Browsing by Author "Oglakci, Burcu"

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    How Does Radiotherapy Affect the Adhesion of Universal Adhesive to Enamel and Dentin? A Qualitative and Quantitative Analysis?
    (2022) Oglakci, Burcu; Burduroglu, Defne; Eri, Ali Hikmet; Mayadagli, Alpaslan; Arhun, Neslihan
    This study investigated the shear bond strength (SBS) of a universal adhesive to enamel/dentin; 1) that had undergone radiotherapy (RT) and 2) that were readily restored and had undergone RT. Enamel and dentin surfaces were obtained from 90 intact human molars. They were randomly divided into six groups according to the presence and timing of irradiation (RTO:no radiotherapy/control, RT1:RT before restoration, RT2:RT after restoration groups) and adhesive application modes (etch&rinse/ER, self-etch/SE)(n=15). A universal adhesive and resin composites were applied. The radiotherapy protocol was conducted with 60 Gy. The SBS test was subjected (1mm/min) and failure type analysis was performed. The resin-enamel/ dentin interfaces were examined. Data were statistically analyzed. For enamel and dentin, the presence and timing of irradiation did not significantly influence the SBS values (p>0.05). For enamel, significantly higher SBS values were obtained using etch&rinse mode than self-etch mode (p<0.05). The predominant failure was mixed type. Loss of enamel prisms and obliterated irregular dentinal tubules were found for the radiotherapy-treated specimens. Resin tags were clearer in the irradiated enamel treated with ER than SE. Irradiation with different timings did not influence the bond strength to enamel and dentin, negatively. Irrespective of radiotherapy, the etch&rinse mode caused higher bond strength to enamel than self-etch mode.
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    The shear bond strength of repaired high-viscosity bulk-fill resin composites with different adhesive systems and resin composite types
    (2019) Oglakci, Burcu; Arhun, Neslihan; 0000-0002-6587-5997
    This study compared the effect of different adhesive systems and composite resins on the shear bond strength (SBS) of repaired high-viscosity bulk-fill composites(Tetric EvoCeram Bulk Fill) and investigated failure modes. One hundred twenty cylindrical bulk-fill composite blocks (diameter 5 mm) were fabricated and thermocycled for 5000 cycles (5-55 degrees C). Specimens were roughened by diamond bur and divided into 8 groups (n = 15). Bulk-fill blocks were repaired with the same material or nanohybrid composite resin(Tetric EvoCeram Nanohybrid) (diameter 3 mm) using different adhesive systems:Tetric N-Bond Universal (TSE);37% phosphoric acid etching + Tetric N-Bond Universal (TER); Clearfil SE Bond (CSE); 37% phosphoric acid etching + AdperSingle Bond 2(SB). After repair procedures, all specimens were thermocycled again. The shear bond strengths were measured for all specimens using a universal test machine (crosshead speed of 1 mm/min). Cohesive strengths of bulk-fill composites were measured and described as control group. Debonded surfaces were observed with a stereomicroscope under 10x magnification to determine mode of failure. The SBS data of all groups was statistically analyzed by two-way ANOVA and Bonferroni correction test (p < 0.05). The specimens repaired with bulk-fill composites showed significantly higher SBS values (25.86 +/- 5.74, 27.05 +/- 4.93, 24.49 +/- 6.95MPa) than those with nanohybrid composites (20.41 +/- 3.70, 22.08 +/- 6.37, 18.74 +/- 6.40 MPa) for TER,CSE,SB, respectively (p < 0.05). There were no significant differences in SBS according to the type of adhesive systems for both repair materials (p > 0.05). The predominant mode of failure was a mixed type in the restorative material except for the ones repaired with nanohybrid composites using AdperSingle Bond 2. High-viscosity bulk-fill composites could be successfully repaired with the same materials. SBS of repaired bulk-fill composites reached cohesive strength for all tested groups.