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Öğe Effect of coffee thermal cycling on the surface properties and stainability of additively manufactured denture base resins in different layer thicknesses(Wiley, 2023) Cakmak, Guelce; Asadolahi, Nura Watson; Schimmel, Martin; Molinero-Mourelle, Pedro; Akay, Canan; Donmez, Mustafa Borga; Yilmaz, BurakPurpose: To compare the effect of coffee thermal cycling on surface roughness (Ra), Vickers microhardness (MH), and stainability of denture base resins additively manufactured in different layer thicknesses with those of subtractively manufactured denture base materials.Materials and methods: Eighty disk-shaped specimens (& Oslash;10x2 mm) were fabricated from two subtractively (Merz M-PM [SM-M] and G-CAM [SM-G]) and three additively (NextDent 3D+ [50 mu m, AM-N-50; 100 mu m, AM-N-100], FREEPRINT Denture [50 mu m, AM-F-50; 100 mu m, AM-F-100], and Denturetec [50 mu m, AM-S-50; 100 mu m, AM-S-100]) manufactured denture base materials (n = 10). Ra measurements were performed before and after polishing by using a non-contact optical profilometer, while MH values and color coordinates were measured after polishing. Specimens were then subjected to 5000 cycles of coffee thermal cycling, all measurements were repeated, and color differences (Delta E00) were calculated. A linear mixed effect model was used to analyze Ra and MH data, while one-way analysis of variance was used to analyze Delta E00 data (alpha = 0.05). Ra values were further evaluated according to a clinically acceptable threshold of 0.2 mu m, while Delta E00 values were evaluated according to perceptibility (1.72 units) and acceptability (4.08 units) thresholds. The interaction between the material type and the time interval affected both Ra and MH (p <= 0.001). Tested materials had their highest Ra before polishing (p <= 0.029). Before polishing, AM-F-100 had the highest, and SM-M and SM-G had the lowest Ra (p < 0.001). After polishing and after coffee thermal cycling, SM-G mostly had lower Ra than those of other materials (p <= 0.036). SM-G mostly had higher MH than that of other materials before and after coffee thermal cycling (p <= 0.025). Coffee thermal cycling reduced the MH of SM-M and increased that of AM-S-100 (p <= 0.024). AM-N-100 had higher Delta E00 than AM-F, AM-S-100, and SM-G (p <= 0.009), while AM-F and SM-G had lower Delta E00 than AM-S-50 and AM-N-50 (p <= 0.024).Conclusions: Polishing reduced the surface roughness of all materials, whereas the effect of coffee thermal cycling was nonsignificant. Most of the tested materials had acceptable surface roughness after polishing and after coffee thermal cycling according to the reported threshold. Layer thickness only affected the microhardness of tested additively manufactured resins, which was material-dependent. Subtractively manufactured specimens mostly had high microhardness and that of nonreinforced subtractively manufactured resin decreased after coffee thermal cycling. When reported color thresholds are considered, all materials had acceptable color stability.Öğe Effect of measurement techniques and operators on measured deviations in digital implant scans(ELSEVIER, 2022) Çakmak, Gülce; Dönmez, Mustafa Borga; Akay, Canan; De Silva, Marcella Paula; Mangano, F. G.; Abou-Ayash, S.; Yılmaz, BurakObjectives: To evaluate the effect of different measurement techniques and operators on measured deviations in in vitro implant scans. Methods: A 2-piece system that comprises a healing abutment (HA) and a scan body (SB) was mounted onto an implant at right first molar site of a polymethylmethacrylate mandibular dentate model. Model was digitized by using an industrial scanner (reference model scan, n=1) and an intraoral scanner (test scan, n=20). All standard tessellation language files were imported into a 3-dimensional analysis software and superimposed. Three operators with similar experience performed circle-based and point-based deviation analyses (n=20). Deviations measured with different techniques were compared with paired samples t-test within each operator, while the reliability of the operators was assessed by using F-tests for both technqiues (?=.05). Results: Point-based technique resulted in lower deviations than circle-based technique for all operators (P=.001) with to higher reliability among operators (ICC=.438, P=.001). The correlation among the operators was nonsignificant when circle-based technique was used (ICC=.114, P=.189). Conclusion: Lower deviations were detected with the point-based technique. In addition, different operators' measurements had higher correlation when point-based technique was used compared with circle-based technique. Clinical significance: Point-based technique may be preferred over circle-based technique for research studies on scan accuracy of implants, given its higher reliability. The accuracy of measured deviations may increase if the number of planes are increased, which can facilitate point generation at different surfaces of the scan body.Öğe Effect of potassium aluminum sulfate application on the viability of fibroblasts on a cad-cam feldspathic ceramic before and after thermocycling(PMID, 2022) Çakmak, Gülce; Akay, Canan; Dönmez, Mustafa Borga; Mumcu, Emre; Akan, Handan Sevim; Sasany, Rafat; Abou-Ayash, Samir; Yılmaz, BurakAbstract: Potassium aluminum sulfate (alum) is a known adjuvant, which has been used as a mordant in textile industry for color fixation. This material has potential to be incorporated into dentistry for color stability, yet its toxicity first needs to be evaluated. The present study aimed to evaluate the cytotoxic potential of potassium aluminum sulfate (alum) on fibroblasts when applied onto feldspathic ceramic before and after thermocycling. Forty-eight feldspathic ceramic specimens were divided into four groups (FC: no alum application or thermocycling; FCT: thermocycling without alum application; FA: alum application without thermocycling; FAT: alum application and thermocycling) (n = 12). Cell viability was assessed by using a tetrazolium salt 3-[4,5-dimethylthiazol2-yl]-2,5-diphnyltetrazolium bromide assay at 24 and 72 h, and cell cultures without any ceramic specimens served as control (C). One sample from each material group was further analyzed with energy dispersive X-ray spectroscopy (EDX). Cell viability at different time intervals within each group was analyzed with Friedman tests, while Kruskal–Wallis tests were used to compare the test groups within each time interval. Pairwise comparisons were further resolved by using Wilcoxon tests (a = 0.05). C had lower (p = 0.01) and FA had higher (p = 0.019) cell viability after 72 h. After 24 h, the highest cell viability was observed in C (p ? 0.036). After 72 h, the differences between C and FA, C and FAT, FC and FA, and FCT and FAT were nonsignificant (p > 0.05). Cell viability was not affected by alum application or thermocycling at any time interval (p ? 0.631). EDX analysis showed an increase in potassium concentration in FA and FAT when compared with FC and FCT. Regardless of the time interval, alum application onto feldspathic ceramic and thermocycling did not influence the cell viability.Öğe Effect of simulated brushing and disinfection on the surface roughness and color stability of CAD-CAM denture base materials(Elsevier Science, 2022) Çakmak, Gülce; Dönmez, Mustafa Borga; Akay, Canan; Atalay, Sevda; Silva de Paula, Marcella; Schimmel, Martin; Yılmaz, BurakPurpose: To evaluate the effect of simulated brushing and chemical disinfection on the surface roughness and color stability of CAD-CAM denture base materials and to compare with those of a heat-cured denture base material. Material and methods: Disk-shaped specimens (Ø 10mm × 2 mm) were prepared from 3 CAD-CAM denture base resins (AvaDent, Ava; Merz M-PM, Merz; Polident d.o.o, Poli) and a heat-cured polymethylmethacrylate resin (Promolux, Conv) (n = 30). After polishing, baseline surface roughness (Ra) and color coordinates were measured. The measurements were repeated after 20000 cycles of simulated brushing, and the specimens were divided into 3 groups according to disinfection protocol (distilled water, 1% sodium hypochlorite (NaOCl), and effervescent tablet) (n = 10). After 9 cleaning cycles over a period of 20 days, Ra and color coordinates were remeasured. Color differences (?E00) were calculated by using CIEDE2000 formula. One-way analysis of vari- ance (ANOVA) and pairwise t-tests were used to analyze Ra and ?E00 data, while repeated measures ANOVA test was used to compare baseline, after brush, and after disinfection Ra values (? = 0.05). Results: Brushing did not affect the Ra values of tested materials (P ? .08). Both before and after brushing, Merz and Conv had higher Ra values than Poli and Ava (P < .001). Among disinfectants, effervescent tablet led to the lowest Ra for Merz (P = .003) and the highest Ra for Poli (P ? .039). Only NaOCl resulted in significant dif- ferences among the Ra of materials (P < .001), as Merz and Conv had higher Ra values than Poli (P ? .002). Repeated measures ANOVA revealed that effervescent tablet disinfection of Merz led to lower Ra values than those of baseline and after brushing (P ? .042). After brushing, Ava and Conv had higher ?E00 values compared with Merz and Poli (P ? .015). When compared with other disinfection protocols, effervescent tablet led to higher ?E00 values for Merz and Poli (P < .001). Significant differences were observed among materials when NaOCl was used; Conv had higher ?E00 values than Ava and Merz (P = .004). Conclusions: Brushing did not increase the surface roughness of materials. Disinfection protocol’s effect on the surface roughness varied. The effect of brushing on the color of materials varied; color of Ava and Conv was affected from brushing more than the other materials. Color stability of materials varied depending on the disinfection protocol. Effervescent tablet caused higher color change with Merz and Poli compared with other disinfectants. NaOCl led to small color change for Poli, Ava, and Merz materials.Öğe Effect of thermal cycling on the flexural strength and hardness of new-generation denture base materials(WILEY, 2022) Cakmak, Gulce; Donmez, Mustafa Borga; Akay, Canan; Abou-Ayash, Samir; Schimmel, Martin; Yilmaz, BurakPurpose To evaluate the flexural strength and Vickers microhardness of different CAD-CAM denture base materials. Materials and methods Sixty rectangular specimens (64 x 10 x 3.3 +/- 0.2 mm) were fabricated from 3 different denture base materials (G-CAM, Graphene-reinforced polymethylmethacrylate, GC), Ivotion Base (Prepolymerized polymethylmethacrylate, IV), and Denturetec (3D-printed resin, DT) either by using additive (DT) or subtractive manufacturing (IV and GC). Specimens of each group were divided into 2 subgroups (thermal cycled or nonthermal cycled, n = 10/group). Nonthermal cycled specimens were stored in distilled water at 37 degrees C for 24 hours and subjected to 3-point flexural strength test with a universal testing machine. Thermal cycled specimens were initially evaluated for Vickers microhardness and subjected to thermal cycling (10,000 cycles at 5-55 degrees C). Vickers microhardness values were remeasured, and the specimens were subjected to 3-point flexural strength test. Data were analyzed by using 2-way analysis of variance and Bonferroni-corrected Tukey honestly significant difference tests (alpha = 0.05). Results Material type and condition significantly affected flexural strength (p <= 0.004), whereas their interaction was nonsignificant (p = 0.778). Overall flexural strength of the materials in decreasing order was GC, IV, and DT (p < 0.001), regardless of the condition. Material had a higher effect on flexural strength (eta p(2) = 0.731) than thermal cycling (eta p(2) = 0.142). The effect of the interaction between the material type and thermal cycling on Vickers microhardness was significant (p < 0.001). GC had the highest microhardness before and after thermal cycling (p < 0.001). IV had higher microhardness than DT before thermal cycling (p < 0.001). However, DT and IV showed similar microhardness after thermal cycling (p = 0.665). Thermal cycling decreased the microhardness of GC and IV (p <= 0.022), whereas its effect on DT's microhardness was nonsignificant (p = 0.538). Material type had the highest effect on microhardness (eta p(2) = 0.864) followed by the interaction between the main factors (eta p(2) = 0.258). Conclusions Graphene-reinforced polymethylmethacrylate had the highest flexural strength and Vickers microhardness values, regardless of thermal cycling. Thermal cycling reduced the flexural strength of all resins. Thermal cycling reduced the microhardness of milled polymethylmethacrylate, but not that of 3D-printed resin.Öğe Flexural Strength and Vickers Microhardness of Graphene-Doped SnO2 Thin-Film-Coated Polymethylmethacrylate after Thermocycling(Mdpi, 2023) Akay, Canan; Cakmak, Gulce; Donmez, Mustafa Borga; Abou-Ayash, Samir; Mumcu, Emre; Pat, Suat; Yilmaz, BurakRemovable dental prostheses are commonly fabricated using polymethylmethacrylate, a material that does not have favorable mechanical properties and needs reinforcement with particles such as graphene. The aim of this study was to evaluate the flexural strength (FS) and Vickers microhardness of a heat-polymerized polymethylmethacrylate coated with graphene-doped stannic oxide (SnO2) thin films using a thermionic vacuum arc method after thermocycling. Forty bar-shaped specimens (65 x 10 x 3 mm) were fabricated using a heat-polymerized denture base resin and divided into four groups according to the graphene-doped SnO2 thin film surface coating performed: No-coat (uncoated), Coat-15 s (coating duration of 15 s), Coat-20 s (coating duration of 20 s), and Coat-30 s (coating duration of 30 s) (n = 10). The thermionic vacuum arc method was used to coat both surfaces of the specimens of each test group with varying durations, and surface coating was verified using Fourier Transform Infrared Spectroscopy. Specimens were subjected to 10,000 cycles of thermocycling. Atomic force microscopy was used to evaluate the surfaces of all specimens before and after thermocycling. Microhardness values were measured five times and averaged. Then, each specimen was subjected to a three-point bending test, and FS values were calculated. Data were analyzed using one-way analysis of variance and Bonferroni tests (& alpha; = 0.05). Differences among test groups were nonsignificant when FS data were considered (p = 0.605). However, significant differences were observed among test groups when Vickers microhardness data were considered (p < 0.001). Coat-30 s had the highest hardness (p & LE; 0.003), while the difference among remaining groups were nonsignificant (p & GE; 0.166). Graphene-doped SnO2 thin film surface coatings did not significantly affect the FS of tested heat-polymerized denture base resin but increased the Vickers microhardness when the coating duration was 30 s.Öğe Influence of polishing technique and coffee thermal cycling on the surface roughness and color stability of additively and subtractively manufactured resins used for definitive restorations(Wiley, 2023) Cakmak, Gulce; Oosterveen-Ruegsegger, Alice Lisa; Akay, Canan; Schimmel, Martin; Yilmaz, Burak; Donmez, Mustafa BorgaPurposeTo evaluate how different polishing techniques and coffee thermal cycling affect the surface roughness and stainability of additively and subtractively manufactured resins used for definitive prostheses. Materials and MethodsTwo additively manufactured composite resins (Crowntec, CT and VarseoSmile Crown Plus, VS) and a subtractively manufactured resin nanoceramic (Cerasmart, CS) were used to fabricate 90 rectangular-shaped specimens (14 x 12 x 1 mm) (n = 30). After baseline surface roughness (R-a) measurements, specimens were divided into three groups based on the polishing technique; conventional polishing with a 2-stage polishing kit (CP) and surface sealant application (Optiglaze, OG or Vita Akzent LC, VA) (n = 10). After polishing, specimens were subjected to 10,000 cycles of coffee thermal cycling. R-a and color coordinate measurements were performed after polishing and after coffee thermal cycling. Color difference (& UDelta;E-00) was calculated. Scanning electron microscope images were taken at each time interval. Kruskal-Wallis or 1-way analysis of variance (ANOVA) were used to evaluate R-a of materials within each polishing-time interval pair and different polishing techniques within each material-time interval pair, while Friedman or repeated measures ANOVA were used to evaluate R-a at different time intervals within each material-polishing pair. & UDelta;E-00 was assessed with 2-way ANOVA (& alpha; = 0.05). ResultsOther than VA-after polishing (p = 0.055), tested materials had significantly different R-a within each polishing-time interval pair (p & LE; 0.038). When R-a differences among different polishing techniques within each material-time interval pair were considered, CS had differences after coffee thermal cycling, CT had differences before polishing and after coffee thermal cycling, and VS had differences within each time interval (p & LE; 0.038). When R-a differences among different time intervals within each material-polishing pair were considered, significant differences were observed among all pairs (p & LE; 0.016), except for CS-VA (p = 0.695) and VS-VA (p = 0.300). & UDelta;E-00 values were affected by material and polishing technique interaction (p = 0.007). ConclusionsR(a) of CS was similar to or lower than the R-a of other materials, regardless of the time interval or polishing technique. CP mostly led to lower R-a than other polishing techniques, whereas VA resulted in a high R-a regardless of the material-time interval pair. Polishing reduced the R-a, while coffee thermal cycling was found to have a small effect. Among tested material-polishing pairs, only CS-VA had moderately unacceptable color change when previously reported threshold values were considered.Öğe Surface roughness and color stability of 3D-Printed denture base materials after simulated brushing and thermocycling(MDPI, 2022) Çakmak, Gülce; Molinero Mourelle, Pedro; De Paula, Marcella Silva; Akay, Canan; Cuellar, Alfonso Rodriguez; Dönmez, Mustafa Borga; Yılmaz, BurakThree-dimensional (3D) printing is increasingly used to fabricate denture base materials. However, information on the effect of simulated brushing and thermocycling on the surface roughness and color stability of 3D-printed denture base materials is lacking. The aim of this study was to evaluate the effect of brushing and thermocycling on the surface roughness and color stability of 3D-printed denture base materials and to compare with those of milled and heat-polymerized denture base resins. Disk-shaped specimens (Ø 10 mm × 2 mm) were prepared from 4 different denture base resins (NextDent Denture 3D+ (ND); Denturetec (SC); Polident d.o.o (PD); Promolux (CNV)) (n = 10). Surface roughness (Ra) values were measured before and after polishing with a profilometer. Initial color coordinates were measured by using a spectrophotometer after polishing. Specimens were then consecutively subjected to simulated brushing (10,000 cycles), thermocycling (10,000 cycles), and brushing (10,000 cycles) again. Ra and color coordinates were measured after each interval. Color differences (?E00) between each interval were calculated and these values were further evaluated considering previously reported perceptibility (1.72 units) and acceptability (4.08 units) thresholds. Data were analyzed with Friedman, Kruskal–Wallis, and Mann–Whitney U tests (? = 0.05). Ra (p ? 0.051) and ?E00 (p ? 0.061) values among different time intervals within each material were similar. Within each time interval, significant differences in Ra (p ? 0.002) and ?E00 values (p ? 0.001) were observed among materials. Polishing, brushing, and thermocycling resulted in acceptable surface roughness for all materials that were either similar to or below 0.2 µm. Color of ND printed resin was affected by brushing and thermocycling. All materials had acceptable color stability when reported thresholds are considered.Öğe Surface roughness and stainability of new-generation denture base materials after brushing and coffee thermocycling(SPRINGER HEIDELBERG, 2022) Çakmak, Gülce; Dönmez, Mustafa Borga; De Paula, Marcella Silva; Akay, Canan; Chavan, Amit; Schimmel, Martin; Yılmaz, BurakDisk-shaped specimens were prepared from additively (NX and DT), subtractively (MZ), and conventionally manufactured denture base resins (CV). Surface roughness and color coordinates were measured after polishing, simulated brushing, and coffee thermocycling, while surface roughness was also measured before polishing. Polishing reduced the surface roughness of all materials. Brushing and coffee thermocycling increased the surface roughness of only DT. CV had the highest susceptibility to consecutive brushing and coffee thermocycling as it had the highest surface roughness, which was above the clinically acceptable threshold. All materials had similar stainability; only MZ had perceptible color change after brushing. Even though stainability of tested denture base resins was similar, additively or subtractively manufactured computer-aided design and computer-aided manufacturing (CAD-CAM) resins had smoother surfaces after brushing and coffee thermocycling, regardless of the material. Therefore, complete dentures made out of these CAD-CAM resins may have favorable surface properties in the long term.Öğe Surface roughness, optical properties, and microhardness of additively and subtractively manufactured CAD-CAM materials after brushing and coffee thermal cycling(Wiley, 2023) Cakmak, Gulce; Donmez, Mustafa Borga; de Paula, Marcella Silva; Akay, Canan; Fonseca, Manrique; Kahveci, Cigdem; Abou-Ayash, SamirPurpose: To evaluate the surface roughness, optical properties, and microhardness of additively or subtractively manufactured CAD-CAM materials after simulated brushing and coffee thermal cycling.Material and methods: Two additively manufactured resins (Crowntec, CT and VarseoSmile Crown Plus, VS) and 3 subtractively manufactured materials (a reinforced composite (Brilliant Crios, BC), a polymer-infiltrated ceramic network (Enamic, VE), and a feldspathic ceramic (Mark II, VM)) were used to fabricate disk-shaped specimens (& Oslash;10x1-mm) (n = 10). Surface roughness, Vickers microhardness, and color coordinates were measured after polishing, while surface roughness was also measured before polishing. Specimens were then subjected to 25000 cycles of brushing and 10000 cycles of coffee thermal cycling, and measurements were repeated after each time interval. Color difference (Delta E-00) and relative translucency parameter (RTP) were calculated. Robust analysis of variance test was used to evaluate surface roughness, Delta E-00, and RTP data, while generalized linear model analysis was used for microhardness data (alpha = 0.05).Results: Material type and time interval interaction affected tested parameters (p <= 0.002). In addition, material type affected all parameters (p < 0.001) other than surface roughness (p = 0.051), and time interval affected surface roughness and microhardness values (p < 0.001). Tested materials mostly had their highest surface roughness before polishing (p <= 0.026); however, there was no clear trend regarding the roughness of materials within different time intervals along with Delta E00 and RTP values within materials or time intervals. VS and CT had the lowest microhardness regardless of the time interval, while the remaining materials were listed as VM, VE, and BC in decreasing order (p < 0.001). Coffee thermal cycling only reduced the microhardness of VM (p < 0.001).Conclusions: Tested additively manufactured resins can be considered more susceptible to simulated brushing and coffee thermal cycling than the other materials, given the fact that their surface roughness and Delta E00 values were higher than previously reported acceptability thresholds and because they had the lowest microhardness after all procedures were complete.Öğe Trueness of crowns fabricated by using additively and subtractively manufactured resin-based CAD-CAM materials(Elsevier, 2022) Çakmak, Gülce; Rusa, Ana Maria; Dönmez, Mustafa Borga; Akay, Canan; Kahveci, Çiğdem; Yılmaz, BurakStatement of problem: Advancements in digital dental technologies have enabled the use of different resin-based materials that can be fabricated either additively or subtractively. However, knowledge on the fabrication trueness of these materials is scarce. Purpose: The purpose of this in vitro study was to investigate the trueness of crowns fabricated by using different resin-based computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Material and methods: A complete crown for a mandibular right first molar with a 30-?m cement space was designed in standard tessellation language (STL) format. This master STL (MC-STL) was used to fabricate 40 complete crowns with 4 different resin-based CAD-CAM materials and either additive (Crowntec [MS]) or subtractive techniques (Brilliant Crios [BC], breCAM.monoCOM [PMMA], and G-CAM [GR]; n=10). All crowns were digitized with an intraoral scanner (CEREC Primescan SW 5.2) to generate their STL files (TC-STLs). MC-STL and TC-STLs were transferred into a 3-dimensional analysis software program (Medit Link v2.4.4), and a trueness (overall, external, occlusal, intaglio occlusal, and marginal) analysis was performed by using the root mean square (RMS) method. The Kruskal-Wallis and Dunn tests were performed to analyze data (?=.05). Results: The test groups had significantly different deviations on all surfaces (P?.001). MS crowns had higher overall (P?.007) and external surface (P?.001) deviations than GR and PMMA crowns, while the differences between GR and PMMA crowns were not significant (P?.441). BC crowns had higher external surface deviations than GR crowns (P=.005), higher occlusal deviations than GR and MS crowns (P?.007), and higher intaglio occlusal deviations than GR and MS crowns (P?.009). However, BC crowns had lower marginal deviations than MS and GR crowns (P?.018). Conclusions: The brand of resin-based CAD-CAM materials affected the trueness of crowns. Additively manufactured crowns (MS) mostly had lower overall and external surface trueness than the other groups. Nevertheless, the deviation values of occlusal, intaglio occlusal, and marginal trueness were generally small; thus, the effect of the tested materials on clinical crown fit may be negligible. © 2022 Editorial Council for the Journal of Prosthetic Dentistry
