The Influence of Saliva pH on the Fracture Resistance of Three Complete Denture Base Acrylic Resins (original) (raw)
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Fracture Strength of Palatal Denture Base Constructed from Different Acrylic Denture Base Materials
European Scientific Journal, 2015
Background: Acrylic resins constitute about 90% of polymeric materials used in prosthetic dentistry. However, they are not devoid of drawbacks. Their weakness includes poor resistance to fracture and abrasion, as well as changes in volume and shape during fabrication and use. Objectives: The aim of this study is to evaluate and compare the mechanical strength in fracture force test of maxillary palatal denture bases, fabricated from different acrylic resins. Materials and Methods: Twenty five maxillary edentulous stone casts were constructed from a standard silicon model of maxillary edentulous jaw. Five palatal denture bases were made from each of the following materials; conventional heat cure acrylic (Control Group), rapid cure acrylic, high impact acrylic and Biostar pure acrylic, according to the manufacturer's instructions. The fracture force test was carried out on a universal testing machine (GUNT HAMBURG) at a crosshead speed of 10mm/min. The results were analyzed using ANOVA and t-test to determine the significant differences between tested groups at a significant level (P<0.05). Results: The high impact acrylic resin showed the highest fracture force value, while the Biostar pure acrylic resin showed the lowest value as compared with other tested materials. The results revealed highly significant differences between the high impact acrylic and conventional heat cure acrylic (P<0.001), and other tested denture base materials (P<0.05). Also, rapid heat cure acrylic resin showed significantly higher fracture force value than those obtained by both conventional heat cure acrylic resin and Biostar pure acrylic resin (P<0.05),(P<0.001) respectively. Finally, significantly lower fracture force value was obtained by the Biostar acrylic resin as compared to the conventional heat cure acrylic (P≤0.05) and other tested denture base materials (P<0.001).
Correlation in the mechanical properties of acrylic denture base resins
Dental Materials Journal, 2012
The aim of the present study was to measure various mechanical properties of acrylic denture base resins, including flexural modulus, flexural strength, fracture toughness, Barcol and Vickers hardness and their related properties, and to investigate correlations between different mechanical properties. Resin specimens were prepared according to manufacturers' recommended instructions. The mechanical properties were measured under specified standards. Data from the mechanical tests were examined using correlation tests. In general, the mean results for mechanical properties of each specimen group were differently ranked depending on the tested mechanical property. The flexural modulus value showed strong or reasonable positive correlation with those of proportional limit, flexural strength, and surface hardness. In contrast, fracture toughness revealed strong negative correlations with the flexural parameters and hardness values. Results of correlation tests for the different parameters can be used for estimation of mechanical performance of acrylic denture bases in clinical situation and for quality control purposes.
Experimental Study on Mechanical Properties of Different Resins Used in Oral Environments
Medicina
Background and Objectives: Acrylic resins remain the materials of choice for removable prosthesis due to their indisputable qualities. The continuous evolution in the field of dental materials offers practitioners today a multitude of therapeutic options. With the development of digital technologies, including both subtractive and additive methods, workflow has been considerably reduced and the precision of prosthetic devices has increased. The superiority of prostheses made by digital methods compared to conventional prostheses is much debated in the literature. Our study’s objective was to compare the mechanical and surface properties of three types of resins used in conventional, subtractive, and additive technologies and to determine the optimal material and the most appropriate technology to obtain removable dentures with the highest mechanical longevity over time. Materials and Methods: For the mechanical tests, 90 samples were fabricated using the conventional method (heat cu...
Objectives: The aim of this study is to compare the effect of artificial saliva on flexural strength of three commercially available denture base acrylic resins. Methods: In this study three commercially available heat cure denture base resins namely Trevalon, Trevalon-Hi and Pyrax Acryl-Hi were taken. The artificial saliva was prepared in one of our laboratory and the samples were immersed in artificial saliva in order to simulate oral environment. The time dependent changes in the flexural strength of acrylic resins was evaluated and compared with the samples soaked in artificial saliva. Results: A total of 84 samples (28 samples of each type) were made. According to the mean value, the flexural strength was in following order: Trecvalon-Hi; Pyrax Acryl-Hi and Trevalon. The flexural strength decreases with time and after soaking in saliva. Conclusion: PYRAX Acryl-Hi possesses good strength and aesthetics and offers better treatment options as the results are concerned. Since it is manufactured in India it is free from import-export charges. Hence it is relatively economical.
Poly(methyl methacrylate) (PMMA) is the material of choice for denture base construction. In spite of its many good qualities, the application of PMMA as an ideal dental base material is still restricted by a few limitations. One of these is the difficulty in achieving intrinsic radiopacity in the material. The aim of the present study is to investigate the possibility of using barium titanate (BaTiO 3 ) as a radiopacifier in PMMA. The formulation used in this study composed of PMMA 89.5 wt%, BaTiO 3 10 wt% and benzoyl peroxide (BPO) 0.5 wt% as an initiator, methyl methacrylate (MMA) 90 wt% as a monomer and ethylene glycol dimethyl acrylate (EGDMA) 10 wt% as a cross-linking agent. The BaTiO 3 was treated by a silane coupling agent, 3-trimethoxysilylpropyl methacrylate (γ-MPS), prior to incorporation in the solid components (PMMA, BPO). The curing was carried out using a water bath at 78°C for 1.5 h. The samples were tested for fracture toughness before and after soaking for 28 days in simulated body fluid (SBF). Moreover, the morphology of the specimens was investigated by scanning electron microscope (SEM). The results showed that the neat PMMA possessed slightly higher fracture toughness properties than the PMMA composite, and after 28 days of immersion, the fracture toughness values were reduced by 4.8% and 3.4% for neat PMMA and PMMA composite, respectively.
The Journal of Contemporary Dental Practice, 2019
Aim: The aim of the present study was to compare and evaluate the flexural strength of heat-polymerized Lucitone 199 and SR Ivocap denture base resin materials which uses polymerization techniques of compression molding and injection molding respectively and effect of artificial saliva and distilled water on long-term. Materials and methods: Ninety specimens each from both the materials measuring 65 × 10 × 3 mm were prepared. After the polymerization, flexural strength was calculated after 24 hours (control group) without immersing in the liquid medium. The test group specimens immersed in saliva and distilled water at 37 0 C was calculated for the flexural strength at 2 weeks, 1 month, 2 months and 4 months. The flexural strength was measured using a universal testing machine. One-way analysis of variance (ANOVA) method was used to analyze the data, pairwise comparisons were done using Bonferroni post hoc test with a probability of less than 0.05 were considered to be statistically significant. Results: The evaluation showed that, despite the duration of immersion and type of acrylic resin, high flexural strength was seen with specimens immersed in saliva than specimens under distilled water. The higher flexural strength was seen in SR Ivocap compared to that of Lucitone199 with the p value less than 0.05 which showed significant statistically. Conclusion: From the results, we can conclude that the higher flexural strength was shown in specimens of SR Ivocap fabricated through injection molding technique compared to specimens of Lucitone 199 fabricated through compression molding technique after immersion in artificial saliva and distilled water for long term. Clinical significance: The homogeneous copolymer beads, the difference in the water sorption and powder to liquid ratios also affect the mechanical properties of the resins other than the type of resin used in the dentures base.
Materials, 2015
The fracture resistance of polymethylmethacrylate (PMMA) as the most popular denture base material is not satisfactory. Different factors can be involved in denture fracture. Among them, flexural fatigue and impact are the most common failure mechanisms of an acrylic denture base. It has been shown that there is a correlation between the static strength and fatigue life of composite resins. Therefore, the transverse strength of the denture base materials can be an important indicator of their service life. In order to improve the fracture resistance of PMMA, extensive studies have been carried out; however, only a few promising results were achieved, which are limited to some mechanical properties of PMMA at the cost of other properties. This study aimed at optimizing the packing and processing condition of heat-cured PMMA as a denture base resin in order to improve its biaxial flexural strength (BFS). The results showed that the plain type of resin with a powder/monomer ratio of 2.5:1 or less, packed conventionally and cured in a water bath for 2 h at 95 °C provides the highest BFS. Also, it was found that the performance of the dry heat processor is inconsistent with the number of flasks being loaded. OPEN ACCESS Materials 2015, 8 2094
Flexural and fatigue strengths of denture base resin
The Journal of Prosthetic Dentistry, 2008
From the perspective of static and dynamic flexural properties, a visible light-polymerized, dough-type resin may be suitable in low stress situations. Statement of problem. Mechanical properties of denture acrylic resins are important for the clinical success of multiple types of prostheses. Acrylic resins must be strong and resilient so as to withstand impact. Few studies utilize cyclic loads to characterize material response to repeated stress.
Fatigue Behavior of Two Acrylic Denture Base Resins
Materiale Plastice, 2018
Acrylic resins based on polymetyl metacrylate are used in dental prosthetics as base for dentures. One of the major failure causes of dentures is the fatigue damage of the acrylic resins. These materials, in addition to mechanical behavior, also present a high risk of structural defects (voids, micro-cracks, residual monomer) that can significantly affect the fatigue behavior. In this paper, two commercial acrylic resins have been experimentally analyzed in terms of mechanical and fatigue behavior. Tensile constant amplitude fatigue tests with stress ratio R = 0 and frequency of 2 Hz have been carried out on samples of the two acrylic resins, prepared according to the manufacturer�s recommendations. The results revealed, besides the brittle fracture character, a similar fatigue behavior following a Weibull distribution. Also, through statistical processing of the results, the fatigue curve equations of the two analyzed materials were estimated for different levels of confidence.