Polymethylmethacrylate Surface Research Articles

Energy Dissipation of Fast Electrons in Polymethylmethacrylate: Toward a Universal Curve for Electron-Beam Attenuation in Solids between ∼0 eV and Relativistic Energies.

Spectroscopy of correlated electron pairs was employed to investigate the energy dissipation process, as well as the transport and the emission of low-energy electrons on a polymethylmethacrylate surface, providing secondary electron spectra causally related to the energy loss of the primary. Two groups are identified in the cascade of slow electrons, corresponding to different stages in the energy dissipation process. The characteristic lengths for attenuation due to collective excitations and momentum relaxation are quantified for both groups and are found to be distinctly different: λ_{1}=(12±2) Å and λ_{2}=(62±11) Å. The results strongly contradict the commonly employed model of exponential attenuation with the electron inelastic mean free path as characteristic length, but they essentially agree with a theory used for decades in astrophysics and neutron transport, albeit with characteristic lengths expressed in units of angstroms rather than light-years.

Polymeric optical fiber biosensor with PAMAM dendrimer-based surface modification and PlGF detection for pre-eclampsia diagnosis

Pre-eclampsia (PE) is a life-threatening complication that occurs during pregnancy, affecting a large number of pregnant women and newborns worldwide. Rapid, on-site and affordable screening of PE at an early stage is necessary to ensure timely treatment and minimize both maternal and neonatal morbidity and mortality rates. Placental growth factor (PlGF) is an angiogenic blood biomarker used for PE diagnosis. Herein, we report the plasmonic fiber optic absorbance biosensor (P-FAB) strategy for detecting PlGF at femtomolar concentration using polymethyl methacrylate (PMMA) based U-bent polymeric optical fiber (POF) sensor probes. A novel poly(amidoamine) (PAMAM) dendrimer based PMMA surface modification is established to obtain a greater immobilization of the bioreceptors compared to a linear molecule like hexamethylenediamine (HMDA). Plasmonic sandwich immunoassay was realized by immobilizing the mouse anti-PlGF (3H1) on the U-bent POF sensor probe surface and gold nanoparticles (AuNP) labels conjugated with mouse anti-PlGF (6H9). The POF sensor probes could measure PlGF within 30 min using the P-FAB strategy. The limit-of-detection (LoD) was found to be 0.19 pg/mL and 0.57 pg/mL in phosphate-buffered saline and 10× diluted serum, respectively. The clinical sample testing, with eleven positive and eleven negative preeclamptic pregnancy samples, successfully confirmed the accuracy, reliability, specificity, and sensitivity of the P-FAB based POF sensor platform, thereby paving the way for cost-effective technology for PlGF detection and its potential for pre-eclampsia diagnosis.

Alginate-based water-soluble adhesives: effect of incorporated phenolic hydroxy groups on adhesiveness

Abstract Alginic acid (Alg) was modified with tyramine (TA), homoveratrylamine (HVTA), and 2-phenylethylamine (PA) to obtain Alg-based adhesives, AlgTA, AlgHVTA, and AlgPA. The adhesiveness of the modified Algs were evaluated and compared with previously reported catechol-modified alginate, AlgDA. AlgTA showed adhesion tendency differently from AlgDA, depending on the incorporation ratios of TA. AlgHVTA with protected phenolic hydroxy groups showed lower adhesiveness than AlgDA for mica surfaces, but higher for polymethyl methacrylate surfaces. AlgPA without a phenolic hydroxy group also exhibited moderate adhesiveness for mica.

A simple and economic method to modify large organic surfaces for enhancing adhesion and transparent Au/PMMA with high electromagnetic shielding efficiency

This study introduces a simple and cost-effective approach for modifying large organic surfaces, facilitating robust adhesion between Au films and polymethyl methacrylate (PMMA) while retaining transparency to visible light and effectively shielding against electromagnetic interference (EMI). The proposed surface modification method employs a cheap low-power conventional UV lamp to illuminate organic surfaces in an open environment, rending it convenient and applicable for surfaces ranging from small to massive, irrespective of size, shape and location. By subjecting transparent PMMA glass to a brief 20–30 min exposure to a 36 W UV lamp positioned 5 cm away from the sample surface, the PMMA surface is dramatically modified and the surface is turned from hydrophobic to hydrophilic, establishing a strong adhesion between PMMA and Au films. The resulting Au/PMMA glass exhibits remarkable transparency about 70% within the visible light spectrum, coupled with an impressive EMI shielding efficiency that surpasses 20 dB across a broad range of electromagnetic wavebands, encompassing the S, C, X and Ku bands that correspond to the wave frequencies of major electromagnetic pollution and crucial applications of 5G communication, credit card validation, radar systems, traffic control, etc. Various characterizations have been conducted, elucidating the underlying mechanisms. This study presents an important advancement, and the accessible and scalable nature of the large-scalable surface modification method has far-reaching implications across numerous industrial sectors and applications, in addition to transparent EMI shielding Au/PMMA glasses.

Laser-assisted direct roller imprinting of large-area microstructured optical surfaces

In this study, a high-throughput fabrication method called laser-assisted direct roller imprinting (LADRI) was developed to lower the cost of nanoimprinting large-area polymer films and to address problems associated with nanoimprinting, namely, microstructural damage and precision in flatness of entire film. With LADRI, the laser directly heats the microstructured surface of the roller mold, which heats and melts the surface of a polymethyl methacrylate (PMMA) film to replicate the microstructures on the mold rapidly. In this study, the effects of laser power density, scanning speed, size of the microstructures, and contact pressure on the replication speed were investigated experimentally. The replication speed increased as the power and scanning speed increased. However, because the film required heating until it filled the entire depth of the microstructure, an appropriate replication speed was necessary. This result was supported by simulation of the temperature distribution inside the mold and the PMMA using transient heat conduction analyses. To demonstrate the applications of LADRI, two different optical surfaces were replicated: an antireflection (AR) structure with conical structures sized several hundred nanometers and a light-extraction structure with a microlens array (MLA) comprising 10 μm lenses, for display and illumination, respectively. The replication degree of the MLA was governed by the contact pressure. Polymer flow simulation indicated that the heat conduction and flow speeds of the melted PMMA surface were comparable within several tens of micrometers. In addition, the reflectivity of the AR structure decreased from 4 to 0.5%, and the light intensity of the light-extraction structure increased by a factor of 1.47.

Preparation of photo-grafted magnetic nano-silver composites and their catalytic studies on organic dyes

More active and stable catalyst is needed for degradation of organic dyes in wastewater. A new kind of polymethyl methacrylate (PMMA) microsphere hybridized with Ag and Fe3O4 was developed as catalyst. PMMA microspheres were prepared by photoinitiated dispersive polymerization, and then acrylic acid (AA) was photo-grafted on the surface of microspheres with 365 nm UV light to prepare PMMA-AA microspheres whose carboxyl group was up to 164 × 1021 per microsphere. Under the effect of NaBH4, the Ag nanoparticles on the surface of PMMA and PMMA-AA microspheres were successfully modified with the help of carboxyl groups on the surface of PMMA and PMMA-AA microspheres. Fe3O4 particles were adsorbed onto the microsphere surface to obtain two kinds of microspheres (PMMA@Ag@Fe3O4, PMMA-AA@Ag@Fe3O4) for the catalytic reduction of methylene blue (MB) and rhodamine B (Rh-B), respectively. PMMA-AA@Ag@Fe3O4 microspheres exhibited excellently catalytic performance that the apparent rate coeffcients of MB and Rh-B were 0.045 s−1 and 0.036 s−1 respectively. The catalytic efficiency of PMMA-AA@Ag@Fe3O4 heterogeneous catalyst can reach 90% even after 8 cycles for MB. It has excellent catalytic performance, high non-selective adsorption and good reusability. Excellent catalytic performance, high non-selective adsorption and reusability even in the presence of mixed dyes.

Antifungal Effect and Durability of Chitosan Oligosaccharide Coating on Heat-cured Polymethylmethacrylate Surface

This study aimed to investigate the antifungal effect against Candida albicans (ATCC® 10231) and the durability of chitosan oligosaccharide (COS) coated on heat-polymerized polymethylmethacrylate (PMMA). The various concentrations of COS solution, 0.5, 1 and 2-fold of minimum fungicidal concentration (0.5, 1 and 2 MFC) were prepared and applied to PMMA specimens treated with sandblasting (SB), application of 3-aminopropyltriethoxysilane (APS), and a combination of both procedures (SB&APS). The toothbrush abrasion test was done to evaluate the remaining COS (n=10). The antifungal effect was determined through the colony count method (n=3). The number of fungal colonies was recorded at 16 and 48 hours. Data were analyzed using two-way and one-way ANOVA at the 95% confidence level. The result of the toothbrush abrasion test revealed that COS concentration and surface treatment affected coating durability. APS and SB&APS groups showed a high percentage of COS and significantly differed from SB groups (P = 0.00). For the antifungal effect, coatings with 1 MFC and 2 MFC demonstrated no difference, but coating with 0.5 MFC differed from others (P = 0.00). At 16 and 48 hours, PMMA coated with 1 MFC and 2 MFC by APS and SB&APS methods inhibited C.albicans. COS can be coated onto PMMA using APS and can inhibit C.albicans. With further development, this method could be applied to treat denture stomatitis alternatively to conventional antifungal drugs. Keywords: Candida albicans, Chitosan, Oligochitosan, Polymethylmethacrylate, Silanes

Effect of denture base acrylic resin containing silver nanoparticles on Candida Albicans adhesion and its release in artificial saliva

Background Candida albicans was considered a main reason of precipitate formations and decomposition of acrylic denture base; so many trials were objected to resist this microbial action and prolong the shelf life of the formulated fitting base. Aim of the work The present study aimed to adopt a new mixture of the silver nanoparticles with the PMMA denture base to get a prolonged antimicrobial protection for the formed base against Candida albicans. Statement of problem Accumulation of Candida Albicans on fitting surface of poly methyl meth-acrylate (PMMA) denture base. Purpose To evaluate the effect of denture base acrylic resin containing silver Nanoparticles (Ag NP) on Candida Albicans adhesion and its release in artificial saliva. Materials and methods Sixty round disks with dimensions of 15 mm diameter and 3 mm thickness specimens were prepared for this research. Control group A: 10 specimens were prepared from pure PMMA. Experimental group B: 50 specimens were prepared from PMMA containing 5% of Ag NP. Isolation and identification of Candida Albicans were taken from oral cavity of 10 patients by swabbing. The Specimens were immersed in artificial saliva for 3, 6, and 9 months. Microbiological test was done for specimens of each group to detect Candida Albicans accumulation at the same interval period by measuring the inhibition zone created around the disks. Specimens were taken from the artificial saliva to evaluate silver release in it by using UV-Vis Spectrophotometer Instrument ‘SHIMADZO UV-310 PC. For Spectrophotometer 1.0 cm and/or 0.2 cm matched silica cells. The amount of accumulated silver released was calculated to detect its cytotoxic effect1. Results For control group A there was no inhibition zone for Candida growth around the specimens. While for group B with Ag NP the greatest antimicrobial effect was found at zero time then was decreased gradually with increasing the time till reaching zero effect after 9 months resembling the control group. The amount of Nano silver in artificial saliva after 3 months was found to be little then it was increased gradually with increasing time. Conclusion Adding Ag NP to PMMA denture base has antimicrobial effect against Candida Albicans for only 9 months; then there was no effect as silver was released in saliva. The amount of released silver was found to be with no cytotoxic effect.

Masquelet Technique: Visualization of Cement Spacer Utilizing Methylene Blue

Masquelet Technique: Visualization of Cement Spacer Utilizing Methylene Blue

The effect of hydrofluoric acid treatment on the repair strength of polyamide denture base materials: An in vitro study.

Although polymethylmethacrylate (PMMA) dentures can be repaired using autopolymerizing acrylic resin, achieving it using polyamides is difficult. This study aimed to achieve acceptable bond strength using autopolymerizing acrylic resin by applying surface treatments to the polyamide denture base material. Thirty-six disc-shaped samples (27 polyamide, 9 PMMA) were prepared. Based on the surface treatment applied, the polyamide samples were divided into three groups: No surface treatment (n=9), tribochemical silica coating+silane coupling agent (n=9), and 9% hydrofluoric acid+tribochemical silica coating+silane coupling agent (n=9). PMMA specimens received no surface treatment. Polyamide and PMMA surfaces had auto-polymerizing acrylic resin bonded on them, and then a shear bond strength test was performed between them after aging. The Kruskal-Wallis test was used, and statistical significance was set at p<0.05. PMMA had the highest shear bond strength, the untreated polyamide group had the lowest shear bond strength, and the difference was significant (p<0.05). The group treated with 9% hydrofluoric acid, tribochemical silica coating, and silane coupling agent exhibited the highest shear bond strength of the polyamide groups, and the bond strength in this group was comparable to the PMMA specimens (p>0.05). The polyamide denture repair strength can be improved by 9% hydrofluoric acid, tribochemical silica coating, and silane coupling agent application to the polyamide surface.

Fabrication of Polymethyl Methacrylate (PMMA) Hydrophilic Surfaces Using Combined Offset-Tool-Servo Flycutting and Hot Embossing Methods.

Polymethyl methacrylate (PMMA) is a material with good surface wettability and has unique and widespread applications in industrial fields. However, fabricating this material in an environmentally friendly way while maintaining its mechanical robustness remains a challenging task. One effective way is through the rational design of microstructure surfaces. The current study fabricated a pyramid microstructure array on a mold surface using offset-tool-servo flycutting, which was then combined with hot embossing to replicate an inverted pyramid microstructure array on a PMMA surface. Firstly, a toolpath compensation algorithm was developed to linearize the arc toolpath and reduce the cost of ultra-precision lathe. Then, the algorithm was further developed to achieve automatic linear toolpath intersection, aiming to ensure the machining accuracy and improve machining efficiency. An experiment testing the linear toolpath intersecting at 90° was conducted, fabricating a pyramid microstructure array with nanoscale roughness on the mold surface. This surface was then employed for replicating an inverted pyramid microstructure array on the PMMA surface using hot embossing. Furthermore, the accuracy of replication was evaluated, and the experimental results demonstrated excellent replication fidelity, exceeding 98%. The microstructural surface of the PMMA exhibited a change in surface wettability. The wettability test showed a water-droplet contact angle reduction from 84.8° ± 0.1° to 56.2° ± 0.1°, demonstrating a good hydrophilic effect. This study introduces a novel, environmentally friendly and high-precision method to fabricate a functional PMMA surface with an inverted pyramid microstructure array. The results of this study also provide strong technical support and theoretical guidance for micro-nanostructure functional surface machining and replicating.

THE EFFECT OF CO2 LASER ENGRAVE PARAMETERS ON SURFACE ROUGHNESS ON POLYMETHYLMETHACRYLATE (PMMA)

The investigation of the laser engraving process has been the focus of a significant amount of research in the field of laser machines. On the surface of the material, gaps and imperfections will appear as a natural result of the engraving process. It is widely held that the surface texture of a material has a significant impact on the material's mechanical qualities, as well as its functional performance and aesthetic appeal. As a result, the purpose of this study is to investigate the influence that different process parameters have on the PMMA (polymethylmethacrylate) surface during the engraving process. PMMA was used throughout this investigation in the engraving process, which was carried out by a machine equipped with a 40W CO2 laser tube. In order to explore the effect that laser engraving has on materials, a total of 25 separate experiments were carried out in line with the Taguchi design principles. It has been investigated how surface roughness (Ra), as well as total machining time, is affected by the laser power, scanning speed, scan gap, and nozzle distance that are considered to be input factors. According to the findings, the surface roughness of the sample had a value that varied from 0.810 to 5.159 micrometres when measured in terms of distance. The factor that has the greatest influence on the Ra value is the scanning speed, which is followed by the nozzle distance, laser power, and scan gap. On the other hand, the amount of time necessary for the machine to finish engraving on the sample can range anywhere from 58 to 135 seconds, with the scanning speed being the characteristic that has the most influence on this figure.

Femtosecond laser induced porous surface on polymethyl methacrylate for filmwise condensation to improve solar still productivity

The decline in freshwater availability has spurred research into employing solar desalination technology. Recent research has concentrated on investigating the use of surface modification to improve the productivity of solar still for desalination. This paper presents the use of femtosecond laser texturing to induce a porous surface on the polymethyl methacrylate (PMMA) cover of a solar still for producing filmwise condensation. Vertical lines 2.5 mm wide were fabricated on the PMMA surface using ultrafast laser texturing, and experiments were conducted using the modified cover on a solar still at a constant basin water temperature. Results show that the static water contact angle measured on the cleaned laser textured surface is hydrophobic. However, the formation of the porous structure leads to a change in wetting state from Cassie-Baxter to Wenzel upon exposure to water vapour. This change in wetting state enables the formation of filmwise condensation under the continuous presence of water vapours. The solar still productivity improves by 15.4 % and 23.1 % using both cleaned and uncleaned laser textured surfaces respectively. The modified surface is stable upon repeated exposure to water vapour, thus proving to be an excellent surface modification method for enhancing PMMA covered solar still performance.

Thermal Reflow Simulation for PMMA Structures with Nonuniform Viscosity Profile.

This paper presents a new approach to the simulation of the thermal reflow of e-beam-exposed polymethyl methacrylate (PMMA) taking into account its nonuniform viscosity profile. This approach is based on numerical "soapfilm" modeling of the surface evolution, processed by the free software "Surface Evolver" in area normalization mode. The PMMA viscosity profile is calculated via the simulation of the exposed PMMA number average molecular weight distribution using the Monte-Carlo method and empirical formulas. The relation between the PMMA viscosity and the mobility of PMMA surface vertices was determined via the thermal reflow simulation for uniform PMMA gratings using analytical and numerical approaches in a wide viscosity range. The agreement between reflowed profiles simulated with these two approaches emphasizes the applicability of "soapfilm" modeling in the simulation of polymer thermal reflow. The inverse mobility of PMMA surface vertices appeared to be proportional to the PMMA viscosity with a high precision. The developed approach enables thermal reflow simulations for complex nonuniform structures, which allows the use of predictable reflow as a stage of 3D microfabrication.

Surface, mechanical and chemical properties of modified denture resin using natural biopolymer.

This laboratory study determined the surface, mechanical and chemical properties of polymethyl methacrylate (PMMA) denture resin reinforced with micron-sized Gum Arabic (GA) powder in different weight ratios. This laboratory study was conducted at the Dental Health Department of the College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia from November 2022 to February 2023. Three experimental denture resins were prepared by incorporating GA powder in heat-polymerized PMMA powder using different wt.% (5, 10, and 20 wt.%). While pristine PMMA served as the control group. A total of ten bar-shaped specimens with dimensions of 65 mm × 10 mm × 3.5 mm were prepared for each study group. The surface properties (micro CT and SEM evaluation), mechanical properties (Nanohardness, elastic modulus and flexural strength) and chemical properties (FTIR) were conducted. The data were statistically analyzed using the one-way analysis of variance and Tukey's post hoc tests (p<0.05). The surface and bulk properties of experimental GA-reinforced PMMA resin materials deteriorated while the mechanical properties were also negatively altered using GA-based PMMA denture resin. A linear correlation was observed between weak mechanical properties and increasing wt.% of GA in denture resin. The incorporation of GA powder in denture resin might not be a viable option. The surface and mechanical properties of experimental PMMA composites were adversely affected compared to the control group.

The adsorption of PAHs on microplastics and desorption in the simulated human digestive system

Plastic debris is widely distributed in the aquatic environment and interacts with other pollutants. Microplastics (MPs) have a stronger binding ability with pollutants and could unconsciously ingested by humans, thus becoming the carrier of pollutants into the human body and affecting human health. In this study, polycyclic aromatic hydrocarbons (PAHs) were selected as model pollutants, polyethylene (PE) and polymethyl methacrylate (PMMA) were selected as research objects. The adsorption of PAHs on different kinds of MPs and desorption behavior in a simulated human digestive system were systematically studied. The results indicated that PAHs with higher molecular weight were more easily adsorbed on MPs, and the adsorption efficiency of PAHs on PE was 1.4–3.8 times higher than PMMA. The desorption experiments were conducted in simulated gastrointestinal fluid, the activity of enzymes directly affected the desorption of PAHs, and the desorption efficiency of PAHs from the surfaces of PMMA (0.7–41.6 %) was significantly higher than PE (0.8–27.7 %). For 15 PAHs, the desorption efficiency from the surfaces of PE decreased gradually with the number of PAHs rings, which was opposite to PMMA. Molecular dynamics simulation showed that enzymes in digestive fluid attenuated the interaction energy between MPs and PAHs, resulting in substantial desorption of PAHs from the surfaces of MPs. The risk assessment demonstrated that the carcinogenic risk of PAHs desorption from PMMA was higher than PE. This study helps understand the adsorption of PAHs on MPs and the potential health risks of accidental ingestion by humans.

Preparation and characterization of PMMA/ZnO nanocomposites for antistatic and biomedical applications

Polymethyl methacrylate (PMMA)/Palm oil/ZnO nanocomposite films of concentrations 0, 0.5, 1, 2, 5, 10, and 15 wt% were prepared by solution casting technique. Tween 80 was used as a surfactant. The prepared films were characterised by different techniques in addition to antimicrobial and cytotoxicity tests. The scanning electron microscope (SEM) micrographs of fractured surfaces of the films showed that palm oil (PO) and Tween 80 enhanced ZnO NPs dispersion. An excess ZnO loading led to polymer saturation with ZnO NPs which accumulate on PMMA surface. X-ray diffraction (XRD) measurements confirmed SEM results as the crystallinity increased by ZnO NPs loading and decreased by excess loading. In addition, the presence of PO and Tween 80 enhanced thermal stability of pure PMMA and the optimum concentration is 0.5 wt% ZnO NPs. Further, the permittivity (ε′), dielectric loss (ε′′), and electrical conductivity (σ) were investigated. It was found that PO addition increased the values of ε′, ε′′, and σ of PMMA. Upon ZnO loading, these values increased up to 10 wt% ZnO NPs then decreased upon reaching 15 wt% ZnO NPs. The conductivity values revealed that the prepared nanocomposites can perform as antistatic materials for lower ZnO content and electrostatic dissipation application at 10 wt% ZnO. The antimicrobial and cytotoxicity studies revealed that the prepared films are nontoxic and the antimicrobial properties of the films against Staphylococcus aureus, Enterococcus faecalis and Candida albicans were enhanced by PO and ZnO NPs addition.

Antifungal Effect of Polymethyl Methacrylate Resin Base with Embedded Au Nanoparticles.

Full and partial restorations in dentistry must replicate the characteristics of the patient's natural teeth. Materials must have good mechanical properties and be non-toxic and biocompatible. Microbes, which can form biofilms, are constantly in contact with restorations. In this study, we investigate how well Candida albicans adheres to a polymethyl methacrylate (PMMA) resin base with gold (Au) nanoparticles. We synthesized Au nanoparticles and characterized them. The average size of Au nanoparticles embedded in PMMA was 11 nm. The color difference ΔE between PMMA and PMMA/Au composites was 2.7 and was still esthetically acceptable to patients. PMMA/Au surfaces are smoother and more hydrophilic than pure PMMA surfaces, and the isoelectric point of both types of surfaces was 4.3. Above the isoelectric point, PMMA/Au surfaces are more negatively charged than PMMA surfaces. The added Au nanoparticles decreased the tensile strength, while the hardness did not change significantly. Adhesion measurements showed that PMMA surfaces modified with Au nanoparticles reduced the extent of microbial adhesion of Candida albicans.

Antibiofilm properties of silver nanoparticles incorporated into polymethyl methacrylate used for dental applications.

Acrylic resins used in dental and biomedical applications do not have antimicrobial properties, their surface is susceptible to colonization of microorganisms. The aim of this study was to evaluate the antibiofilm properties of silver nanoparticles (AgNPs) deposited in a polymethyl methacrylate (PMMA) surface against a Staphylococcus aureus biofilm. The PMMA was impregnated with AgNPs by using the in-situ polymerization method. To determine the solubility of the incorporated silver (Ag+) atomic absorption spectrophotometry was used (AAS) at 24 h, 48 h, 7 days, and 30 days. Thirty specimens of PMMA with AgNPs and without NP (control group) were assembled in the CDC Biofilm Bioreactor system with a cell suspension of S. aureus. The specimens were removed at 6, 12, 24, 48, and 72 h to determine the viability profile and quantify the Arbitrary Fluorescence Units (AFU). The AgNPs showed an irregular and quasispherical shape with an average size of 25 nm. AAS analysis demonstrated a low solubility of Ag+. The formation of the S. aureus biofilm increased as the evaluation periods continued up to 72 h. The experimental group showed poor growth, and a decrease in the intensity of the fluorescence demonstrated a statistically significant inhibition of the formation of the biofilm (P < 0.05) in relation to the control group at 6, 12, 24, 48, and 72 h. AgNPs incorporated into PMMA decreased the growth and maturation of S. aureus biofilm.

Wear effects between polymethyl methacrylate occlusal splints and opposing dentin surfaces during bruxism mimicking events

ObjectivesTo compare the surface wear rate between polymethyl methacrylate (PMMA)-based occlusal splints and opposing dentin-exposed teeth in bruxism simulating models.Materials and methodsPMMA-based occlusal splints and extracted premolars were tested on a chewing stimulator at 30,000 or 60,000 cycles. Dentin wear was measured under a stereomicroscope and PMMA wear was determined with an optical profilometer. In addition, wear surface topography was assessed and quantified by scanning electron microscopy (SEM).ResultsWear rate of PMMA was significantly greater (11 times) than that of dentin specimens at 60,000 cycles, though these findings were not observed at 30,000 cycles. When comparing wear rates within each group at different duration cycles, PMMA surfaces exhibited an average wear rate 1.4 times higher with high duration cycles, while dentin surfaces displayed a marginal decrease in wear. In SEM micrographs, PMMA surfaces displayed more wear abrasion lines with higher duration cycles. However, dentin surfaces did not exhibit major differences between low and high duration cycles.ConclusionWear rate on PMMA-based occlusal splints remarkably increases upon high chewing cycles mimicking bruxism comparing with the rate on dentin. Hence, it is reasonable for bruxing patients to wear single-arch PMMA-based occlusal splints to protect opposing dentin-exposed teeth.