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Öğe Bond Strength of Porcelain Bonded to Enamel and Dentin Surfaces Prepared with Different Surface Treatments(TAYLOR & FRANCIS LTD, 2015) Dilber, Erhan; Ozturk, A. NilgunAlthough acid etching is routinely used to condition tooth surfaces, it increases the caries susceptibility of enamel and enhances enamel demineralization; thus the role of alternative surface treatments such as alumina air abrasion and erbium-doped yttrium aluminium garnet (Er: YAG) laser irradiation for tooth conditioning is controversial. This study was undertaken to compare the effects of different conditioning methods on the shear bond strength (SBS) of resin cement on enamel and dentin. Prepared permanent human dentin and enamel samples (N = 210) embedded in clear acrylic resin were conditioned by 37% phosphoric acid etching, 50-mu m alumina air abrasion, Er: YAG laser irradiation (120 mJ, 10 Hz, medium short pulse mode), or their combinations. Porcelain laminates were cemented by using photo-polymerizing luting composite. SBS was evaluated after thermal cycling (10,000 cycles, 5-55 degrees C) and fracture types (adhesive, cohesive, or mixed) were observed by stereomicroscopy. Data were analyzed by Kruskal-Wallis analysis of variance and followed by Tamhane's test (p < 0.05). Enamel and dentin specimens showed significant differences in SBS (p < 0.000). Er: YAG laser etching presents successful alternatives to acid etching on dentin surfaces; it does not enhance adhesion of the resin cement on enamel surfaces.Öğe Bond strengths of two ceramic laminate systems to bleached enamel(MANEY PUBLISHING, 2011) Ozturk, A. Nilgun; Ozturk, B.; Malkoc, M. Arslan; Buyukozer, T.The aim of this study was to evaluate the microtensile bond strengths of ceramic laminate veneers bonded to bleached and non-bleached enamel. Ninety-six extracted maxillary central incisors were divided into two groups of 48 specimens each, bleached group and non-bleached group. After bleaching, teeth were prepared to accommodate veneers of equal thickness. Two ceramic systems, Cerec 3 and IPS Empress 2, were used for restoration. Each of the two ceramic groups was luted with Variolink 2 and RelyX veneer cement. Specimens were then subjected to tensile forces. The bond strength values were analysed with two-way analysis of variance and Tukey honestly significant difference tests. Microtensile bond strength significantly reduced after bleaching procedure (p < 0.05). Variolink 2 resin cement showed higher bonding strength than RelyX veneer cement (p < 0.05). The results of this in vitro study suggest that the bleaching procedure is an important factor on the bonding effectiveness of ceramic laminate veneers.Öğe Comparison of the Effects of Surface Treatments on Roughness of Two Ceramic Systems(MARY ANN LIEBERT, INC, 2012) Dilber, Erhan; Yavuz, Tevfik; Kara, Haluk Baris; Ozturk, A. NilgunObjective: The aim of this study was to evaluate the effects of different surface treatments on the surface roughness of lithium disilicate-based core (IPS Empress 2, shade 210, Ivoclar Vivadent, Schaan, Liechtenstein) and feldspathic ceramics (Vita VM9, VITA Zahnfabrik H. Rauter GmbH & Co. KG, Bad Sackingen, Germany). Background data: Er:YAG laser irradiation is expected to be an alternative surface treatment, thus enhances surface roughness of procelains and produces morphological changes. Methods: Fifty lithium disilicate-based core ceramic discs and 50 feldspathic ceramic discs were prepared (diameter, 10 mm; thickness, 1 mm) according to the manufacturers' instructions. All-ceramic discs were polished to standardize, and surface roughness of the discs was evaluated before treatment and serving as controls. Both of two ceramic groups were divided into five groups (n = 10), and the following treatments were applied: (1) sandblasting with aluminum oxide (Al2O3; Group SB); (2) Al2O3 + Er:YAG laser (Group SB-L); (3) Er:YAG laser irradiation (distance, 1 mm; 500 mJ; 20 Hz; 10W; manually, contact handpiece [R 14]) (Group L); (4) 5% hydrofluoric acid etching (Group HF); and (5) Er: YAG laser + 5% hydrofluoric acid (Group HF-L). Surface roughness was evaluated by profilometry, and specimens were then examined with atomic force microscopy. Results: Data were analyzed by Wilcoxon signed rank, Mann-Whitney U, and Kruskal-Wallis tests (alpha = 0.05). The Wilcoxon signed rank test results indicated that surface roughness after sandblasting was significantly different from the surface roughness after laser irradiation and acid etching (p < 0.001). Mann-Whitney U and Kruskal-Wallis test results indicated that groups SB and SB-L had significantly higher mean roughness values (p < 0.05) than those in the other groups. Conclusions: Groups SB and SB-L had rougher surfaces than the groups subjected to the other surface treatment methods. There was no significant difference in surface roughness between the HF acid etching, Er:YAG laser irradiation, and HF and Er:YAG (p < 0.05).Öğe Effect of different surface treatments on roughness of IPS Empress 2 ceramic(SPRINGER LONDON LTD, 2012) Kara, Haluk Baris; Dilber, Erhan; Koc, Ozlem; Ozturk, A. Nilgun; Bulbul, MehmetThe aim of this study was to evaluate the influence of different surface treatments (air abrasion, acid etching, laser irradiation) on the surface roughness of a lithium-disilicate-based core ceramic. A total of 40 discs of lithium disilicate-based core ceramic (IPS Empress 2; Ivoclar Vivadent, Schaan, Liechtenstein) were prepared (10 mm in diameter and 1 mm in thickness) according to the manufacturer's instructions. Specimens were divided into four groups (n = 10), and the following treatments were applied: air abrasion with alumina particles (50 mu m), acid etching with 5% hydrofluoric acid, Nd:YAG laser irradiation (1 mm distance, 100 mJ, 20 Hz, 2 W) and Er:YAG laser irradiation (1 mm distance, 500 mJ, 20 Hz, 10 W). Following determination of surface roughness (R-a) by profilometry, specimens were examined with atomic force microscopy. The data were analysed by one-way analysis of variance (ANOVA) and Tukey HSD test (alpha = 0.05). One-way ANOVA indicated that surface roughness following air abrasion was significantly different from the surface roughness following laser irradiation and acid etching (P < 0.001). The Tukey HSD test indicated that the air abrasion group had a significantly higher mean value of roughness (P < 0.05) than the other groups. No significant difference was found between the acid etching and laser irradiation (both Er:YAG and Nd:YAG) groups (P > 0.05). Air abrasion increased surface roughness of lithium disilicate-based core ceramic surfaces more effectively than acid-etching and laser irradiation.Öğe The effect of different surface treatments on roughnessand bond strength in low fusing ceramics(SPRINGER LONDON LTD, 2011) Kara, Haluk Baris; Ozturk, A. Nilgun; Aykent, Filiz; Koc, Ozlem; Ozturk, BoraThe aim of this study was to evaluate the influence of different surface treatments (air abrasion, acid etching, and laser irradiation) on the surface roughness and bond strength of a low fusing ceramic. Thirty-six discs of low fusing ceramic (Finesse, Ceramco) were prepared (10 mm in diameter and 2 mm in thickness) according to the manufacturer's instructions. Specimens were divided into three groups (n = 12), and the following treatments were performed: Air abrasion with alumina particles (50 mu m), acid etching with 5% HF and Nd:YAG laser irradiation (distance: 1 mm, 100 mJ, 20 Hz, 2 W, and 141.54 J/cm(2)). Following determination of surface roughness (R-a) by profilometry, specimens were examined with scanning electron microscopy (SEM). The luting cement (Clearfil Esthetic Cement) was bonded to the ceramic specimens using Teflon tubes. After 24 h of water storage, shear bond strength test was performed using a universal testing machine at a crosshead speed of 1 mm/min. The data were analyzed with two-way analysis of variance (ANOVA) and Tukey HSD tests (alpha = .05). Two-way ANOVA indicated that surface roughness was significantly affected by surface treatments (p < .001). Tukey honestly significant difference (HSD) indicated that the air abrasion group had a significantly higher mean value (p < .05) than the other groups. Shear bond strength was significantly affected by surface treatments (p < .001). Tukey HSD indicated that the air abrasion group had a significantly higher mean value (p < .05) than the other groups. No significant difference was found between the acid-etching and laser-irradiation groups (p > .05). The SEM image of the laser irradiation surface appeared to be relatively smooth as compared to the images of other the groups. Air abrasion of low-fusing porcelain surfaces was effective in improving the bond strength as compared to the acid-etching and laser-irradiation methods.Öğe Effect of Different Surface Treatments on the Bond Strength of Lithium Disilicate Ceramic to the Zirconia Core(MARY ANN LIEBERT, INC, 2016) Yilmaz-Savas, Tuba; Demir, Necla; Ozturk, A. Nilgun; Kilic, Hamdi SukurObjective:The aim of this study was to evaluate the effect of different surface treatments [sandblasting, Erbium:Yttrium-Aluminium-Garnet (Er:YAG), and femtosecond lasers] on the shear bond strength (SBS) of the CAD-on technique. Background data:Although demand for all-ceramic restorations has increased, chipping remains one of the major problems for zirconia-based restorations. Materials and methods:Forty yttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) zirconia plates (IPS e.max ZirCAD, Ivoclar Vivadent) were cut, sintered (12.4 x 11.4 x 3 mm) and divided into four groups according to the surface treatments (n = 10): a control group with no surface treatment (Group C), sandblasting with 50 mu m Al2O3 (Group S), Er:YAG laser irradiation (Group E), and femtosecond laser irradiation (Group F). Also, 40 cylindrical (5mm diameter, 2mm height) lithium disilicate (IPS e.max CAD) veneer ceramics were cut and fused to all zirconia cores by a glassfusion ceramic and crystallized according to the CAD-on technique. Specimens were subjected to shear force using a universal testing machine. The load was applied at a crosshead speed of 0.5 mm/min until failure. Mean SBS (MPa) were analyzed with one way ANOVA (p < 0.05). The failed specimens were examined under a stereomicroscope at x 20 to classify the mode of failure. Results:The highest SBS was observed in Group F (36 +/- 3.31 MPa), followed by Group S (33.03 +/- 5.05 MPa), and Group C (32.52 +/- 10.15 MPa). The lowest SBS was observed in Group E (31.02 +/- 4.96 MPa), but no significant differences were found between the control and surface treated groups (p = 0.377). All the specimens showed a mixed type of failure. Conclusions: Femtosecond laser application increased the bond strength between zirconia-veneer specimens. However, the novel CAD-on technique with no surface treatment also showed high bonding strength. Thus, this technique could prevent ceramic chipping without additional surface treatments.Öğe Effects of different surface treatments on shear bond strength in two different ceramic systems(SPRINGER LONDON LTD, 2013) Yavuz, Tevfik; Dilber, Erhan; Kara, Haluk Baris; Tuncdemir, Ali Riza; Ozturk, A. NilgunThe purpose of this study was to evaluate the influence of different surface treatments (sandblasting, acid etching, and laser irradiation) on the shear bond strength of lithium disilicate-based core (IPS Empress 2) and feldspathic ceramics (VITA VM 9). One hundred ceramic discs were divided into two groups of 50 discs each for two ceramic systems: IPS Empress 2 (group I) and VITA VM 9 (group II). Each of the two groups was further divided into five surface treatment groups (ten each) as follows: group SB, sandblasting with alumina particles (50 mu m); group HF, 5 % hydrofluoric acid etching; group L, Er:YAG laser irradiation (distance, 1 mm; 500 mJ; 20 Hz; 10 W; manually, noncontact R14 handpiece); group SB-L, sandblasting + Er:YAG laser; and group HF-L, 5 % hydrofluoric acid + Er:YAG laser. Luting cement (Panavia 2.0) was bonded to the ceramic specimens using Teflon tubes. After 24 h of water storage, a shear bond strength test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min. The data were analyzed with a two-way analysis of variance (ANOVA) and Tukey's honestly significant difference tests (alpha = 0.05). The two-way ANOVA indicated that the shear bond strength was significantly affected by the surface treatment methods (p < 0.05), but there was no significant interaction between the ceramic systems. Group SB-L had the highest mean values for each ceramic system. Sandblasting, followed by Er:YAG laser irradiation, enhanced the bond strength, indicating its potential use as an alternative method. The atomic force microscopic evaluation revealed that group SB had the most distinct sharp peaks among the groups.Öğe Effects of laser and acid etching and air abrasion on mineral content of dentin(SPRINGER LONDON LTD, 2011) Malkoc, Meral Arslan; Tasdemir, Serife Tuba; Ozturk, A. Nilgun; Ozturk, Bora; Berk, GizemThe aim of this study was to evaluate the mineral content of dentin prepared using an Er,Cr:YSGG laser at four different power settings, acid etching, and air abrasion. The study teeth comprised 35 molars which were randomly divided into seven equal groups. The occlusal third of the crowns were cut with a slow-speed diamond saw. The groups were as follows: group A, control group; group B, dentin etched with 35% buffered phosphoric acid for 30 s; group C, dentin abraded at 60 psi with 50-A mu m aluminium oxide for 1 s; groups D-G, dentin irradiated with the Er,Cr:YSGG laser at 1.50 W (group D), 2.25 W (group E), 3.00 W (group F), and 3.50 W (group G). The levels of Mg, P, Ca, K and Na in each dentin slab were measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Data were analysed by one way analysis of variance and Tukey HSD tests. There were no significant differences between the groups in the levels of Ca, P and Na, and the Ca/P ratio (p > 0.05); however, there were significant differences in the levels of K (p < 0.001) and Mg (p=0.13). In addition, the levels of Mg in the air abrasion group were higher than in the other groups (p < 0.01). Etching with the Er,Cr:YSGG laser system, air abrasion and acid etching did not affect the levels of Ca, P and Na, or the Ca/P ratio, in the dentin surface.Öğe Mechanical properties of zirconia after different surface treatments and repeated firings(KOREAN ACAD PROSTHODONTICS, 2014) Subasi, Meryem Gulce; Demir, Necla; Kara, Ozlem; Ozturk, A. Nilgun; Ozel, FarukPURPOSE. This study investigated the influence of surface conditioning procedures and repeated firings on monoclinic content and strength of zirconia before cementation. MATERIALS AND METHODS. Sintered bar-shaped zirconia specimens were subjected to no surface treatment (control), air abrasion, Or grinding (n=21). Their roughness was evaluated using a profilometer, and microscope analysis was performed on one specimen of each group. Then, 2 or 10 repeated firings (n=10) were executed, the monoclinic content of specimens was analyzed by X-ray diffraction, and a three-point flexural strength test was performed. Surface roughness values were compared using one-way analysis of variance (ANOVA) and Tukey honestly significant difference (HSD) tests, the monoclinic content values were tested using Kruskal-Wallis and Mahn-Whitney U tests, and the flexural strength values were tested using two-way ANOVA and Tukey HSD tests (P=.05). Spearman's correlation test was performed to define relationships among measured parameters. RESULTS. Surface-treated specimens were rougher than untreated specimens and had a higher monoclinic content (P<.005), and the relationship between roughness and monoclinic content was significant (P<.000). Neither surface treatment nor firing significantly affected the flexural strength, but Weibull analysis showed that for the air-abraded samples the characteristic strength was significantly. lower after the 10th firing than after. the 2nd firing. CONCLUSION. After firing, a negligible amount of monoclinic content remained on the zirconia surfaces, and rougher surfaces had higher monoclinic contents than untreated surfaces. Multiple firings Could be performed if necessary, but the fracture probability could increase after multiple firings for rougher surfaces.Öğe MICROLEAKAGE OF CERAMIC INLAYS LUTED WITH DIFFERENT RESIN CEMENTS AND DENTIN ADHESIVES(MOSBY-ELSEVIER, 2009) Uludag, Bulent; Ozturk, Ozge; Ozturk, A. NilgunStatement of problem. Despite recent advances in adhesive dentistry, resin cement/dentin adhesive combinations are not able to prevent microleakage in ceramic inlays. Marginal quality of tooth-colored restorations in large Class 11 cavities is satisfactory in enamel margins, but microleakage in dentin margins remains a concern. Purpose. The purpose of this study was to evaluate the microleakage of all-ceramic inlays luted with 2 dual-polymerizing resin cements or 1 auto polymerizing resin cement in combination with different dentin adhesives. Material and methods. One hundred and twenty extracted human mandibular third molars were used in this study. Teeth were prepared to receive Class 11 MOD inlays with enamel gingival margins on 1 proximal surface and dentin gingival margins on the other surface. One hundred and twenty prepared teeth were divided into 3 groups of 40; 1 group for each resin cement: RelyX ARC, Variolink 11, or Panavia 21. Each of the 3 groups were further divided into 4 dentin adhesive groups; Single Bond, ExciTE DSC, ED Primer, or Admira Bond. Each of the resin cements were used in combination with the 4 dentin adhesives, and IPS Empress ceramic inlays were placed with 12 different cement/adhesive combinations. After 1000 thermal cycles In a 5 degrees-55 degrees C water bath with a dwell time of 30 seconds, all specimens were subjected to cyclic axial mechanical loading. Then the restored teeth were stored in 0.5% basic fuchsin solution for 24 hours. The extent of dye penetration along the margins was measured with a stereomicroscope at x40 magnification. The data were evaluated statistically using repeated-measures ANOVA and Duncan tests (alpha=.05). Results. Microleakage at dentin margins was greater than that at enamel margins (P<.05) for all groups. Variolink 11 and RelyX ARC resin cements showed significantly lower microleakage results than Panavia 21 with all dentin adhesives in enamel margins. For dentin margins, Variolink II/Admira Bond combination showed the lowest microleakage value in dentin (P<.05). Conclusions. The overall microleakage at the enamel margins was significantly less than at the dentin margins (P<.05). Panavia 21 showed higher microleakage values than Variolink 11 and RelyX ARC in enamel margins. (J Prosthet Dent 2009;102:235-241)Öğe Surface Roughness and Morphologic Changes of Zirconia Following Different Surface Treatments(MARY ANN LIEBERT, INC, 2012) Demir, Necla; Subasi, M. Gulce; Ozturk, A. NilgunObjective: The aim of this study was to evaluate the roughness and morphology of zirconia after air abrasion and erbium:yttrium-aluminum-garnet (Er:YAG) laser application of different intensities. Background data: Although surface roughness is important to obtain micromechanical retention, it is unclear which surface treatment is most appropriate for zirconia. Methods: Fifty sintered zirconia specimens were divided into five groups (n = 10). The following treatments were applied: control, Er:YAG laser irradiation with different energy intensities (200, 300, and 400 mJ), and air abrasion with aluminum oxide (Al2O3) particles (110 mu m). Morphologic changes after surface treatments were examined in microscope analyses. Then, the surface roughness (Ra in mu m) of the specimens was evaluated using a surface texture measuring instrument. Roughness data were analyzed using one-way analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) test (p = 0.05). Results: Results of microscope analyses revealed changes in surface morphology after surface treatments, including the formation of rare pits in the 400 mJ laser group and the formation of microretentive grooves in the air abrasion group. According to the results of the statistical analysis, the mean surface roughness value for the air abrasion group was significantly higher than that of the other groups (p < 0.001). Except for the air abrasion group, there were no statistically significant differences within other groups (p > 0.05). Conclusions: According to the results of the statistical and microscopic analyses, 400 mJ Er: YAG laser energy or air abrasion can be used to obtain micromechanical retention prior to luting; however, air abrasion is the most effective surface treatment method.
