Diş Hekimliği Fakültesi / Faculty of Dentistry
Permanent URI for this collectionhttps://hdl.handle.net/11727/2120
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Item An Alternative Impression Technique for Complete Dentures(2014) Yilmaz, Burak; Ozcelik, Tuncer Burak; https://orcid.org/0000-0001-5685-4409; 24286641; JJF-5618-2023This article describes a technique for creating adequate space for an even thickness of polyvinyl siloxane (PVS) impression material at the periphery during complete denture impression making. A PVS border molding material is injected around the borders of a custom tray, a 17-mu m-thick stretch wrap film is folded into 4 layers, and a tray-shaped piece slightly larger than the size of the custom tray is placed on the tray covering the borders. After the border molding procedure is completed, the film is removed and the definitive impression completed with a medium-viscosity PVS impression material.Item A Clinical Comparison of Cordless and Conventional Displacement Systems Regarding Clinical Performance and Impression Quality(2014) Acar, Ozlem; Erkut, Selim; Ozcelik, Tuncer Burak; Ozdermr, Erdem; Akcil, Mehtap; https://orcid.org/0000-0001-5685-4409; 24360008; JJF-5618-2023Statement of problem. it is not clear whether newly introduced cordless displacement systems are better able to manage gingiva than conventional systems. Purpose. The purpose of this in vivo study was to evaluate the gingival management ability of 4 different displacement methods with a standardized subgingival preparation finish line. Material and methods. The effects of 4 displacement techniques on gingival management and impression quality were evaluated by means of 6 evaluation criteria. A subgingival preparation finish line of between 1 and 2 mm was ensured, and the buccal aspects of 252 (n=63) teeth were clinically assessed for ease of application, time spent, bleeding, remnants, and dilatation. The complete reproduction of the preparation finish line and the bubble and void formations on polyether impressions were also evaluated. The data were statistically analyzed with the chi(2) test (alpha=.05). The Bonferroni correction was used to control Type I error for the pairwise comparison groups (alpha=.008). Results. Statistically significant differences were found for all criteria among the groups (P<.05). The nonimpregnated displacement cord group was the least effective group in terms of bleeding and impression quality (P<.008). The aluminum chloride impregnated cord group and the displacement paste with cap group were found to be comparable in terms of remnants, dilatation, and impression quality (P>.008). The retraction cap with paste group showed better results for ease of application, time spent, and bleeding than the aluminum chloride impregnated cord group (P<.008). Although the group with aluminum chloride impregnated cord, displacement paste, and cap showed better results for dilatation, it was time consuming and difficult (P<.008). Conclusions. Except for the nonimpregnated cord group, all of the groups were comparable and clinically useful, with perfect or acceptable impression qualities.Item Digital Evaluation of The Accuracy of Impression Techniques and Materials in Angulated Implants(2014) Kurtulmus-Yilmaz, Sevcan; Ozan, Oguz; Ozcelik, Tuncer Burak; Yagiz, Ayberk; https://orcid.org/0000-0001-5685-4409; 25446736; JJF-5618-2023Objectives: The aim of this study was to investigate the accuracy of 2 different impression techniques and 3 different impression materials in models simulating parallel and angulated implants. Methods: Three master models simulating partial edentulous mandible with 2 implants at the sites of second premolars (parallel) and second molars with different angulations (parallel, 10 degrees or 20 degrees angulated) were fabricated. Two different impression techniques [ splinted direct (D), indirect (I)] and 3 different monophase impression materials [ polyether (PE), vinyl polysiloxane (VPS), vinyl polyether silicone (VPES)] were used for each master model and a total of 180 impressions were made (n = 10). Master model and casts were scanned by a modified laser scanner and data were transferred to VRMesh software. Master model and duplicate cast scans were digitally aligned observing the superposition of anatomic markers. Angular and coronal deviations between master and duplicated copings were calculated and data were statistically analyzed. Results: Mean angular and coronal deviations were in a range of 0.205-0.359 degrees and 22.5633.33 mu m, respectively. Statistical analysis revealed that the angulation of implant affected both coronal and angular deviations of the impression copings (P < 0.05). According to statistical analyses, for parallel implants, the accuracy of impression materials and techniques were ranging as VPS-D = PE-D > VPS-I = PE-I > VPES-D > VPES-I from most accurate to the least. For 10 degrees and 20 degrees angulated implants the most accurate material and technique was VPS-D whereas the least accurate combination was VPES-I (P < 0.05). Conclusion: Angulation, impression technique and material were found to be effective on the accuracy of implant impressions. Clinical significance: Clinicians may prefer VPS impression material and splinted direct technique for impressions of both parallel and up to 20 degrees angulated implants. (C) 2014 Elsevier Ltd. All rights reserved.Item The Effect of Different Polishing Sequences on the Adhesion of Streptococcus mutans to Feldspathic Porcelain(2016) Yuzugullu, Bulem; Celik, Cigdem; Ozcelik, Tuncer Burak; Erkut, Selim; Yurdakul, Pinar; Ocal, Yesim; Sener, Burcin; https://orcid.org/0000-0002-5936-0196; AAA-1576-2021The aim of this research was to determine whether extra-oral surface treatments on feldspathic porcelain surfaces influence initial adhesion of Streptococcus mutans. Ninety-six porcelain specimen discs were fabricated and divided into six equal groups according to surface treatment: fine-grit diamond polishing (Group 1); self-glazing (Group 2); overglazing (Group 3); overglazing followed by a finishing procedure and then overglazing (Group 4); Pearl Surface polishing (Group 5); and Diamond Twist SCLTM polishing (Group 6). Surface roughness and hydrophobicity were assessed. An S. mutans suspension was incubated on each specimen group and evaluated. A one-way analysis of variance, post-hoc Tukey honestly significantly different test, Friedman test, and t-test were used for statistical analysis. Group 1 showed the highest surface roughness (p < 0.001) and bacterial adhesion (p < 0.05). Groups 5 and 6 specimen surfaces presented significantly higher contact angles (p < 0.05). Group 1 had the highest S. mutans adhesion, followed by Groups 3, 5, 6, 2, and 4 (p < 0.05). Reglazing after grinding may therefore decrease bacterial adhesion beneficially.Item Effect of Cement Space on The Marginal Fit of CAD-CAM-Fabricated Monolithic Zirconia Crowns(2016) Kale, Ediz; Seker, Emre; Yilmaz, Burak; Ozcelik, Tuncer Burak; 0000-0001-8761-0298; 0000-0002-7101-363X; 27460314; O-2753-2013; AAE-5350-2019Statement of problem. Monolithic zirconia crowns fabricated with computer-aided design and computer-aided manufacturing (CAD-CAM) have recently become a common practice for the restoration of posterior teeth. The marginal fit of monolithic zirconia crowns may be affected by different cement space parameters set in the CAD software. Information is scarce regarding the effect of cement space on the marginal fit of monolithic zirconia crowns fabricated with CAD CAM technology. Purpose. The purpose of this in vitro study was to evaluate the effect of cement space on the marginal fit of CAD-CAM-fabricated monolithic zirconia crowns before cementation. Material and methods. Fifteen 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 3-dimensionally using software and then milled from presintered monolithic zirconia blocks in a computer numerical control dental milling machine. The cement space was set at 25 mu m around the margins for all groups, and additional cement space starting 1 mm above the finish lines of the teeth was set at 30 mu m for group 25-30, 40 mu m for group 25-40, and 50 mu m for group 25-50 in the CAD software. A total of 120 images (3 groups, 5 crowns per group, 8 sites per crown) were measured for vertical marginal discrepancy under a stereoscopic zoom microscope and the data were statistically analyzed with 1-way analysis of variance, followed by the Tukey honestly significant difference test (alpha=.05). Results. The results showed that different cement space values had statistically significant effect on the mean vertical marginal discrepancy value of tested crowns (P<.001). The mean marginal discrepancy was 85 mu m for group 25-30, 68 mu m for group 25-40, and 53 mu m for group 25-50. Conclusions. Within the limitations of this in vitro study, it was concluded that the cement space had a significant effect on the marginal fit of CAD-CAM-fabricated monolithic zirconia crowns. The marginal fit improved as the cement space decreased.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 Depigmented skin and phantom color measurements for realistic prostheses(2014) Tanner, Paul; Leachman, Sancy; Boucher, Kenneth; Ozcelik, Tuncer BurakPurposeThe purpose of this study was to test the hypothesis that regardless of human skin phototype, areas of depigmented skin, as seen in vitiligo, are optically indistinguishable among skin phototypes. The average of the depigmented skin measurements can be used to develop the base color of realistic prostheses. Methods and MaterialsData was analyzed from 20 of 32 recruited vitiligo study participants. Diffuse reflectance spectroscopy measurements were made from depigmented skin and adjacent pigmented skin, then compared with 66 pigmented polydimethylsiloxane phantoms to determine pigment concentrations in turbid media for making realistic facial prostheses. ResultsThe Area Under spectral intensity Curve (AUC) was calculated for average spectroscopy measurements of pigmented sites in relation to skin phototype (P=0.0505) and depigmented skin in relation to skin phototype (P=0.59). No significant relationship exists between skin phototypes and depigmented skin spectroscopy measurements. The average of the depigmented skin measurements (AUC 19,129) was the closest match to phantom 6.4 (AUC 19,162). ConclusionAreas of depigmented skin are visibly indistinguishable per skin phototype, yet spectrometry shows that depigmented skin measurements varied and were unrelated to skin phototype. Possible sources of optical variation of depigmented skin include age, body site, blood flow, quantity/quality of collagen, and other chromophores. The average of all depigmented skin measurements can be used to derive the pigment composition and concentration for realistic facial prostheses.Item Marginal Adaptation of Provisional CAD/CAM Restorations Fabricated Using Various Simulated Digital Cement Space Settings(2018) Ozcelik, Tuncer Burak; Yilmaz, Burak; Seker, Emre; Shah, Karnik; 30231093Purpose: The ideal digital cement space value for the fabrication of provisional computer-aided design/ computer-aided manufacturing (CAD/CAM) crowns with clinically acceptable marginal adaptation is not well known. The aim of this study was to evaluate the effect of different simulated cement space settings on the marginal tit of poly(methyl methacrylate) (PMMA) provisional CAD/CAM restorations. Materials and Methods: An extracted premolar tooth was prepared using ceramic crown preparation guidelines and represented both natural teeth and/or custom implant abutments. The prepared tooth abutment was scanned with a three-dimensional (3D) laboratory scanner (D900, 3Shape). CAD design software was used to subsequently design a premolar crown core with three different simulated cement space settings (20 to 40 mu m, 20 to 50 mu m, 20 to 60 mu m). PMMA blocks were used to mill the specimens (n = 9, N = 27). Using a stereo zoom microscope, a total of 36 images for each of the 3 groups (9 crowns per group, 4 sites per crown) were captured to measure the mean vertical marginal discrepancy for every group. One-way analysis of variance (ANOVA) was used to analyze the data, and the post hoc Tukey multiple comparison test was performed. Results: The marginal gap values of the PMMA cores fabricated using the three cement space settings were significantly different from each other (P < .001). The marginal gap was smaller with a 20- to 60-mu m setting compared with 20 to 50 mu m and 20 to 40 mu m, and the 20- to 50-mu m setting allowed for smaller marginal gaps compared with 20 to 40 mu m (P < .001). Conclusion: Within the limitations of this study, the marginal gaps of CAD/CAM-fabricated PMMA cores were smaller when the cement space was larger. The smallest marginal gaps were achieved when a 20- to 60-mu m cement space was used (P < .001).