Denture Base Composites Research Articles

A19-saponin–modified polymethyl methacrylate base denture composites: antimicrobial, mechanical and water absorption potentials

Abstract The increased growth of Candida albicans (C. albicans) with allergy reaction of MMA remains an issue of concern among denture wearers. C. albicans growth inhibition, mechanical and water absorption potentials of extracted A19-saponin–commingled PMMA denture base composites were investigated. Soxhlet extraction technique for defatting of Dialium guineense (D. guineense) stem powder was used with ethanol to extract A19-saponin. Fungicidal inhibition concentration of A19-saponin extract of D. guineense was determined. PMMA denture base was prepared with incorporation of A19-saponin at different concentrations of obtained 23.2 % yield. The mechanical and water absorption properties were determined. The minimum and maximum fungicidal inhibition concentrations and susceptibility of 25 and 100 % for extracted A19-saponin were obtained, respectively. PMMA, MMA and extracted A19-saponin of ratio of 30 g: 5 ml: 5 ml denture was optimally fabricated. A19-saponin increased the impact strength and hardness by 352.94 and 11.54 % with reduced water absorption by 82.85 %. Thus, A19-saponin as an additive improved quality of denture.

Evaluating Polishability of Zirconia Impregnated PMMA Nanocomposite for Denture Base Application

Artificial biomaterials are being developed for use in denture base with symmetrical properties to restore the aesthetics and functionalities. The rough surface of denture base resin promotes the adhesion of microorganisms and plaque accumulation. This study aimed to explore the consequences of polishing times on the surface roughness of high-impact (HI) heat-polymerized PMMA denture base acrylic resin reinforced with zirconia nanoparticles (nanocomposite). Thirty specimens (25 ± 0.50 mm in diameter and 2 ± 0.10 mm thickness) were fabricated from HI PMMA by adding zirconia nanoparticles at different concentrations of (0 wt.%, 1.5 wt.%, 3 wt.%, 5 wt.%, 7 wt.%, and 10 wt.%). Specimens were divided into six groups (n = 5) and surface roughness (Ra) was measured before and after polishing with a standard protocol for one and two minutes. The addition of zirconia in PMMA at low concentrations (1.5 wt.%, 3 wt.%, and 5 wt.%) did not negatively affect the surface finish of the denture base composites following conventional polishing and remained below the clinically acceptable limit (0.2 µm). After one minute of polishing, only the 10 wt.% zirconia (0.17 ± 0.03 µm) demonstrated a substantial rise in median surface roughness, in comparison with the control group (0.11 ± 0.01 µm). It is concluded that the group containing 3 wt.% (0.10 ± 0.01 µm) of zirconia is the optimum concentration to obtain the best symmetrical surface finish after two minutes of polishing.

Surface silanization and grafting reaction of nano-silver loaded zirconium phosphate and properties strengthen in 3D-printable dental base composites

In this work, surface modification of nano silver-loaded zirconium phosphate (6S-NP3) were obtained from simultaneous silanization of γ-methacryloxypropyltrimethoxysilane (MPS) and grafting reaction of methyl methacrylate (MMA), and then mixed with denture base resin (E-Denture) to prepare denture base composites using 3D printer printing. FT-IR spectra confirmed that surface silanization and grafting reaction had occurred and MPS and MMA were successfully anchored on the surface of 6S-NP3. XRD results demonstrated that surface modification had occurred on the surface of hexagonal lattice. The average diameter data indicated that the surface modification decreased the average diameter of nanoparticles. The water contact angle (WCA) was found increasing as the surface modification. SEM images illustrated that the dispersion and compatibility of nanoparticles in denture base composite materials had improved. The results of mechanical properties presented that composites with the addition of P-6S-NP3 nanoparticles achieved higher flexural strength, flexural modulus and impact strength. The data of antibacterial activities revealed that composites had exhibited good antibacterial activities against either S. aureus or E. coli and the latter showed better antibacterial efficacy than the former.

Denture Base Composites: Effect of Surface Modified Nano- and Micro-Particulates on Mechanical Properties of Polymethyl Methacrylate.

The most commonly used denture base material, polymethyl methacrylate, lacks ideal mechanical properties, which are reflected in its relatively high failure rate. Several methods have been explored to reinforce the material and reduce the cost of denture repair and replacement. In this study, various surface modified filler particles at different concentrations were dispersed in conventional and high-impact denture base materials and tested for their improvement in mechanical properties. Inorganic filler particles were coated with different silane coupling agents using an ultrasonic device. The particulates were dispersed in the resin and the composites polymerised through an innovative dual-cure technique. Charpy impact test, single-edge notch three-point bend fracture toughness test and Biaxial Flexural Strength (BFS) were performed on the specimens. The results showed that mechanical properties of the denture base resin can be improved by incorporating filler particles; however, the surface characteristics, quantity and level of dispersion of the particles play critical role in the mechanical behaviour of the composites. The results of this study are a promising step towards developing more fracture-resistant denture base materials.

Effect of nitrile butadiene rubber/Al2O3/YSZ fillers for PMMA denture base on the thermal and mechanical properties

This study is to investigate the effect of nitrile butadiene rubber (NBR as impact modifier) together with Al2O3/YSZ (toughening) as filler loading in PMMA denture base on the thermal and mechanical properties. PMMA matrix without fillers was mixed between PMMA powder and 0.5 mass% of BPO, and it is used as the control group. The liquid components consist of 90% of methyl methacrylate (MMA) and 10% as the cross-linking agent of ethylene glycol dimethacrylate. The denture base composites were fabricated by incorporating PMMA powder and BPO and fixed at 7.5 mass% NBR particles and filler loading (1, 3, 5, 7 and 10 mass%) of Al2O3/YSZ mixture filler by (1:1 ratio) as the powder components. The ceramic fillers were treated with silane (γ-MPS) and the powder/liquid ratio (P/L) according to dental laboratory practice. The TGA data obtained show that the PMMA composites have better thermal stability compared to unreinforced PMMA, while DSC curves show slightly similar Tg values. DSC results also indicated the presence of unreacted monomer content for both reinforced and unreinforced PMMA composites. The fracture toughness, Vickers hardness and flexural modulus values were statistically increased compared to the unreinforced PMMA matrix (P < 0.05).

Effect of nano- and micro-alumina fillers on some properties of poly(methyl methacrylate) denture base composites

This research investigated the effects of alumina (Al2O3) micro- and nano-particles on poly(methyl methacrylate) (PMMA) denture base. Al2O3 was surface treated using (3-methacryloxypropyl)trimethoxysilane (?-MPS), added to methyl methacrylate (MMA), and mixed with PMMA powder. The filler volume fractions in the micro-composites were 0.5, 1, 2, 5 and 7 wt. %, whereas those in the nano-composites were 0.13, 0.25, 0.5, 1, 2 and 5 wt. %. The treated fillers were examined using Fourier transform infrared spectroscopy (FTIR). The influence of filler size and loading on mechanical properties was studied using fracture toughness and flexural tests. The thermal stability of the PMMA/Al2O3 composites was investigated using thermogravimetric analysis (TGA). In addition, the water absorption and solubility characteristic of the prepared composites was also investigated. The FTIR spectra showed new absorption bands, indicating the occurrence of surface modifications. Both micro- and nanoscale particles showed increased fracture toughness. The maximum value of 2.02 MPa?m1/2 was achieved with the addition of 0.5 wt. % nano-Al2O3, which accounts for a 39 % increase. In contrast to the flexural strength, the flexural modulus improved with increasing filler content. The micro-composites showed higher thermal stability than nano-composites. The water absorption and solubility of the prepared composites were slightly higher than those of the control. The use of low concentrations of Al2O3 nanoparticles may be of considerable interest in future studies to improve the mechanical properties of PMMA denture base.

Studies on the effects of titanate and silane coupling agents on the performance of poly (methyl methacrylate)/barium titanate denture base nanocomposites

ObjectivesThis study aimed to fabricate and characterise silanated and titanated nanobarium titanate (NBT) filled poly(methyl methacrylate) (PMMA) denture base composites and to evaluate the behaviour of a titanate coupling agent (TCA) as an alternative coupling agent to silane. The effect of filler surface modification on fracture toughness was also studied. MethodsSilanated, titanated and pure NBT at 5% were incorporated in PMMA matrix. Neat PMMA matrix served as a control. NBT was sonicated in MMA prior to mixing with the PMMA. Curing was carried out using a water bath at 75°C for 1.5h and then at 100°C for 30min. NBT was characterised via Fourier transform-infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Brunauer–Emmett–Teller (BET) analysis before and after surface modification. The porosity and fracture toughness of the PMMA nanocomposites (n=6, for each formulation and test) were also evaluated. ResultsNBT was successfully functionalised by the coupling agents. The TCA exhibited the lowest percentage of porosity (0.09%), whereas silane revealed 0.53% porosity. Statistically significant differences in fracture toughness were observed among the fracture toughness values of the tested samples (p<0.05). While the fracture toughness of untreated samples was reduced by 8%, an enhancement of 25% was achieved after titanation. In addition, the fracture toughness of the titanated samples was higher than the silanated ones by 10%. ConclusionFormation of a monolayer on the surface of TCA enhanced the NBT dispersion, however agglomeration of silanated NBT was observed due to insufficient coverage of NBT surface. Such behaviour led to reducing the porosity level and improving fracture toughness of titanated NBT/PMMA composites. Thus, TCA seemed to be more effective than silane. Clinical significanceMinimising the porosity level could have the potential to reduce fungus growth on denture base resin to be hygienically accepTable Such enhancements obtained with Ti-NBT could lead to promotion of the composites’ longevity.

Evaluation of the Mechanical and Radiopacity Properties of Poly(Methyl Methacrylate)/Barium Titanate-Denture Base Composites

This study aimed to evaluate the flexural and hardness properties of poly(methyl methacrylate) (PMMA) denture base filled with barium titanate (BaTiO3). The baTiO3 filler was treated with 3-trimethoxysilylpropyl methacrylate, which is a silane coupling agent. Curing was performed in a water bath at 78 °C for 1.5 h. The samples were tested for tensile and flexural strength and surface hardness. The samples were also radiographed, and their optical densities were determined. Radiopacity values were compared with that of an aluminium (Al) plate with equivalent thickness. A reduction in the tensile and flexural strength of the PMMA composite was observed at high filler loadings. However, the surface hardness of the denture base composites was enhanced as a function of filler loading. The radiopacity of the PMMA/BaTiO3 composites was also improved. Adding 10 wt.% of baTiO3 to PMMA resulted in a higher optical density (OD) (p&lt; 0.07) compared with that of Al.

Impact strength, fracture toughness and hardness improvement of PMMA denture base through addition of nitrile rubber/ceramic fillers

Abstract Background/purpose PMMA resin mostly used the fabrication of denture base by heat-curing technique. It has poor strength, including low impact strength and low fatigue resistance. In this work the combination of nitrile butadiene rubber (NBR) with two types of ceramic fillers (Al2O3 and YSZ, respectively) on the mechanical properties of denture base are investigated. Materials and methods The denture base composites were fabricated by incorporating PMMA powder, 0.5 wt% of benzoyl peroxide (BPO), fixed at 7.5 wt% NBR particles and ceramic fillers (fixed at 5 wt%) as powder components. In total, 180 specimens were prepared for all tests and divided into 6 groups for each test (N = 10) coded G1–G6. Group 1 as the control group (without fillers) was mixed between PMMA powder and BPO; whereas the other five groups (G2–G6) were reinforced with NBR particles and different concentrations of ceramic fillers. The morphology of the fracture surface of specimens was examined by Field Emission Scanning Electron Microscopy (FESEM). Results Statistical analysis, shows that the mean impact strength (IS) and fracture toughness (KIC) of control dentures when compared to reinforced PMMA at 7.5% NBR and 2.5% Al2O3/2.5% YSZ improved significantly (5.27 ± 0.21–10.25 ± 0.41 kJ/m2 and 1.60 ± 0.24–2.58 ± 0.30 MPa·m1/2, respectively). Conclusion The reinforced PMMA denture bases are significantly different in IS and KIC between study groups (P = 0.001). However, the Vickers hardness (VH) is statistically not significantly different (P > 0.05).

Pmma Denture Base Composites Reinforced by Nitrile Rubber and Ceramic Fillers

Poly(methyl methacrylate) (PMMA) denture base composites were fabricated by incorporating nitrile butadiene rubber (NBR) particles and ceramic fillers (Al2O3, YSZ, and SiO2). PMMA powder was mixed with liquid methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA) as crosslinking agents. The different types of ceramic fillers were fixed at 5 wt.% and NBR particles in proportions of 5, 7.5 and 10 wt.%, respectively, mixed with PMMA. The impact strength (IS) increased and the fracture toughness (KIC) decreased with the increase of NBR content in PMMA matrix. The composites with Al2O3 showed better IS and KIC when compared to YSZ and SiO2 particles. It has been demonstrated that the combination of 10 wt.% NBR/5 wt.% Al2O3 produced the optimum density (1.049 g/cm3), IS (7.41 KJ/m2), KIC (2.45 MPa.m1/2) and statistically the values was significantly increased (p &lt; 0.05).

Influence of Al2O3/ Y-TSZ Mixture as Filler Loading on the Radiopacity of PMMA Denture Base Composites

The radiopacity of alumina/yttrium stabilizer zirconia (Al2O3/Y-TSZ) particles with nitrile butadiene rubber (NBR) dispersed in PMMA denture base material has been investigated. PMMA matrix without filler was prepared from PMMA powder with 0.5% benzoyl peroxide (PBO) as the control material. The similar PMMA matrix was mixed with Al2O3/Y-TSZ (1:1) together with NBR particles as the reinforcement. The amount of NBR was fixed at 7.5wt %, however, Al2O3/Y-TSZ varied from 1 to 10wt %, respectively. Samples with 4mm thickness for each composition were irradiated using 60 KV, 10mA, 0.4 s to examine their radiopacity. This radiopacity was compared to radiopacity of aluminum plate which having the same thickness. The result shows that the radiopacity (i.e. the lower optical density the higher radiopacity) of reinforced PMMA matrix slightly increased from 1.40 to 1.05, respectively, with the increased of filler loading compared to unreinforced PMMA matrix.

Poly(methyl methacrylate) denture base composites enhancement by various combinations of nitrile butadiene rubber/treated ceramic fillers

Nitrile butadiene rubber (NBR) particles as impact modifier mixed with treated ceramic fillers (aluminum oxide, yttria-stabilized zirconia, and silicon dioxide) were used to reinforce poly(methyl methacrylate) (PMMA) denture base material. The powder components are PMMA, benzoyl peroxide, NBR (5, 7.5, and 10 wt%), and ceramic fillers (5 wt%) treated with silane. The liquid components are 90% methyl methacrylate and 10% ethylene glycol dimethacryate. Fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy analyses confirmed that the ceramic fillers were successful. The morphology of fracture surfaces of specimens was characterized using field emission scanning electron microscopy. The impact strength (IS) and fracture toughness ( KIC) improved significantly. IS increased to 56% (8.26 kJ m−2) and 73% (2.77 MPa m1/2) for KIC when compared with unreinforced PMMA matrix. Statistical analyses of data results were significantly improved ( p &lt; 0.005). PMMA denture base reinforced by NBR particles mixed with treated ceramic fillers are ideally suited for dentistry applications with the ability to withstand high mastication forces.

Effects of titanate coupling agent on the mechanical, thermal, and morphological properties of poly(methyl methacrylate)/hydroxyapatite denture base composites

Poly(methyl methacrylate) (PMMA)/hydroxyapatite (HA) denture base composites were prepared using heat-processing polymers powder–liquid method, according to dental laboratory practice. The HA was pre-treated by isopropyl triisostearoyl titanate coupling agent (TCA) in order to improve the interfacial bonding between HA and PMMA. The effects of different concentration of titanate coupling agent (i.e., 2–8%) on the mechanical and morphological properties of PMMA were investigated. It was found that PMMA/2% TCA-treated HA composites exhibited higher flexural modulus and strength compared to PMMA/untreated HA composites. This is attributed to the enhanced interfacial interaction between PMMA and HA by the titanate coupling agent. However, for the PMMA/HA treated with 6% and 8% of TCA, the flexural properties was slightly reduced, which may associated to the plasticizing effects caused by excessive concentration of coupling agent. In addition, the fracture toughness properties of PMMA/5HA composites were influenced by the different concentration of TCA. The thermal properties of the PMMA/HA composites were enhanced by the treatment of titanate coupling agent.

Simulated body fluid and water absorption effects on poly(methyl methacrylate)/hydroxyapatite denture base composites

Poly(methyl methacrylate) (PMMA)/hydroxyapatite (HA) composite has potential application in denture base materials. The denture base materials should exhibit good mechanical properties and dimensional stability in moist envi- ronment. Silane coupling agent (3-methacryloxypropyltrimethoxy silane (γ-MPS)) was used to treat the HA fillers in order to enhance the interfacial interaction between the PMMA and HA. In this research, the kinetics and effects of Simulated Body Fluid (SBF) and water absorption on the flexural properties of PMMA/HA composites were studied for an immersion duration of 2 months. The mathematical treatment used in analyzing the data was the single free phase model of diffusion, which assumed Fickian diffusion and utilized Fick's second law of diffusion. The kinetics of water absorption of the PMMA/HA composites conformed to Fickian law behavior, whereby the initial moisture absorption follows a linear rela- tionship between the percentage gain at any time t and t 1/2 , followed by saturation. It was found that the equilibrium mois- ture content and the diffusion coefficient are depending on the concentration of γ-MPS in PMMA/5HA composites. The reduction of equilibrium moisture content of PMMA/5HA is due to the hydrophobic behavior of γ-MPS and compatibility of PMMA with HA. The retention ability in flexural modulus and strength of PMMA/HA composites upon subjected to water absorption are considerably good. The reduction of flexural strength of the PMMA/HA composites after water absorption and SBF absorption could be attributed to the plasticizing effect of water molecules.

Development for Organic Fiber of Denture Base Composites

Development for Organic Fiber of Denture Base Composites