Effect of cavity preparation on the flexural strengths of acrylic resin repairs (original) (raw)
Related papers
2017
For those who lost their teeth either partially or completely, they may require some kinds of removable prosthesis such removable partial denture and complete denture. A recognizable and well-known material to fabricate these types of dental prosthesis is polymethylmethacrylate (PMMA) [1]. Even though, long term service of denture base has been reported previously [2,3], but they are not quite stable. They changed overtime because of various degree of alveolar bone resorption, poor management of occlusal force, which result in being loose. Even worse, they were broken as a consequence of poor processing or denture wearers themselves. Another reason is low fracture strength of acrylic denture base. Some literature reported that denture fracture happened twice as more frequent in maxillary as in mandibular prosthesis [4,5]. Therefore repairing is a good solution for treatment or even it is indicated if there were slight modifications and the denture was still in good condition; becaus...
IP Annals of prosthodontics and restorative dentistry, 2023
The purpose of this vitro study was to comparatively evaluate the flexural strength of repaired denture base resin using different surface treated reinforcement materials. Materials and Methods: According to ADA specification No. 12, typical heat polymerized acrylic resin specimens were created, and various repairs were made to them. Autopolymerizing resin was used for repair. The flexural strength was evaluated using the INSTRON universal testing equipment on a total of 90 samples (with 15 samples in each group). Result: In this study the highest value of flexural strength was obtained for group in which the reinforcement was done with surface treated half round wires that were sandblasted, etched followed by application of alloy primer. Conclusion: Specimens repaired with reinforcement increases flexural strength. Reinforcement with silanized woven roving e glass fibers showed significant increase in flexural strength compared to unreinforced specimens. There was no statistical difference between the samples repaired with sandblasted wires and etched wires group.
To investigate the effect of the selected chemical surface treatment agents on the flexural strength of heat-polymerized acrylic resin repaired with autopolymerized acrylic resin. Materials and Methods: Ninety heat-polymerized acrylic resin specimens (Meliodent) were prepared according to ISO1567 and randomly divided into nine groups: positive and negative control groups (groups I and II), and seven experimental groups (groups III to IX). Specimens in groups II to IX were cut in the middle and beveled 45 • . Group III was then treated with methyl methacrylate (the liquid part of Unifast TRAD) for 180 seconds. Group IV was treated with Rebase II adhesive according to the manufacturer's instructions. Groups V to IX were treated with methyl formate, methyl acetate, and a mixture of methyl formate-methyl acetate at various concentrations (75:25, 50:50, 25:75% v/v, respectively) for 15 seconds. They were then repaired with autopolymerized acrylic resin (Unifast TRAD). A three-point loading test was performed using a universal testing machine. One-way ANOVA and post hoc Tukey's analysis at p < 0.05 were used for statistical comparison. Failure analysis was then recorded for each specimen. The morphological changes in untreated and treated specimens were observed by scanning electron microscopy. Results: The flexural strengths of groups III to IX were significantly higher than that of group II (p < 0.05). The flexural strengths of groups IV to IX showed no significant difference among them (p > 0.05). All specimens in groups V to IX showed 100% cohesive failure, while groups II, III, and IV showed cohesive failure of 10%, 60%, and 60%, respectively. From scanning electron micrographs, the application of methyl formate, methyl acetate, and a mixture of methyl formate-methyl acetate solutions on heat-polymerized acrylic resin resulted in a 3D honeycomb appearance, while specimens treated with methyl methacrylate and Rebase II adhesive developed shallow pits and small crest patterns, respectively. Conclusion: Treating surfaces with methyl formate, methyl acetate, and a mixture of methyl formate-methyl acetate solutions significantly enhanced the flexural strength of heat-polymerized acrylic denture base resin that had been repaired with autopolymerized acrylic resin.
International Journal of Advanced Research, 2020
The aim of the present study was to evaluate and compare the flexural strength of self-cure and visible light cure denture base resin as repair material using different design of repair. Material and Method:Forty samples of dimensions 65 x 10 x 2.5 mm were made of heat cure acrylic resin and the prepared intact specimens were divided into two equal parts, i.e. 31mm each. Samples in pairs were placed in the mould of dimension 65 x 10 x 2.5 mm with 45° bevel and butt joint design and a gap of 3 mm was created in middle of mould for adhering with self cure and visible light cure repair material. Testing was done for flexural strength on Universal testing machine. Result: Significant differences were found among the groups in terms of repair resin type (P < 0.001). Flexural strength of samples with bevel design and repaired with self cure resin was higher than those repaired with visible light cure resin. Conclusion:The repair design and procedure with self cure acrylic resin exhibited significantly higher flexural strength than that of visible light-cure resins.
Annals of the Romanian Society for Cell Biology , 2019
Various dental prostheses and appliances show failure due to fatigue that is inherited as a result of decreased flexural strength. They need to function in wet environments like saliva and during non function, they need to be stored in water. This study was aimed to assess the influence of water sorption on flexural strength of two heat and self cure denture resins and to evaluate any difference between storage in artificial saliva and water on its flexural strength. A digitally designed stainless steel die was used to fabricate molds for making samples from heat cure (Trevalon HI, Colto Cure H) and self cure (Colto Cure C,Dentsply RR) denture base acrylic resins. Samples were tested immediately after processing (Group (GP) Acontrol), immersed in water (GP B) and artificial saliva (GP C). After storage of samples at four different time intervals (1 day, 1 week, 2 months, 4months), flexure test was performed on a universal testing machine. Various levels of variables were tested using Kruskal-Wallis H test (p<0.001) while differences between groups was tested using Mann Whitney test (p<0.05). Trevalon demonstrated highest dry strength. All samples demonstrated decline in flexural strength with heat cure showing less than self cure denture base resins. Reduction of flexural strength observed at 2 and 4 month time, showed a statistical difference between groups. Reduction of flexural strength was also significant when self cure resins were stored in artificial saliva. Flexural strength tends to decrease as water sorption within the denture polymer increases. Both saliva and water show pronounced effect on flexural strength.
Strength of Denture Base Resins Repaired with Auto- and Visible Light-Polymerized Materials
Journal of Prosthodontics, 2009
Clinicians are still confused about the choice of repair method, which depends on factors such as the length of time required for processing, the mechanical strength of the repaired material, and the effect of stress concentration in the acrylic resins before the repair. The aim was to determine the impact and flexural strength characteristics, such as stress at yield, Young's modulus, and displacement at yield of denture base resins fractured and repaired by three methods using heat-, auto-, and visible light-polymerized acrylic resins. Material and Methods: For impact and flexural strength tests, 18 rectangular specimens measuring 50 × 6 × 4 mm 3 and 64 × 10 × 3.3 mm 3 , respectively, were processed using Impact 2000, Lucitone 550, Impact 1500, and QC-20 acrylic resins. Fracture tests were performed according to ISO1567:1999. Afterward, all fractured specimens were stored in distilled water at 37 • C for 7 days, and then repaired with (1) the same acrylic resin used for specimen fabrication (n = 6), (2) an autopolymerized acrylic resin (TruRepair, n = 6), and (3) a visible light acrylic resin (Versyo.com, n = 6). The repaired specimens were again submitted to the same fracture tests, and the failures were classified as adhesive or cohesive. Data from all mechanical tests after repair by the different methods were submitted to two-way ANOVA, and mean values were compared by the Tukey test. Results: All acrylic resins showed adhesive fractures after impact and flexural strength tests. Differences (p < 0.05) were found among repair methods for all acrylic resins studied, with the exception of displacement at yield, which showed similar values for repairs with auto-and visible light-polymerized acrylic resins. The highest values for impact strength, stress, and displacement at yield were obtained when the repair was made with the same resin the specimen was made of. Conclusion: Denture base acrylic resins repaired with the same resin they were made of showed greater fracture strength.
Influence of surface treatments on the flexural strength of denture base repair
Gerodontology, 2012
Influence of surface treatments on the flexural strength of denture base repair Objective: The purpose of this study was to evaluate the flexural strength of repairs made with autopolymerising acrylic resin after different treatments of joint surfaces. Material and Methods: Fifty rectangular specimens were made with heat-polymerised acrylic resin and 40 were repaired with autopolymerising acrylic resin following joint surface treatments: group 1 (intact specimens), group 2 (chemical treatment: wetting with methyl-methacrylate for 180 s), group 3 (abraded with silicon carbide paper), group 4 (abraded and wetting with methyl-methacrylate for 180 s) and group 5 (without surface treatment). The flexural strength was measured by a three-point bending test using a universal testing machine with a 100 Kgf load cell in the centre of repair at 5 mm/min cross-head speed. All data were analysed using one-way ANOVA and Tukey HSD test for multiple comparisons (p < 0.05). Results: Among repaired specimens, groups 2 and 4 had 66.53 ± 3.4 and 69.38 ± 1.8 MPa mean values and were similar. These groups had superior flexural strength than groups 3 and 5 that were similar and had 54.11 ± 3.4 and 51.24 ± 2.8 MPa mean values, respectively. Group 1 had a mean value of 108.30 ± 2.8 MPa being the highest result. Conclusion: It can be concluded that the treatment of the joint surfaces with methyl-methacrylate increases the flexural strength of denture base repairs, although the strength is still lower than that observed for the intact denture base resin. Abrasion with sandpaper was not able to influence the flexural strength of repaired denture bases.
Background: Addition of reinforced fiber on heat cured acrylic denture needed because this material lack of flexural strength that easy to fracture. The reinforced fiber used is E-glass fiber and UHWMPE fiber, however along the denture usage in oral cavity the flexural strength can be reduced due to water absorption. Materials and Methods: This is an experimental laboratory study with 36 samples divided into 6 groups, consist of without reinforced fiber, with addition of glass fiber and polyethylene fiber (with and without thermocycling). The effect thermocycling on the flexural strength of heat cured acrylic resin denture base with and without reinforced fiber analyzed with T-Independent Test. The effect reinforced fiber on flexural strength of heat cured acrylic resin denture base with and without thermocycling analyzed with One Way ANOVA and need to LSD analysis to see which fiber has the best effect to strengthen the flexural strength. Results: There was no effect of thermocycling with the simulation of oral cavity condition for 3 years denture usage on flexural strength in all group. But there was a significant effect the addition of the reinforced fiber to improve the flexural strength of heat cured acrylic resin denture base with and without thermocycling. Conclusion: There was no significant effect of 3000 cycle of thermocycling but the glass fiber material can significantly increase the flexural strength.
2008
Purpose of Study: Denture repair involves joining two parts of fractured denture with a denture repair material. The success of denture repair relies on the phenomenon of adhesion. Polymer surface can be etched by appropriate chemical, which changes the morphology and chemical properties of surface and promotes better adhesion. Taking into account the importance of adhesion in denture repair, the study was designed to evaluate and compare the transverse strength of repaired conventional, high-impact and glass fiber-reinforced heat cure denture base resins with and without surface chemical treatment with ethyl acetate and methylene chloride. Methodology: The study was conducted by surface treatment of different denture base resins (conventional, high impact, and glass fiber) with different chemicals (ethyl acetate and methylene chloride), with control group formed without surface chemical treatment. Specimens were repaired with autopolymerizing acrylic resin using 'sprinkle on...
KHYBER MEDICAL UNIVERSITY JOURNAL
OBJECTIVE: To compare the flexural strength of maxillary denture bases made in high impact and conventional heat cure acrylic resin. METHODS: This experimental laboratory-based study was conducted in Peshawar Dental College, Materials Research and Centralized Resource Laboratories University of Peshawar, Pakistan. Total 120 edentulous maxillary casts, sixty each of conventional acrylic (30 in subgroup-IA for shallow palate and 30 in subgroup-IB for deep palate and high impact acrylic (30 in subgroup II-A for shallow palate and 30 in subgroup II-B for deep palate) were made. These were then tested for flexural strength using universal testing machine. The load was applied at the rate of 5.0 mm/min. Independent samples t-test was applied for statistical analysis. RESULTS: Mean values of deflection at fracture, fracture load and flexure strength were 0.309±0.059 cm, 87.729±22.497 Kg and 13.645± 4.453 kg/cm² respectively. Mean Flexure Strength (kg/cm2) was 8.30±1.27, 16.54±1.77, 10.88±1....