Diş Hekimliği Fakültesi / Faculty of Dentistry
Permanent URI for this collectionhttps://hdl.handle.net/11727/2120
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Item Effect of Biodentine on Secondary Caries Formation: An in Vitro Study(2016) Ozgul, Betul Memis; Tirali, R. Ebru; Cehreli, S. Burcak; https://orcid.org/0000-0001-6487-3984; 27295863; AAZ-1977-2021; AAD-2907-2020; AAD-6138-2021Purpose: To compare the effects of two materials, Biodentine and conventional glass-ionomer cement (CGIC), on secondary caries formation around restorations when used as a dentin replacement material. Methods: 30 approximal cavities were prepared on mesial and distal surfaces of 15 caries-free human premolar teeth extracted for orthodontic or periodontal reasons. Cavities were filled with A: Biodentine as a base + Filtek Z250 composite (n = 15) or B: CGIC as a base + Filtek Z250 composite (n= 15). The materials were applied according to the manufacturers' instructions. Teeth were thermocycled, and placed in a demineralizing solution for 5 weeks. Secondary caries formation was assessed using the International Caries Detection and Assessment System (ICDAS) II and quantitative computer aided image measurement of caries depth. Results: The computer-aided measurements showed that the Biodentine group had significantly lower lesion depth measurements than the CGIC group (P = 0.004). However, there was no significant difference among the groups based on the ICDAS II scores (P > 0.05).Item Effect of Fabrication Stages and Cementation on The Marginal Fit of CAD-CAM Monolithic Zirconia Crowns(2017) Kale, Ediz; Yilmaz, Burak; Seker, Emre; Ozcelik, Tuncer Burak; 28434679Statement of problem. Monolithic zirconia crowns fabricated using computer-aided design and computer-aided manufacturing (CAD-CAM) technology have recently become an alternative dental prosthetic treatment. The marginal fit of monolithic zirconia crown may be affected by different stages of the fabrication procedures in the laboratory and cementation. Information regarding the accuracy of fit of monolithic zirconia crowns at different stages of fabrication and cementation is limited. Purpose. The purpose of this in vitro study was to evaluate the effect of different stages of fabrication and cementation on the vertical marginal discrepancy (VMD) of CAD-CAM fabricated monolithic zirconia crowns. Material and methods. Six ivorine right maxillary first molar typodont teeth with standardized anatomic preparations for complete coverage ceramic crowns were scanned with a 3-dimensional laboratory scanner. Crowns were designed using CAD software and milled from presintered monolithic zirconia blocks in a 5-axis dental milling machine. A cement space of 25 pm for the margins and a 50-gm space starting 1 mm above the finish lines of the teeth were virtually set in the CAD software. A total of 144 measurements were performed on 6 specimens with 8 measurement locations in 3 different stages using stereoscopic zoom microscopy; after initial production of the crowns (post-sintering group), after glazing (post-glazing group), and after cementation (post-cementation group). The VMD values were statistically analyzed with 1-way repeated measures ANOVA and the Holm-Sidak method (alpha=.05). Results. Different stages of fabrication and cementation significantly affected the VMD of tested crowns (P=.003). The mean VMD was 38 gm for post-sintering group, 38 pm for post-glazing group, and 60 mu m for post-cementation group, with statistical differences between the post-sintering group, the post-cementation group (P<.002), and the post-glazing group and post-cementation group (P<.003); there were no statistical differences between the post-sintering group and the post-glazing group (P=.966). Conclusions. Within the limitations of this in vitro study, glazing did not significantly change the VMD of CAD-CAM monolithic zirconia crowns. Cementation significantly increased the VMD values.Item Effect of Metal Opaquer on The Final Color of 3 Ceramic Crown Types on 3 Abutment Configurations(2018) Arif, Rabia; Yilmaz, Burak; Mortazavi, Aras; Ozcelik, Tuncer B.; Johnston, William M.; 29724553Statement of problem. The effect of a recently introduced metal opaquer when used to mask the color of a titanium abutment under ceramic crown systems is unknown. Purpose. The purpose of this study was to compare the color coordinates of 3 ceramic crown types-characterized monolithic lithium disilicate (LDC) (IPS e.max; Ivoclar Vivadent AG), layered lithium disilicate (LDL) (IPS e.max; Ivoclar Vivadent AG), and layered zirconia (ZL) (H.C. Starck)-on 3 abutment configurations, nonopaqued titanium (Ti), resin opaqued titanium (Op), and zirconia (Zir). In addition, the color differences (CIEDE2000) were evaluated among the 3 crown types on 3 different abutment substrates. Material and methods. Ten Ti disks (10x1 mm) were fabricated with computer-aided design and computer-aided manufacturing (CAD-CAM) to represent the Ti abutments. Five Ti specimens were opaqued (Op) (whiteMetal Opaquer wMO; Blue Sky Bio), and 5 were not opaqued (Ti). Ten zirconia disks were fabricated with CAD-CAM and sintered (10x1.2 mm). Five disks were used as backings to represent Zir abutments, and 5 disks were layered with 1 mm of porcelain (131, IPS e.Max Ceram; Ivoclar Vivadent AG) to represent layered zirconia crowns (ZL). Ten lithium disilicate plates (14x14x1.2 mm) were sectioned from CAD blocks (B1 IPS e.Max CAD; Ivoclar Vivadent AG). Five plates were layered with the same porcelain (B1, 1 mm), and 5 plates were surface characterized and glazed. An LDL crown on a Zir abutment configuration was used as the control. The 3 simulated crown types (n=5) were optically connected to each of the 3 abutment types, and the color of the 9 groups was measured using a spectroradiometer. Measured data were reported in CIELab coordinates. CIELab data were used to calculate color differences between the control and the 8 experimental groups. Color data were summarized for each group, and analyzed by repeated-measures ANOVA. For pairwise comparisons, a Bonferroni correction of t tests was used, and for interpretive analysis of resulting color difference data, a 1-way ANOVA and subsequent Tukey testing for pairwise comparisons were used. Results. The statistical significance of the analysis of color coordinates was found to be P <=.002. Although 3-way interaction was not found to be significant (P=.335), all three 2-way interactions of the main effects were found to be significant (P <=.002). All crown types on the Zir abutment revealed color differences from the control group. The color differences of the crown types on the Op and Zir abutment configurations compared with the control (LDL/Zir) were not (P>.05) statistically different. Conclusions. Colors of tested crown systems on Ti backing were each unacceptably different from the control group. Colors of these systems on zirconia backing were not perceivably different. Use of opaquer on titanium backing resulted in a small color difference from the control group (P>.05) for each crown system, demonstrating that it may be used to prevent the unfavorable metal show-through that can influence the final color of all ceramic crown systems tested.Item Marginal fit of CAD-CAM monolithic zirconia crowns fabricated by using cone beam computed tomography scans(2020) Kale, Ediz; Cilli, Mesutcan; Ozcelik, Tuncer Burak; Yilmaz, Burak; 31653403Statement of problem: Information regarding the precision of monolithic zirconia crowns fabricated by using a standard computer-aided design and computer-aided manufacturing (CAD-CAM) workflow is available. However, information on the effect of a modified workflow using 3D laboratory scanning and/or cone beam computed tomography (CBCT) for monolithic zirconia crown fabrication is lacking. Purpose: The purpose of this in vitro study was to evaluate the effect of different scans on the marginal fit of CAD-CAM monolithic zirconia crowns fabricated by 3D laboratory scanning and CBCT. Material and methods: An extracted maxillary left first molar was prepared and digitized by using a 3D laboratory scanner (D900; 3Shape A/S) (control group). The tooth was also scanned by CBCT (i-CAT; Imaging Sciences) to generate a second virtual 3D model (CBCTscan group). A tooth cast out of polyurethane (PU) (Zenotec Model; Wieland) was reproduced from the CBCT data by using a CAD software program (Dental System 2.6; 3Shape A/S) and milling machine (CORiTEC 550i; imes-icore) and further scanned by using the 3D laboratory scanner to generate a third virtual 3D model to represent a clinical scenario where a patient's cast is needed (PU3DLab group). A monolithic zirconia crown design (cement space: margin 40 mu m, 1 mm above 70 mu m) was used on the virtual models, and crowns were fabricated out of presintered zirconia blocks (ZenostarT4; Wieland) by using a 5-axis milling machine (CORiTEC 550i; imes-icore). The crowns were sintered (Sinterofen HT-S Speed; Mihm-Vogt), and the vertical marginal discrepancy (VMD) was measured by x100-magnification microscopy. Measurements were made at 384 points in 3 groups of 16 specimens. The measurements for each specimen were averaged, and VMD mean values were calculated. The Kruskal-Wallis test was used for the statistical analysis (alpha=.05). The Mann-Whitney U test and Bonferroni adjustment were further used to compare the pairs (alpha=.017). Results: The mean VMD value was 41 mu m (median: 38 mu m) for the control group, 44 mu m (median: 42 mu m) for the CBCTscan, and 60 mu m (median: 58 mu m) for the PU3DLab. No significant difference was found between control and CBCTscan groups (P=.274). However, there was a significant difference between control and PU3DLab and CBCTscan and PU3DLab groups (P<.001). Conclusions: Marginal fit of the crowns fabricated by using the 3D laboratory scanner and through the direct use of CBCT was better than that of the crowns fabricated by using the workflow that combined the use of CBCT, PU cast, and 3D laboratory scanner. All tested protocols enabled the fabrication of monolithic zirconia crowns with a marginal discrepancy smaller than 120 mu m.