgroups of 15 specimens each. The specimens, in first subgroup were subjected to Vicker's testing whereas the second subgroup underwent surface roughness testing. The results were analyzed using one-way ANOVA and Tukey tests. Significant differences were observed in microhardness among the test groups, citric acid group being the least hard (p 0.05). Also, citric acid significantly increased surface roughness.Öğe Effect of gutta-percha solvents on mineral contents of human root dentin using ICP-AES technique(LIPPINCOTT WILLIAMS & WILKINS, 2004) Erdemir, A; Eldeniz, AU; Belli, SThe purpose of this in vitro study was to evaluate the mineral contents of root-canal dentin before and after treatment with two commonly used gutta-percha solvents: chloroform and halothane. Twenty extracted human premolars, whose crowns and apical thirds had been removed, were used. Pulp tissues were removed and the teeth were randomly divided into two groups including 10 teeth each. Root canals were enlarged with Gates Glidden burs (#1, 2, and 3). Dentin chips were obtained and saved in plates to serve as a control. Root-canal-dentin walls were then treated with chloroform or halothane for 15 min. Dentin chips were again obtained using Gates Glidden burs (#4, 5, and 6). The levels of five elements, calcium, phosphorus, magnesium, potassium, and sulfur, in each specimen were analyzed using ICP-AES (inductively coupled plasma atomic emission spectrometry) technique. Changes in the levels of the chemical elements were recorded. Differences between the groups were statistically analyzed using Mann-Whitney U test. There was a significant decrease in Ca level and significant increase in Mg level after treatment with halothane (p < 0.05). There was a significant increase in Mg level after treatment with chloroform. The changes in other elements levels after treatment with gutta-percha solvents were minimal and statistically not significant (p > 0.05). As a result it was concluded that gutta-percha solvents have effect on mineral contents of root dentin.Öğe Effect of solvents on bonding to root canal dentin(LIPPINCOTT WILLIAMS & WILKINS, 2004) Erdemir, A; Eldeniz, AU; Belli, S; Pashley, DHThe long-term success of resin cementation of post/cores is likely increased with improvement in resin-root canal dentin bonding. The adverse effect of some irrigation constituents (NaOCl, H2O2) or medications (eugenol) on the bond strengths of resins to dentin have been reported. The purpose of this in vitro study was to evaluate the effect of two gutta-percha solvents (chloroform versus halothane) on microtensile bond strength to root canal dentin. Thirty, extracted, human, single-rooted teeth were instrumented to a #70 file and randomly divided into 3 groups of 10 each. The root canals were treated with water, chloroform, or halothane for 60 s. All root canals were obturated using C&B Metabond. After 24 h of storage in distilled water, serial 1-mm-thick cross-sections were cut and trimmed. Microtensile bond strength to apical, middle, and coronal root canal dentin were measured using an Instron machine. Using pooled data, the results indicated that water-treated roots had significantly higher resin-dentin bond strengths compared with chloroform or halothane treatment groups (control: 23.9 MPa; chloroform: 18.3 MPa; halothane: 17 MPa; p < 0.05). Gutta-percha solvents have an adverse effect on bond strengths of adhesive cements to root canal dentin.Öğe Effect of the gutta-percha solvents on the microhardness and the roughness of human root dentine(WILEY, 2004) Erdemir, A; Eldeniz, AU; Belli, SThe purpose of this in vitro study was to evaluate the effect of gutta-percha solvents on the microhardness and the roughness of human root dentine. Forty-five recently extracted human mandibular anterior teeth were used. The teeth were sectioned longitudinally, embedded in acrylic resin and polished. Ninety specimens were divided into three groups containing 30 teeth each. In group 1, the specimens were treated with chloroform for 15 min. In group 2, the specimens were treated with halothane for 15 min. In group 3, distilled water was used and this group was served as control. All groups were then divided into two subgroups of 15 specimens each. The specimens, in groups 1a, 2a and 3a, were submitted to Vicker's microhardness indentations. Groups 1b, 2b and 3b were used for determination of the roughness of root dentine. The data were recorded as Vicker's numbers and Ra, mum for roughness test. The results were then analysed by one-way ANOVA and post hoc Tukey tests. The results indicated that chloroform and halothane did not affect the microhardness and the roughness of root dentine (P > 0.05).Öğe Pulpal temperature rise during light-activated bleaching(WILEY, 2005) Eldeniz, AU; Usumez, A; Usumez, S; Ozturk, NThe purpose of this study was to measure intrapulpal temperature rise induced by two kinds of bleaching gels when the tooth was exposed to a variety of light-curing units and a diode laser in vitro. The root portions of 80 extracted intact human maxillary central incisors were sectioned with a carborundum disk approximately 2 mm below the cementoenamel junction perpendicular to the long axis of the teeth. Two bleaching agents containing heat-enhancing colorant was applied to the labial surface. Light-curing units used were a conventional halogen (40 s), a high-intensity halogen (30 s), a light-emitting diode unit (40 s), and a diode laser (15 s). The temperature rise was measured in the pulpal chamber with a J-type thermocouple wire that was connected to a data logger. Ten specimens were used for each system and bleaching-agent combination. Differences between the starting temperature and highest temperature reading were taken and the calculated temperature changes were averaged to determine the mean value in temperature rise. Temperature rise values were compared using two-way analysis of variance (ANOVA) at a preset a of 0.05. Temperature rise varied significantly depending on curing unit and diode laser used. The diode laser induced significantly higher temperature increases than any other curing unit (11.7degreesC). The light-emitting diode unit produced the lowest temperature changes (6.0degreesC); however, there were no statistically significant differences among the curing units and there were no statistically significant differences between bleaching agents. Light activation of bleaching materials with diode laser caused higher temperature changes as compared to other curing units and the temperature rise detected was viewed as critical for pulpal health. (C) 2004 Wiley Periodicals, Inc.Öğe Shear bond strength of three resin based sealers to dentin with and without the smear layer(ELSEVIER SCIENCE INC, 2005) Eldeniz, AU; Erdemir, A; Belli, SBond strength of root canal sealers to dentin is an important property for the integrity of the sealings of root-canals. The purpose of this study was to test shear bond strength of three endodontic sealers (Diaket, AH Plus and Endo-REZ). The coronal two thirds of ninety extracted human third molars were removed. The smear layer of the exposed dentin surfaces were removed using 17% EDTA followed by 5.25% NaOCl and the teeth were randomly divided into two groups (n = 45). Group 1 was kept as control and in group 2, uniform smear layer was created using waterproof polishing papers. Three-mm long sections of polyethylene tubing were filled with freshly mixed sealer and placed on the dentin surfaces for conducting a shear bond strength test. The data was calculated as MPa and was statistically analyzed using a two way ANOVA, Kruskal-Wallis and Mann-Whitney U tests. A significant difference was found among the bond strength of the sealers, smear layer, and control groups. AH Plus sealer showed the highest bond strength in smear layer removed surfaces (p < 0.05). Pretreatment with EDTA/NaOCl affected bond strength of AH Plus. AH Plus had the highest bond to dentin with or without smear layer.Öğe Thermal changes in the pulp chamber during different adhesive clean-up procedures(E H ANGLE EDUCATION RESEARCH FOUNDATION, INC, 2005) Uysal, T; Eldeniz, AU; Usumez, S; Usumez, AThe aim of this in vitro study was to measure the temperature changes in the pulpal chamber when different adhesive clean-up procedures were used. Ninety intact extracted human maxillary central incisors were used in the study. The teeth were divided into six groups of 15 teeth each. The removal of the remaining composite on the tooth surface was performed with a tungsten carbide bur. The residual adhesive was removed using a high-speed handpiece with and without water cooling and a contra-angle handpiece with and without water cooling at high and low speeds. A J-type thermocouple wire was positioned in the center of the pulp chamber. The results were analyzed with analysis of variance (ANOVA) and the Tukey-honestly significant difference test. Two-factor ANOVA revealed significant interaction between the handpiece type and water cooling. In this study, the high-speed contra-angle handpiece without water cooling group had the highest Delta T values (7.58 degrees C +/- 1.84 degrees C) among all the clean-up procedures. The decrease in pulpal temperature with water cooling was -5.34 degrees C for the handpiece, -5.36 degrees C for the lowspeed contra-angle handpiece and -4.98 degrees C for the high-speed contra-angle handpiece. Clinicians should be aware of the potential thermal damage to the pulp, which may result from long clean-up procedures without water cooling. Adhesive removal procedures should be performed with adequate water cooling to prevent temperature increases that might be harmful to pulpal tissues.
