scholarly journals Surface Topography, Gloss and Flexural Strength of Pressable Ceramic After Finishing-Polishing Protocols

2019 ◽  
Vol 30 (2) ◽  
pp. 164-170 ◽  
Author(s):  
Fernanda P. Silva ◽  
Ana L. R. Vilela ◽  
Matheus M. G. Almeida ◽  
André R. F. Oliveira ◽  
Luís H. A. Raposo ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Flexural Strength ◽  
Glass Ceramic ◽  
Lower Surface ◽  
Good Alternative ◽  
Sem Analysis ◽  
Force Microscopy ◽  
Biaxial Flexural Strength ◽  
Surface Irregularities ◽  
Post Hoc

Abstract This study evaluated the effect of different finishing-polishing protocols on surface roughness, gloss, morphology and biaxial flexural strength of pressable fluorapatite glass ceramic. Thirty ceramic discs (12x1 mm) were produced and divided into five groups (n=6): CT: control (glaze); DA: fine grit diamond bur; DG: DA + new glaze layer; DP: DA + felt disk with fine grit diamond paste; DK: DA+ sequential polishing with silicon abrasive instruments, goat hair brush and cotton wheel. The specimens were analyzed for surface roughness (Ra) under profilometry and atomic force microscopy (AFM). Gloss was measured with spectrophotometry and micromorphology with scanning electron microscopy (SEM). Flexural strength was assessed by biaxial flexural strength test. Data were analyzed using one-way ANOVA and Tukey’s post hoc test (a=0.05). DK showed the lowest surface roughness values and DA presented the highest in the perfilometer analysis. No significant differences were observed in the AFM for the CT, DG and DK groups, which presented the lower surface roughness; DA and DP had the higher Ra values. The DA, DP and CT showed the lowest surface gloss values, and the reflectance was significantly different from those observed for DK and DG groups. SEM analysis revealed the smoothest surface for DK group, followed by DG and CT groups; DA and DP groups exhibited variable degrees of surface irregularities. No significant differences were observed among groups for the biaxial flexural strength. The polishing protocol used in DK group can be a good alternative for chairside finishing of adjusted pressable fluorapatite glass ceramic surfaces.

Impact of Silane-containing Universal Adhesive on the Biaxial Flexural Strength of a Resin Cement/Glass-ceramic System

2019 ◽  
Vol 44 (2) ◽  
pp. 200-209 ◽  
Author(s):  
F Murillo-Gómez ◽  
RB Wanderley ◽  
MF De Goes
Keyword(s):  
Flexural Strength ◽  
Glass Ceramic ◽  
Resin Cement ◽  
Weibull Analysis ◽  
Ceramic System ◽  
Universal Adhesive ◽  
Bonded Interface ◽  
Biaxial Flexural Strength ◽  
Digital Caliper ◽  
One Way Anova

SUMMARY The aim of this study was to determine whether using a silane-containing universal adhesive as a silane primer in glass-ceramic/resin cement systems affects biaxial flexural strength (BFS) and bonded interface integrity after loading. Glass-ceramic (IPS e.max CAD, Ivoclar/Vivadent, Schaan, Liechtenstein) disc-shaped specimens (6.5±0.1mm in diameter, 0.5±0.1mm thick) were etched with 5% hydrofluoric acid (HF) for 20 seconds and divided into four groups of 30 specimens, to be treated as follows: 1) One bottle silane primer (RCP); 2) Separate application of silane and adhesive (RCP+SB); 3) Silane-containing universal adhesive (SBU); 4) No treatment (C). After silanization, all specimens were resin cement– coated and polymerized for 40 seconds. Each specimen layer was measured, as well as each assembly's thickness, using a digital caliper and scanning electron microscope (SEM). Specimens were stored for 24 hours and submitted to a BFS test (1.27 mm/min). BFS values were calculated using the bilayer disc-specimen solution. Bonded interfaces were analyzed on fractured fragments using SEM. One-way ANOVA and Tukey tests (α=0.05) were applied, as well as the Weibull analysis. Factor “silane treatment” was statistically significant (p<0.0001). RCP+SB (372.2±29.4 MPa) and RCP (364.2±29.5 MPa) produced significantly higher BFS than did the C (320.7±36.3 MPa) or SBU (338.0±27.1 MPa) groups. No differences were found in the Weibull modulus (m: RCP: 10.1-17.3; RCP+SB: 10.1-17.0; SBU: 12.3-22.4; C: 7.4-12.9). Bonded interface analysis exhibited ceramic-cement separation (SBU, C) and voids within the resin cement layer (all groups). Neither the ceramic/cement system's BFS nor its bonded interface stability were improved by SBU after loading.

scholarly journals Biaxial flexural strength of different types of monolithic zirconia

2019 ◽  
Vol 22 (1) ◽  
pp. Process
Author(s):  
Shereen Ahmed Nossair ◽  
Tarek Salah ◽  
Kamal Khaled Ebeid
Keyword(s):  
Flexural Strength ◽  
Zirconia Ceramic ◽  
Group 4 ◽  
Dental Esthetics ◽  
Biaxial Flexural Strength ◽  
Different Types ◽  
Monolithic Zirconia ◽  
Group 5 ◽  
Group 2 ◽  
Post Hoc

Objective: This study was designed to evaluate the biaxial flexural strength (BFS) of different types of unshaded and shaded monolithic zirconia. Material and Methods: 120 monolithic zirconia ceramic discs were fabricated. They were divided into twelve groups (n=10), Group 1; Bruxzir unshaded, Group 2; Bruxzir shaded A2, Group 3; Bruxzir anterior white, Group 4; Bruxzir anterior shade A2, Group 5; Prettau unshaded, Group 6; Prettau shaded with A2 coloring liquid, Group 7; Prettau anterior white, Group 8; Prettau anterior shaded with A2 coloring liquid, Group 9; Katana HT white, Group 10; Katana HT shade A2, Group 11; Katana ST white, Group 12; Katana ST shade A2. All discs were milled using a dental milling machine, and had final dimensions after sintering of 15 mm diameter and 1 mm thickness. BFS was tested using piston on three ball technique. Results:  One-way ANOVA revealed significant differences among the 12 groups. Tukey post-hoc tests revealed no significant differences between the groups 3, 4, ,7 ,8 11, and 12. However, they all had BFS values that are significantly lower than all other groups. Group 2 showed statistically significant higher BFS values when compared to group 3,4, 7, 8, 11, and 12 while it showed statistically significant lower values when compared to groups 1, 5, 6, 9, and 10. Conclusion: Increase in the yttria content in zirconia led to a decrease in its BFS. Shading of zirconia did not have a significant effect on the final strength of zirconia. KeywordsDental ceramics; Dental esthetics; Flexural strength; Shaded zirconia. 

scholarly journals Effect of the bur grit size on the flexural strength of a glass-ceramic

Cerâmica ◽  
2016 ◽  
Vol 62 (362) ◽  
pp. 121-127 ◽  
Author(s):  
P. P. Kist ◽  
I. L. Aurélio ◽  
M. Amaral ◽  
L. G. May
Keyword(s):  
Surface Roughness ◽  
Flexural Strength ◽  
Glass Ceramic ◽  
Glass Ceramics ◽  
Internal Surface ◽  
Grit Size ◽  
Diamond Grit ◽  
Cad Cam ◽  
Negative Effect ◽  
Ceramic Blocks

Abstract The purpose of the present study was to determine the biaxial flexural strength (BFS) of a CAD/CAM leucite reinforced glass-ceramic ground by diamond burs of different grit sizes and the influence of surface roughness on the BFS. For this, 104 plates were obtained from CAD/CAM ceramic blocks and divided into 4 groups (n = 26), according to bur grit size: extra-fine, fine, medium and coarse. Roughness parameters (Ra, RyMax) were measured, and plates were kept dry for 7 days. The flexural test was carried out and BFS was calculated. Ra, RyMax and BFS data were subjected to analysis of variance and post-hoc test. Weibull analysis was used to compare characteristic strength and Weibull modulus. Regression analysis was performed for BFS vs. Ra and RyMax. When burs with coarse grit were used, higher surface roughness values were found, causing a negative effect on the ceramic BFS (117 MPa for extra-fine, and 83 MPa for coarse). Correlation (r) between surface roughness and BFS was 0.78 for RyMax and 0.73 for Ra. Increases in diamond grit size have a significant negative effect on the BFS of leucite-reinforced glass-ceramics, suggesting that grinding of sintered glass-ceramic should be performed using burs with the finest grit possible in order to minimize internal surface flaws and maximize flexural strength.

Effect of Surface Sealants and Polishing Time on Composite Surface Roughness and Microhardness

2018 ◽  
Vol 43 (4) ◽  
pp. 408-415 ◽  
Author(s):  
VC Ruschel ◽  
VS Bona ◽  
LN Baratieri ◽  
HP Maia
Keyword(s):  
Surface Roughness ◽  
Composite Resin ◽  
Resin Composite ◽  
Composite Surface ◽  
Force Microscopy ◽  
Atomic Force ◽  
Surface Sealants ◽  
Post Hoc ◽  
Surface Sealant ◽  
Effect Of Surface

SUMMARY The objective of this study was to evaluate the effect of surface sealants and polishing delay time on a nanohybrid resin composite roughness and microhardness. Eighty disc specimens were made with a nanohybrid resin (Esthet-X HD, Dentsply). The specimens were divided into two groups (n=40) according to polishing time: immediate, after 10 minutes; delayed, after 48 hours. Each group was subdivided into four groups (n=10), according to the surface treatment: CG, control–rubber points (Jiffy Polishers, Ultradent); PP, rubber points + surface sealant (PermaSeal, Ultradent); PF, rubber points + surface sealant (Fortify, Bisco); PB, rubber points + surface sealant (BisCover, Bisco). Surface roughness (Ra) and microhardness (50 g/15 seconds) were measured. Surface morphology was analyzed by scanning electron microscopy and atomic force microscopy. The data were analyzed statistically using one-way analysis of variance and the Games-Howell post hoc test (α=0.05). PermaSeal roughness (G2) in the delayed polishing group was significantly higher (p=0.00) than that of the other groups. No difference was observed among the groups between immediate and delayed polishing (p=1.00), except for PermaSeal (p=0.00). Moreover, PermaSeal showed the lowest microhardness values (p=0.00) for immediate polishing. Microhardness was higher at delayed polishing for all the surface treatments (p=0.00) except Fortify (p=0.73). Surface smoothness similar to polishing with rubber points was achieved when surface sealants were used, except for PermaSeal surface sealant, which resulted in a less smooth resin composite surface. However, surface sealant application did not significantly improve composite resin microhardness.

Surface Roughness Prediction in End Milling of Machinable Glass Ceramic and Optimization by Response Surface Methodology

2011 ◽  
Vol 189-193 ◽  
pp. 1376-1381
Author(s):  
Moola Mohan Reddy ◽  
Alexander Gorin ◽  
Khaled A. Abou El Hossein
Keyword(s):  
Surface Roughness ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Glass Ceramic ◽  
End Milling ◽  
Removal Rate ◽  
Cutting Speed ◽  
Lower Surface ◽  
Depth Of Cut ◽  
Machining Parameters

This paper presents the prediction of a statistically analyzed model for the surface roughness,R_a of end-milled Machinable glass ceramic (MGC). Response Surface Methodology (RSM) is used to construct the models based on 3-factorial Box-Behnken Design (BBD). It is found that cutting speed is the most significant factor contributing to the surface roughness value followed by the depth of cut and feed rate. The surface roughness value decreases for higher cutting speed along with lower feed and depth of cut. Additionally, the process optimization has also been done in terms of material removal rate (MRR) to the model’s response. Ideal combinations of machining parameters are then suggested for common goal to achieve lower surface roughness value and higher MRR.

scholarly journals Effect of Hydrofluoric Acid Surface Treatments on Surface Roughness and Three-Point Flexural Strength of Suprinity Ceramic

2020 ◽  
Author(s):  
Nazanin Keshmiri ◽  
Homayoon Alaghehmand ◽  
Faraneh Mokhtarpour
Keyword(s):  
Surface Roughness ◽  
Flexural Strength ◽  
Hydrofluoric Acid ◽  
Testing Machine ◽  
Etching Time ◽  
Control Group ◽  
Force Microscopy ◽  
Atomic Force ◽  
Significant Difference ◽  
Before And After

Objectives: This study aimed to evaluate the effects of hydrofluoric acid (HF) concentration and etching time on the surface roughness (SR) and three-point flexural strength of Suprinity and to analyze the surface elements before and after etching. Materials and Methods: To measure the SR, 70 specimens of Suprinity (2×4×5mm3) were assigned to seven groups (n=10). Six groups were etched for 20, 60, and 120 seconds with 5% and 10% HF and 7th group was the control group. Specimens were evaluated using atomic force microscopy (AFM). One specimen from each group was used to analyze the surface elements using scanning electron microscopy (SEM). For measuring the three-point flexural strength, 60 specimens were divided into six groups (n=10) and etched as previously described. The flexural strength was measured using a universal testing machine. T-test, one-way analysis of variance (ANOVA), and two-way ANOVA were used for statistical analyses (P<0.05). Results: The 10% concentration of HF caused higher SR compared to the 5% HF. The effect of HF concentration on the flexural strength was significantly different in the 20- and 60-second etching groups. Different etching times had no significantly different effect on the SR. With 5% HF, the flexural strength was significantly higher for 20-second etching time than for the etching times of 60 and 120 seconds. With 10% HF, there was a significant difference in flexural strength between etching times of 20 and 120 seconds. The atomic percentage (at%) of silica was enhanced by increasing the etching time. Conclusions: The best surface etching protocol comprises 10% HF used for 20 seconds.

scholarly journals Preparation and characterization of PTFE flat sheet membrane: Effect of sodium benzoate content

2017 ◽  
Vol 13 (4) ◽  
pp. 598-601
Author(s):  
Faezeah Abd Ghani ◽  
Khaidir Hamzah ◽  
Wan Norharyati Wan Salleh ◽  
Hasimah Mohamed
Keyword(s):  
Surface Roughness ◽  
Pore Size ◽  
Sodium Benzoate ◽  
Sem Analysis ◽  
Average Pore ◽  
Force Microscopy ◽  
Flat Sheet ◽  
Pore Size Distributions ◽  
Flat Sheet Membrane ◽  
Porous Microstructures

Polytetrafluoroethylene (PTFE) flat sheet membranes were prepared through casting and sintering methods. The effect of sodium benzoate salt on the characteristics of PTFE flat sheet membranes such as  morphology, surface roughness, porosity, mechanical strength and crystallinity were studied through scanning electron microscopy (SEM), atomic force microscopy (AFM), mercury intrusion porosimetry, tensile test and X-ray diffraction (XRD). SEM analysis confirmed the formation of irregular porous microstructures in sponge-like configuration. All the fabricated membranes exhibited narrow pore size distributions and have relatively small average pore diameters between 0.074 and 1.068 µm despite having porosity between 36.41 and 74.32 %. In addition, the roughness of the PTFE flat sheet membranes increased as the sodium benzoate content increased. Increasing sodium benzoate content was positive for pore size, porosity and roughness but negative for surface roughness and mechanical properties. This research confirmed that the addition of sodium benzoate salt in aqueous PTFE solution is a useful approach for the fabrication of porous PTFE flat sheet membranes

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