Residual monomer concentrations in denture-base acrylic resin after an additional, soft-liner, heat-cure cycle

1999 ◽  
Vol 15 (4) ◽  
pp. 296-300 ◽  
Author(s):  
J.-S Shim ◽  
D.C Watts
2020 ◽  
Vol 14 (02) ◽  
pp. 268-273
Author(s):  
Sareh Habibzadeh ◽  
Arman Omidvaran ◽  
Solmauz Eskandarion ◽  
Ahmad Reza Shamshiri

Abstract Objectives This study aimed at assessing the effect of the addition of silver nanoparticles (SNPs) to a silicone soft liner on its tensile bond strength to denture base resin. Materials and Methods SNPs were added to Mucopren cold cure soft liner in 0 (control), 0.5, 1, 2, and 3 wt% concentrations and bonded in 120 stainless steel molds with processed heat cure acrylic resin blocks. Liner/resin combination samples were divided into two groups. The first half was stored for 2 days in distilled water at 37°C and then subjected to tensile bond strength, while the other half were thermocycled 3000 times before testing. Mean bond strength, expressed in mega pascals (MPa), was determined in the tensile test with the use of a universal testing machine at a crosshead speed of 5 mm/min. Statistical Analysis Data were analyzed using SPSS via one-way analysis of variance test, t-test, and Tukey’s posthoc, at a 95% confidence level (p < 0.05). Results Addition of SNPs and thermocycling both caused a significant reduction in the tensile bond strength of Mucopren to acrylic resin; however, in the thermocycled group, the bond strength increased with the increase in the concentration of SNPs (p < 0.001). Conclusion Addition of SNPs to Mucopren soft silicone liner reduces its tensile bond strength to denture acrylic resin.


2020 ◽  
pp. 4-6
Author(s):  
Joy PT ◽  
Bennett Atlin Correya ◽  
V. K Zahida ◽  
Gilsa K. Vasunni ◽  
Julie George Alapatt

The conversion of monomer to polymer is not complete in denture base resins and residual monomer left can cause mucosal irritation, inflammation, and allergic reactions in tissues adjacent to dentures. The mechanical properties of denture base resins have been found to be lacking with increased residual monomer content. Therefore, it is desirable to reduce the residual monomer content in the processed denture. In the present study Gas chromatography method was used to determine the levels of residual methyl methacrylate monomer of two different brands of heat cure denture base resins processed by two different polymerization cycles. The study concluded that while processing the denture sufficient length of boiling phase should be given and for each brand, manufacturer’s instructions should be strictly followed while selecting polymerization cycle.


2008 ◽  
Vol 9 (4) ◽  
pp. 67-74 ◽  
Author(s):  
Behnaz Ebadian ◽  
Mohammad Razavi ◽  
Solmaz Soleimanpour ◽  
Ramin Mosharraf

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.


2018 ◽  
Vol 2 (2) ◽  
pp. 150-161
Author(s):  
Bestun Akram ◽  
Rizgar Hasan

Adequate retention is a basic requirement for the acceptance of complete denture. The aim of this study was to evaluate the retention quality of fluid denture base materials and compare it with conventional acrylic denture base materials Method: Sixteen edentulous male patients with an age 45-60 years participated in the study. For each patient two denture bases were constructed, one of them made from fluid denture base materials and the other made from hot acrylic denture base materials. A specially designed strain gauge measuring device was used to measure the force required to dislodge the two dentures from basal seats. Six measurements of retention of newly inserted denture base were recorded for each patient (three for maxillary acrylic denture base and three for maxillary fluid denture base). Results: The results of the retention test showed that the fluid denture base materials required more force in order to dislodge denture than the heat cure denture base materials, which means a significant improvement in retention quality obtained by fluid denture base materials. Conclusions: It has appeared that the fluid acrylic denture base materials produce denture base material with excellent retentive efficiency to the underlying tissue when compared to conventional denture base materials.


2015 ◽  
Vol 9 (1) ◽  
pp. 402-408 ◽  
Author(s):  
A.A.R. Khaledi ◽  
M. Bahrani ◽  
S. Shirzadi

Statement of the Problem: Bonding failure between acrylic resin and soft liner material and also gradual loss of soft liner resiliency over time are two impending challenges frequently recognized with a denture base embraced with a resilient liner. Since patients drink various beverages, it is crucial to assess the influences of these beverages on physical characteristics of soft liners. Purpose: This in vitro study envisioned to assess the influence of food simulating agents (FSA) on the hardness of a silicone soft liner by employing a Shore A durometer test and also evaluate its bond strength to a denture base resin by using tensile bond strength test. Materials and Methods: To test the hardness of samples, 50 rectangular samples (40 mm × 10 mm × 3 mm) were prepared from a heat-polymerized polymethyl methacrylate (Meliodent). Mollosil, a commercially available silicone resilient liner, was provided and applied on the specimens following the manufacturer’s directions. In order to test tensile bond strength, 100 cylindrical specimens (30 mm × 10 mm) were fabricated. The liners were added between specimens with the thicknesses of 3 mm. The specimens were divided into 5 groups (n=10) and immersed in distilled water, heptane, citric acid, and 50% ethanol. For each test, we used 10 specimens as a baseline measurement; control group. All specimens were kept in dispersed containers at 37ºC for 12 days and all solutions were changed every day. The hardness was verified using a Shore A durometer and the tensile bond strength was examined by an Instron testing machine at a cross-head speed of 5 mm/min. The records were analyzed employing one-way ANOVA, Tukey’s HSD, and LSD tests. Results: The mean tensile bond strength ± standard deviation (SD) for Mollosil was as follows for each group: 3.1 ± 0.4 (water), 1.8 ± 0.4 (citric acid), 3.0 ± 0.4 (heptane), 1.2 ± 0.3 (50% ethanol), and 3.8 ± 0.4 (control). The hardness values for each group were: 28.7 ± 2.11 (water), 33.2 ± 2.82 (citric acid), 39.2 ± 4.8 (heptane), 32.3 ± 3.56 (50% ethanol) and 22.2 ± 2.08 (control). Mean values for hardness indicated that all of the food simulating agents significantly increased hardness of the Mollosil soft liner compared to the control group (p<0.05). The results of tensile bond strength depicted that water and FSA decreased the bond strength of the soft liner -denture base resin compared to the control group and it was statistically significant (p<0.05). Conclusion: The food simulating agents could influence the mechanical properties of silicone soft liners; hence, clinicians should inform their patients concerning their possible adverse effects and complications.


2008 ◽  
Vol 19 (3) ◽  
pp. 201-206 ◽  
Author(s):  
Nilüfer Çelebi ◽  
Bulem Yüzügüllü ◽  
Şenay Canay ◽  
Ülkü Yücel

2021 ◽  
Vol 25 (2) ◽  
pp. 108-113
Author(s):  
Ozlem Gurbuz Oflezer ◽  
Hakan Bahadır ◽  
Senem Ünver ◽  
Ceyhan Oflezer

Summary Background/Aim: Relining is defined as the procedure used to resurface the tissue side of a denture with new base material, thus producing an accurate adaptation is provided at the denture foundation area. During mastication, relined dentures have to withstand masticatory forces to prevent fracture. The aim of this study was to evaluate the flexural strength of acrylic resin denture base relined with different methods and materials. Material and Methods: Fourteen experimental groups and one control group were determined to consider different reline materials and processing methods. Acrylic resin specimens were prepared with the dimensions of 65× 10× 1.5 mm and reline materials (1.5 mm thickness) were placed on acrylic resins. Reline material was not used in control group specimens. Flexural strength values of relined and control specimens were measured with three-point bending test at a speed of 5 mm/min. Data were analyzed with using one way Anova and Student t tests. Results: The highest flexural strength values were shown in control group (86.51±1.08 MPa). There were significant differences among relined specimens (p< 0.05). For the relined specimens, the highest flexural strength values were found in the relined specimens with denture base material (77.90±1.93 MPa), and the lowest values were found in relined with autopolymerize acrylic material (59.81±1.50 MPa). Conclusions: Relining of the heat cure denture base material significantly decreases the flexural strength for all processing methods and materials.


Sign in / Sign up

Export Citation Format

Share Document