Heat-cured PMMA Research Articles

Evaluating the influence of Ti6Al4V alloy particles on mechanical properties of heat-cured PMMA

Evaluating the influence of Ti6Al4V alloy particles on mechanical properties of heat-cured PMMA

Exploring Flexural Strength Variation in Polymeric Materials for Provisional Fixed Prosthetic Structures: Comparative Analysis with and without Reinforcement through Laboratory Experimentation and Statistical Evaluation

Provisional fixed partial dentures represent a critical phase in dental treatment, necessitating heightened mechanical durability, particularly in comprehensive and extended treatment plans. Strengthening these structures with various reinforcing materials offers a method to enhance their resilience. Utilizing a three-point testing methodology on standardized trial specimens allows for a comparative assessment of various materials and reinforcement techniques for pre-prosthetic applications. This study aims to validate and assess the significance of integrating different reinforcing materials into standardized test bodies. The study focuses on test specimens comprising three types of unreinforced laboratory and clinical polymers for provisional constructions (n = 6)—heat-cured PMMA (Superpont C+B, Spofa Dental, Czech Republic), CAD-CAM prefabricated PMMA (DD temp MED, Dental Direkt, Germany), CAD-CAM printing resin (Temporary CB Resin, FormLabs, USA), self-polymerizing PEMA (DENTALON plus, Kulzer, Germany), light-polymerizing composite (Revotek LC, GC, Japan), and dual-polymerizing composite (TempSpan, Pentron, USA). Additionally, laboratory polymers are evaluated in groups with five types of reinforcing filaments (n = 15)—Glass Fiber (Fiber Splint One-Layer, Polydentia, Switzerland), Polyethylene thread (Ribbond Regular 4.0 mm, Ribbond Inc., USA), triple-stranded chrome-cobalt wire for splinting 015″ (Leone S.p.a., Italy), Aesthetic ligature wire 012″ (Leone S.p.a., Italy), and Glass Fiber coated with light-cured composite 8.5 × 0.2 mm (Interlig, Angelus, Brazil). Analysis of the data using Generalized Linear Models (GLMs) reveals that the experimental bodies, produced via the subtractive digital method using PMMA (DD temp MED, Dental Direkt GmbH, Germany) as the polymer and glass filaments as the reinforcement, exhibit superior mechanical properties, particularly when pre-wetted with Interlig liquid composite (Angelus, Brazil).

3D-Printed Resin Showed Higher Water Sorption than Heat-Cured PMMA and Polyamide

3D-Printed Resin Showed Higher Water Sorption than Heat-Cured PMMA and Polyamide

Comparative Evaluation to Surface Roughness of Modified Heat Cured Acrylic Resin by Zinc Oxide Nanoparticles and CAD/CAM Denture Base Materials - In Vitro Study

One of the most promising CAD/CAM approaches is milling denture base materials from highly condensed pre-polymerized resin discs. In an effort to overcome the disadvantages of acrylic resin denture base materials, nano-filler materials have been added as well as denture base chemistry adjusted to strengthen the denture base.This eliminates disadvantages associated with polymerization shrinkage compared to conventional heat-cured acrylic resin. Aim of this study: evaluate the surface roughness of PMMA acrylic resin after strengthening the denture- base by addition of zinc oxide nano-filler material to acrylic resin PMMA with concentration (1%) and compare with milled CAD/CAM and non-modified heat-cured PMMA denture base materials. Materials and methods: thirty specimens of acrylic resin PMMA were prepared and divided into three groups 10 specimens for each groups as follows; Control Group (Group1) without ZnO nanoparticles ; Group (2) with (1%) by weight of ZnO nanoparticles ; Group (3) milled CAD/CAM.Each specimen is of dimension ( 10 x 10 x 3 ) in mm and was fabricated using conventional processing method and milling the CAD/CAM blocks .Results: showed the lowest mean value was recorded by milled CAD/CAM (0.230 Ra) Then the non-significant reduction with mean value (0.312 Ra) by PMMA+ ZnO 1% and highest mean value of surface roughness was recorded by pure PMMA without additive (0.327 Ra).Conclusions: There were significant differences between control group PMMA and milled (CAD/CAM) with slight reduction of surface roughness of PMMA with (1%) Zno nanoparticles.

Effect of Knitting Pattern of PP Mesh on the Flexural Properties of Heat-cured PMMA Denture Base Resin

Heat-cured polymethyl methacrylate is (PMMA) is the most common denture base material and some mechanical properties such as flexural strength and impact resistance etc. may lead to fail, besides its excellent properties. Polypropylene (PP) hernia mesh is a commercially available medical textile used in surgical repair of different types of hernia. It was aimed to investigate the effect of two different knitting patterns of PP meshes on the flexural properties of the PMMA denture base resin when they are used as reinforcement and compare with glass fiber mesh reinforced and no mesh used resins. Knitting patterns of the PP mesh structures were hexagonal honeycomb pattern and square pattern and these were used as single or double layer as reinforcement. 6 groups were established in the study: control group with no mesh and 5 reinforced groups with meshes (glass fiber mesh, single layer honeycomb patterned PP mesh, double layer honeycomb patterned PP mesh, single layer square patterned PP mesh, double layer square patterned PP mesh). A total of 60 samples with the dimensions of 65x10x3 mm, n=10 in each group were fabricated. The flexural strength, maximum deformation, and flexural modulus were determined by three-point bending test. Fracture surfaces were evaluated by scanning electron microscopy. The obtained data were statistically analyzed by two-way ANOVA test with Bonferroni corrections. The single layer square patterned PP mesh group exhibited the highest (76.67 ± 7.64 MPa), and the control group showed the lowest (63.49 ± 7.18 MPa) flexural strength values. The single layer glass fiber mesh group showed the highest (7.13 ± 0.55 mm) and the control group showed the lowest (4.72 ± 0.81 mm) maximum deformation values. The single layer glass fiber mesh group exhibited the highest (2131.87 ± 205.76 MPa), and the control group exhibited the lowest (1582.26 ± 98.63 MPa) flexural modulus values. Significant increase in flexural strength was observed in all polypropylene mesh-reinforced groups compared to the control group except double layer honeycomb patterned PP mesh group (p < 0.05). Using PP fiber mesh for reinforcement provide a very favorable aesthetic view and PP fiber mesh is concluded to be a promising material for reinforcement of heat-cured PMMA denture base resins.

Effect of Adding Silver-Doped Carbon Nanotube Fillers to Heat-Cured Acrylic Denture Base on Impact Strength, Microhardness, and Antimicrobial Activity: A Preliminary Study.

Poly (methyl methacrylate) (PMMA), is an acrylic polymer substance that is mostly used for denture base applications. The purpose of this laboratory study was to investigate the effect of adding 0.05 wt.% Ag-doped carbon nanotubes (CNT) to PMMA-based (PMMA and MMA) denture base material on the impact strength, microhardness, and antimicrobial activity. A total of 60 heat-cured acrylic resin specimens were prepared. The specimens were randomly divided into two main groups (n = 30/group), according to the powder used: (a) control group, using heat-cured PMMA; (b) treatment group, using a powder prepared by blending 0.05 wt.% silver-doped CNT nanoparticles with heat-cured PMMA. The impact strength, microhardness and anticandidal activity for each group were assessed via the Charpy, Vickers and agar diffusion tests, respectively (n = 10/test for each subgroup). Data were analyzed using independent-sample t-tests (p ≤ 0.05). The results of the impact strength test revealed that the treated heat-cured PMMA-MMA with Ag-doped CNT (2.2 kJ/mm2) was significantly higher than that of the control heat-cured PMMA (1.6 kJ/mm2). Similarly, the Vickers microhardness of the treatment group (52.7 VHN) was significantly higher than that of the control group (19.4 VHN). Regarding the agar diffusion test, after 24 h of incubation, the treated heat-cured PMMA with the Ag-doped CNT exhibited significantly higher anticandidal activity than that of the control group. Therefore, Ag-doped carbon nanotubes could be considered as promising fillers for the dental heat-cured acrylic resin to improve the resistance of the resultant denture against sudden fractures, scratching, and candida invasion.

Tensile Bond Strength between Different Denture Base Materials and Soft Denture Liners.

(1) Background: Various materials are available for CAD-CAM denture base fabrication, for both additive and subtractive manufacturing. However, little has been reported on bond strength to soft denture liners. Therefore, the aim of this study was to investigate tensile bond strength, comparing between different denture base materials and soft denture liners. (2) Methods: Seven different materials were used for denture base fabrication: one heat-polymerized polymethyl methacrylate, three materials for subtractive manufacturing, two materials for additive manufacturing and one polyamide. Two materials were used for soft denture lining: one silicone-based and one acrylate-based. The study was conducted according to the specification ISO No. 10139-2:2016, and the type of failure was determined. The Kruskal-Wallis test with Dunn's post hoc test was used to analyse the values of tensile bond strength, and Fisher's exact test was used to analyse the type of failure. p Values < 0.05 were considered statistically significant. (3) Results: The tensile bond strength values were not statistically significantly different combining all the materials used for denture base fabrication with the acrylate-based soft denture liner (p > 0.05), and the average values ranged between 0.19 and 0.25 Mpa. The tensile bond strength values of the different denture base materials and silicone-based denture liner were statistically significantly different (p < 0.05), and the average values ranged between 1.49 and 3.07 Mpa. The type of failure was predominantly adhesive between polyamide and both additive-manufactured denture base materials in combination with the acrylate-based soft liner (p < 0.05). (4) Conclusions: The use of digital technologies in denture base fabrication can have an influence on different tensile bond strength values for soft denture liners, with different types of failure when compared with heat-cured PMMA. Similar tensile bond strength values were found between the acrylate-based soft denture liner and denture base materials. Significant differences in tensile bond strength values were found between the silicone-based soft denture liner and denture base materials, where the additive-manufactured and polyamide denture base materials showed lower values than heat-cured PMMA and subtractive-manufactured denture base materials.

Effect of Recycled Denture Base Polymeric Powder Incorporation on the Surface Properties of Heat-cured PMMA Denture Base Acrylic Resin: An In Vitro Study

Effect of Recycled Denture Base Polymeric Powder Incorporation on the Surface Properties of Heat-cured PMMA Denture Base Acrylic Resin: An In Vitro Study

Factors Affecting Sorption and Solubility of Denture Base Acrylic Materials: A Review

Heat-cured PMMA is one of the most frequently used materials in the manufacture of removable dentures. Heat-cured material used to fabricate dentures contain soluble elements, allowing the material to absorb and release substances. These factors all directly affect the longevity and performance of protheses fabricated from polymethyl methacrylate denture base material. Various procedures associated with fabrication of removable dentures from heat-cure denture base material are reported to significantly influence the sorption and solubility experienced by the prosthesis. A comprehensive search of peer-reviewed journals located within academic databases was conducted to identify relevant literature pertaining to sorption and solubility of denture base materials. Key aspects of each paper were captured in Microsoft® Excel® to record author/s, location, study design, sample size, methodology, results and conclusions. Mixing ratios and polymerisation cycles have been identified as variables that can negatively influence the rate of sorption and solubility of denture base materials during the fabrication process. Certain surface treatment procedures, as well as storing the denture in artificial saliva solution may reduce the levels of sorption and solubility experienced and optimise its lifespan. In this review we identify these factors and consider the detrimental effects of sorption and solubility on denture base acrylic materials.

Effects of occlusal splint therapy on opposing tooth tissues, filling materials and restorations.

BackgroundLittle is known about the effect of the type of splint material, heat‐cured PMMA (HC) or chemical‐cured PMMA (CC) on the wear of opposing tooth surfaces.ObjectiveThe aim of this in vitro study was to evaluate two‐body wear of dentin, enamel, glass‐ceramic or one of four resin composites when opposing splint materials, namely ProBase HC and CC.MethodsThe two‐body wear of bovine dentine, bovine enamel, glass‐ceramic IPS e.max CAD (EMAX) and four composites (Filtek Z250 [Z250], Clearfil AP‐X [AP‐X], Clearfil Majesty Posterior [CMP], Filtek Supreme XTE [FSE]) opposing three antagonists (HC and CC and stainless steel as control) were evaluated in the ACTA wear machine. In addition, all the surfaces were evaluated with scanning electron microscopy.ResultsThe highest average wear was observed in the case of dentin. The lowest average wear was found EMAX. In every case—except for EMAX—the wear rate was higher with HC than with CC (all differences being statistically significant).ConclusionsThe level of wear of enamel, dentin and various resin composites was higher in contact with HC than in CC, the wear of dentin being the highest. In the case of a patient with no or little tooth wear or whose teeth are restored with composite material or glass‐ceramic, the splint HC might be preferred because of its better durability. However, when the splint is in contact with opposing dentin preservation of the dentin, CC might be the best choice.

Synthesis and Characterization of Antifungal Nanocomposite AgSiO2 Polymethyl Methacrylate

Objectives Polymethyl methacrylate as the most common material used in denture bases has some problems. The aim of this study was to introduce a new nanocomposite of PMMA to improve flexural strength and antifungal properties. Materials and Methods In this experimental study, AgSiO 2 nanoparticles were prepared, and their characteristics were confirmed by scanning electron microscope and energy dispersive spectroscopy techniques. Then the nanoparticles in the weight ratio of 0.1, 0.3, 0.5, and 0.7% were incorporated to heat-cured PMMA and the control group included no nanoparticles. To measure the flexural strength before and after thermocycling three-point bending test was used. Eight samples per group with dimensions of 65 × 10 × 2.5 mm were used. Antifungal activity against Candida albicans (PTCC 5027) was investigated through colony count method. Statistical analysis was done by SPSS at significance level of p -value ≤0.05. Results The mean flexural strength in groups 0.1, 0.3, and 0.7% was significantly higher than the control. After thermocycling flexural strength of the control group was significantly lower than 0.3 and 0.5% groups. As the concentration of nanoparticles increased the antifungal activity improved ( p < 0.05). Conclusion Addition of nanoparticles AgSiO 2 improved flexural strength and antifungal characteristics of PMMA.

Comparison of cooling methods on denture base adaptation of rapid heat-cured acrylic using a three-dimensional superimposition technique.

Aim:To investigate the effect of different cooling methods on denture base adaptation of rapid heat-cured acrylic resin using 3D superimposition technique.Setting and Design:In vitro - Comparative study.Materials and Methods:Denture base adaptation of two different rapid heat-cured polymethyl methacrylate acrylic resins using five different cooling methods were compared. Forty maxillary edentulous stone cast were prepared to produce the denture bases with standardized thickness. The specimens were divided into five groups (n = 8) according to type of materials and cooling methods. The master stone cast and all forty denture bases were scanned with 3Shape E1 laboratory scanner. The scanned images of each of the denture bases were superimposed over the scanned image of the master cast using Materialize 3-matic software. Three dimensional differences between the two surfaces were calculated and color surface maps were generated for visual qualitative assessment.Statistical Analysis Used:Generalized Linear Model Test, Bonferroni Post Hoc Analysis.Results:All bench-cooled specimens showed wide green-colored area in the overall palatal surface, while the rapid cooled specimens presented with increased red color areas especially at the palate and post dam area. Generalized Linear Model test followed by Bonferroni post hoc analysis showed significant difference in the root mean square values among the specimen groups.Conclusion:Samples that were bench cooled, demonstrated better overall accuracy compared to the rapid cooling groups. Regardless of need for shorter denture processing time, bench cooling of rapid heat-cured PMMA is essential for acceptable denture base adaptation.

Impact of phosphate ester addition on the cytotoxicity of heat cured denture base material

This study aims to evaluate and compare the cytotoxicity and biocompatibility of a modified heat-cured acrylic denture base material containing 15% phosphoric acid 2-hydroxyethyl methacrylate ester (PA2HEME) with those of nonmodified PMMA. Discs with a diameter of 12 mm and a thickness of 2 mm were prepared using a heat-cured PMMA denture base material and divided into control and experimental groups. The experimental group was modified with 15% phosphoric acid 2-hydroxyethyl methacrylate ester (PA2HEME). The modified and nonmodified materials were tested via FTIR, and the effect of modification on surface roughness was evaluated with AFM. An in vitro test was conducted to examine the cytotoxicity and biocompatibility of heat-cured acrylic denture base materials (control and experimental groups) by using a rat embryonic fibroblast cell line (REF). Cell culture viability was estimated with a methyltetrazolium solution cytotoxicity assay. The surface roughness of PA2HEME-modified acrylic resin (mPMMA) was not significantly different from that of nonmodified PMMA acrylic resin. The cytotoxicity test on mPMMA demonstrated no significant change in the cell viability compared with that of the negative control. No deteriorating or inhibitory effect on cell growth was observed after 24 and 72 h. The modification of denture base materials with 15% PA2HEME has no cytotoxic or inhibitory effects on the growth of the studied fibroblast cell line.

Impact and Flexural Strength of Kaolinite / Glass Fibers Reinforced Heat-Cured Acrylic Denture

Nowadays, most materials used to manufacture denture base are heat-cured PMMA, to overcome the low strength of this material, different methods were used to strengthen the denture base and enhanced their properties. This study investigated the effect of glass fiber woven powder kaolinite (Al2Si2O5 (OH) 4) to influence and strength of flexure. Acrylic and kaolinite powders were mixed together and mixed again with acrylic liquid to prepare hybrid composite samples. Woven glass fiber composite was prepared by inserting woven glass fiber between the two halves of the dough. PMMA reinforced by (0, 20) wt% of woven glass fibers or/and (0, 2, 5, 7) wt% of kaolinite powder to prepare eight experimental groups (n= 7). The fractured surface was an evaluation by scanning electron microscope (SEM). X-ray diffraction and Fourier transforminfrared spectra FTIR tests were used to examine kaolinite powder. Samples were tested with the use of a Charpy testing machine for impact test and Instron tensile testing machine for flexural test after storage in water for 10 days at 37 °C. The results showed woven glass fibers with clay powder together significantly increased the mechanical properties of PMMA.

Relationship between Polishing Techniques and Bacterial Count on Different Denture Base Materials

Introduction: Wearing of dentures cause alteration in the oral microflora and increasing in number of bacteria and candida. The polished and fitting surfaces of the denture are both affected. Different polishing techniques influence the total count of bacterial accumulation on the denture surface. Aim: To count the bacterial colonies after polishing three denture base materials before and after six months of denture wearing by different polishing techniques. Materials and Method: Eighteen patients were randomly selected for construction of maxillary partial denture. They were divided into 3 groups: Group 1: Patients received conventional heat-cured PMMA (Acrostone) denture. Group 2: Patients received thermoformed polyamide (NEWULTRA) denture. Group 3: Patients received thermoformed acetal (Bio Dentaplast) denture. In each group, three patients had their dentures polished by pre polishing with brown rubber disc and fine pumice with wet rag wheel, and the other three patients with the same technique but followed by tripoli compound with dry rag wheel. Evaluation of bacterial counting was conducted before denture wearing and after six months of denture wearing. Swabs were taken from the palate of the patients and bacteria were counted. Findings: No significant difference was found between technique no. I and no. II in decreasing the bacterial count between the tested materials. Thermoformed polyamide showed the highest bacterial count after six months of wearing denture polished by technique no. II followed by thermoformed acetal and heat-cured PMMA. Conclusion: The second polishing technique produced less surface roughness and bacterial colonization on the tested materials than the first one.

Effect of adding aluminum oxide on the flexural strength of heat-cured poly (methyl methacrylate) denture base resin

Background: Apart from its numerous advantages, poly (methyl methacrylate) (PMMA) has certain limitations such as its low strength, brittle on impact, poor thermal conductivity, and resultant low flexural strength. This study is, therefore, planned to investigate the flexural strength of heat-cured PMMA denture base resin with the addition of different percentage of aluminum oxide powder. Materials and Methods: A total of 120 specimens of PMMA (DPI® Heat Cure) of standard dimension (64mm x 10mm x 2.5mm) as per the American Dental Association specification No. 12/International Standards Organization specification No. 1567 for the determination of flexural strength were prepared: 30 for each of the four study groups. Aluminum oxide powder was added in specific percentage (5%, 15%, and 25% by weight) to the polymer component of heat-cure denture base resin as per the different subgroups. Results: The results of this study showed that the highest mean flexural strength was for specimens in Subgroup A, i.e., PMMA reinforced with 5% aluminum oxide powder by weight, with a mean value of 124.39 Mpa. Conclusions: Among the experimental group, the highest mean flexural strength of 124.39 Mpa was found with Subgroup A (5%) followed by Subgroup B (15%) which was 116.83 Mpa. The least flexural strength of 95.81 Mpa was found with Subgroup C (25%).

The effects of adding various ratios of zirconium oxide nanoparticles to poly(methyl methacrylate) on physical and mechanical properties.

The aim of the present study is to evaluate the transverse strength, modulus of elasticity, surface roughness, hardness, and water sorption/solubility of nanoparticle zirconium oxide (nano-ZrO2) added to heat-cured poly(methyl methacrylate) (PMMA) after thermocycling. The specimens were divided into four groups according to the ratio of nano-ZrO2 addition to heat-cured PMMA; group 1: 5% nano-ZrO2; group 2: 10% nano-ZrO2; group 3: 20% nano-ZrO2, and group 4 (control): PMMA without nano-ZrO2. A statistically significant decrease in transverse strength was observed by all additional rates of nano-ZrO2 compared with group 4 (control; P < 0.025). When hardness results were evaluated, groups 1 and 2 showed statistically higher values compared with groups 3 and 4 (P < 0.025). The surface roughness of group 3 was statistically higher than the other groups (P < 0.025), but it was within the clinically acceptable limits. As the nano-ZrO2 addition rate increased, water sorption/solubility values of the specimens also increased. Although nano-ZrO2 addition had an adverse effect on some mechanical and physical properties of heat-cured PMMA, it increased hardness values, implying that the addition of nano-ZrO2 would contribute positively to some mechanical properties of PMMA denture base material when nano-ZrO2 was homogeneously distributed in PMMA.

Physical, mechanical, thermal, and dynamic characterization of carbon nanotubes incorporated poly(methyl methacrylate)-based denture implant

The objective of this study was targeted to synthesize and characterize a carbon nanotubes (CNTs) incorporated poly(methyl methacrylate) (PMMA)-based denture polymer. Two experimental denture base polymers were fabricated either by incorporating single-walled CNTs (SWCNTs) (SW-group) or multi-walled CNTs (MWCNTs) (MW-group). In both groups, 0.5 wt% of the CNTs were incorporated into MMA monomer. Using a commercially available heat-cured PMMA (Interacryl Hot, Interdent, Opekarniska, Slovenia), a polymer-to-monomer ratio of 3:1 was used to fabricate the specimens (14 × 14 × 3 mm3 in dimensions) of the control group (without CNTs) (C-group) and the experimental groups (either SWCNT–PMMA or MWCNT–PMMA) ( n = 30, N = 90). Physical, mechanical, thermal, and rheological attributes of the tested materials were assessed. The data were statistically analyzed using SPSS version 21.0 (SPSS®, Chicago, IL, USA) and results were explored with one-way ANOVA. Incorporation of CNTs changed the surface morphology and topography of the PMMA specimens. No thermal changes were observed among C-, SW-, and MW-groups. Conversely, the hardness, elastic modulus and wear resistance were improved in both SW-group and MW-group. Additionally, the dynamic mechanical analyzer showed improvement in storage modulus in SW-group, affirming the load transfer capability of SW–PMMA composite. The CNT–PMMA composite might favorably be used as a potential denture base polymer.

Effect of Cigarette Smoke on Surface Roughness of Different Denture Base Materials.

Surface roughness is an important property of denture bases since denture bases are in contact with oral tissues and a rough surface may affect tissues health due to microorganism accumulation. Therefore, the effect of cigarette smoke on the surface roughness of two commercially available denture base materials was evaluated to emphasize which type has superior properties for clinical use. A total numbers of 40 specimens were constructed from two commercially available denture base materials; heat-cured PMMA and visible light cured UDMA resins (20 for each). The specimens for each type were randomly divided into: Group I: Heat cured resin control group; Group II: Heat cured acrylic resin specimens exposed to cigarette smoking; Group III: Light cured resin control group; Group IV: Light cured resin specimens exposed to cigarette smoking. The control groups used for immersion in distilled water and the smoke test groups used for exposure to cigarette smoking. The smoke test groups specimens were exposed to smoking in a custom made smoking chamber by using 20 cigarettes for each specimen. The surface roughness was measured by using Pocket SurfPS1 profilometer and the measurements considered as the difference between the initial and final roughness measured before and after smoking. The t-test for paired observation of test specimens after exposure to smoking was indicated significant change in surface roughness for Group II (p< 0.05) but has no significance with Group IV. Otherwise, there were no significant differences with control groups (Group I and III). The surface roughness of the dentures constructed from heat cured acrylic resin had been increased after exposure to cigarette smoke but had no impact on the dentures constructed from visible light cured resin.

An In-Vitro Evaluation of the Flexural Strength of Heat-Polymerized Poly (Methyl Methacrylate) Denture Resin Reinforced with Fibers

Fracture strength of denture base resins is of great concern and many approaches have been made to improve the fracture resistance of acrylic resin dentures by strengthening them. Purpose of the study was to assess the effect of a Novel pre-impregnated glass fiber reinforcement system and nylon fiber reinforcement on the flexural strength of conventional heat-polymerized poly(methylmethacrylate) [PMMA] denture resin under dry and wet storage conditions. Forty specimens of standard dimensions were prepared for each of the four experimental groups; unreinforced conventional acrylic resin and the same reinforced with unidirectional Stick (S) glass fibers, woven Stick Net (SN) glass fibers and nylon fibers. Each group was further subdivided into two groups of 20 specimens each on the basis of storage conditions (dry and wet). All 160 specimens were then subjected to a 3-point bending test and flexural strength was calculated. Statistical analysis was carried out using student t test and 1-way analysis of variance (ANOVA). Stick and Stick Net glass fiber reinforcements enhanced the flexural strength of conventional heat-cured PMMA denture resin. Specimens reinforced with Stick glass fibers exhibited highest flexural strength followed by those reinforced with Stick Net glass fibers. Nylon fiber reinforcement decreased the flexural strength of acrylic resin. All the specimens in the four groups stored under wet conditions showed decrease in flexural strength in comparison to those stored in dry conditions. The reinforcement of denture base resin with pre-impregnated glass fibers may be a useful means of strengthening denture bases. Use of nylon as a reinforcement fiber is not desirable as it decreased the flexural strength of acrylic resin.