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 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.

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.

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 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.

scholarly journals Enhancement of the Tensile and the Compression Properties for Heat- Cured Acrylic Resin Denture Base Materials

2018 ◽  
Vol 15 (4) ◽  
pp. 449-454
Author(s):  
Baghdad Science Journal
Keyword(s):  
Polymethyl Methacrylate ◽  
Compression Strength ◽  
Base Material ◽  
Acrylic Resin ◽  
Tensile Tests ◽  
Strength Test ◽  
Denture Base ◽  
Compression Properties ◽  
Base Materials ◽  
Styrene Butadiene

This work aims to investigate the tensile and compression strengths of heat- cured acrylic resin denture base material by adding styrene-butadiene (S- B) to polymethyl methacrylate (PMMA). The most well- known issue in prosthodontic practice is fracture of a denture base. All samples were a blend of (90%, 80%) PMMA and (10%, 20%) S- B powder melted in Oxolane (Tetra hydro furan). These samples were chopped down into specimens of dimensions 100x10x2.5mm to carry out the requirements of tensile tests. The compression strength test specimens were shaped into a cylinder with dimensions of 12.7mm in diameter and 20mm in length. The experimental results show a significant increase in both tensile and compression strengths when compared to control (standard) results for the preparation material.

scholarly journals Tensile and transverse strength of novel copolymers for denture base.

2019 ◽  
Vol S (1) ◽  
pp. 7-10
Author(s):  
Ahmed Asim Saeed Al-Ali ◽  
◽  
Ammar k. Al-Noori ◽  
Amer A. Taqa ◽  
◽  
...  
Keyword(s):  
Acrylic Resin ◽  
P Value ◽  
Transverse Strain ◽  
The Novel ◽  
Denture Base ◽  
Transverse Strength ◽  
Base Materials ◽  
Propenoic Acid ◽  
Significant Difference ◽  
Transverse Strains

Objectives: Compare tensile and transverse strength of new copolymers for denture base. Materials and methods: The specimens were prepared from heat cured acrylic resin with three types of additives: Acryester B, Ethoxycarbonylethylene, and Propenoic acid at a percentage of 5% and 10%. The tensile and transverse strains were tested, recorded and compared. Results: The analysis of variance display statistically significant difference. The p-value was 0.001 for each of tensile and transverse strain tests. Conclusions: The tensile strength of the novel copolymers increased. The transverse strength of some of the novel copolymers increased.

Evaluation of Tissue Reaction to Some Denture-base Materials: An Animal Study

2008 ◽  
Vol 9 (4) ◽  
pp. 67-74 ◽  
Author(s):  
Behnaz Ebadian ◽  
Mohammad Razavi ◽  
Solmaz Soleimanpour ◽  
Ramin Mosharraf
Keyword(s):  
Animal Study ◽  
Weight Ratio ◽  
Acrylic Resin ◽  
Tissue Reaction ◽  
Control Group ◽  
Denture Base ◽  
Base Materials ◽  
Heat Cure ◽  
Two Samples ◽  
Significant Difference

Abstract Aim Controversy continues regarding the biocompatibility of denture base materials. One method to evaluate the biocompatibility of materials is in an animal study. Using dogs as subjects, the purpose of this study was to evaluate the vestibular tissue reaction to cobalt chromium (Co-Cr), heat cure acrylic resin, and acrylic resin mixed with aluminum oxide (Al2O3) compared with a control group using the histopathologic method. Methods and Materials Twelve disk shape samples (2 mm × 8 mm) in four groups of Co-Cr, acrylic resin, acrylic resin mixed with a 20% weight ratio of Al2O3, and a control group (Teflon) were fabricated. In one stage surgery two samples of each material (8 samples) was implanted in the buccal vestibule of each dog (n=6), subcutaneously. At 45 and 90-day intervals, half of the samples were excised along with peripheral tissue to assess the presence of inflammation by grading on a scale from 0 to 3 and the presence of a fibrotic capsule using histological observations. Data were analyzed using the Kruskal-Wallis, Mann-Whitney, and Tau b Kendal tests. Results Tissue reaction between Co-Cr and the control group was significant (P=0.02), but it was not significant between other groups. There was no significant difference between the 45 and 90-day postinsertion samples. The formation of fibrotic capsule groups was significant (P=0.01). It was significant between the Co-Cr and acrylic resin groups (P=0.01) and the acrylic resin and control groups (P=0.01). Conclusion The Co-Cr group was more toxic than the other groups. The inflammation increased during time. The inflammation in two acrylic groups was greater than the control and less than the Co-Cr group. The formation of fibrotic capsule, except in the acrylic resin with Al2O3 group, increased over time. Clinical Significance Co-Cr alloys are toxic and can produce damage to living tissue. Heat cure acrylic resin materials have less toxicity, and their use is safer than Co-Cr alloys. Citation Ebadian B, Razavi M, Soleimanpour S, Mosharraf R. Evaluation of Tissue Reaction to Some Denture-base Materials: An Animal Study. J Contemp Dent Pract 2008 May; (9)4:067-074.

Leachability of denture-base acrylic resins in artificial saliva

1990 ◽  
Vol 6 (1) ◽  
pp. 13-16 ◽  
Author(s):  
T. Koda ◽  
H. Tsuchiya ◽  
M. Yamauchi ◽  
S. Ohtani ◽  
N. Takagi ◽  
...  
Keyword(s):  
Artificial Saliva ◽  
Denture Base ◽  
Acrylic Resins

scholarly journals The Biomechanical Effect of Different Denture Base Materials on the Articular Disc in Complete Denture Wearers: A Finite Element Analysis

2015 ◽  
Vol 3 (3) ◽  
pp. 455-461
Author(s):  
Mohamed M. El-Zawahry ◽  
Ahmed A. El-Ragi ◽  
Mohamed I. El-Anwar ◽  
Eman Mostafa Ahmed Ibraheem
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Base Material ◽  
Acrylic Resin ◽  
Complete Denture ◽  
Articular Disc ◽  
Stress Strain ◽  
Element Analysis ◽  
Denture Base ◽  
Base Materials

AIM: The objective of the present study was to evaluate the effect of different denture base materials on the stress distribution in TMJ articular disc (AD) in complete denture wearers.MATERIAL AND METHODS: Two three dimensional Finite Element (FEA) models of an individual temporomandibular joint (TMJ) were built on the basis CT scan. The FEA model consisted of four parts: the condyle, the articular disc, the denture base, and the articular eminence skull. Acrylic resin and chrome-cobalt denture base materials were studied. Static loading of 300N was vertically applied to the central fossa of the mandibular second premolar. Stress and strain were calculated to characterize the stress/strain patterns in the disc.RESULTS: The maximum tensile stresses were observed in the anterior and posterior bands of (AD) on load application with the two denture base materials. The superior boundaries of the glenoid fossa showed lower stress than those on the inferior boundaries facing the condyle.CONCLUSIONS: Within the limitations of the present study it may be concluded that: The denture base material may a have an effect in stress-strain pattern in TMJ articular disc. The stiffer denture base material, the better the distribution of the load to the underling mandibular supporting structures & reducing stresses induced in the articular disc.

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