Papers by Bogna Stawarczyk
Dental Materials Journal, Mar 27, 2020
To test the impact of the pressing furnace on flexural strength and facture toughness of the lith... more To test the impact of the pressing furnace on flexural strength and facture toughness of the lithium-disilicate-ceramics HS10PC (HS) and IPS e.max Press (IP). Three hundred and sixty specimens (3×4×30 mm) were pressed (n=180/ceramic) using different pressing furnaces, namely Austromat 654 Press-i-dent (AUS), Programat EP5000 (PRO), and Vario Press 300 (VAR). Three-point flexural strength (n=30) and fracture toughness (n=30) were measured. Flexural strength (336-360 MPa) was not affected by pressing furnace or ceramic and showed comparable values between all groups. Fracture toughness (2.65-2.81 MPa√m) provided higher values for HS pressed using AUS compared to specimens pressed in PRO and VAR. For IP, no impact of the pressing furnace on fracture toughness was found. IP presented higher fracture toughness than HS when pressed using PRO. No correlations were found. Both lithium disilicate ceramics showed comparable flexural strength regardless of the pressing furnace. Fracture toughness depended on the ceramic and on the pressing furnace.
Materials, Mar 9, 2016
The aim of this work was to evaluate the influence of specimen preparation and test method on the... more The aim of this work was to evaluate the influence of specimen preparation and test method on the flexural strength results of monolithic zirconia. Different monolithic zirconia materials (Ceramill Zolid (Amann Girrbach, Koblach, Austria), Zenostar ZrTranslucent (Wieland Dental, Pforzheim, Germany), and DD Bio zx 2 (Dental Direkt, Spenge, Germany)) were tested with three different methods: 3-point, 4-point, and biaxial flexural strength. Additionally, different specimen preparation methods were applied: either dry polishing before sintering or wet polishing after sintering. Each subgroup included 40 specimens. The surface roughness was assessed using scanning electron microscopy (SEM) and a profilometer whereas monoclinic phase transformation was investigated with X-ray diffraction. The data were analyzed using a three-way Analysis of Variance (ANOVA) with respect to the three factors: zirconia, specimen preparation, and test method. One-way ANOVA was conducted for the test method and zirconia factors within the combination of two other factors. A 2-parameter Weibull distribution assumption was applied to analyze the reliability under different testing conditions. In general, values measured using the 4-point test method presented the lowest flexural strength values. The flexural strength findings can be grouped in the following order: 4-point < 3-point < biaxial. Specimens prepared after sintering showed significantly higher flexural strength values than prepared before sintering. The Weibull moduli ranged from 5.1 to 16.5. Specimens polished before sintering showed higher surface roughness values than specimens polished after sintering. In contrast, no strong impact of the polishing procedures on the monoclinic surface layer was observed. No impact of zirconia material on flexural strength was found. The test method and the preparation method significantly influenced the flexural strength values.
Acta Odontologica Scandinavica, Jan 28, 2013
Objectives. The aims of this study were to test whether the bond strength of a hybrid composite a... more Objectives. The aims of this study were to test whether the bond strength of a hybrid composite and a PMMA-based veneer to CAD/CAM polymers would improve after pre-treatment and to evaluate the failure types after debonding. Materials and methods. Three types of PMMA-based (CAD-Temp, artBloc Temp and TelioCAD) CAD/CAM blocks were obtained (N = 360, n = 15 per test group). They were divided into four groups to be conditioned with the following methods: (a) no-treatment, (b) airabrasion (50 m Al(2)O(3)), (c) air-abrasion (50 m Al(2)O(3)) + MPS-Silane (Monobond S) + Adhesive resin (StickResin) (for Gradia)/MMA (for Integral Esthetic Press) application, (d) Silica coating and silanization (CoJet-System). The conditioned surfaces were veneered with a hybrid composite (Gradia) or a PMMA-based resin (Integral esthetic press). After water storage (1 week, 37°C), the bond strength was measured. Data were analyzed using 3-way ANOVA and post-hoc Scheffé test (= 0.05). Results. Surfaceconditioning method, veneer type and CAD/CAM polymers significantly affected the results. Hybrid composite did not bond to non-conditioned CAD/CAM polymers. Regardless of the conditioning method, PMMA-based resin showed significantly higher bond strength to all CAD/CAM polymers compared to hybrid composite. Air-abrasion increased the bond strength in all tested groups. Additional silane application after air-abrasion did not significantly increase the bond strength of hybrid composite. While exclusively adhesive failures were observed between the hybrid composite and the CAD/CAM polymers, PMMA veneer demonstrated cohesive failures in the CAD/CAM polymers. Conclusion. CAD/CAM polymers could be veneered with only a PMMA-based veneer with and without air-abrasion.
Journal of The Mechanical Behavior of Biomedical Materials, Oct 1, 2018
OBJECTIVES To determine the Martens hardness parameters for five different classes of CAD/CAM res... more OBJECTIVES To determine the Martens hardness parameters for five different classes of CAD/CAM restorative materials after storage in water and thermo-cycling. MATERIALS AND METHODS Lithium disilicate ceramic IPS e.max CAD (EX), silicate ceramic IPS Empress CAD (EC), a polymer infiltrated interpenetrating network material (hybrid material) VITA Enamic (VE), two compact filled composites Lava Ultimate (LU), experimental material (EM), two low filled resin composites Katana Avencia (KA), Ambarino High-Class (AH) and ultra-low/unfilled acrylic polymers CAD-Temp (CT), Telio CAD (TC), breCAM.HIPC (BC) were tested. Specimens were stored in water at 37°C for 30, 60, 90, 120 days and afterwards thermo-cycled (30,000×, 5°C/55°C). Martens hardness (HM) and indentation modulus (E IT) were longitudinally investigated after each storage time. For structural analysis, each material was analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). RESULTS The groups of unfilled polymers/ultra-low filled composite (CT, TC, BC) followed by low (KA, AH) and compact filled resin composites (LU, EM) showed the lowest HM and E IT values (p < 0.001). The highest values presented ceramics (EX, EC) followed by hybrid material (VE) (p < 0.001). High influence on the Martens hardness parameters was exerted by the aging duration (HM: P 2 = 0.108, p < 0.001; E IT : P 2 = 0.074, p < 0.001). Structural analyses of resin composites revealed big differences in shape, size and distribution of filler particles. CONCLUSIONS The tested CAD/CAM materials showed differences in Martens hardness and indentation modulus pursuant to the material class. Ceramics showed highest values, followed by the hybrid material. For resin composites the Martens hardness and indentation modulus increased with the filler content. Artificial aging affected CAD/CAM materials differently. Some materials tested are prone to aging, the Martens hardness and indentation modulus decreased after thermo-cycling.
Journal of Dentistry, Jun 1, 2014
Objective: This study aimed to evaluate the amount of light (360-540 nm) passing through shaded z... more Objective: This study aimed to evaluate the amount of light (360-540 nm) passing through shaded zirconia with respect to material thickness, exposure distance, and different curing modes. Methods: The specimens were divided into groups according to thickness as follows: 0.5, 1, 1.5, 2, 2.5, and 3 mm. Thirty-five zirconia and seven glass-ceramic (control group) specimens were fabricated for each group (N = 252). Zirconia was divided into five subgroups (n = 7) and stained to the following shades: CL1, CL2, CL3, and CL4. One zirconia group remained unstained (CL0). Irradiance passing through the different specimens was measured using a violet-blue LED curing unit in three curing modes (Xtra-power, high-power, and standardpower mode) with a fibre-optic USB4000 spectrometer. Irradiance was measured at varying exposure distances, ranging from direct contact of the curing unit with the surface to a distance of 7 mm from the surface, increasing in 1 mm steps. Data were analyzed using a multivariate analysis and linear mixed models (p < 0.05). Results: The control group, the glass-ceramics, transmitted the highest irradiance values, followed by CL0 (unshaded zirconia), CL1
Journal of Prosthetic Dentistry, Dec 1, 2018
STATEMENT OF PROBLEM The development of zirconia materials with optimized properties has been rap... more STATEMENT OF PROBLEM The development of zirconia materials with optimized properties has been rapid, and studies comparing the mechanical and optical properties of recently introduced zirconia with lithium disilicate materials are limited. PURPOSE The purpose of this in vitro study was to compare the mechanical and optical properties of cubic/tetragonal zirconia materials with those of a lithium disilicate ceramic. MATERIAL AND METHODS Specimens were fabricated from 6 different noncolored zirconia materials: Ceramill Zolid FX (CZ), CopraSmile (CS), DD cubeX 2 (DD), NOVAZIR MaxT (NZ), priti multidisc ZrO (PD), and StarCeram Z-Smile (SC), and 1 lithium disilicate ceramic as a control, IPS e.max Press LT A2 (CG). Four-point flexural strength (N=105/n=15) and fracture toughness using the single-edge V-notched beam (N=105/n=15) were examined according to International Organization for Standardization standard 6872:2015. Translucency (N=70/n=10) was evaluated with an ultraviolet spectrophotometer. Grain size (N=6/n=1) of zirconia was investigated by using scanning electron microscopy. Data were analyzed using the Kolmogorov-Smirnov test, multivariate analysis, 1-way analysis of variance, followed by the post hoc Scheffé test and Kruskal-Wallis and Mann-Whitney U tests, and Weibull analysis, using the maximum likelihood estimation method at 95% confidence level (=.05). RESULTS Zirconia materials showed higher mechanical and lower optical properties than CG (P<.001). No differences were observed among the zirconia materials with respect to flexural strength (P=.259) or fracture toughness (P=.408). CG and CS showed significantly higher Weibull modulus than SC and PD. The lowest translucency values were measured for NZ and SC, followed by CS, DD, and PD (P<.001). CZ showed the highest translucency values (P<.001). The lowest grain sizes were found for NZ, DD, and SC; the largest were shown for CS (P<.001). CONCLUSIONS Cubic/tetragonal zirconia showed better mechanical properties than lithium disilicate ceramic. However, the optical properties and the reliability of zirconia are lower than those of lithium disilicate ceramic.
Journal of Prosthetic Dentistry, Feb 1, 2015
Prospective studies have shown reliable clinical results of 3-and 4-unit partial fixed dental pro... more Prospective studies have shown reliable clinical results of 3-and 4-unit partial fixed dental prostheses (FDPs) with frameworks made of zirconia. 1,2 The only problems encountered were fractures of the veneering ceramic (chipping) and decementations. 1,2 To avoid such complications, the use of hybrid-structure FDPs comprising computeraided design and computeraided manufacturing (CAD/ CAM) porcelain parts adhering to a CAD/CAM zirconia framework or of anatomic contour zirconia FDPs made of high-translucency zirconia have been proposed. 3 High-translucency zirconia are newly introduced products which enable esthetic improvement for veneered zirconia structures and the production of posterior anatomic contour zirconia FDPs with good esthetic results. 4 Compared to glass-based ceramic, zirconia is less translucent, 5 but it is also less sensitive to variation in thickness in terms of translucency. 6 The esthetic characteristics of zirconia can be improved by reducing residual porosity 7 and the generation of a nanometric microstructure because the in-line transmittance of 50% at the visible wavelength range is expected for grain sizes <40 nm. 8 The characteristics of both porosity and nanometric microstructure can be manipulated by adjusting the blank press technique, the sintering parameters, and the primary particle size. 7,9,10 In addition, the translucency of zirconia is
Journal of Prosthetic Dentistry, Nov 1, 2014
STATEMENT OF PROBLEM Polyetheretherketone (PEEK) can be used as a framework material for fixed de... more STATEMENT OF PROBLEM Polyetheretherketone (PEEK) can be used as a framework material for fixed dental prostheses. However, information about the durable bond to veneering resins is still scarce. PURPOSE The purpose of this study was to investigate the effect of chemical treatments of PEEK on tensile bond strength (TBS) to veneering resins with special emphasis on surface free energy (SFE) and surface roughness (SR). MATERIAL AND METHODS Seven-hundred fifty PEEK specimens were fabricated and divided into the following 3 pretreatment groups (n=250/group): etching with sulfuric acid for 60 seconds, etching with piranha acid for 30 seconds, and an unetched control. After pretreatment, SFE was determined by using contact angle measurements and SR with a profilometer (n=10/group). The topography of pretreated PEEK surfaces was examined with scanning electron microscopy. Remaining specimens (n=240 per group) were conditioned with visio.link or Signum PEEK Bond, or were left untreated as the control group. Half of each group was veneered with Sinfony or VITA VM LC (n=40/group), and TBS was measured after storage in distilled water at 37°C for either 24 hours or 60 days. Data were analyzed by 4-way and 1-way ANOVA followed by the Scheffé post hoc test and chi-square test (=.05). RESULTS PEEK specimens etched with sulfuric acid resulted in higher SFE and SR than specimens without pretreatment or etching with piranha acid. Etching with sulfuric acid or piranha acid led to no general recommendations with respect to TBS. Conditioning with visio.link or Signum PEEK Bond significantly increased the TBS (P<.001). PEEK veneered with Sinfony showed significantly higher TBS values than those veneered with VITA VM LC (P<.001). CONCLUSIONS Sufficient TBS for bonding to veneering resin can only be achieved when additional adhesive materials were applied.
Journal of Dentistry, May 1, 2008
Objectives: The flexural strengths of veneering ceramics for zirconia were compared. Methods: Wit... more Objectives: The flexural strengths of veneering ceramics for zirconia were compared. Methods: With different veneering ceramics for zirconia (test group) and 3 different veneering ceramics for the metal-ceramic technique (control group) 3-point flexural strength and biaxial flexural strength according to ISO 6872:1995 as well as 4-point flexural strength according to EN 843-1:2005 were measured (n=10). Statistical analysis was performed with one-way ANOVA and post-hoc Scheffé test (SPSS, p < 0.05). Results: For the test group 3-point flexural strength ranged between 77.8±8.7MPa and 106.6±12.5MPa without any statistically significant differences, biaxial flexural strength between 69.1±4.8MPa and 101.4±10.5MPa with 3 homogeneous groups, and 4-point flexural strength between 59.5±6.2MPa and 89.2±9.5MPa with 5 homogeneous groups. The control group showed 3-point flexural strength values ranging from 93.3±13.5MPa to 149.4±20.5MPa, biaxial flexural strength values from 93.4±10.0MPa to 141.2±11.6MPa, and 4-point flexural strength values from 82.7±8.5MPa to 116.9±9.8MPa. In every case the results of the 4-point flexure test were significantly lower than those obtained in the 3-point flexure test. The 3-point flexural strengths of the test group are similar to those of 2 ceramics of the control group. The flexural strength of 1 ceramic of the control group significantly exceeded the strengths of all other ceramics investigated. Conclusion: 3-point flexural strength values of veneering ceramics for zirconia are similar to those of veneering ceramics for the metal-ceramic technique. The 4-point flexure test among all 3 tests showed highest discrimination between the different ceramic materials.
Materials, May 7, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
PLOS Computational Biology, Apr 27, 2023
Cross-disciplinary collaborative research projects are often essential in many fields for making ... more Cross-disciplinary collaborative research projects are often essential in many fields for making scientific progress, but they are notoriously difficult to conceptualize and design. The recent increased focus on reproducible science makes the design of such research projects even more challenging. We demonstrate that simple rules provided by three editorial articles from the series "Ten Simple Rules" greatly impacted the process of writing of our research proposal, leading to a design that can serve researchers from a wide range of disciplines to conceptualize their own collaborative projects that promote reproducible science.
Clinical Oral Investigations, Dec 28, 2022
Objectives To investigate the initial bacterial adhesion on 3D-printed splint materials in relati... more Objectives To investigate the initial bacterial adhesion on 3D-printed splint materials in relation to their surface properties. Materials and methods Specimens of five printable splint resins (SHERAprint-ortho plus UV, NextDent Ortho Rigid, LuxaPrint Ortho Plus, V-Print Splint, KeySplint Soft), one polymethylmethacrylate (PMMA) block for subtractive manufacturing (Astron CLEARsplint Disc), two conventional powder/liquid PMMA materials (FuturaGen, Astron CLEARsplint), and one polyethylene terephthalate glycol (PETG) thermoplastic sheet for vacuum forming (Erkodur Thermoforming Foil) were produced and finished. Surface roughness R a was determined via contact profilometry. Surface morphology was examined under a scanning electron microscope. Multi-species bacterial biofilms were grown on entire splints. Total biofilm mass and viable bacterial counts (CFU/ml) within the biofilms were determined. Statistical analyses were performed with a one-way ANOVA, Tukey's post hoc test, and Pearson's test (p < 0.05). Results Astron CLEARsplint and KeySplint Soft specimens showed the highest surface roughness. The mean total biofilm mass on KeySplint Soft splints was higher compared to all other materials (p < 0.05). Colony-forming unit per milliliter on FuturaGen, Astron CLEARsplint, and KeySplint Soft splints was one log scale higher compared to all other materials. The other four printable resins displayed overall lower R a , biofilm mass, and CFU/ml. A positive correlation was found between R a and CFU/ml (r = 0.69, p = 0.04). Conclusions The 3D-printed splints showed overall favorable results regarding surface roughness and bacterial adhesion. Thermoplastic materials seem to display a higher surface roughness, making them more susceptible to microbial adhesion. Clinical relevance The development of caries and gingivitis in patients with oral appliances may be affected by the type of material.
Journal of Biomedical Materials Research Part B, Jun 16, 2012
Dental Materials, Dec 1, 2017
Dental Materials Journal, 2015
This study investigated the influence of different surface treatments on fracture load (FL) of ca... more This study investigated the influence of different surface treatments on fracture load (FL) of canine crowns fabricated from two different pressable lithium-disilicate ceramics: A (HS10PC, estetic ceram, n=180) and B (IPS e.max Press, IvoclarVivadent, n=120). The standardized specimens were divided into groups of six different surface treatments and two glazing temperatures. A-group specimens were additionally assigned two glazing pastes with various thermal expansion coefficients (TEC). FL was measured and TECs were determined. Data were analyzed using three/one-way ANOVA followed by post-hoc Scheffe's test. B showed comparable or higher FL than A (B: 503-876 N; A: 375-734 N). Lithium-disilicate crowns show higher FL when not grinded but only polished or glazed. Glazing pastes affected FL depending on their TECs, firing temperature and crown treatment. TEC of A and B was 10 ppm/K, glazing pastes for A presented TECs of 7.5 ppm/K and 10 ppm/K and for B of 9 ppm/K.
Journal of Applied Biomaterials & Functional Materials, Oct 1, 2019
The dental trend is toward highly esthetic tooth-colored restorations, preferably imitating a nat... more The dental trend is toward highly esthetic tooth-colored restorations, preferably imitating a natural tooth appearance combined with minimally invasive tooth preparations. Thin restorations should provide sufficient mechanical strength as well as stable color matching. Besides the manual fabrication process, the computer-aided design and computer-aided manufacturing (CAD/CAM) technique offers restorations fabricated from polymer material blanks with improved mechanical properties, higher wear resistance, lower polymerization shrinkage, lower discoloration rates, and better biocompatibility than manually polymerized polymers. 1-4 The improved material quality, with higher edge strength, for example, stems from an optimized fabrication process with a constant high pressure and temperature, making thin restorations for minimally invasive treatment options possible. 1-4 With continuous development in this class of material, concerning its compositions,
Dental Materials Journal, 2014
This study evaluated and compared the influence of different supporting abutment models on the fr... more This study evaluated and compared the influence of different supporting abutment models on the fracture loads of three-unit fixed dental prostheses (FDPs) fabricated from the following materials (n=24/material): (i) IPS e.max CAD-on, (ii) IPS e.max ZirCAD, and (iii) Telio CAD. Twelve FDPs of each group were adhesively cemented on a polymeric model and on a base metal alloy one. For the fracture load test the FDPs were loaded at the centre of the pontic (1 mm/min). The data were analyzed using descriptive statistics, two-and one-way ANOVA followed by post-hoc Scheffé test and Weibull statistics. Fracture loads were found to be affected by the choice of materials used for the abutment models. The fracture load for zirconia FDPs cemented on metal abutments was higher than on polymeric abutment group. In contrast, Telio CAD cemented on polymeric abutments presented higher fracture loads than group on base metal alloy support.
Dental Materials, Jul 1, 2012
OBJECTIVES: This study evaluated and compared Weibull parameters of resin bond strength values us... more OBJECTIVES: This study evaluated and compared Weibull parameters of resin bond strength values using six different general-purpose statistical software packages for two-parameter Weibull distribution. METHODS: Two-hundred human teeth were randomly divided into 4 groups (n=50), prepared and bonded on dentin according to the manufacturers' instructions using the following resin cements: (i) Variolink (VAN, conventional resin cement), (ii) Panavia21 (PAN, conventional resin cement), (iii) RelyX Unicem (RXU, self-adhesive resin cement) and (iv) G-Cem (GCM, self-adhesive resin cement). Subsequently, all specimens were stored in water for 24h at 37°C. Shear bond strength was measured and the data were analyzed using Anderson-Darling goodness-of-fit (MINITAB 16) and two-parameter Weibull statistics with the following statistical software packages: Excel 2011, SPSS 19, MINITAB 16, R 2.12.1, SAS 9.1.3. and STATA 11.2 (p0.05). Additionally, the three-parameter Weibull was fitted using MNITAB 16. RESULTS: Two-parameter Weibull calculated with MINITAB and STATA can be compared using an omnibus test and using 95% CI. In SAS only 95% CI were directly obtained from the output. R provided no estimates of 95% CI. In both SAS and R the global comparison of the characteristic bond strength among groups is provided by means of the Weibull regression. EXCEL and SPSS provided no default information about 95% CI and no significance test for the comparison of Weibull parameters among the groups. In summary, conventional resin cement VAN showed the highest Weibull modulus and characteristic bond strength. SIGNIFICANCE: There are discrepancies in the Weibull statistics depending on the software package and the estimation method. The information content in the default output provided by the software packages differs to very high extent.
Dental Materials, May 1, 2012
The aim of this study was to compare the fracture load of veneered anterior zirconia crowns using... more The aim of this study was to compare the fracture load of veneered anterior zirconia crowns using normal and Weibull distribution of complete and censored data. METHODS: Standardized zirconia frameworks for maxillary canines were milled using a CAD/CAM system and randomly divided into 3 groups (N=90, n=30 per group). They were veneered with three veneering ceramics, namely GC Initial ZR, Vita VM9, IPS e.max Ceram using layering technique. The crowns were cemented with glass ionomer cement on metal abutments. The specimens were then loaded to fracture (1mm/min) in a Universal Testing Machine. The data were analyzed using classical method (normal data distribution (,); Levene test and one-way ANOVA) and according to the Weibull statistics (s, m). In addition, fracture load results were analyzed depending on complete and censored failure types (only chipping vs. total fracture together with chipping). RESULTS: When computed with complete data, significantly higher mean fracture loads (N) were observed for GC Initial ZR (=978, =157; s=1043, m=7.2) and VITA VM9 (=1074, =179; s=1139; m=7.8) than that of IPS e.max Ceram (=798, =174; s=859, m=5.8) (p<0.05) by classical and Weibull statistics, respectively. When the data were censored for only total fracture, IPS e.max Ceram presented the lowest fracture load for chipping with both classical distribution (=790, =160) and Weibull statistics (s=836, m=6.5). When total fracture with chipping (classical distribution) was considered as failure, IPS e.max Ceram did not show significant fracture load for total fracture (=1054, =110) compared to other groups (GC Initial ZR: =1039, =152, VITA VM9: =1170, =166). According to Weibull distributed data, VITA VM9 showed significantly higher fracture load (s=1228, m=9.4) than those of other groups. SIGNIFICANCE: Both classical distribution and Weibull statistics for complete data yielded similar outcomes. Censored data analysis of all ceramic systems based on failure types is essential and brings additional information regarding the susceptibility to chipping or total fracture.
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Papers by Bogna Stawarczyk