Evaluation of the flexural strength and surface roughness of  dental material after immersion in coffee

This study was done in order to evaluate the changes in flexural strength and surface roughness in dental material restorations after immersion in coffee. Bars specimens (2mm x 2mm x 25 mm) of Z100 3M/ESPE were made according to ISO 4049 using aluminum molds. After curing, the specimens were then randomly divided into five groups and conditioned at 37°C in physiological serum. In all groups, except control, samples were immersed in coffee for ten minutes daily. In group A, the samples were immersed in coffee. For group B, after to be immersed in coffee, samples were immersed in distilled water for one minute. For group C, samples were immersed in mouthwash for one minute. For group D, samples were brushing for ten minutes, with load of 250g and 4250 cycles after all treatments the samples were stored in physiological serum again. In control group, samples were only stored in physiological serum. The five groups were then divided into 2 subgroups according storage time, six and nine weeks, respectively. Flexural strength was determined using three point bending test in a universal testing machine. All the tests were carried out at a room temperature and samples were maintained in physiological serum during the test. Surface roughness measurements were made using a surface roughness tester. All data were analyzed using one-way analysis of variance (ANOVA) followed by Dunnet tests. The ANOVA indicated no difference in the means of surface roughness and significant was observed for flexural strength between control group and one group (coffee).

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Effects of Er:YAG Laser on Mineral Content of Sound Dentin in Primary Teeth

The Scientific World JOURNAL ◽

10.1155/2014/578342 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 3

Author(s):

Cigdem Guler ◽

Meral Arslan Malkoc ◽

Veli Alper Gorgen ◽

Erhan Dilber ◽

Mehmet Bulbul

Keyword(s):

Surface Roughness ◽

Mineral Content ◽

Primary Teeth ◽

Er:Yag Laser ◽

Short Pulse ◽

Pulse Mode ◽

Emission Spectrometry ◽

Control Group ◽

Group A ◽

Group B

The aim of the present study was to evaluate the mineral content of sound dentin in primary teeth prepared using an Er:YAG laser at two different power settings. Thirty-six primary second molars were used in this study. Three dentin slabs were obtained from each tooth, and the slabs were randomly divided into three groups: Group A, control; Group B, Er:YAG laser at 3.5 W, 175 mJ, and 20 Hz, short pulse mode; and Group C, Er:YAG laser at 4 W, 200 mJ, and 20 Hz, medium-short pulse mode. One dentin slab per group was used to evaluate the dentinal morphology and surface roughness values using SEM and profilometer, respectively. Mineral content in the dentin slabs were calculated by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The data were analyzed by one-way analysis of variance and Tukey’s HSD tests. No significant differences in Ca, K, Mg, Na, and P levels or Ca/P ratio were found among the groups(P>0.05). SEM micrographs showed that surface irregularities increased with a higher power setting. The surface roughness after laser treatment in Group B and Group C was found to be similar, unlike Group A.

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A Comparative Evaluation of Flexural Strength of Commercially Available Acrylic and Modified Polymethylmethacrylate: An in vitro Study

The Journal of Contemporary Dental Practice ◽

10.5005/jp-journals-10024-1275 ◽

2013 ◽

Vol 14 (1) ◽

pp. 80-83 ◽

Cited By ~ 1

Author(s):

Naveen S Yadav ◽

Teerthesh Jain ◽

Amrita Pandita ◽

SMA Feroz ◽

UK Kartika ◽

...

Keyword(s):

Flexural Strength ◽

Methacrylic Acid ◽

Comparative Evaluation ◽

Testing Machine ◽

Acrylic Resin ◽

Bending Test ◽

Control Group ◽

Diabetic Patients ◽

Denture Stomatitis

ABSTRACT Aim The purpose of this study was to evaluate and compare the flexural strength of commercially available acrylic (trevalone) and modified polymethylmethacrylate (PMMA). Materials and methods Four groups were tested; Group 1— control group regular MMA, group 2—2% methacrylic acid, 88% MMA, group 3—16% methacrylic acid, 84% MMA group 4— 20% methacrylic acid, 80% MMA 15 resin specimens of each group were polymerized. After processing, the specimens were subjected for flexural strength testing using three point bending test in a Universal Testing Machine. All data was statistically analyzed with one-way ANOVA, differences within the groups were analyzed by Scheffe's analysis. Results As the ratio of incorporated methacrylic acid to PMMA increased, the flexural strength decreased. Analysis of data revealed a significant decrease in flexural strength of specimens (p < 0.000) after incorporation of 12%, 16%, 20% methacrylic acid to heat polymerized acrylic resin, when compared with the control group. Lowest flexural strength was observed with specimens containing 20% methacrylic acid and highest flexural strength was observed with specimens containing conventional monomer without methacrylic acid. Conclusion It was observed that as the concentration of methacrylic acid in heat polymerized acrylic resin increases, the flexural strength decreases. Lowest flexural strength was observed with specimens containing 20% methacrylic acid and highest flexural strength was observed with specimens containing conventional monomer without methacrylic acid. Clinical significance The major advantages of addition of methacrylic acid to polymethylmethacrylate could be for the elderly people with restricted manual dexterity or cognitive disturbances, especially for patients who do not follow an adequate denture cleansing protocol and diabetic patients who are more susceptible for denture stomatitis. How to cite this article Jain T, Yadav NS, Pandita A, Feroz SMA, Kartika UK, Singh PP. A Comparative Evaluation of Flexural Strength of Commercially Available Acrylic and Modified Polymethylmethacrylate: An in vitro Study. J Contemp Dent Pract 2013;14(1):80-83.

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Influence of Silver Nanoparticles on the Specific Properties of Acrylic Resin for Ocular Prosthesis

Biomedical & Pharmacology Journal ◽

10.13005/bpj/1524 ◽

2018 ◽

Vol 11 (3) ◽

pp. 1573-1581 ◽

Cited By ~ 1

Author(s):

Maha M. Turki ◽

Faiza M. Abdul-Ameer

Keyword(s):

Surface Roughness ◽

Impact Strength ◽

Flexural Strength ◽

Bond Strength ◽

Shear Bond Strength ◽

Acrylic Resin ◽

Control Group ◽

Mean Values ◽

The Mean ◽

Group B

Scleral acrylic resin is widely used to synthesize ocular prosthesis. However, the properties of this material change over time, thus requiring the prosthesis to be refabricated. Many studies were conducted to improve these properties by reinforcing this material with nanoparticles. This study aims to evaluate the effect of silver nanoparticle powder on the mechanical properties (transverse flexural strength, impact strength, shear bond strength, surface microhardness, and surface roughness) of scleral acrylic resin used for ocular prostheses. Two concentrations were selected from the pilot study and evaluated for their effects on scleral acrylic resin properties. According to the pilot study, 0.01 and 0.02wt% AgNPs powder improved the transverse flexural strength, microhardness, and surface roughness compared with other percentages. The specimens in the main study were divided into (3) main groups, (50) specimens without additives (control group A), (50) experimental specimens (with 0.01wt% AgNPs group B), and (50) experimental specimens (with 0.02 wt% AgNPs group C). Each group was subdivided into (5) equal subgroups depending on the tests used. The data were studied using one way ANOVA and post hoc LSD test. At 0.01 wt% AgNPs addition, the mean values of transverse flexural strength insignificantly increased (p> 0.05), and those of impact strength and shear bond strength significantly increased (p< 0.05) compared with those of the control group. At 0.02 wt% AgNPs addition (group C), the mean value of transverse flexural strength significantly increased (p< 0.05), that of impact strength insignificantly increased (p> 0.05), and that of shear bond strength increased with high significance (p< 0.01) compared with those of the control group. Group C showed insignificant increase in the mean values of transverse flexural strength, impact strength, and shear bond strength (p. 0.05) compared with group B. The scleral acrylic resin added with 0.01 and 0.02 wt% AgNPs showed insignificant increase in microhardness and insignificant decrease in surface roughness. The addition of AgNPs powder in both concentrations improved the mechanical properties of scleral acrylic resin used for ocular prostheses.

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Effects of SiO2 Incorporation on the Flexural Properties of a Denture Base Resin: An In Vitro Study

European Journal of Dentistry ◽

10.1055/s-0041-1732806 ◽

2021 ◽

Author(s):

Sara T. Alzayyat ◽

Ghadah A. Almutiri ◽

Jawhara K. Aljandan ◽

Raneem M. Algarzai ◽

Soban Q. Khan ◽

...

Keyword(s):

Elastic Modulus ◽

Flexural Strength ◽

Testing Machine ◽

Base Material ◽

Bending Test ◽

Control Group ◽

Denture Base ◽

Nano Sio2 ◽

Base Resin ◽

Denture Base Resin

Abstract Objective The aim of this study was to evaluate the effects of the addition of low-silicon dioxide nanoparticles (nano-SiO2) on the flexural strength and elastic modulus of polymethyl methacrylate (PMMA) denture base material. Materials and Methods A total of 50 rectangular acrylic specimens (65 × 10 × 2.5 mm3) were fabricated from heat-polymerized acrylic resin. In accordance with the amount of nano-SiO2, specimens were divided into the following five groups (n = 10 per group): a control group with no added SiO2, and four test groups modified with 0.05, 0.25, 0.5, and 1.0 wt% nano-SiO2 of acrylic powder. Flexural strength and elastic modulus were measured by using a 3-point bending test with a universal testing machine. A scanning electron microscope was used for fracture surface analyses. Data analyses were conducted through analysis of variance and Tukey’s post hoc test (α = 0.05). Results Compared with the control group, flexural strength and modulus of elasticity tended to significantly increase (p ˂ 0.001) with the incorporation of nano-SiO2. In between the reinforced groups, the flexural strength significantly decreased (p ˂ 0.001) as the concentrations increased from 0.25 to 1.0%, with the 1.0% group showing the lowest value. Furthermore, the elastic modulus significantly increased (p ˂ 0.001) at 0.05% followed by 1.0%, 0.25%, 0.5%, and least in control group. Conclusion A low nano-SiO2 addition increased the flexural strength and elastic modulus of a PMMA denture base resin.

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Influence of grinding procedures on the flexural strength of zirconia ceramics

Brazilian Dental Journal ◽

10.1590/s0103-64402010000600008 ◽

2010 ◽

Vol 21 (6) ◽

pp. 528-532 ◽

Cited By ~ 17

Author(s):

Ufuk İşerı ◽

Zeynep Özkurt ◽

Ender Kazazoğlu ◽

Davut Küçükoğlu

Keyword(s):

Flexural Strength ◽

High Speed ◽

Testing Machine ◽

Fracture Load ◽

Bending Test ◽

Control Group ◽

Zirconia Ceramics ◽

Significance Level ◽

Universal Testing ◽

Short Time

The surface of zirconia may be damaged during grinding, influencing the mechanical properties of the material. The purpose of this study was to compare the flexural strength of zirconia after different grinding procedures. Twenty bar-type zirconia specimens (21 x 5 x 2 mm) were divided into 4 groups and ground using a high-speed handpiece or a low-speed straight handpiece until the bars were reduced 1 mm using two different grinding times: continuous grinding and short-time grinding (n=5). Control specimens (n=5) were analyzed without grinding. The flexural strengths of the bars were determined by using 3-point bending test in a universal testing machine at a crosshead speed of 0.5 mm/min. The fracture load (N) was recorded, and the data were analyzed statistically by the Kruskal Wallis test at a significance level of 0.05. In the test groups, high-speed handpiece grinding for a short time had produced the highest mean flexural strength (878.5 ± 194.8 MPa), while micromotor continuous grinding produced the lowest mean flexural strength (733.8 ± 94.2 MPa). The control group was the strongest group (928.4 ± 186.5 MPa). However, there was no statistically significant differences among the groups (p>0.05). Within the limitations of the study, there was no difference in flexural strength of zirconia specimens ground with different procedures.

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An in vitro Study to evaluate the Effects of Various Polymerizing Conditions on the Flexural Strength of Autopolymerizing Resins

Journal of Health Sciences & Research ◽

10.5005/jp-journals-10042-1042 ◽

2017 ◽

Vol 8 (1) ◽

pp. 15-19

Author(s):

Sanjeev Singh, ◽

Abid Z Hussain, ◽

RU Thombare, ◽

BK Motwani, ◽

Shweta Singh,

Keyword(s):

Flexural Strength ◽

Constant Pressure ◽

Testing Machine ◽

In Vitro Study ◽

Bending Test ◽

Control Group ◽

Time Interval ◽

Time Intervals ◽

Increased Strength

ABSTRACT Aim To investigate the effect of variation in temperature and time intervals on the flexural strength of two brands of autopolymerizing resins polymerized at constant pressure. Materials and methods Two autopolymerizing resins RR Cold Cure resin (DPI) and RR-Rapid Repair Powder (Dentsply) were used. A total of 20 samples were fabricated for each group. Samples were polymerized at temperature ranges of 40°, 50°, 60°, and 70°C and at time intervals of 5, 10, and 15 minutes in the customized curing pot, maintaining pressure of 30 psi. Results Flexural strength was verified using universal testing machine using three-point bending test and was then compared with all samples and also with the samples cured in open air (control group). The samples cured at higher temperature, i.e., 60° and 70°C, have shown increased strength than those at 40° and 50°C as well as control group. Time interval of 10 minutes is considered sufficient to increase the strength of the resin, as per the results of this study. Conclusion The samples cured under varied condition of time and temperature but under constant pressure showed increased strength than those cured in open air. Clinical significance The effect of pressure and temperature has been demonstrated, which could be utilized for enhancing the durability of the prosthesis fabricated from autopolymerized resins. How to cite this article Singh S, Hussain AZ, Thombare RU, Motwani BK, Singh S, Mangalekar SB. An in vitro Study to evaluate the Effects of Various Polymerizing Conditions on the Flexural Strength of Autopolymerizing Resins. J Health Sci Res 2017;8(1):15-19.

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Evaluation of fracture resistance of zirconia monolithic restorations: an in vitro study

Brazilian Dental Science ◽

10.14295/bds.2021.v24i2.2326 ◽

2021 ◽

Vol 24 (2) ◽

Author(s):

Ahmed Mohamed Arafa ◽

Ahmad El-Kouedi ◽

Tamer Hamza ◽

Hisham Katamish

Keyword(s):

Stainless Steel ◽

Fracture Resistance ◽

Artificial Aging ◽

Testing Machine ◽

Control Group ◽

Hydrothermal Conditions ◽

Finish Line ◽

M Phase ◽

Group A ◽

Group B

Objective: The aim of the study was to evaluate fracture resistance of zirconia monolithic restorations after ageing procedures. Material and methods: The fracture resistance of zirconia-based restoration after ageing procedures was evaluated. Monolithic translucent zirconia 3-unit FDPs were fabricated using Cerec inLab CAD/CAM system on 2 stainless steel dies prepared from stainless steel with a uniform 120 degrees circumferential deep chamfer finish line of 1 mm width and were placed into a stainless steel holder. FDPs were divided into 2 groups, the first group (Group A) was subjected to aging procedures in an autoclave at hydrothermal conditions 134 °C /2 bars for 5 hours. The second group (Group B) was not subjected to any ageing procedures and was designed as control group. All specimens of group A (Aged TZI) and group B (non- aged TZI) were loaded compressively in a universal testing machine at cross head speed 0.5 mm/min until fracture occurred. The percentage of monoclinic (m) phase was detected by XRD device. Scanning electron microscope (SEM) was used to examine the fractured surfaces for Aged TZI (Group A) and Non-aged TZI (Group B). Student’s t-test was used to compare between fracture resistances of both groups. The significance level was set at P ? 0.05. Results: The fracture resistance mean (SD) values of non-aged TZI (Group B) was 2406.9±306.8 N which showed statistically significantly higher than that of aged group (Group A) which was 1964.5±234.5 N. The percentage of monoclinic (m) phase detected by XRD device software in non-aged TZI (Group B) was nearly 0 weight % and in aged TZI (Group A) was about 42 weight %. Conclusion: Accelerated artificial aging decreases the fracture resistance of monolithic TZI FDPs. Keywords Artificial aging; Fracture resistance; Monolithic zirconia.

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

Frontiers in Dentistry ◽

10.18502/fid.v17i22.4316 ◽

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.

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Comparison of physical and mechanical properties of microwave-polymerized acrylic resin after disinfection in sodium hypochlorite solutions

Brazilian Dental Journal ◽

10.1590/s0103-64402009000400012 ◽

2009 ◽

Vol 20 (4) ◽

pp. 331-335 ◽

Cited By ~ 20

Author(s):

Helena de Freitas Oliveira Paranhos ◽

Letícia Resende Davi ◽

Amanda Peracini ◽

Rafael Bellini Soares ◽

Cláudia Helena da Silva Lovato ◽

...

Keyword(s):

Surface Roughness ◽

Flexural Strength ◽

Sodium Hypochlorite ◽

Testing Machine ◽

Physical And Mechanical Properties ◽

Color Stability ◽

Acrylic Resin ◽

Bending Test ◽

Water Control ◽

Before And After

This study evaluated the color stability, surface roughness and flexural strength of a microwave-polymerized acrylic resin after immersion in sodium hypochlorite (NaOCl), simulating 20 min of disinfection daily during 180 days. Forty disk-shaped (15 x 4 mm) and 40 rectangular (65 x 10 x 3 mm) specimens were prepared with a microwave-polymerized acrylic resin (Onda-Cryl). Specimens were immersed in either 0.5% NaOCl, 1% NaOCl, Clorox/Calgon and distilled water (control). Color measurements were determined by a portable colorimeter. Three parallel lines, separated by 1.0 mm, were registered on each specimen before and after immersion procedures to analyze the surface roughness. The flexural strength was measured using a 3-point bending test in a universal testing machine with a 50 kgf load cell and a crosshead speed of 1 mm/min. Data were analyzed statistically by ANOVA and Tukey's test (?=0.05). There was no statistically significant differences (p>0.05) among the solutions for color, surface roughness and flexural strength. It may be concluded that immersion in NaOCl solutions simulating short-term daily use during 180 days did not influence the color stability, surface roughness and flexural strength of a microwave-polymerized acrylic resin.

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Flexural strength of direct composites submitted to post-polymerization heat

Brazilian Dental Science ◽

10.14295/bds.2006.v9i3.202 ◽

2010 ◽

Vol 9 (3) ◽

Author(s):

Sicknan Soares da Rocha ◽

Gelson Luis Adabo ◽

Renata Garcia Fonseca

Keyword(s):

Flexural Strength ◽

Testing Machine ◽

Bending Test ◽

Control Group ◽

Additional Heat ◽

Multiple Comparison Test ◽

Strength Behavior ◽

Indirect Composite ◽

Heat Polymerization ◽

One Way Anova

The purpose of this study was to assess the effects of post-polymerization heat on the flexural strength of direct composites. Direct composite specimens (n=10), measuring 25×2×2 mm (Z-250 and P-60), were polymerized by 3 methods: (1) light-polymerized for 40 seconds, (2) (1) + post-polymerization in an oven at 120ºC for 20 minutes, and (3) (1) post-polymerization in an autoclave at 120ºC for 20 minutes. Specimens (n=10) of the indirect composite Artglass (control group) were polymerized in a UniXS oven. Specimens were stored in distilled water for 24 hours at 37ºC and then submitted to a flexural 3-point bending test with a universal testing machine. Flexural strength (MPa) data were analyzed by one-way ANOVA and Tukey´s multiple comparison test (α=.05). Results showed that (1) additional heat polymerization in an oven provided significantly (p<.05) higher flexural strengths (Z250: 158.85 MPa and P60: 147.10 MPa) than that of the Artglass resin (121.52 MPa); (2) with additional heat polymerization in an autoclave, these direct resins presented mean flexural strengths (Z250: 134.54 MPa and P60: 130.18 MPa) similar to that of Artglass (P>.05); (3) groups that were only light-polymerized (Z250: 124.75 MPa and P60: 128.96 MPa) were similar to Artglass (P>.05). When composites were only light-polymerized, they showed a flexural strength behavior similar to that of the indirect composite Artglass. The post-polymerization heat do not enhanced the resistance of the Filtek P60, but increased the strength of the Filtek Z250 when additional heat polymerization in a oven

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