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Öğe Additive or subtractive manufacturing of crown patterns used for pressing or casting: A trueness analysis(Elsevier Science, 2022) Çakmak, Gülce; Dönmez, Mustafa Borga; Cuellar, Alfonso Rodrigues; Kahveci, Çiğdem; Schimmel, Martin; Yılmaz, BurakObjectives: To investigate the effect of subtractive and additive manufacturing techniques on the trueness of crown patterns used for pressing or casting. Material and Methods: A complete-coverage mandibular right first molar crown was designed in standard tessellation language (STL) format. This STL served as the control (C- STL) and was used to fabricate 30 crown patterns in 3D-printed resin (PR, ProArt Print Wax), millable wax suitable for casting (BW, ProArt CAD Wax Blue), and millable wax suitable for pressing (YW, ProArt CAD Wax Yellow) (n=10). Subtractively manufactured patterns were fabricated by using a 5-axis milling unit (PrograMill PM7), while 3D-printed patterns were fabricated by using a digital light processing-based 3D printer (PrograPrint PR5; Ivoclar Vivadent, Schaan, Liechtenstein). All fabricated patterns were digitized by using an intraoral scanner (CEREC Primescan SW 5.2) to generate test-STLs. C-STL and test-STLs were transferred into a 3D analysis software (Medit Link v 2.4.4). Trueness evaluation was performed at 4 different surfaces (external, intaglio with margin, marginal, and intaglio without margin) and for complete scan meshes (overall) by using the root mean square (RMS) method. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests (?=.05). Results: RMS values varied significantly at all surfaces (P<.001), except for marginal surface (P=.151). PR had the highest RMS values at external surface (P?.007), intaglio surfaces (with (P?.003) and without margin (P?.005)), and overall (P?.01). No significant differences were observed between YW and BW (P?.223). Conclusion: Patterns fabricated by using subtractive manufacturing exhibited high trueness. The deviation values, in general, were small, particularly at intaglio and marginal surfaces; thus, clinical difference in crown-fit may be negligible using additive or subtractive technique. Clinical Significance The fit of definitive crowns may be similar when tested crown patterns are additively or subtractively manufactured. However, crowns fabricated by using tested 3D-printed resin patterns may require more chairside adjustments compared with those fabricated by using subtractively manufactured wax patterns.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 coffee thermocycling on the surface roughness and stainability of denture base materials with different chemical compositions manufactured with additive and subtractive technologies(Wiley, 2024) Cakmak, Gulce; Weber, Franziska Alexandra; Donmez, Mustafa Borga; Kahveci, Cigdem; Schimmel, Martin; Yilmaz, BurakObjectiveTo evaluate the effect of coffee thermocycling (CTC) on the surface roughness (Ra) and stainability of denture base materials with different chemical compositions fabricated by using additive and subtractive manufacturing.Materials and MethodsDisk-shaped specimens were additively (FREEPRINT denture, AM) or subtractively (G-CAM, GSM and M-PM, SM) fabricated from three pink denture base materials in different chemical compositions (n = 10). Ra was measured before and after polishing, while color coordinates were measured after polishing. Specimens were subjected to CTC (5000 cycles) and measurements were repeated. Color differences (& UDelta;E00) after CTC were calculated. Ra among different time intervals within materials was evaluated by using repeated measures analysis of variance (ANOVA), while 1-way ANOVA was used to evaluate the Ra of different materials within each time interval and the & UDelta;E00 values. Color coordinates within each material were compared by using paired samples t-tests (a = 0.05).ResultsRa before polishing was the highest for all materials (p < 0.001), while SM had its lowest Ra after CTC and AM had its lowest Ra after polishing (p & LE; 0.008). Before polishing, AM had the highest Ra among the materials (p < 0.001). After polishing, SM had higher Ra than AM (p < 0.001). After CTC, GSM had the lowest Ra (p & LE; 0.048). SM had the lowest (p & LE; 0.031) and AM had the highest (p < 0.001) & UDelta;E00. CTC decreased the a* and b* values of SM and AM (p & LE; 0.017), and increased the L* values of AM (p < 0.001).ConclusionsPolishing significantly reduced the surface roughness of all materials. CTC did not increase the surface roughness of materials above the clinically acceptable threshold. Only AM had perceptible color change when previously reported threshold values for denture base materials were considered.Clinical SignificanceTested denture base materials may have similar surface stability after coffee thermocycling. However, subtractively manufactured denture base materials may have improved color stability when subjected to long-term coffee consumption.Öğe Effect of coffee thermocycling on the surface roughness and stainability of nanographene-reinforced polymethyl methacrylate used for fixed definitive prostheses(Mosby-Elsevier, 2023) Cakmak, Gulce; Herren, Kira Vera; Donmez, Mustafa Borga; Kahveci, Cigern; Schimmel, Martin; Yilmaz, BurakStatement of problem. A nanographene-reinforced polymethyl methacrylate (PMMA) has been introduced for definitive prostheses. However, knowledge on the surface roughness and stainability of this material is lacking.Purpose. The purpose of this in vitro study was to compare the surface roughness and stainability of nanographene-reinforced PMMA with those of a prepolymerized PMMA and a reinforced composite resin after coffee thermocycling.Material and methods. Disk-shaped specimens (F10x1.5-mm) were prepared from 3 different A1-shade millable resins (prepolymerized PMMA [M-PM; PMMA]; nanographene-reinforced PMMA [G-CAM; G-PMMA]; reinforced composite resin [Brilliant Crios; RCR]). Surface roughness (R-a) values were measured before and after conventional polishing by using a noncontact profilometer. Initial color coordinates were measured over a gray background with a spectrophotometer after polishing. Specimens were then thermocycled in coffee for 5000 cycles. Measurements were repeated after coffee thermocycling, and color differences (?E-00) were calculated. R-a values among different time intervals were analyzed by using either the Friedman and Dunn tests (RCR) or repeated measures analysis of variance (ANOVA) and Bonferroni corrected paired samples t tests (PMMA and G-PMMA), while R-a values within a time interval were analyzed by using either the Kruskal-Wallis and Dunn tests (before polishing) or 1-way ANOVA and Tukey HSD (after polishing) or Tamhane T2 tests (after coffee thermocycling). ?E-00 values were analyzed by using 1-way ANOVA and Tukey HSD tests, while color coordinates of the specimens after polishing and after coffee thermocycling were compared by using paired samples t tests (a=.05).Results. All materials had their highest R-a values before polishing (P=.011), while differences after polishing and after coffee thermocycling values were nonsignificant (P=.140). PMMA had higher R(a )than RCR before polishing (P=.002), and RCR had higher values than G-PMMA after polishing and after coffee thermocycling (P=.023). RCR had the highest ?E-00 (P=.001). Polishing increased the b* values of PMMA, and coffee thermocycling increased the a* values of G-PMMA and all values of RCR (P=.012).Conclusions. The tested materials had similar and acceptable surface roughness after polishing. The surface roughness of materials was not affected by coffee thermocycling. Considering the reported color thresholds, all materials had acceptable color change, but the computer-aided design and computer-aided manufacturing composite resin had perceptible color change after coffee thermocycling.Öğe Effect of computer-aided design and computer-aided manufacturing technique on the accuracy of fixed partial denture patterns used for casting or pressing(Elsevier Sci Ltd, 2023) Donmez, Mustafa Borga; Yilmaz, Burak; Yoon, Hyung-In; Kahveci, Cigdem; Schimmel, Martin; Cakmak, GulceObjectives: To evaluate the effect of additive and subtractive manufacturing on the accuracy (trueness and pre-cision) of fixed partial denture patterns (FPDPs) used for casting or pressing.Materials and Methods: A 3-unit complete coverage FPD on mandibular right first premolar and first molar teeth was virtually designed. Using the design data, FPD patterns were fabricated from an additively manufactured resin (PR, ProArt Print Wax) and 2 CAD-CAM wax discs (YW, ProArt CAD Wax Yellow and BW, ProArt CAD Wax Blue) (n = 10). Each pattern was then digitized with a scanner (CEREC Primescan) and evaluated for 3D surface deviation at 4 different surfaces (overall, external, marginal, and intaglio surfaces) by using a 3D analysis software (Medit Link). Root mean square (RMS) values were automatically calculated. Data were analyzed by using Kruskal-Wallis and Dunn's post hoc tests for trueness and precision (alpha= 0.05).Results: Significant differences were found among the RMS values for overall (P<.001) and each surface (P <=.040) evaluated. PR had the highest overall (P <=.011) and intaglio surface (P <=.01) deviations, while the difference between YW and BW was not significant (P >=.199). PR had the highest (P <=.027) and BW had the lowest (P <=.042) external surface mean RMS values. BW had higher mean marginal RMS value than YW (P=.047). For precision, significant differences were observed among test groups only for marginal RMS values (P=.002). PR had lower precision than BW (P=.002).Conclusions: BW and YW FPDPs mostly had higher trueness compared with PR FPDPs. However, considering relatively smaller deviations at marginal and intaglio surfaces and the fact that patterns mostly had similar precision, clinical fit of FPDs fabricated by using tested patterns may be similar.Clinical Significance: Definitive 3-unit fixed partial dentures fabricated by using tested patterns may be similar. However, FPDs fabricated with tested additively manufactured resin patterns might result in more chairside adjustments than those fabricated with tested subtractively manufactured wax patterns.Öğe Effect of internal connection type and screw channel angle on the screw stability of anterior implant-supported zirconia crowns(Wiley, 2023) Cakmak, Guelce; Guven, Mehmet Esad; Donmez, Mustafa Borga; Kahveci, Cigdem; Schimmel, Martin; Abou-Ayash, Samir; Yilmaz, BurakObjectivesTo investigate the effect of implant-abutment connection and screw channel angle on screw stability by comparing a newly introduced and an established connection, before and after cyclic loading.Materials and MethodsImplants (N = 44) with Torcfit (TF) or Crossfit (CF) connection were divided to be restored with a straight (CFS and TFS) or an angled screw access channel (CFA and TFA) titanium-base abutment (n = 11). CFA and TFA received screw-retained crowns, whereas CFS and TFS received hybrid zirconia abutments and cement-retained crowns. The initial torque value (ITV) of each complex (ITVI) and removal torque value (RTV) after 24 h (RTVI) were measured. Screws were replaced with new ones, ITVs were recorded again (ITVF), and crowns were cyclically loaded (2.4 million cycles, 98 N) to measure RTVs again (RTVF). Percentage torque loss was calculated. Data were analyzed (a = 0.05).ResultsITVs were similar among groups (p = .089). CF led to higher RTVs (p = .002), while CFS had higher RTVI than CFA (p = .023). After 24 h, CFS had lower percentage torque loss than TF, while CFA had lower percentage torque loss than TFA (p = .011). After cyclic loading, CF led to lower percentage torque (p < .001).ConclusionThe implant-abutment connection affected the removal torque values. However, no screw loosening occurred during cyclic loading, which indicated a stable connection for all groups. Screw access channel angle did not affect screw stability after cyclic loading.Öğe Effect of number of supports and build angle on the fabrication and internal fit accuracy of additively manufactured definitive resin-ceramic hybrid crowns(Elsevier Sci Ltd, 2023) Cakmak, Gulce; Agovic, Dino; Donmez, Mustafa Borga; Kahveci, Cigdem; de Paula, Marcella Silva; Schimmel, Martin; Yilmaz, BurakObjectives: To evaluate the effect of number of supports and build angle on the fabrication and internal fit ac-curacy (trueness and precision) of additively manufactured resin-ceramic hybrid crowns. Methods: A mandibular first molar crown was designed and nested on the build platform of a printer either with a 30 degrees angle between the occlusal surface and the build platform (BLS (less support) and BMS (more support)) or its occlusal surface parallel to the build platform (VLS (less support) and VMS (more support)) to fabricate addi-tively manufactured resin-ceramic hybrid crowns (n = 14). After fabrication, supports were removed by a blinded operator and all crowns were digitized with an intraoral scanner. Fabrication accuracy (overall, external, intaglio occlusal, occlusal, and marginal) was evaluated by using root mean square (RMS) method, while internal fit was evaluated with triple scan method. RMS, average gap, and precision of these data were analyzed (alpha= 0.05).esults: VLS had higher overall deviations than BLS and VMS (P <=.039). VMS had higher occlusal deviations than BLS (P=.033). While BMS and BLS had higher marginal deviations than VLS (P <=.006), BMS also had higher values than VMS (P=.012). BLS led to higher precision than VMS (intaglio occlusal and occlusal surfaces) and VLS (occlusal surface) (P <=.008). VLS led to higher precision than BMS (marginal surface) (P=.027). Average gap values were similar (P=.723); however, BLS resulted in higher precision than VLS (P=.018).Conclusions: Considering their high marginal and occlusal surface trueness, and similar internal occlusal de-viations and average gaps (trueness), clinical fit of resin-ceramic hybrid crowns fabricated with tested parameters may be similar. Reduced number of supports and angled orientation may lead to higher precision of fit. Clinical Significance: Tested resin-ceramic hybrid-printer pair may be used to fabricate crowns with reduced number of supports to maintain occlusal surface integrity without compromising the fabrication accuracy and fit.Öğe Effect of polishing and denture cleansers on the surface roughness of new-generation denture base materials and their color change after cleansing(Wiley, 2023) Cakmak, Guelce; Hess, Julia Anouk; Donmez, Mustafa Borga; Yilmaz, Deniz; Alhotan, Abdulaziz; Schimmel, Martin; Peutzfeldt, AnnePurpose: To evaluate the effect of polishing and denture cleansers on the surface roughness (Ra) of new-generation denture basematerials that are additively, subtractively, and conventionally fabricated, while also assessing their color change after cleansing. Material and Methods: One hundred and fifty disk-shaped specimens (O10 x 2 mm) were prepared from five denture base materials (one subtractively manufactured nanographene-reinforced prepolymerized polymethylmethacrylate (PMMA) (SM-GC), one subtractively manufactured prepolymerized PMMA (SM-PM), two additively manufactured denture base resins (AM-DT and AM-ND), and one heat-polymerized PMMA (CV) (n = 30). The R-a of the specimens was measured before and after conventional laboratory polishing, while color coordinates were measured after polishing. Specimens were then divided into three subgroups based on the denture cleanser: distilled water, 1% sodium hypochlorite (NaOCl), and effervescent tablet (n = 10). The R-a and color coordinates were remeasured after nine cleansing cycles over a period of 20 days. The CIEDE2000 formula was used to calculate the color differences (Delta E-00). Two-way analysis of variance (ANOVA) was used to analyze the R-a values before (n = 30) and after (n = 10) cleansing, while repeated measures ANOVA was used to analyze the R-a of material-time point pairs within each denture cleanser (n = 10). Delta E-00 data after denture cleansing was also analyzed by using two-way ANOVA (n = 10) (a = 0.05). Results: Before polishing, Ra varied significantly among the materials. SM-GC and SM-PM had the lowest and AM-ND the highest Ra values (P < 0.001). Polishing significantly reduced R-a of all materials (P < 0.001), and after polishing, Ra differences among materials were nonsignificant (P >= 0.072). Regardless of the denture cleanser, the R-a of AM-DT, AM-ND, and CV was the highest before polishing when different time points were considered (P < 0.001). After cleansing, AM-ND had the highest R-a of all the materials, regardless of the cleanser (P <= 0.017). AM-DT had higher R-a than SM-PM when distilled water (P = 0.040) and higher R-a than SM-GC, SM-PM, and CV when NaOCl was used (P < 0.001). The type of cleanser significantly influenced the R-a of AM-DT, AM-ND, and CV. For AM-DT, NaOCl led to the highest R-a and the tablet led to the lowest R-a (P <= 0.042), while for AM-ND, distilled water led to the lowest R-a (P <= 0.024). For CV, the tablet led to lower R-a than distilled water (P = 0.009). Color change varied among the materials. When distilled water was used, SM-GC had higher Delta E-00 than SM-PM and AM-DT (P <= 0.034). When NaOCl was used, AM-ND had higher Delta E-00 than SM-GC, SM-PM, and AM-DT, while CV and SM-GC had higher Delta E-00 than SM-PM and AM-DT (P = 0.039). Finally, when the tablet was used, AM-ND and CV had the highest Delta E-00, while AM-DT had lower Delta E-00 than SM-GC (P = 0.015). Conclusions: The tested materials had unacceptable surface roughness (>0.2 mu m) before polishing. Roughness decreased significantly after polishing (<0.2 mu m). Denture cleansers did not significantly affect the surface roughness of the materials, and roughness remained clinically acceptable after cleansing (<0.2 mu m). Considering previously reported color thresholds, AM-ND and CV had unacceptable color change regardless of the denture cleanser, and the effervescent tablet led to perceptible, but acceptable color change for SM-GC, SM-PM, and AM-DT.Öğe Effect of printing layer thickness on the trueness and fit of additively manufactured removable dies(Elsevier, 2022) Yılmaz, Burak; Dönmez, Mustafa Borga; Kahveci, Çiğdem; Cuellar, Alfonso Rodrigues; de Paula, Marcella Silva; Schimmel, Martin; Abou-Ayash, Samirl; Çakmak, GülceStatement of problem: Additive manufacturing is commonly used for the fabrication of definitive casts with removable dies. However, how the trueness and fit of removable dies are affected by printing layer thickness is lacking. Purpose: The purpose of this in vitro study was to investigate the trueness and fit of additively manufactured removable dies printed in different layer thicknesses. Material and methods: A mandibular cast with a prepared right first molar tooth was digitized (CEREC Primescan), and its standard tessellation language (STL) file was imported into a software program (DentalCAD 3.0). A removable die (D-STL) and a hollow cast with (M-STL) or without the die (SM-STL) were designed. D-STL and SM-STL were imported into a nesting software program (Composer), and 45 removable dies in 3 layer thicknesses (100 ?m, 50 ?m, and 50 to 100 ?m) (n=15) and 1 cast (100-?m) were additively manufactured. Each removable die (TD-STLs), the cast with each die (TM-STLs), and the cast without the die (TSM-STL) were digitized by using the same scanner. All STL files were imported into a software program (Medit Link v 2.4.4), and TD-STLs were superimposed over D-STL. The root mean square (RMS) method was used to analyze the trueness of the dies at 2 different areas (crown and root portion) and as a complete unit (overall). Overall RMS values of the cast with and without the die were also calculated after superimposing TM-STLs over M-STL. The fit of the dies in the cast was evaluated by using a triple-scan protocol to measure deviations at 5 different points (point M: most mesial point of the margin; point TM: tip of the mesial cusp; point O: deepest point of the occlusal fossa; point TD: tip of the distal cusp; point D: most distal point of the margin) on the crown portion. One-way ANOVA and Tukey honestly significant difference tests were used to evaluate data (?=.05). Results: The RMS values of removable dies showed significant differences at each area (P?.002). The 50- to 100-?m group had higher overall RMS values than the 100-?m group (P=.017). The 100-?m group had the highest RMS values for the crown portion (P?.019), while the 50-?m group had the highest RMS values for the root portion (P<.001). The 50-?m group had the lowest RMS values for the crown portion when the die was in the cast (P<.001). Except for point TM (P=.228), significant differences were observed among the test groups at all points (P<.001). The 50-?m group had the lowest distance deviations at points M, TD, and D (P?.005), while the 100-?m group had the highest distance deviations at points O and D (P?.010). Conclusions: Removable dies fabricated by using a 100-?m or 50- to 100-?m combined layer thickness had trueness that was either similar to or better than that of dies fabricated with a 50-?m layer thickness. When the die was on the cast, the 50-?m layer thickness resulted in the best crown portion trueness. However, because the deviation differences among groups were clinically small, the 100-?m layer thickness can be considered for the efficient fabrication of removable dies when the tested printer and resin are used. © 2022 Editorial Council for the Journal of Prosthetic DentistryÖğe Effect of printing layer thickness on the trueness of 3-unit interim fixed partial dentures(Elsevier Science, 2022) Çakmak, Gülce; Cuellar, Alfonso Rodriguez; Dönmez, Mustafa Borga; Abou-Ayash, Samir; Lu, Wei-En; Schimmel, Martin; Yılmaz, BurakStatement of problem. Three-dimensional printing has facilitated the fabrication processes in dentistry. However, knowledge on the effect of layer thickness on the trueness of 3D-printed fixed partial dentures (FPDs) is lacking. Purpose. The purpose of this in vitro study was to compare the effect of printing layer thickness on the trueness of 3-unit interim FPDs fabricated by using additive manufacturing with that of those fabricated by subtractive manufacturing. Material and methods. The right first premolar and first molar teeth of a dentate mandibular model were prepared for a 3-unit restoration and then digitized by using an intraoral scanner. A 3-unit interim FPD was designed to fabricate 40 restorations by using either the additive (NextDent C&B MFH) with layer thicknesses of 20 mm (n=10), 50 mm (n=10), and 100 mm (n=10) or subtractive manufacturing technique (Upcera) (milled, n=10). After fabrication, the interim FPDs were digitized by using the same intraoral scanner and were superimposed over the design data by using a 3D analysis software program. Root mean square (RMS) was used to analyze the trueness of the restorations at 4 different surfaces (external, intaglio, marginal area, and intaglio occlusal) and as a complete unit (overall). Data were analyzed with the Kruskal-Wallis and Wilcoxon tests with Bonferroni correction (a=.05). Results. The 100-mm-layer thickness interim FPDs showed the greatest overall (P .015), external (P .021), and intaglio occlusal (P .021) deviations, whereas the milled interim FPDs showed the lowest (P=.001). No significant differences were found among the test groups for marginal RMS (P .108). The differences between the 50-mm-layer thickness and 100-mm-layer thickness interim FPDs for the intaglio surface deviations (P=.064) and between the 20-mm-layer thickness and 50- mm-layer thickness interim FPDs for each surface tested were not statistically significant (P .108). Conclusions. The printing layer thickness had a significant effect on the trueness of the additively manufactured interim FPDs. However, subtractively manufactured interim FPDs presented higher trueness than those additively manufactured, regardless of the printing layer thickness. (J Pros- thet Dent 2022;-:---)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 Implementation of triple-scan protocol to evaluate the fit of complete-arch implant-supported fixed prostheses(Wiley, 2024) Donmez, Mustafa Borga; Cakmak, Gulce; Schimmel, Martin; Yilmaz, BurakPassive fit is essential for multiple-unit implant-supported prostheses. Conventional methods to assess the passivity of complete-arch implant-supported prostheses do not allow 3-dimensional (3D) visualization and quantification of misfit. This report describes the marginal and internal fit evaluation of a complete-arch implant-supported prosthesis by using the triple-scan protocol involving a scanner and a 3D analysis freeware. This technique allows researchers, clinicians, or dental technicians to detect and quantify 3D prosthetic misfit, which may facilitate the preparation for dental appointments and objective measurement of misfit for research studies.Öğe Influence of intraoral scanner and finish line location on the fabrication trueness and margin quality of additively manufactured laminate veneers fabricated with a completely digital workflow(Mosby-Elsevier, 2024) Cakmak, Guelce; Chebaro, Jad; Donmez, Mustafa Borga; Yilmaz, Deniz; Yoon, Hyung-In; Kahveci, Cigdem; Schimmel, MartinStatement of problem. Knowledge of the fabrication trueness and margin quality of additively manufactured (AM) laminate veneers (LVs) when different intraoral scanners (IOSs) and finish line locations are used is limited. Purpose. The purpose of this in vitro study was to evaluate the fabrication trueness and margin quality of AM LVs with different finish line locations digitized by using different IOSs. Material and methods. An LV preparation with a subgingival (sub), equigingival (equi), or supragingival (supra) finish line was performed on 3 identical maxillary right central incisor typodont teeth. Each preparation was digitized by using 2 IOSs, (CEREC Primescan [PS] and TRIOS 3 [TS]), and a reference LV for each finish line-IOS pair (n=6) was designed. A total of 90 LVs were fabricated by using these files and urethane acrylate-based definitive resin (Tera Harz TC-80DP) (n=15). Each LV was then digitized by using PS to evaluate fabrication trueness (overall, external, intaglio, and marginal surfaces). Each LV was also qualitatively evaluated under a stereomicroscope (x60), and the cervical and incisal margin quality was graded. Fabrication trueness and cervical margin quality were evaluated by using 2 -way analysis of variance, while Kruskal-Wallis and Mann Whitney -U tests were used to evaluate incisal margin quality (alpha=.05). Results. The interaction between the IOS type and the finish line location affected measured deviations at each surface (P <=.020). PS -sub and TS -supra had higher overall trueness than their counterparts. and the subgingival finish line resulted in the lowest trueness (P <=.005). PS and the subgingival finish line led to the lowest trueness of the external surface (P <=.001). TS -sub had the lowest intaglio surface trueness among the TS subgroups, and PS -sub had higher trueness than TS -sub (P<.001). PS -sub and PS -supra had higher marginal surface trueness than their TS counterparts (P<.001). TS resulted in higher cervical margin quality (P=.001). Conclusions. Regardless of the IOS tested, subgingival finish lines resulted in the lowest trueness. The effect of IOS on the measured deviations varied according to the surface evaluated and finish line location. The cervical margin quality of AM LVs was higher when TS was used. (J Prosthet Dent 2024;131:313.e1 -e9)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 stainability of CAD-CAM denture base materials after simulated brushing and coffee thermocycling(Elsevier, 2022) Çakmak, Gülce; Dönmez, Mustafa Borga; Atalay, Sevda; Silva de Paula, Marcella; Fonseca, Manruque; Schimmel, Martin; Yılmaz, BurakStatement of problem: Denture bases machined from prepolymerized materials have become popular. However, information on the effect of simulated brushing and coffee thermocycling (CTC) on their surface roughness and stainability is lacking. Purpose: The purpose of this in vitro study was to compare the effect of simulated brushing and CTC on the surface roughness (Ra) and stainability of computer-aided design and computer-aided manufacturing (CAD-CAM) denture base materials and a heat-polymerized denture base material. Material and methods: Forty disk-shaped specimens were prepared from 3 CAD-CAM denture base resins (AvaDent, AV; Merz M-PM, M-PM; and Polident d.o.o, Poli) and a heat-polymerized polymethylmethacrylate resin (Promolux, CV) (n=10). Ra values of the specimens were measured by using a noncontact profilometer after conventional polishing. The color coordinates were also measured over a gray background with a spectrophotometer. Specimens were then consecutively subjected to simulated brushing for 20 000 cycles, CTC for 5000 cycles, and another 10 000 brushing cycles. Ra and color coordinates were measured after each interval. Color differences (?E00) were calculated by using the CIEDE2000 formula, and the data were analyzed by using 2-way analysis of variance and Tukey honestly significant difference tests (?=0.05). Results: The time interval had a significant effect on Ra (P<.001) as brushing cycles resulted in higher values than those at baseline and after CTC (P<.001). However, the differences between brushing cycles (P=.143) and between the baseline and after CTC (P=.994) were not significant. The interaction between the material type and time interval was significant for ?E00 (P=.016). The only significant difference in ?E00 values was observed between M-PM and CV after all treatments were completed (P=.029). Conclusions: Brushing increased the Ra of all materials when compared with the baseline. All materials showed similar stainability throughout the brushing and CTC processes. However, M-PM CAD-CAM denture base resin underwent a greater color change after all treatments were completed than conventional denture base resin. All color changes can be considered clinically small, considering reported perceptibility and acceptability thresholds.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.
