Person: KARA, ÖZLEM
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Publication Metadata only Effect of Various Lasers on the Bond Strength of Two Zirconia Ceramics(2015-02-01) Kara, Ozlem; Kara, Haluk Baris; Tobi, Elif Sumeyye; Ozturk, Atiye Nilgun; Kilic, Hamdi Sukur; KARA, ÖZLEMObjective: The purpose of this study was to compare and evaluate the effects of various laser systems on surface roughness and shear bond strengths of zirconia ceramics. Material and methods: Seventy-two ceramic discs (10 mmx2 mm) obtained from two sintered zirconia ceramics (Zirkonzahn, Zirkonzahn Prettau((R))) were divided into two groups (n=36) according to the computer-aided design (CAD)-computer-aided manufacturing (CAM) technique and then further divided into three groups (n=12). Each group was treated with one of the following: (1) femtosecond (FS), (2) Nd:YAG (NY), and (3) Er:YAG (EY) lasers. After laser irradiation, a scanning electron micrograph (SEM) was taken at 500x magnification for qualitative examination. Following surface roughness measurement by profilometry, resin cement (Rely X U200) was bonded to the ceramic specimens using Teflon tubes (3 mm height, 4 mm diameter). Specimens were stored in distilled water at 37 degrees C for 24 h and then thermal cycled for 5000 cycles. A shear bond strength (MPa) test was performed using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed by two way analysis of variance (ANOVA) and Tukey honest significant difference (HSD) tests for pairwise comparisons among groups (p=0.05). Results: MPa and roughness were significantly affected by laser type (p0.05). In the SEM, the surfaces of the FS group were rougher than those of the NY and EY groups. NY and EY surfaces were nearly smooth. Conclusions: FS laser is an effective surface treatment for roughening surfaces of zirconia ceramics. Furthermore, it reveals the highest MPa.Publication Metadata only The effect of surface treatments on the bonding strength of ceramic inlays to dentin(2017-01-01) Kara, Ozlem; Ozturk, Atiye Nilgun; KARA, ÖZLEMAim: To compare and evaluate the effects of different surface treatments on surface roughness and the microtensile bonding strengths of four different ceramics to dentin. Methods: 160 human molar teeth were used. The teeth were divided into four groups (n=40). FC (Finesse), LC (IPS Empress Esthetics), LDC (IPS Empress e-Max) and MZC (Zirkonzahn Prettau) ceramic restorations were prepared. The specimens were divided into eight groups: (1) control, (2) air abrasion (AA), (3) HF acid etching (HF), (4) experimental hot etching (EHE), (5) Nd:YAG laser irradiation, (6) Nd:YAG laser+air abrasion, (7) Nd:YAG laser+HF acid, and (8) Nd:YAG laser+experimental hot etching. The surface roughness of the ceramics was determined with atomic force microscopy. After the cementation process, the specimens were thermal cycled and subjected to a microtensile bond strength (MBS) test. Two-way ANOVA and a Tukey-s test were used to analyse the surface roughness and MBS values of variance (p=0.05). Results: HF acid etching showed the highest surface roughness in FC (p<0.05). HF increased MBS in LC specimens where AA and HF increased MBS in LCD specimens. For the MZC specimens, AA and Nd:YAG+AA was effective in increasing the MBS (p<0.05). Conclusion: Different surface treatments must be applied to different ceramics to improve the mechanical retention and MBS.