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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, Burak
Objectives: 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.
Color and translucency of milled polymethyl methacrylate crowns on non-tooth-colored interim abutments with different surface treatments
(2022) Çakmak, Gülce; Cuellar, Alfonso Rodriguez; Treviño Santos, Alejandro; Johnston, William M; Dönmez, Mustafa Borga; Yılmaz, Burak
Statement of problem: The interim rehabilitation of implants has become a necessity, particularly for those placed in the esthetic regions. However, the optical properties of computer-aided design and computer-aided manufacturing (CAD-CAM) polymethyl methacrylate (PMMA) crowns on interim abutments with different surface treatments are unclear. Purpose: The purpose of this in vitro study was to investigate the color and translucency of CAD-CAM PMMA crowns when different surface treatments were used on titanium interim abutments. Material and methods: A maxillary dentate stone cast with a narrow-diameter implant analog at the left lateral incisor site was used. Three titanium interim abutments (blue) were divided into 3 groups according to the surface treatment they received: control (steam cleaning), opaqued (120-?m Al2O3 airborne-particle abrasion and opaque application), and airborne-particle abraded (120-?m Al2O3). Thirty PMMA crowns (A2 shade) were milled (n=10). The color coordinates of the crown-interim abutment pairs and a shade tab (A2) were measured by using a colorimeter. The color differences (?E00) between the crowns and the shade tab and the relative translucency parameter (RTP) values of the crowns were calculated by using the CIEDE2000 formula. One-way ANOVA was used to analyze the ?E00 and RTP values with subsequent Tukey honestly significant difference tests (?=.05). Results: The abutment surface treatment significantly affected the ?E00 of interim crowns from the shade tab (P<.001), but no significant effect was found on RTP (P=.26). The control group had the highest ?E00 from the shade tab (P?.011). No significant difference (P=.14) was found between the opaqued and the ?E00 of the airborne-particle abraded groups from the shade tab. Conclusions: The surface treatments of interim abutments affected the color of CAD-CAM PMMA crowns, which differed from that of the shade tab. The color of crowns on opaqued or airborne-particle abraded interim abutments was closer to the color of the shade tab. Abutment surface treatments did not affect the translucency of crown-interim abutment pairs.
Comparison of measured deviations in digital implant scans depending on software and operator
(Elsevier, 2022) Çakmak, Gülce; Marques, Vinicius Rizzo; Dönmez, Mustafa Borga; Lu, Wei-En; Abou-Ayash, Samir; Yılmaz, Burak
Objectives: To investigate the effect of 3-dimensional (3D) analysis software and operator on the measured deviations in implant scans. Material and Methods: A combined healing abutment-scan body (CHA-SB) system was digitized with an industrial scanner (ATOS Core 80) to generate a master standard tessellation language file (MRM-STL) and an intraoral scanner (TRIOS 3) to generate 9 test-scan STL files, which were transferred into metrology-grade (Geomagic Control X, GX and GOM Inspect, GM) and nonmetrology-grade (Medit Link, ML) software for deviation analysis. Test-scan STLs were superimposed over MRM-STL and 2 planes passing through the center of the SB were generated. Distance deviations at 8 points on these planes were analyzed by two different operators with similar level of experience. Data were analyzed with analysis of variance and F tests (?=.05). Results: Only model 1 (P=.049) analyzed by operator 2 showed significant differences among tested software, and the highest deviations were measured with GM (P?.037). However, the difference in values measured with GX and ML was nonsignificant (P=.91). Operator correlation was high (ICC?.712, P?.011), except for models 1 (GM, ICC=-.335, P=.813), 2 (GM, ICC=.025, P=.468 and ML, ICC=-.013, P=.507), 6 (GM, ICC=-.085, P=.583), and 8 (GM, ICC=-.386, P=.85). Conclusion: The measured deviations in implant scans in all models, except for one, were similar among the tested software, regardless of the operator. The inter-rater reliability of operators while using tested 3D analysis software was overall high. When observed, low inter-rater reliability was mostly with only one of the metrology grade software. Clinical Significance: Nonmetrology-grade 3D analysis software may be a suitable alternative to metrology-grade software to measure the deviations in digital implant scan body scans. When GOM metrology-software is used, measured deviations in implant scan body scans may vary more across operators. © 2022
Effect of different surface treatments and thermomechanical aging on the ion elution of CAD-CAM materials
(Elsevier Science, 2022) Sert, Murat; Gülce Subaşı, Meryem; Çakmak, Gülce; Dönmez, Mustafa Borga; Yılmaz, Burak
Statement of problem. Dental ceramics have been reported to elute ions when subjected to nonneutral pH. However, the effect of surface treatments and thermomechanical aging on the ion elution of CAD-CAM ceramics is unclear. Purpose. The purpose of this in vitro study was to compare the effect of surface treatment (glazed or polished) and thermomechanical aging on the ion elution of CAD-CAM materials before and after 2-body wear simulation. Material and methods. Specimens were prepared from 6 CAD-CAM materialsdleucite (LC), feldspathic (FP), zirconia-reinforced lithium silicate (ZLS), lithium disilicate (LDS) glass-ceramics, polymer-infiltrated ceramic network (PICN), and zirconia (ZIR)dand divided into 2 groups according to the surface treatments (glazed or polished) (n=6). For baseline ion elution values, specimens were placed into polyethylene bottles containing deionized water (pH 7.4) that had been stored in an incubator for 168 hours at 37 C. The eluted ions in the immersion solution were measured by using inductively coupled plasma-optic emission spectrophotometry. The specimens were then subjected to thermomechanical aging by using human enamel as an antagonist. After aging, the ion elution of the specimens was remeasured. Ion elution data before and after 2-body wear were analyzed by using the Mann-Whitney U test, while the effect of 2-body wear was assessed by using the Wilcoxon signed rank test (a=.05). Results. The presence of some ions varied depending on the material-surface treatment pair before (Al, As, B, Ba, Ca, K, Li, Mg, Na, P, and Zn) and after (Al, B, Ba, Ca, Co, Li, Mg, and P) 2-body wear. Polished materials had higher ion elution than the glazed materials before 2-body wear (P .041), except for LC (P and Zn) and PICN (Ca, Cu, and K) (P .009). After 2-body wear, polished LC (B and Ba), FP (Al, B, and Mg), ZLS (Al, Ba, Ca, and Li), ZIR (B and Ba), glazed PICN (Ca, Mg, and P), ZLS (P), and ZIR (Co) presented higher ion elution than their counterparts (P .041). The effect of 2-body wear on the ion elution of polished LC (Al, K), FP (Na), ZLS (Li), LDS (K, Na), PICN (Al, Na), ZIR (Na, Y), glazed LC (Na), FP (Ba, Na), ZLS (B, Ba, Y), LDS (Na), PICN (Y), and ZIR (Na) was nonsignificant (P .075). However, the elution of remaining ions showed a significant difference before and after 2-body wear (P .046). Conclusions. The chemical stability of tested CAD-CAM materials was affected by the 2-body wear. Glazing led to a lower ion elution except for LDS and PICN. While polishing resulted in lower ion elution for PICN, both surface treatments resulted in similar ion elution for LDS. (J Prosthet Dent 2022;-:---)
Effect of different surface treatments on the surface roughness and orthodontic bond strength of partially-stabilized zirconia
(GALENOS YAYINCILIK, 2022) Dönmez, Mustafa Borga; Demirel Ballı, Betül; Demirel, Münir; Gündoğdu, Yasemin; Kılıç, Hamdi Şükür
Objective: To investigate the effect of different surface treatments on the surface roughness (Ra) and shear bond strength (SBS) of partially stabilized zirconia (Y-PSZ) with different yttrium content.Materials and Methods: Zirconia samples were milled from 5Y-PSZ and 4Y-PSZ disks and divided into 5 groups: Control (C), sandblasting (APA), single-step self -etch primer etching (MEP), Er:YAG laser (ER), and femtosecond laser (FS) irradiation (n=11). Surface Ra was measured and metallic mandibular incisor brackets were bonded. SBS test was performed after thermocycling. Data were analyzed using two-way ANOVA and Tamhane's T2 tests (alpha=0.05).Results: Only surface treatment affected Ra and SBS (p<0.001). FS groups had the highest (p<0.001), and C groups had the lowest values Ra (p <= 0.001). MEP groups had lower Ra than ER and APA (p <= 0.002). FS and APA groups resulted in the highest SBS (p<0.001), while MEP groups achieved significantly higher SBS than ER groups (p<0.001). The C group showed the lowest SBS (p<0.001).Conclusion: Within the limitations of this in vitro study, sandblasting and FS irradiation was found to be the most effective surface treatments for metallic bracket bonding to Y-PSZ.
Effect of firing cycle and aging on long-term chemical degradation of monolithic CAD-CAM ceramics
(Elsevier Science, 2022) Sert, Murat; Gülce Subaşı, Meryem; Dönmez, Mustafa Borga; Çakmak, Gülce; Yiımaz, Burak
Statement of problem. Previous studies have shown the susceptibility of dental ceramics to degradation when subjected to certain media. However, knowledge on the effect of repeated firings and thermocycling on the ion elution of computer-aided design and computer-aided manufacturing (CAD-CAM) ceramics is lacking. Purpose. The purpose of this in vitro study was to compare the effect of repeated firings on the ion elution of CAD-CAM materials before and after thermocycling. Material and methods. Bar-shaped specimens were prepared from 4 different CAD-CAM materials (monolithic zirconia [Z], zirconia- reinforced lithium silicate glass-ceramic [S], lithium disilicate glass-ceramic [EX], and leucite-reinforced glass-ceramic [E]) and divided into 3 groups according to the number of repeated glaze firings (1 firing [1F], 2 firings [2F], and 4 firings [4F]). Specimens were placed into deionized water (pH 7.4) and stored at 37 C for 168 hours. Inductively coupled plasma-optic emission spectrophotometry (ICP-OES) was used to measure the baseline values of the eluted ions in immersion. The specimens were then subjected to thermocycling. Then, surface roughness (Ra) and ion elution values were measured. The Kruskal-Wallis and Mann-Whitney U tests were used to analyze the ion elution data before and after thermocycling, and the effect of thermocycling on ion elution was assessed by the Wilcoxon signed rank test. Ra data were analyzed with 2-way analysis of variance (ANOVA) and the Tukey honestly significant difference tests (a=.05). Results. Elution of some ions varied depending on the material-firing pair before (Al, As, B, Ba, Cr, Cu, Li, Mg, Na, P, and Zn) and after (Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, K, Li, Mg, Na, P, Y, and Zn) thermocycling. Before thermocycling, all firing groups within each material showed a similar number of significantly higher eluted ions. After thermocycling, the number of significantly higher eluted ions decreased in all materials, except for EX. The effect of thermocycling on the ion elution of the 1F group of Z (Al, Be, Ca, Cd, Co, Cr, Cu, K, Li, P, Y, and Zn), S (As, Be, Cd, Co, Cr, K, P, and Y), EX (B, Cu, and P), and E (B and Ba); 2F group of Z (Al, Be, Ca, Co, Cr, Cu, K, Li, P, and Y), S (Be, Cd, Co, K, Li, and Y), EX (P), and E (P); 4F group of Z (Al, As, Ba, Be, Ca, Cd, Co, Cr, Cu, K, Li, P, and Y), S (Al, Be, Cd, Co, Cr, Li, Mg, and Y), EX (Be, Ca, Cd, Co, K, Y, and Zn), and E (Ca and P) was nonsignificant (P .051). The interaction between material and repeated firings (P<.001) had a significant effect on Ra. For 1F groups, E showed the highest Ra (P .003), while Z had higher Ra than S (P=.009). For 2F groups, Z had higher Ra than S (P=.01). The differences among 4F groups were nonsignificant (P .677). An increased number of repeated firings (2F and 4F) decreased the Ra of E (P<.001). Conclusions. The effect of repeated firings and thermocycling on the chemical stability of the tested CAD-CAM materials varied. No clear trend was observed on the elution of different ions within material-firing pairs before thermocycling. However, thermocycling increased the number of significantly higher eluted ions for EX. The effect of thermocycling on the ion elution of materials varied depending on ions. Repeated firings decreased the surface roughness of E. (J Prosthet Dent 2022;-:---)
Effect of intraoral scanner and fixed partial denture situation on the scan accuracy of multiple implants: an in vitro study
(Wiley, 2023) Abou Ayash, Samir; Yılmaz, Burak; Mathey, Amber; Gaeumann, Fabio; Mathey, Ayşe; Dönmez, Mustafa Borga
BackgroundAccuracy of intraoral implant scans may be affected by the region of the implant and the type of the intraoral scanner (IOSs). However, there is limited knowledge on the scan accuracy of multiple implants placed for an implant-supported fixed partial denture (FPD) in different partially edentulous situations when digitized by using different IOSs. PurposeTo investigate the effect of IOS and FPD situation on the scan accuracy of two implants when partial-arch scans were performed. Materials and MethodsTissue level implants were placed in 3 maxillary models with implant spaces either at right first premolar and right first molar sites (Model 1, 3-unit FPD), at right canine and right first molar sites (Model 2, 4-unit FPD), or at lateral incisor sites (Model 3, 4-unit FPD). Reference standard tessellation language (STL) files of the models were generated by using an optical scanner (ATOS Capsule 200MV120). Two IOSs (CEREC Primescan [CP] and TRIOS 3 [TR]) were used to perform partial-arch scans (test-scans) of each model (n = 14), which were exported in STL format. A metrology-grade analysis software (GOM Inspect 2018) was used to superimpose test-scan STLs over the reference STL to calculate 3D distance, inter-implant distance, and angular (mesiodistal and buccopalatal) deviations. Trueness and precision analyses were performed by using bootstrap analysis of variance followed by Welch tests with Holm correction (alpha = 0.05). ResultsTrueness of the scans was affected by IOS and FPD situation when 3D distance deviations were considered, while inter-implant distance, mesiodistal angular, and buccopalatal angular deviations were only affected by the FPD situation (p < 0.001). Scan precision was affected by the interaction between the IOSs and the FPD situation when 3D distance and buccopalatal angular deviations were concerned, while IOSs and FPD situation were effective when all deviations were concerned (p <= 0.001). When 3D distance deviations were considered, CP scans had higher accuracy TR scans in Models 1 and 3 (p <= 0.002), and the Model 1 scans had the highest accuracy (p < 0.001). When inter-implant distance deviations were considered, Model 1 scans had the highest accuracy with CP and higher accuracy than Model 2 when TR was used (p <= 0.030). When mesiodistal angular deviations were considered, Model 1 scans had the highest accuracy (p <= 0.040). When buccopalatal angular deviations were considered, Model 1 scans had the highest accuracy among models when CP was used (p <= 0.020). ConclusionsPosterior 3-unit fixed partial denture implant scans, CP scans, and combination of these two factors had accuracy either similar to or better than their tested counterparts.
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, Burak
Objectives: 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.
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, Burak
Abstract: 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.
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, Gülce
Statement 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 Dentistry
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, Burak
Statement 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;-:---)
Effect of printing orientation on the fracture strength of additively manufactured 3-unit interim fixed dental prostheses after aging
(Elsevier Science, 2022) Diken Türksayar, Almira Ada; Dönmez, Mustafa Borga; Olcay, Emin Orkun; Demirel, Münir; Demir, Esra
Objectives: To evaluate the effect of printing orientation on the fracture strength of 3-unit interim fixed dental prostheses fabricated by using additive manufacturing and to compare with those fabricated by subtractive manufacturing after thermomechanical aging. Materials and Methods: A 3-unit fixed dental prosthesis was designed by using a dental design software (exocad DentalCAD 2.2 Valetta) in standard tessellation language (STL) format. This STL file was exported into a nesting software (PreForm) and 3-unit interim fixed dental prostheses with 5 different orientations (0°, 30°, 45°, 90°, and 150°) were printed by using a 3-dimensional (3D) printing interim resin (Temporary CB) (n=10). The same STL file was also used to mill polymethymethacrylate (DuoCAD) 3-unit interim fixed dental prostheses as the control group (n=10). All specimens were cemented onto cobalt-chromium test models representing a maxillary first premolar and first molar tooth with a long-term temporary cement (DentoTemp), and subjected to thermomechanical aging (120000 cycles, 1.6 Hz, 50 N, 5-55°C). Then, all specimens were loaded until fracture by using a universal tester. The data were analyzed with nonparametric 1-way analysis of variance (Kruskal- Wallis) and Dunn’s tests (? = 0.05). 3 Results: Additively manufactured specimens printed with 90° showed the lowest fracture strength values (P?.048). However, the difference between specimens printed with 45° and 90° was nonsignificant (P>.05). Milled 3-unit interim fixed dental prostheses withstood significantly higher loads than 3-unit interim fixed dental prostheses printed with 45° and 150° (P?.012). In addition, specimens printed with 0° showed higher fracture strength than the specimens printed with 45° (P=.01). Specimens printed with 0° and 30° presented similar fracture strength values with milled (P?.057) and 150° printed (P>.05) specimens. Conclusion: Printing orientation had a significant effect on the fracture strength of 3-unit interim fixed dental prostheses. Among the additively manufactured samples, those printed with 0° showed similar fracture strength values with the subtractively manufactured samples. Clinical Significance Three-unit interim fixed dental prostheses fabricated with 0° and 30° using the 3D printing interim resin tested may be alternatives to milled PMMA in terms of fracture strength
Effect of scanned area and operator on the accuracy of dentate arch scans with a single implant
(MDPI, 2022) Marques, Vinicius Rizzo; Çakmak, Gülce; Yılmaz, Hakan; Abou-Ayash, Samir; Dönmez, Mustafa Borga; Yılmaz, Burak
Studies have shown the effect of the operator and scanned areas on the accuracy of single implant scans. However, the knowledge on the scan accuracy of the remaining dental arch during single implant scans, which may affect the occlusion, is limited. The aim of this study was to investigate the effect of scanned areas and the operator on the scan accuracy of a dentate arch while scanning a single implant. A dentate model with an anterior implant was digitized with a laboratory scanner (reference scan). Three operators with similar experience performed 10 complete- and 10 partial-arch scans (left 2nd molar to right canine) with an intraoral scanner (TRIOS 3), and these scans were superimposed over the reference. The accuracy was analyzed at 22 points in complete-arch and at 16 points in partial-arch scans on 2nd molars and incisors. Data were evaluated with 2-way ANOVA and Tukey HSD tests (? = 0.05). The trueness of the total scanned area was higher in partialthan in complete-arch scans (p < 0.001). The trueness and precision of the scans were higher in the anterior site compared with the posterior in complete- (trueness: p ? 0.022, precision: p ? 0.003) and partial-arch (trueness: p ? 0.016, precision: p ? 0.016) scans of each operator and when the operator scan data were pooled. The complete-arch scan’s precision was not influenced by the operator (p ? 0.029), whereas the partial-arch scans of operator 1 and 2 were significantly different (p = 0.036). Trueness was higher in partial- compared with complete-arch scans, but their precision was similar. Accuracy was higher in the anterior site regardless of the scan being a partial- or a complete-arch. The operator’s effect on the accuracy of partial- and complete-arch scans was small.
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, Burak
Purpose: 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.
Effect of the thickness of CAD-CAM materials on the shear bond strength of light-polymerized resin cement
(Wiley, 2022) Okutan, Yener; Kandemir, Banuçiçek; Dönmez, Mustafa Borga; Yücel, Münir Tolga
This study aimed to investigate the effect of the thickness of computer aided design-computer aided manufacturing (CAD-CAM) restorative materials on the bond strength of light-polymerized resin cement. Ninety specimens were prepared from three different CAD-CAM materials (a leucite-based glass-ceramic [Empress CAD], a polymer-infiltrated ceramic network [Vita Enamic], and a zirconia-reinforced lithium silicate glass-ceramic [Vita Suprinity]) in different thicknesses (1, 2, and 3 mm). One surface of each specimen was treated by using a single-step self-etching ceramic primer (Monobond Etch & Prime). Light-polymerized resin cement was bonded to treated surfaces by exposure to a light-emitting diode curing unit from the untreated side of the samples. Shear bond strength (SBS) between the ceramic and the resin cement was measured by using a universal testing machine. The leucite-based glass-ceramic had higher SBS values than the other materials at each thickness. For each material, 1 mm-thick specimens had the highest SBS values. The difference between the SBS values of 2 mm- and 3 mm-thick polymer-infiltrated ceramic network was nonsignificant, whereas the SBS values of 2 mm-thick leucite-based glass-ceramic and the zirconia-reinforced lithium silicate glass-ceramic were significantly higher than those of the corresponding 3 mm-thick specimens. The choice of the material and its thickness may be highly important for clinical success when light-polymerized resin cements are used for cementation.
In vitro scan accuracy and time efficiency in various implant-supported fixed partial denture situations
(Elsevier, 2022) Abou Ayash, Samir; Mathey, Amber; Gäumann, Fabio; Mathey, Ayşe; Dönmez, Mustafa Borga; Yılmaz, Burak
In vitro scan accuracy and time efficiency in various implant-supported fixed partial denture situations
Influence of digital implant analog design on the positional trueness of an analog in additively manufactured models: an in-vitro study
(John Wiley and Sons Inc, 2022) Mata-Mata, Severino J.; Dönmez, Mustafa Borga; Meirelles, Luiz; Johnston, William Michael; Yılmaz, Burak
Background: Limited evidence exists regarding the accuracy of implant analog position in printed models, particularly when implant analogs with varying designs are used. Purpose: To evaluate the effect of digital implant analog (DIA) design on the trueness of their position in additively manufactured digital implant models (DIMs) and to compare with that of a conventional implant analog in a stone cast. Materials and Methods: A dentate maxillary model with a conventional implant analog (Nobel Biocare Implant Replica 4.3 mm CC RP) at left second premolar site was digitized by using a laboratory scanner (3Shape D2000) and a (SB) scan body to generate the master standard tessellation language (STL) file (M0). 12 custom trays were fabricated on M0 file and conventional polyvinylsiloxane impressions of the model were made. All impressions were poured after inserting conventional implant analogs (Nobel RP Implant Replica) (Group A). Model was then digitized with an intraoral scanner (TRIOS 3) and the same SB, and DIMs with three different DIA designs (Nobel Biocare [Group B], Elos [Group C], and NT-trading [Group D]) were generated (Dental System-Model Builder). 12 DIMs of each design were additively manufactured and corresponding DIAs were inserted. All models were digitized by using the same laboratory scanner and SB, and these STLs were transferred to a 3D analysis software (Geomagic Control X), where the STL files of the models were superimposed over M0. Linear and 3D deviations at three selected points on SB (implant-abutment connection, most cervical point on SB, and most coronal point on SB) as well as angular deviations on two planes (buccolingual and mesiodistal) were calculated. Analysis of variance (ANOVA) and Bonferroni corrected t-tests were used to analyze the trueness of implant analog positions (? = 0.05). Results: The interaction of main effects significantly affected linear (p < 0.001) and angular deviations (p = 0.020). At point 1, group D had higher deviations than groups A and B (p ? 0.015). In addition, groups A and D had higher deviations than group B at point 4 (p < 0.001). While group C had similar linear deviations to those of other groups at point 1 and point 4 (p ? 0.192), the differences among test groups at point 2 were nonsignificant (p ? 0.276). Group B had lower angular deviations than groups C (p = 0.039) and D (p = 0.006) on buccolingual plane. Conclusions: Analog design affected the trueness of analog position as proprietary, pressure/friction fit DIA (group B) had higher linear trueness than screw-retained DIA (Group D) and conventional implant analog (group A). In addition, pressure/friction fit DIA had the highest angular trueness among tested DIAs.
Load-to-failure resistance and optical characteristics of nano-lithium disilicate ceramic after different aging processes
(MDPI, 2022) Dönmez, Mustafa Borga; Olcay, Emin Orkun; Demirel, Münir
The aim of this study was to compare the load-to-failure resistance and optical properties of nano-lithium disilicate (NLD) with lithium disilicate (LDS) and zirconia-reinforced lithium silicate (ZLS) in different aging processes. Thirty crowns were milled from NLD, LDS, and ZLS (n = 10). All crowns were subjected to thermomechanical aging and loaded until catastrophic failure. Ten specimens from each material were prepared in two different thicknesses (0.7 mm and 1.5 mm, n = 5), and color coordinates were measured before and after coffee thermocycling. Color differences (Delta E00) and relative translucency parameter (RTP) were calculated. Data were analyzed by using ANOVA and Bonferroni-corrected t-tests (alpha = 0.05). ZLS had the highest load-to-failure resistance (p <= 0.002), while the difference between LDS and NLD was nonsignificant (p = 0.776). The interaction between material type and thickness affected Delta E00 (p < 0.001). Among the 0.7 mm thick specimens, ZLS had the lowest Delta E00 (p < 0.001). Furthermore, 1.5 mm thick ZLS had lower Delta E00 than that of 1.5 mm thick LDS (p = 0.036). Other than ZLS (p = 0.078), 0.7 mm thick specimens had higher Delta E00 (p < 0.001). The interaction between material type, thickness, and thermocycling affected RTP (p < 0.001). Thinner specimens presented higher RTP (p < 0.001). NLD and LDS had higher RTP than ZLS (p <= 0.036). However, 0.7 mm thick specimens had similar RTP after coffee thermocycling (p >= 0.265). Coffee thermocycling reduced the RTP values of 0.7 mm thick NLD (p = 0.032) and LDS (p = 0.008). NLD may endure the occlusal forces present in the posterior region. However, long-term coffee consumption may impair the esthetics of restorations particularly when thin NLD is used.
Marginal gap and fracture resistance of implant-supported 3D-printed definitive composite crowns: An in vitro study
(Elsevier Science, 2022) Dönmez, Mustafa Borga; Okutan, Yener
Objectives: To compare the marginal gap and fracture resistance of implant-supported 3-dimensional (3D) printed definitive composite crowns with those fabricated by using 3 different millable materials. Material and methods: A prefabricated abutment was digitized by using a laboratory scanner (E4 Lab Scanner) and a complete-coverage maxillary first premolar crown was designed (Dental Designer). Forty crowns were fabri- cated either by 3D printing (Saremco Print Crowntec, SP) or milling (Brilliant Crios, BC; Vita Enamic, VE; Cerasmart 270, CS) (n = 10). Baseline marginal gap values were evaluated by measuring 60 predetermined points on an abutment (15 points for each side) with a stereomicroscope at ×40 magnification. Marginal gap values were reevaluated after adhesive cementation. Load-to-fracture test was performed by using a universal testing machine. Two-way analysis of variance (ANOVA) was used to evaluate the effect of material type and cementation on marginal gap values. While Tukey HSD tests were used to compare the materials’ marginal gap values before and after cementation, the effect of cementation on marginal gap values within each material was analyzed by using paired samples t-tests. Fracture resistance data were analyzed by using 1-way ANOVA (?=0.05). Results: Material type and cementation significantly affected marginal gap values (P < .001). Regardless of cementation, SP had the lowest marginal gap values (P < .001), while the differences among milled crowns were nonsignificant (P ? .14). Cementation significantly increased the marginal gap values (P < .001). Material type did not affect fracture resistance values (F = 1.589, P = .209). Conclusion: Implant-supported 3D-printed composite crowns showed higher marginal adaptation compared with the milled crowns before and after cementation. In addition, all crowns endured similar forces before fracture.
Optical properties, biaxial flexural strength, and reliability of new-generation lithium disilicate glass-ceramics after thermal cycling
(WILEY, 2023) Türksayar, Almira Ada Diken; Demirel, Münir; Dönmez, Mustafa Borga
PurposeTo investigate the color stability, translucency, biaxial flexural strength (BFS), and reliability of nano-lithium disilicate and fully crystallized lithium disilicate after thermal cycling and to compare with those of a commonly used lithium disilicate. Materials and methodsThree lithium disilicate glass-ceramics were used to prepare disk-shaped specimens (o:12 mm, thickness: 1.2 mm) from A2 shaded HT blocks (Amber Mill, AM; Initial LiSi Block, IN; IPS e.max CAD, EX). AM and EX specimens were crystallized, and all specimens were polished with a polishing paste (Diamond Polish Mint). A spectrophotometer (CM-26d) was used to measure color coordinates before and after thermal cycling. BFS test was performed after thermal cycling. Color differences (Delta E-00) and relative translucency parameter (RTP) values were calculated. One-way analysis of variance (ANOVA) (Delta E-00 and BFS), two-way ANOVA followed by Tukey's HSD tests (RTP), and chi-square tests (Weibull modulus and characteristic strength) were used for the statistical analyses (alpha = 0.05). ResultsNo significant differences were observed among the Delta E-00 values of tested materials (df = 2, F = 2.933, p = 0.070). RTP values were only affected by material type (p < 0.001) as AM had the highest RTP (p < 0.001), whereas IN and EX had similar values (p >= 0.165). BFS values varied among tested materials (df = 2, F = 21.341, p < 0.001). AM and EX had similar BFS values (p = 0.067) that were higher than that of IN (p <= 0.001). Weibull moduli of the materials were similar (p = 0.305), whereas EX had the highest and IN had the lowest characteristic strength values (p < 0.001) ConclusionsAlthough nano-lithium disilicate had the highest translucency, all materials had imperceptible color and translucency changes after thermal cycling when reported threshold values were considered. Newly introduced lithium disilicate glass-ceramics had adequate flexural strength as compared to the precursor material.