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    The Effect of Different Surface Finishing Procedures on Surface Roughness and Fracture Toughness in All-Ceramic Restorations
    (WILEY, 2011) Yondem, Isa; Inan, Ozgur
    The aim of this study was to determine the effect of different surface treatments on the flexural strength of four different ceramic specimens. The four ceramic systems investigated in this study were lithium disilicate reinforced, zirconium oxide reinforced, glass-infiltrated alumina reinforced, and feldspathic ceramic. For the first group, grinding burs, for the second group polishing kit and for the third group glazing procedures were applied for surface treatment. Surface roughness, mean fracture toughness, and a SEM were used to describe surface features. The surface treatments affected the flexural strength and surface roughness of the ceramic systems evaluated.
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    Effect of finishing methods on surface roughness and color stability in all-ceramic systems
    (ELSEVIER SCIENCE BV, 2011) Yondem, Isa; Secilmis, Asli; Inan, Ozgur
    The objectives of the study were to evaluate the effect of the finishing methods on the surface roughness, and to investigate changes in CIE L*a*b* color coordinates of all-ceramic systems after different finishing methods and accelerated aging. Sixty specimens were prepared, 20 specimens each for Vitadur-N, IPS Empress II, and Cerec Vita Block Mark II. The surface roughness (Ra) following treatment with the different finishing methods was measured using a profilometer. Surface examinations in all groups were made by using a scanning electronic microscope. CIE L*a*b* values of the specimens were determined. After all specimens were subjected to accelerated aging, color measurements were repeated, and the total color differences (Delta E) were calculated. Data were analyzed statistically. Significant differences in surface roughness among all-ceramics were found (P < 0.05). No significant differences were found between the surface roughness of the glazed and polished all-ceramics (P > 0.05). After accelerated aging, all groups had acceptable color changes (Delta E < 2). (c) 2011 Elsevier B.V. All rights reserved.
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    Effect of surface treatment methods on the shear bond strength between resin cement and all-ceramic core materials
    (ELSEVIER, 2012) Yucel, Munir Tolga; Aykent, Filiz; Akman, Serhan; Yondem, Isa
    This study compared the influence of various surface treatments on the shear bond strength between resin cement and lithium disilicate glass-ceramics. A series of 120 lithium disilicate ceramic samples were prepared to compare the effect of different surface treatments on the shear strength of a luting cement bonded to two all-ceramic systems. IPS Empress 2 and IPS e.max Press ceramic samples were fabricated according to the manufacturer's instructions. The ceramic samples were divided into the following 6 surface treatment groups for each ceramic system: 1-no treatment (C), 2-airborne-particle abrasion (A), 3-acid etching (E), 4-airborne-particle abrasion + acid etching (AE), 5-Nd:YAG laser (L), 6-Nd:YAG laser + acid etching (LE). Resin cement was then bonded to the treated ceramic surfaces and light polymerized. The shear bond strengths of the specimens were measured using a universal testing machine. Two-way ANOVA and Tukey HSD (alpha=0.05) test were used to determine differences in shear bond strength between the groups. The ANOVA revealed significant differences between the treatment groups and ceramic types (p < 0.05). The shear bond strengths of IPS Empress 2 were significantly higher than those of IPS e.max Press. (C) 2012 Elsevier B.V. All rights reserved.
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    The effects of water flow rate on shear bond strength of self etch resin cement to dentin surface after Er, Cr: YSGG laser etching
    (TAYLOR & FRANCIS LTD, 2017) Kurt, Aysegul; Yilanci, Hilal; Yondem, Isa; Usumez, Aslihan
    The aim of the present study was to evaluate the effect of water flow rate on the morphological features of dentin and shear bond strength (SBS) of self-etching resin cement after Er, Cr: YSGG laser etching. Dentin specimens obtained from extracted human third molars were randomly assigned to four groups (n = 23), including one that received no laser irradiation (control-group D) and three others with different laser parameters: 2.25 W, 50 Hz, 60% air with water flow rates of 19 mL/min-100% water (group A), 2.25 W, 50 Hz, 6.75 mL/min-50% water (group B), and 2.25 W, and 50 Hz, 2.75 mL/min-25% water (group C). The morphological features of each group were examined with scanning electron microscopy and atomic force microscopy. The SBS of resin cement disks (Panavia F2.0, Kuraray; Tokyo, Japan) (3 mm in diameter and 2 mm in height) to the dentin specimens was measured using a universal testing machine at a cross head speed of 0.5 mm/min. Bond strength values were analyzed with one-way ANOVA/Tukey tests. There were no significant differences between the SBS values of groups A and B (p > 0.05). However, the SBS values of these groups were significantly higher when compared to groups C and D (p < 0.001). Er, Cr: YSGG laser application with water flow rates of 6.75 or 19 mL/min resulted in better dentin surface alterations and increased the SBS of self-etching resin cement to dentin.
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    Temperature rise under normal and caries-affected primary tooth dentin disks during polymerization of adhesives and resin-containing dental materials
    (JAPANESE SOC DENTAL MATERIALS DEVICES, 2008) Tosun, Gul; Usumez, Aslihan; Yondem, Isa; Sener, Yagmur
    The purpose of this study was to compare the temperature rise under normal and caries-affected primary tooth dentin during photopolymerization of two adhesives and resin-containing restorative materials. Caries-affected and normal dentin disks were prepared from extracted primary molars with only mesial or distal approximal caries (4 mm in diameter, 1 mm in height). Temperature rise during photopolymerization of adhesive materials was measured with a J-type thermocouple wire that was connected to a data logger. Data were analyzed with two-way ANOVA and independent samples t-test. Temperature rise under caries-affected primary tooth dentin disks was higher than that of normal primary tooth dentin disks during polymerization of both adhesive systems and resin-containing dental materials (p<0.05). It was found that adhesive systems induced a higher temperature rise during polymerization as compared to the resin-containing restorative materials (p<0.05). In particular, temperature rise during polymerization of adhesive materials exceeded 5.5 degrees C under caries-affected primary tooth dentin.