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

2013 ◽  
Vol 14 (1) ◽  
pp. 80-83 ◽  
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.

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

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.

scholarly journals Polymethylmethacrylate Incorporating Nanodiamonds for Denture Repair: In Vitro Study on the Mechanical Properties

2021 ◽  
Author(s):  
Mohammed Moustafa Ahmed Gad ◽  
Mohamed Saber Ali ◽  
Ahmad M. Al-Thobity ◽  
Yousif A. Al-Dulaijan ◽  
Mai El Zayat ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Impact Strength ◽  
Flexural Strength ◽  
In Vitro Study ◽  
Acrylic Resin ◽  
Bending Test ◽  
Control Group ◽  
Nd Addition ◽  
The Impact

Abstract Objective This study aimed to evaluate the effect of nanodiamond (ND) addition to repair resin with repair gap modifications on the flexural and impact strength of repaired polymethylmethacrylate denture base. Materials and Methods Heat-polymerized acrylic resin specimens (N = 100/test) were prepared and sectioned to half creating two repair gaps: 2.5- and 0 mm with 45 degrees beveling. They were further divided into subgroups (n = 20) according to ND concentration (control, 0.25%ND, and 0.50%ND), thermocycling (500 cycles) was done to half the specimens in each subgroup. Flexural strength was tested using 3-point bending test and impact strength was tested by Charpy's impact test. Analysis of variance and post-hoc Tukey's tests were performed for data analysis (α = 0.05). Scanning electron microscope was employed for fracture surface analysis and ND distribution. Results Before and after thermocycling, the addition of ND significantly increased the flexural strength and elastic modulus in comparison to control group (p ˂ 0.001), while 0 mm repair gap showed insignificant difference between ND-reinforced groups (p ˃ 0.05). Regarding impact strength, ND addition increased the impact strength with 0 mm gap in comparison to control and 2.5 mm with ND (p˂0.001), while later groups showed no significant in between (p ˃ 0.05). Comparing thermocycling effect per respective concentration and repair gap, thermocycling adversely affected all tested properties except elastic modulus with 0 mm–0.25 and 0 mm–0.5% and impact strength with 2.5 mm, 2.5 mm–0.25%, 2.5 mm– 0.5% (p ˃ 0.05). Conclusion ND addition combined with decreased repair gap improved the flexural strength, elastic modulus, and impact strength of repaired denture resin, while thermocycling has a negative effect on denture repair strength.

scholarly journals A Comparative Evaluation of the Dimensional Accuracy of Heat Polymerized Acrylic Resin Denture Base Clamped by the Conventional Method and by New-press Technique and Cured by Long Curing Cycle: An in vitro Study

2012 ◽  
Vol 13 (6) ◽  
pp. 842-849
Author(s):  
T Shankar ◽  
N Venugopal Rao ◽  
Snigdha Gowd ◽  
Syed Tauqheer Ahmed ◽  
V Vinod ◽  
...  
Keyword(s):  
Conventional Method ◽  
Comparative Evaluation ◽  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Reference Points ◽  
Control Group ◽  
Denture Base ◽  
Group A ◽  
Curing Cycle

ABSTRACT Aim The aim of this study is to evaluate the dimensional accuracy of heat polymerized acrylic resin denture base clamped by the conventional method and by new-press technique and cured by long curing cycle. Materials and methods In this study, a total of 60 standardized maxillary record bases were fabricated with seven reference points as follows: • Point A Incisive papilla, • Point B and C Canine region on either side • Point E and G Midpoint of tuberosities on either side • Point F Midpoint of the line joining the two tuberosities • Point D Midpoint between the line joining A and F Group A Ten maxillary record bases were fabricated by conventional clamping method and cured by long curing cycle. Group A’ Ten maxillary record bases were fabricated by New Press or RS tension clamping method and cured by long curing cycle. The distances between the reference points, i.e. A-B, A-C, A-D, D-F, B-E, C-G, E-F, F-G, B-D, D-G, C-D, D-E of all three thermoplastic denture base plates were measured and recorded with the help of travelling microscope and were used for comparison with the measured and recorded readings of processed acrylic denture bases. The data obtained was analyzed by using the one-way analysis of variance and HSD Multiple Comparison Test. Results The overall results of the study indicate that among all the denture bases cured by the two clamping systems and the long curing cycle, group A‘ were the most dimensionally stable, followed by control group A. Conclusion The study concluded that the denture bases fabricated by the New Press method using the long curing cycle would produce the most dimensionally stable denture bases. How to cite this article Shankar T, Gowd S, Ahmed ST, Vinod V, Goud MV, Rao NV. A Comparative Evaluation of the Dimensional Accuracy of Heat Polymerized Acrylic Resin Denture Base Clamped by the Conventional Method and by New-press Technique and Cured by Long Curing Cycle: An in vitro Study. J Contemp Dent Pract 2012;13(6):842-849.

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

2021 ◽  
Vol 10 (3) ◽  
pp. e30510312486
Author(s):  
Patrícia Capellato ◽  
Ana Paula Rosifini Alves Claro
Keyword(s):  
Surface Roughness ◽  
Flexural Strength ◽  
Testing Machine ◽  
Dental Material ◽  
Bending Test ◽  
Control Group ◽  
Test Surface ◽  
Physiological Serum ◽  
Group A ◽  
Group B

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).

scholarly journals Influence of Exposing Root Canal Dentin to Calcium Hydroxide on Its Flexural Strength

2015 ◽  
Vol 1 (3) ◽  
pp. 143
Author(s):  
Diatri Nari Ratih
Keyword(s):  
Flexural Strength ◽  
Calcium Hydroxide ◽  
Root Canal ◽  
Artificial Saliva ◽  
Testing Machine ◽  
In Vitro Study ◽  
Control Group ◽  
Sterile Saline ◽  
Root Canal Dentin

Calcium hydroxide has been used extensively in endodontic treatments, for instance as an intra-canal dressing; however, the exposure of root canal dentin to calcium hydroxide may affect its flexural strength and could have important clinical implications for endodontic treatment. The purpose of this in vitro study was to investigate the influence of calcium hydroxide on the flexural strength of root canal dentin.Seventy-two extracted single-rooted human mandibular premolars were used in this study. Each tooth was instrumented using crown-down technique and was irrigated using sterile saline. The teeth were assigned into three groups of 24 each. The prepared root canal system of each tooth was filled with calcium hydroxide mixed with sterile saline (group 1), a calcium hydroxide commercially available product (UltraCal®) (group 2) or saline solution (group 3, as control). The apices and access opening were sealed using composite resin, and the teeth were immersed in artificial saliva. After 7, 14 and 30 days of immersion, the inner root canal dentin of 8 teeth respectively from each group were sectioned to create dentin bars (1 X 1 mm, with 7 mm in length). Each dentin bar then was subjected to a three-point bending flexural test using MTS (Universal Testing Machine). Data gathered were then analyzed using two-way ANOVA, followed by Tukey’s test with the level of significance of 95%. The results showed that exposure to calcium hydroxide either using calcium hydroxide mixed with sterile saline or UltraCal® for 14 and 30 days can reduce flexural strength of root canal dentin compared to control group (p<0.05). In contrast, after 7 days exposure, there was no significantly different of flexural strength between three groups (p>0.05).   It can be concluded that calcium hydroxide reduced the flexural strength of root canal dentin. The longer the exposure to calcium hydroxide would produce a greater effect on flexural strength of root canal dentin.   

scholarly journals Influence of Concentrations of Methacrylate and Acrylate Monomers on the Properties of Fiber Reinforced Polymethyl Methacrylate Denture Base Materials

2018 ◽  
Vol 26 (2) ◽  
pp. 329-350 ◽  
Author(s):  
Faik Tugut ◽  
Mehmet Turgut ◽  
Dursun Saraydin
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Testing Machine ◽  
Weight Ratio ◽  
Acrylic Resin ◽  
Bending Test ◽  
Control Group ◽  
Test Machine ◽  
Fiber Reinforced ◽  
Significant Difference

Abstract The study aimed to evaluate the effects of adding different concentrations of 2 hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), ethyl methacrylate (EA) and isobutyl methacrylate (IBMA) monomers on the structural, thermal and mechanical properties of a fiber reinforced heat-polymerized acrylic resin. For each test, 126 acrylic resin specimens were fabricated and divided into 6 groups with 7 specimens each. One group was the control group, the other one is a fiber reinforced group and others were the test groups, which were formed according to the different concentrations of monomers. 6 mm length, and the weight ratio of 3% short glass fibers are added to acrylic powder polymerized by heating. The 2%, 5%, 10%, at 20 % ratios of different comonomers added to a monomer of MMA are composed of copolymer structures. Flexural strength was assessed with a three-point bending test using a universal testing machine. Impact strength testing was conducted using an impact test machine by the Charpy method. The analysis of the connection between acrylic resin and fiber by SEM and structural changes in the acrylic resin was investigated by FTIR spectroscopy. Data analyses using analysis of Kruskal-Wallis and Mann-Whitney U tests (α=0.05) significant difference tests showed that adding 2%, 5% HEMA and IBMA monomers significantly increased the flexural and impact strength compared to the control, only fiber and others group (P< 0.05). It is observed that the process of adding low concentration of HEMA and IBMA monomers improved certain mechanical properties of fiber reinforced with polymethylmethacrylate.

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

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.

scholarly journals Evaluation of a novel fixed-space maintainer made of light-cured acrylic resin: an in vitro study

BDJ Open ◽  
2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Yasser R. Souror ◽  
Tayseer Maaly ◽  
Mohammed Sameer Khawandanah
Keyword(s):  
Flexural Strength ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Acrylic Resin ◽  
Tooth Surface ◽  
Significant Difference ◽  
Space Maintainer ◽  
Fixed Space

Abstract To evaluate a fixed-space maintainer made of light-cure acrylic resin (LCAR) for its flexural and shear bond strength using different bonding systems to the enamel. 45 extracted primary teeth were selected. They were randomly divided into three equal groups (n = 15) along with the type of adhesive system (Tetric Flow, Transbond XT, and Fuji Ortho LC) used for bonding (LCAR) to the tooth surface. Surfaces were treated; LCAR was attached to the treated surfaces using a split Teflon mold. For flexural strength testing, ten bars of LCAR were made using another Teflon-split mold. Shear bond strength and mean flexural strength values were evaluated by a universal testing machine. The highest values of bond strength were recorded for Transbond XT, followed by Tetric Flow, while the lowest values were for Fuji Ortho LC. Various groups had a significant difference as investigated by ANOVA. ARI scores showed no significant difference in debond sites. Mean value and standard deviation of flexural strength for LCAR were 82.83  ± 5.2. LCAR has superior mechanical properties and could be an alternative to currently-in-use space maintainer though in vivo and in vitro trials are needed to progress the ultimate design of LCAR.

PENGARUH MINUMAN TEH HITAM TERHADAP KEKUATAN TRANSVERSAL RESIN AKRILIK POLIMERISASI PANAS

2015 ◽  
Vol 3 (2) ◽  
pp. 68-73
Author(s):  
Riezka Hanafiah Putri ◽  
Zulkarnain Agus ◽  
Eni Rahmi
Keyword(s):  
Immersion Time ◽  
Testing Machine ◽  
Base Material ◽  
Acrylic Resin ◽  
Black Tea ◽  
Bending Test ◽  
Control Group ◽  
Denture Base ◽  
Transverse Strength ◽  
Acrylic Resins

Heat-polymerized  acrylic  resins  is  the  most  used  denture  base  material  in  prosthodontics.  One  of  mechanical properties of acrylic resins is transverse strength. It represents the masticatory pressure that is applied to denture base. Black tea is the second largest consumed beverage in the world. The aim of this study was to investigate the effect of black tea beverage on transverse strength of heat-polymerized acrylic resins. A total of 24 heat-polymerized acrylic resin plates (65×10×2,5 mm) were immersed in black tea beverage for 1, 4, and 20 days as treatment group and in aquadest for 1, 4, and 20 days as control group. The transverse strength of  acrylic samples were measured by three–point bending test by universal testing machine. Data were statistically analyzed using Independent t test. The transverse strength values of acrylic resin immersed in black tea beverage had no significant differences to the transverse strength values of acrylic resin immersed in aquadest with similar immersion time (p>0,05). There was no effect of black tea beverage on transverse strength of heat-polymerized acrylic resins. Immersion time decrease the transverse strength of heat-polymerized acrylic resins due to water sorption. Keywords: Heat-polymerized acrylic resins, black tea, transverse strength

scholarly journals Influence of grinding procedures on the flexural strength of zirconia ceramics

2010 ◽  
Vol 21 (6) ◽  
pp. 528-532 ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document