scholarly journals The Influence of Saliva pH on the Fracture Resistance of Three Complete Denture Base Acrylic Resins

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Juliana de Sá ◽  
Francisca Vieira ◽  
Carlos Manuel Aroso ◽  
Mónica Cardoso ◽  
José Manuel Mendes ◽  
...  
Keyword(s):  
Fracture Resistance ◽  
Artificial Saliva ◽  
Testing Machine ◽  
Acrylic Resin ◽  
Low Ph ◽  
Data Sets ◽  
Denture Base ◽  
Base Materials ◽  
Acrylic Resins ◽  
Ph Conditions

Aim and Background. The absorption of fluids by denture base materials diminishes the mechanical properties such as hardness, strength, and fatigue limit due to the plasticizing effect of water. This study aimed to evaluate the influence of oral pH on the fracture resistance of prosthetic bases made of three different heat-polymerizable acrylic resin brands: RS Vertex®, Triplex Hot®, and Megacryl®. The strength needed to fracture the resins and the resistance to fracture each resin were evaluated. Methods. Ten prosthesis bases prepared with each brand of resin were subjected to neutral and low pH conditions (pH 7 and pH 4) by submerging them in artificial saliva for 30 days. After exposure, the fatigue resistance of the resins was tested using a Dental CS® Testing Machine. Statistical Analysis Test. The data sets were described quantitatively in terms of mean (M) and standard deviation (SD). Shapiro–Wilk tests and unilateral analysis of variance (ANOVA) were performed and complemented by Tukey’s multiple comparison tests. The effect size (η2), whose cohort points followed Cohen’s recommendations: 0.01 (low), 0.06 (medium), and 0.14 (high), was calculated. The results were considered significant if p < 0.05 and marginally significant if p < 0.10 . Results. One-way ANOVA showed that Megacryl® had the highest fracture resistance at pH 7 (52.23 Kgf), compared with Triplex Hot® ( p < 0.001 ) and RS Vertex® ( p = 0.034 ). Two-way ANOVA confirmed the interaction between brand and pH ( p = 0.022 ), also revealing that brands comparison is significant or marginally significant, when pH is not considered (Megacryl® versus Triplex Hot®, p < 0.001 , and RS Vertex®, p = 0.058 ; Triplex Hot® versus RS Vertex®, p = 0.051 ), and pH 7 results were significantly higher ( p = 0.003 ), even when brands are not considered. Hence, Megacryl® at pH 7 was found to have the highest fracture resistance, detached from other brands and pH values. Conclusion. It can be concluded within the limitations of this study that there are differences in the fracture resistance among the three brands of acrylic resin. Megacryl® was found to have the highest fracture resistance, and Triplex Hot® was the lowest. The results also show that exposure to a low pH environment decreases the fracture resistance of the Megacryl® and RS Vertex® resins.

scholarly journals Artificial saliva effect on toxic substances release from acrylic resins

2015 ◽  
Vol 72 (10) ◽  
pp. 899-905 ◽  
Author(s):  
Milena Kostic ◽  
Nebojsa Krunic ◽  
Stevo Najman ◽  
Ljubisa Nikolic ◽  
Vesna Nikolic ◽  
...  
Keyword(s):  
Surface Structure ◽  
Artificial Saliva ◽  
Acrylic Resin ◽  
Toxic Substances ◽  
Surface Design ◽  
Denture Base ◽  
Applied Model ◽  
Base Materials ◽  
Acrylic Resins ◽  
High Degree

Background/Aim. Acrylic-based resins are intensively used in dentistry practice as restorative or denture-base materials. The purpose of this study was to analyze the surface structure of denture base resins and the amount of released potentially toxic substances (PTS) immediately upon polymerization and incubation in different types of artificial saliva. Methods. Storage of acrylic samples in two models of artificial saliva were performed in a water bath at the temperature of 37 ? 1?C. Analysis of the surface structure of samples was carried out using scanning electronic microscopy analysis immediately after polymerization and after the 30-day incubation. The amounts of PTS per day, week and month extracts were measured using high-pressure liquid chromatography. Results. Surface design and amount of PTS in acrylic materials were different and depended on the types and duration of polymerization. The surfaces of tested acrylates became flatter after immersing in solutions of artificial saliva. The degree of acrylic materials release was not dependent on the applied model of artificial saliva. Conclusion. In order to improve biological features of acrylic resin materials, it was recommended that dentures lined with soft or hard coldpolymerized acrylates should be kept at least 1 to 7 days in water before being given to a patient. So, as to reach high degree of biocompatibility preparation of prosthetic restorations from heat-polymerized acrylate was unnecessary.

scholarly journals Comparison of Fracture Resistance in Thermal and Self-Curing Acrylic Resins—An In Vitro Study

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1234
Author(s):  
António Sérgio Silva ◽  
Aurora Carvalho ◽  
Pedro Barreiros ◽  
Juliana de Sá ◽  
Carlos Aroso ◽  
...  
Keyword(s):  
Fracture Resistance ◽  
Research Work ◽  
Testing Machine ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Thermosetting Resins ◽  
Acrylic Resins ◽  
The Difference

Thermal and self-curing acrylic resins are frequently and versatilely used in dental medicine since they are biocompatible, have no flavor or odor, have satisfactory thermal qualities and polishing capacity, and are easy and fast. Thus, given their widespread use, their fracture resistance behavior is especially important. In this research work, we comparatively analyzed the fracture resistance capacity of thermo and self-curing acrylic resins in vitro. Materials and Methods: Five prosthesis bases were created for each of the following acrylic resins: Lucitone®, ProBase®, and Megacryl®, which were submitted to different forces through the use of the CS® Dental Testing Machine, usually mobilized in the context of fatigue tests. To this end, a point was defined in the center of the anterior edge of the aforementioned acrylic resin bases, for which the peak tended until a fracture occurred. Thermosetting resins were, on average, more resistant to fracture than self-curable resins, although the difference was not statistically significant. The thermosetting resins of the Lucitone® and Probase® brands demonstrated behavior that was more resistant to fracture than the self-curing homologues, although the difference was not statistically significant. Thermosetting resins tended to be, on average, more resistant to fracture and exhibited the maximum values for impact strength, compressive strength, tensile strength, hardness, and dimensional accuracy than self-curing resins, regardless of brand.

Cytotoxicity of long-term denture base materials

2018 ◽  
Vol 41 (10) ◽  
pp. 677-683 ◽  
Author(s):  
Merve Çakırbay Tanış ◽  
Canan Akay ◽  
Handan Sevim
Keyword(s):  
Cell Viability ◽  
Cytotoxic Effect ◽  
Water Storage ◽  
Acrylic Resin ◽  
Denture Base ◽  
Base Materials ◽  
Acrylic Resins ◽  
Group I ◽  
Significant Difference ◽  
Similar Cell

Introduction: The aim of this study was to evaluate the cytotoxic effect of various denture base materials following four different aging periods. Methods: In total, 48 disc-shaped specimens per each group were prepared: Group I: acrylic resin polymerized in cool water and heated up to 100°C over 45 min and boiled for 15 min; Group II: acrylic resin polymerized under pressure in 40°C–45°C water bath for 10 min; Group III: autopolymerized hard relining resin Cold Liner Rebase; Group IV: autopolymerized hard relining resin Truliner; Group V: soft relining resin DentuSil. Then the specimens were stored in water for 24 h or 15 days, or thermocycled 2500 times or 10,000 times. Cytotoxicity was evaluated with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay using L929 cells after 72-h cell incubation. Cell viability percentages were counted and statistical analyses were performed. The results were also evaluated according to ISO standard 10993-5. Results: All materials showed similar cell viability percentages following 24-h water storage and 2500 and 10,000 thermal cycles. Following 15-day water storage, a statistically significant difference was observed between the materials. Comparisons of the aging periods for each material showed statistically significant differences. Groups III and IV showed moderately cytotoxic effect following 15-day water storage. The remaining groups showed slightly cytotoxic or non-cytotoxic effect. Discussion: Polymerizing acrylic resins under pressure can be an alternative to conventional polymerizing to ensure a faster denture repair while providing similar cell viability values. Heat-cured acrylic resins provide higher cell viability than hard chairside lining materials in a 15-day period.

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 Pengaruh Desinfeksi Energi Microwave Terhadap Kekuatan Transversal Resin Akrilik Polimerisasi Panas

2019 ◽  
Vol 8 (1) ◽  
pp. 17
Author(s):  
Sefty Aryani Harahap ◽  
Lasminda Syafiar ◽  
Yosepha Yulinda Esdaria Lubis
Keyword(s):  
Testing Machine ◽  
Acrylic Resin ◽  
Electronic System ◽  
Microwave Energy ◽  
Denture Base ◽  
Mean Values ◽  
Base Materials ◽  
Test Speed ◽  
Universal Testing ◽  
One Way Anova

Disinfectant by microwave energy is highly recommended as a solution to solve the problem of chemical disinfection on denture bases. One of the denture base materials is heat cured acrylic resin. Aim, to evaluate the effect of disinfectant by microwave energy with different time on the transversal strength of heat cured acrylic resin. 30 plates (n = 6) of heat cured acrylic resin with size 65x10x2,5 mm were divided into 5 groups (control; and microwave energy disinfected for 2, 4 , 6, and 8 minutes with 650 Watts of power). Transversal strength test was carried out using Torsee's Electronic System Universal Testing Machine with a test speed of 0.1 mm / second, and a load cell of 50 kgf. Data analyzed using one-way ANOVA and LSD pos hoc. Results, there were significant differences in the transverse strength among all groups (p <0.05). Mean values of all groups were 103.59 ± 0.66 MPa; 112.02 ± 2.10 MPa; 117.48 ± 1.73 MPa; 125.46 ± 2.25 MPa; and 135.89 ± 1.56 MPa respectively. Conclusion, the longer it is disinfected by microwave energy, the higher the transversal strength of heat cured acrylic resin.

scholarly journals Effect of Thermocycling, Teeth, and Polymerization Methods on Bond Strength Teeth-Denture Base

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Sandra Lúcia Andrade de Freitas ◽  
William Cunha Brandt ◽  
Milton Edson Miranda ◽  
Rafael Pino Vitti
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Acrylic Resin ◽  
Water Bath ◽  
Microwave Method ◽  
Denture Base ◽  
Mean Values ◽  
Acrylic Resins ◽  
Artificial Teeth

Objective. To evaluate the shear bond strength between different artificial teeth and denture base polymerized by two polymerization methods submitted to thermocycling. Materials and Methods. Two acrylic resins were selected according to the polymerization method (water-bath and microwave), and four different artificial teeth (Biotone, Dentsply; Trilux, Vipi Dent; Premium 8, Heraeus Kulzer; Soluut PX, Yamahachi) were also tested. The polymerization of the acrylic resin was performed by using conventional cycle (8 h at 74°C) in water-bath and using two cycles (20 min at 270 W + 5 min at 360 W) by the microwave method. The shear bond strength was evaluated after 24 h of water storage at 37°C (immediately) and after the thermocycling test (5,000 cycles, 5–55°C). The shear bond strength (n=10) was performed using a universal testing machine (Instron 4411) at a crosshead speed of 1.0 mm/min. Modes of failures were classified as cohesive and adhesive. The data (MPa) were statistically analyzed by three-way ANOVA, and the mean values were compared by the Tukey test (α = 0.05). Results. In general, the polymerization by microwave showed the highest shear bond strength values, and Trilux artificial teeth had the lowest bond strength values (p<0.05). Thermocycling did not affect the shear bond strength (p<0.05). There was a predominance of cohesive failures for all groups. Conclusions. The chemical composition of the artificial teeth affects the bond strength, and the microwave method is preferable to perform the acrylic resin polymerization.

scholarly journals Variations in Flexural Strength of Heat-polymerized Acrylic Resin after the Usage of Denture Cleansers

2016 ◽  
Vol 17 (4) ◽  
pp. 322-326 ◽  
Author(s):  
M Kalavathi ◽  
Mallikarjuna Ragher ◽  
G Vinayakumar ◽  
Sanketsopan Patil ◽  
Aishwarya Chatterjee ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Testing Machine ◽  
Peak Load ◽  
Acrylic Resin ◽  
Control Group ◽  
Denture Base ◽  
Acrylic Resins ◽  
Significant Difference ◽  
Base Resin ◽  
Denture Cleansers

ABSTRACT Objective The objective of this study was to evaluate and compare changes in the flexural strength of heat-cured denture base resins when treated using denture cleansers. Study design A total of 40 specimens with dimension 65 mm length, 10 mm width, and 3 mm thickness were prepared as per ISO 1567 specification. A total of 10 specimens were immersed in distilled water to be used as control. Of the remaining 30 samples, 10 were treated with Clinsodent, 10 with VI-Clean, and 10 with Clanden denture cleansers. Specimens in each group were subjected to three-point flexural load in universal testing machine at a cross-head speed of 5 mm/min. The peak load (N) was recorded and flexural strength was calculated. The findings were analyzed using Kruskal–Wallis analysis of variance and Mann–Whitney test. Results Heat-cured denture base resin selected for this study showed significant difference in flexural strength after immersion in denture cleansers Clinsodent, VI-Clean, and Clanden solutions, when compared with the control group. Conclusion Findings of this study showed that denture cleansers altered the flexural strength of heat polymerized acrylic resins that endured soaking cycles which simulated 180 days of use. Hence, denture cleansers should be used with caution, once a day after brushing the dentures. It is advisable for patients to follow the manufacturer's instructions. How to cite this article Ragher M, Vinayakumar G, Patil S, Chatterjee A, Mallikarjuna DM, Dandekeri S, Swetha V, Pradeep MR. Variations in Flexural Strength of Heat-polymerized Acrylic Resin after the Usage of Denture Cleansers. J Contemp Dent Pract 2016;17(4):322-326.

scholarly journals Hardness of denture base and hard chair-side reline acrylic resins

2005 ◽  
Vol 13 (3) ◽  
pp. 291-295 ◽  
Author(s):  
Andrea Azevedo ◽  
Ana Lucia Machado ◽  
Carlos Eduardo Vergani ◽  
Eunice Teresinha Giampaolo ◽  
Ana Cláudia Pavarina
Keyword(s):  
Surface Hardness ◽  
Acrylic Resin ◽  
Polymerization Reaction ◽  
Time Intervals ◽  
Denture Base ◽  
Continuous Increase ◽  
Hardness Tester ◽  
Dry Storage ◽  
Base Materials ◽  
Acrylic Resins

INTRODUCTION: The hardness of denture base materials may undergo changes due to continued polymerization reaction and water uptake. However, the extent to which these processes affect the hardness of materials is still unclear. OBJECTIVE: In this study, the degree of conversion of two hard chair-side reline resins (Duraliner II-D and Kooliner-K) and one heat-cured acrylic resin (Lucitone 550-L) was evaluated indirectly by measuring the surface hardness. The effect of immersion in water on this property was also analyzed. MATERIALS AND METHODS: After processing following the manufacturers' instructions, specimens (5mm diameter and 2mm thickness) were dry stored at room temperature and the Vickers hardness (VHN) was measured with a hardness tester after 0, 2, 7, 30 and 90 days. Specimens were then immersed in water at 37ºC and hardness was evaluated after the same time intervals. Five specimens were prepared for each material. Data were analyzed by Kruskal-Wallis test (P=.01). RESULTS: When dry stored, material L showed an increase in hardness (P<.01) from 0-day (VHN=23.2) to 30-day (VHN=27.1), after which no significant change was observed. A continuous increase in hardness was observed for material D from 0-day (VHN=4.6) to 90-day dry storage (VHN=7.3). For material K, an increase in hardness was observed up to 7-day (VHN=9.2), and then leveled off (P>.01). After 2-day water storage, all materials showed a significant reduction in hardness (P<.01). CONCLUSION: In general, the hardness of the materials evaluated increased during dry storage and decreased after immersion in water.

scholarly journals Effects of Denture Base Thicknesses and Reinforcement on Fracture Strength in Mandibular Implant Overdenture with Bar Attachment: Under Various Acrylic Resin Types

2019 ◽  
Vol 13 (01) ◽  
pp. 064-068
Author(s):  
Selen Tokgoz ◽  
Arda Ozdiler ◽  
Burc Gencel ◽  
Ergun Bozdag ◽  
Gulbahar Isık-Ozkol
Keyword(s):  
Fracture Strength ◽  
Fracture Resistance ◽  
Glass Fibers ◽  
Testing Machine ◽  
Acrylic Resin ◽  
Base Thickness ◽  
Denture Base ◽  
Significant Difference ◽  
Implant Overdenture ◽  
Student’S T

Abstract Objective This study aimed to assess the effect of reinforcement, denture base thickness, and acrylic resin types on dynamic and static fracture strength in mandibular implant overdentures with bar attachment. Materials and Methods One hundred and eight experimental mandibular implant overdentures with bar attachments were fabricated in three main groups, namely unreinforced (control: C), reinforced with unidirectional glass fibers (FR), and Co–Cr cast metal (MR). Each group included denture bases of 2-, 3-, and 4-mm thicknesses and produced with conventional (CA) and high-impact acrylic (HIA) resins. Specimens were thermocycled (5,000 times, 5–55°C) then subjected to a 400,000 cyclic load regime. Unbroken specimens were then loaded until fracture by a universal testing machine. Differences in mean fracture resistance among the groups were compared using the one-way analysis of variance (with post hoc Tukey's honestly significant difference test) and Student's t-tests (α = 0.05). Results Fracture strength increased significantly when the denture base thickness was increased (p = 0.001). The 2-mm denture base thickness was not enough for reinforcement. The fracture strength of the FR groups was significantly higher than other groups for 3- and 4-mm thicknesses (p = 0.001). The fracture strength of the HIA resin was significantly higher than CA resin in FR groups (p = 0.029 and p = 0.001). MR groups showed the weakest fracture strength. Conclusions The 2-mm denture base thickness had sufficient fracture strength without reinforcement and a positive relationship between acrylic resin thickness and fracture resistance was found.

scholarly journals The comparison of surface hardness between thermoplastic nylon resin and heat-cured acrylic resin

2009 ◽  
Vol 21 (3) ◽  
Author(s):  
Marina Utami ◽  
Renny Febrida ◽  
Nina Djustiana
Keyword(s):  
Vickers Microhardness ◽  
Surface Hardness ◽  
Base Material ◽  
Acrylic Resin ◽  
Polymer Chains ◽  
Denture Base ◽  
Hardness Level ◽  
Base Materials ◽  
Acrylic Resins ◽  
Materials Used

The surface hardness level of a denture base material is related to the resistance to abrasion, scratch, polishing and water sorption. Nowadays, thermoplastic nylon resins and heat-cured acrylic resins are used as denture base materials. Denture base must be immersed in water to maintain its humidity. The objective of this research was to compare the surface hardness level between thermoplastic nylon resins and heat-cured acrylic resins. Materials used for the research were thermoplastic nylon resins from Valplast and heat-cured acrylic resins QC-20, with a sample size of 64x(10±0.03)x(2.5±0.03) mm. Surface hardness is measured with Vickers Microhardness Tester and the data were analyzed by ANOVA method. The results showed that comparison ratio of surface hardness level between thermoplastic nylon resins and heat-cured acrylic resins before immersion is 3.2:7.3 VHN respectively, while the comparison value of both resins after immersion is 2.8:6.6 VHN. In conclusion, the surface hardness level of thermoplastic nylon resins is lower compared to heat-cured acrylic resins. This result is due to thermoplastic nylon resin’s higher porosity, its different polymer chains, and the plasticizers effect after immersion in water.

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