Microwave Disinfection Research Articles

Comparative Evaluation of the Effect of Microwave, 1% Sodium Hypochlorite, and Sodium Perborate Disinfection on the Color Stability of Two Nanoparticle-Reinforced Heat-Polymerized PMMA Denture Base Resins: An In Vitro Study.

Introduction Older adults experience significant improvement in their quality of life by using removable prosthetics to replace missing teeth. Poly(methyl methacrylate) (PMMA) has become the most popular material for denture bases due to its ease of use and affordability. Recently, scientists have started adding nanoparticles like titanium dioxide (TiO2) and zirconium oxide (ZrO2) to PMMA to enhance its physical properties. These resins with nanoparticles need to stay the same color after being disinfected in different ways if they are going to be used for a long time. So, the purpose of this investigation was to assess whether or not there exists any difference between two kinds of thermally cured acrylic resin for artificial tooth bases strengthened with nanoparticles when subjected to various chemical sterilizers alongside microwave irradiation, as well as determine their comparative colorfastness levels. Materials and methods In this lab experiment, we tested how well 5% TiO2 and 7% ZrO2 nanoparticle-reinforced PMMA resins held their color when exposed to microwave irradiation, 1% sodium hypochlorite, or sodium perborate disinfection. We made 120 specimens shaped like discs; half were treated using one method, while the other half were treated using a different method. Color was measured at baseline (T0), after one cycle (T1), after five cycles (T2), and after six months (T3) using a reflectance spectrophotometer, which calculates the color difference (∆E). Results All three methods of disinfection caused significant color changes (p<0.001); however, sodium perborate caused the least amount of change, followed by 1% sodium hypochlorite and microwave irradiation. The mean ∆E values showed that after one day, there was a change in color by 1.1 due to microwave disinfection, which increased to 5.7 after five days; on the other hand, for 1% sodium hypochlorite, the change was recorded as 0.7 after one month and 1.6 after three months and finally reached up to 2.6 after six months, while sodium perborate showed the least amount of change, with ∆E values recorded as 0.2 after one month, 0.5 after three months, and 0.8 after six months. Conclusion Sodium perborate proved to be the most effective disinfectant for maintaining color stability in 5% TiO2 and 7% ZrO2 nanoparticle-reinforced PMMA resins, thus making it ideal for routine disinfection. Therefore, according to this study, sodium perborate should be used as a disinfection method because it results in minimal color change in nanoparticle-reinforced PMMA dentures.

Cumulative effect of microwave disinfection on flexural strength and dimensional stability of CAD/CAM milled versus 3D-printed denture resins (INVITRO STUDY)

Cumulative effect of microwave disinfection on flexural strength and dimensional stability of CAD/CAM milled versus 3D-printed denture resins (INVITRO STUDY)

Microwave disinfection of facial silicone prostheses, Part 1: Color stability

The choice of cleaning method is an important consideration for lengthening the serviceable time of facial prostheses as microbial organisms and biofilms could degrade facial prostheses and cause skin irritation. Whether microwave disinfection is a suitable cleaning method without degradation of the properties of a prosthesis is unclear. The purpose of this in vitro study was to measure the color stability of 6 commonly used facial silicone elastomers after microwave disinfection over a simulated 1.5-year period. Six different facial silicone elastomers: MDX4-4210, MDX4-4210/Type A, M511, A-2186, VST-50, and A-2000 were mixed with intrinsic silicone white opacifier (except for the control group) and subsequently combined with 4 silicone intrinsic pigment color groups: red (R), yellow (Y), burnt sienna (B), and a mixture of R+Y+B (M). The control group was a silicone elastomer without opacifier or pigment. Each of the 30 experimental groups consisted of 5 specimens (N=150). Five specimens were placed in a 250-mL Erlenmeyer flask filled with 160mL of tap water. Seven flasks were then placed in a 660-W microwave oven. An exposure of 6 minutes was used according to the antimicrobial efficacy of microwave disinfection protocol on facial silicone prostheses with a final water temperature of 60°C for 18 times (simulating 1.5 years of microwave disinfection with one 6-minute exposure monthly). A spectrophotometer was used to measure reflectance color change values (∆E). Color differences were calculated following CIELab (∆E*ab) and CIEDE2000 (∆E00) formulae. ∆E*ab and ∆E00 were statistically analyzed by a linear mixed effects model with 3 factors (silicone type, color shade, and time) using the R Statistical software program (α=.05). Both ∆E*ab and ∆E00 of all silicone elastomers studied were less than the visual perceptibility thresholds (∆E*ab<1.1 and E00<0.7) and were considered clinically acceptable (∆E*ab<3.0 and E00<2.1) after the 1.5-year simulation of microwave disinfection. Yellow and blue pigments had more effect on MDX4-4210 and M511, while red pigment had more effect on MDX4-4210, MDX4-4210/Type A, and M511 (P<.05). Nevertheless, the values were still below the perceptibility threshold (∆E*ab≤1.0 and E00<0.6). All 6 facial silicone elastomers maintained clinically acceptable color after 18 months of exposure to microwave disinfection.

Microwave disinfection of facial silicone prostheses, part 2: Mechanical properties

Statement of problemPart 1 of this 2-part study determined that microwave disinfection did not degrade the color stability of facial silicone prostheses. However, investigations on the effects of microwave disinfection on the mechanical properties of different silicone elastomers are lacking. PurposeThe purpose of this in vitro study was to examine the mechanical properties of commonly used colored facial silicone elastomers before and after microwave disinfection over a simulated 1.5-year period. Material and methodsSix commonly used facial silicone elastomers: MDX4–4210, MDX4–4210/Type A, M511, A-2186, VST-50, and A-2000 were combined with functional intrinsic silicone pigments and opacifier (red, yellow, blue, and white). A total of 288 specimens were fabricated (n=12). Half of the specimens were tested for mechanical properties as the baseline, while the other specimens were tested after microwave disinfection. Microwave disinfection was performed with 660 W, 6 minutes of exposure time, and microwaved for 18 cycles to simulate 1.5 years of usage (one 6-minute exposure monthly). For mechanical property testing, all specimens were tested for tensile strength and percentage elongation (ASTM D412), tear strength (ASTM D624), and hardness (ASTM D2240). For each property, a 2-way ANOVA (silicone type and microwave disinfection factors) and Tukey multiple comparison test were performed using the R statistical software program (α=.05). ResultsFollowing microwave disinfection, tensile strength and percentage elongation of A-2000 increased significantly (P<.05). MDX4–4210, MDX4–4210/Type A, and A-2000 showed significant increases in their hardness (P<.001). Tear strength also increased significantly for MDX4–4210 and VST-50 (P<.05). Among the materials tested (ranked from highest to lowest value,=not statistically significant different), for tensile strength, VST-50>A-2186=A-2000>MDX4–4210/Type A=M511=MDX4–4210 (P<.05). For percentage elongation, VST-50>MDX4–4210/Type A>A-2186>M511=A-2000=MDX4–4210=M511 (P<.05). For hardness, A-2000=A-2186>M511=VST-50>MDX4–4210>MDX4–4210/Type A (P<.05). For tear strength, VST-50>A-2186>A-2000>M511>MDX4–4210/Type A=MDX4–4210 (P<.05). ConclusionsOverall, the mechanical properties of all the silicones tested were not adversely affected by microwave disinfection. VST-50 showed the best mechanical properties among the materials tested both before and after microwave disinfection. Microwave energy is a safe method of disinfecting the silicone elastomers tested in this study.

A Comparative Evaluation of Three Methods of Disinfection of Gypsum Casts and the Changes in Surface Roughness and Dimensional Accuracy after Disinfection-An Ex Vivo Study.

One of the major problems of everyday dental practice is cross-contamination. It can place office personnel, dentists, and patients at risk of acquiring serious illness. Disinfection helps in controlling this cross-contamination to an extent. The evaluation was done to find the efficient disinfection method on gypsum casts. The aim of this study is to evaluate and compare the efficacy of three methods of disinfection of gypsum casts, namely, chemical disinfection by immersion, spray method, and microwave method, and also to evaluate and compare changes in surface roughness and dimensional accuracy between the three methods after disinfection. Ex vivo and experimental study. Thirty participants were selected, and impressions of the maxillary arch were made using polyvinyl siloxane impression material. Ninety type IV die stone gypsum casts were poured. It was divided into three groups and was subjected to chemical disinfection by immersion and spray methods, and microwave method. The disinfected casts were evaluated for microbial growth, surface roughness, and dimensional accuracy. It was performed by using the one-way analysis of variance test and paired t-test followed by the Kruskal - Wallis test and Wilcoxon signed rank test (α = 0.05). Microwave disinfection was more effective than both immersion and spray chemical disinfection methods (P < 0.010 and <0.001). The surface roughness of the microwave-irradiated casts had significantly increased after disinfection. However, there were no significant dimensional changes by any of the methods of disinfection. Within the limitations of the study, the microwave method of disinfection is more effective in eradicating microorganisms when compared to chemical methods of disinfection by immersion and spray methods.

Enhancing Microwave Disinfection: Impact of Sodium Chloride on Microbial Inactivation

Enhancing Microwave Disinfection: Impact of Sodium Chloride on Microbial Inactivation

Effect of Microwave Energy Disinfection on Roughness of Soft Lining Material

Introduction: Soft lining material enhance the patient’s comfort, its rough surface affect oral health, the risk with soft reliners was difficult hygienic maintenance, sterilization by microwave method more favor compared with chemicals disinfections. Objective to study the effect of disinfection by microwave irradiation at different exposure time on surface roughness of long-term soft-liner material. Material and Methods: 45 Specimens of long-term soft liner were made in the form of square metal shaped pattern. The preparation of mould was done by conventional procedures according to manufacture instruction and divided into three groups: GroupA control (without disinfection), Group B daily disinfection by microwave for 5min at 650W and GroupC daily disinfection by microwave for15min at 650W. The specimens were irradiated daily for 15 days (both group B&amp;C). Roughness measurement were made for three groups by profilometer device and analyzed by ANOVA ‘test. Result show that high mean value surface roughness of long term soft liner after expose to microwave disinfection for 15 min(Group C), and low mean value before expose to microwave disinfection(Group A), there were highly significant differences (P&lt;0.01) among tested groups and there was no significance difference (p&gt;0.05) between control Group with (Group B) 5 min disinfection, while the difference was significance (p&lt;0.05) between (Group C )15 min disinfection with : (Group B) 5 min disinfection and with (Group A )control group. Conclusions: the roughness of long-term soft-liner material was not adversely affected by microwave disinfection at 5 min, there was no significant differences with control group while adversely affected by microwave disinfection at 15 min, there was significant differences with control group also with group 5 min disinfection.

Feasibility study of reusing surgical masks and evaluation of the effectiveness of different disinfection methods

This study assessed various disinfection methods' impact on surgical mask reusability amid the high demand and limited supply of medical surgical masks during the respiratory disease pandemic. Volunteers wore masks for 4 h, and masks were disinfected using methods including moist heat, dry heat, ultraviolet (UV) radiation, alcohol soaking, washing machine cleaning, ultrasonic cleaning, or microwave disinfection. Key indicators measured included filtration efficiency, mask pressure, electrostatic charge, tensile strength, and blood penetration. Scanning electron microscopy and 16S bacterial DNA testing were used to evaluate fiber changes and disinfection effectiveness. After three disinfection cycles using any method, masks met Chinese standard YY0469-2011 requirements for filtration efficiency, mask pressure, strength, and blood penetration. However, non-oily particle filtration efficiency significantly decreased with moist heat, alcohol soaking, or machine washing. Bacterial filtration efficiency decreased with dry heat, alcohol soaking, or machine washing. All disinfection methods caused structural changes, particularly with dry heat, ultrasonic cleaning, and microwave disinfection. UV radiation effectively sterilized masks while maintaining filtration performance, making it the preferred method for mask reuse in emergencies.

A consensus-based Fermatean fuzzy WASPAS methodology for selection of healthcare waste treatment technology selection

Healthcare waste (HCW) management is a complex issue influenced by many factors, including technological, economic, environmental, and social factors. It is possible to regard the evaluation of the best treatment technique for HCW management as a challenging case of MCDM (multi-criteria decision-making), where various alternatives and evaluation criteria must be considered. The presentation and handling of the shaky data are crucial to choosing the HCW treatment technology. In order to address the issue of MCDM issues with Fermatean fuzzy (FF) data, we first build a consensus-based WASPAS approach in this study. In the suggested integrated methodology, the rank of the alternatives is determined using the WASPAS method in an FF environment, and the attribute weights are estimated using the entropy measure technique. In the preceding, an HCW treatment technology assessment issue is considered to make the proposed structure's applicability more transparent. In this study, four HCW treatment methods—chemical disinfection, microwave disinfection, cremation, and autoclaving—are considered options. According to the study's findings, autoclaving is the most effective HCW treatment method. Additionally, we demonstrate a sensitivity assessment using several criteria weight sets to test the stability of our intriguing proposed approach. We also call attention to a contrast between our suggested approach to decision-making and the practices now in use.

Microwave disinfection strengthened by a biochar-based microwave absorbing material for sewage resource utilization

ABSTRACT Proper disinfection treatment is the basic guarantee for safe utilisation of sewage. However, the commonly used disinfection methods are not suitable for nutrients containing reclaimed water. In this work, the microwave disinfection method assisted by a microwave-absorbing material in recycled water samples was investigated. Magnetic corn stalk biochar (MCSB), the microwave absorbing material, was prepared by high temperature carbonisation of corn stalk particles impregnated with ferrous sulfate. Escherichia coli and fecal coliforms were selected as target microorganisms to investigate the disinfection efficiency of MCSB assisted microwave radiation (MW/MCSB). The addition of microwave absorbing materials significantly improves the disinfection effect of water samples. Compared with the microwave radiation (MW) without MCSB, the bactericidal rate by using 107 CFU/L E. coli suspension increased from 63.5% to 100% at 480 W for 30 s after adding 4 g/L MCSB. Besides, the effects of MCSB dosage, microwave power, microwave radiation time, and initial bacterial concentration on disinfection efficiency were explored. Moreover, the bactericidal efficiency for actual sewage samples was also demonstrated by treating the effluent from septic tank sewage. The residual fecal coliforms in treated water samples met China’s farmland irrigation water standard (GB 5084-2021). The result indicates that the proposed method of microwave disinfection strengthened by MCSB has a promising application prospect for reclaimed water disinfection.

Dimensional Change During Microwave Disinfection of Dentures

Dimensional Change During Microwave Disinfection of Dentures

Interlayer Electrons Polarization of Asymmetric Metal Nanoclusters/g-C3 N4 for Enhanced Microwave Therapy of Pneumonia.

Interlayer interactions in two dimensional (2D) materials promote catalytic performance but often depend on the transport of inter rather than intralayer electrons. In this study, it is found that asymmetric metal-nanocluster-doped 2D g-C3 N4 greatly enhances catalytic performance by inducing microwave excitation of interlayer electron delocalization, resulting in a polarization of interlaminar charge transport for microwave disinfection and pneumonia therapy. Asymmetric Fe and Cu nanocluster doping (DCN-FeCu) enables g-C3 N4 to generate interlayer electrons under microwave irradiation, leading to interlayer polarization processes and electron delocalization effects, thus enhancing the interlayer migration efficiency of electrons. It also improves impurity energy levels and leads to a decrease in work function, allowing DCN-FeCu to produce microwave carriers across the photoelectric potential barrier under low-energy microwave radiation (2.45GHz). This asymmetric doping modulation produces layer number-dependent microwave electron excitations that are verified using multi-metal doping. Therefore, structurally modulated asymmetric doping of 2D materials with interfacial spatial effects can provide efficient microwave disinfection and pneumonia therapy.

Management of Chronic Atrophic Candidiasis (Denture Stomatitis)-A Narrative Review.

One of the most common oral diseases affecting people wearing dentures is chronic atrophic candidiasis or denture stomatitis (DS). The aim of the paper is to provide an update on the pathogenesis, presentation, and management of DS in general dental practice settings. A comprehensive review of the literature published in the last ten years was undertaken using multiple databases, including PubMed via MEDLINE, EMBASE, and Scopus. The eligible articles were analyzed to identify evidence-based strategies for the management of DS. Despite its multifactorial nature, the leading cause of DS is the development of oral Candida albicans biofilm, which is facilitated by poor oral and denture hygiene, long-term denture wear, ill-fitting dentures, and the porosity of the acrylic resin in the dentures. DS affects between 17 and 75% of the population wearing dentures, with a slight predominance in elderly females. The mucosal denture surfaces and posterior tongue are the common sites of DS, and the affected areas exhibit erythema, the swelling of the palatal mucosa and edema. Oral and denture hygiene protocols, adjusting or re-fabricating poorly adapting dentures, smoking cessation, avoiding nocturnal denture wear, and the administration of topical or systemic antifungals are the mainstay of management. Alternate treatments such as microwave disinfection, phytomedicine, photodynamic therapy, and incorporation of antifungals and nanoparticles into denture resins are being evaluated for the treatment of DS but require further evidence before routine use in clinical practice. In summary, DS is the most common oral inflammatory lesion experienced by denture wearers. Most patients with DS can be managed in general dental practice settings. Effective management by general dental practitioners may be supported by a thorough understanding of the pathogenesis, the recognition of the clinical presentation, and an awareness of contemporary treatment strategies.

A Review and Perspective of Environmental Disinfection Technology Based on Microwave Irradiation.

In the context of COVID-19 sweeping the world, the development of microbial disinfection methods in gas, liquid, and solid media has received widespread attention from researchers. As a disinfection technology that can adapt to different environmental media, microwave-assisted disinfection has the advantages of strong permeability, no secondary pollution, etc. The purpose of this review is to put forward new development requirements for future microwave disinfection strategies by summarizing current microwave disinfection methods and effects. From the perspective of the interaction mechanism of microwave and microorganisms, this review provides a development direction for more accurate and microscopic disinfection mechanism research. Compared to other traditional environmental disinfection techniques, microwave-assisted disinfection means have the advantages of being more destructive, free of secondary contamination, and thorough. Currently, researchers generally agree that the efficiency of microwave disinfection is the result of a combination of thermal and non-thermal effects. However, the performance of microwave disinfection shows the differences in the face of different environmental media as well as different types of microorganisms. This review highlights the inactivation mechanism of microwave-assisted disinfection techniques used in different scenarios. Suggestions for promoting the efficiency and overcoming the limitations of low energy utilization, complex reactor design, and inaccurate monitoring methods are proposed.

Development of thermoplastic recycled blends from biomedical waste: evaluation of properties and value addition thereof

AbstractThe recycled polyolefin waste which included polypropylene (PP) and low‐density polyethylene (LDPE) were collected from hospital and subsequently sterilized by 1% sodium hypochlorite and followed by microwave disinfection. The sterilized BMW were analyzed for growth of pathogens if any. FTIR analysis was performed to analyze the composition of the waste as well as Carbonyl index to evaluate the extent of degradation post sterilization process. Recycled blends were prepared using melt extrusion technique and ethylene diene monomer was added to balance the interface between the varied polyolefin waste. Blends were studied for mechanical and morphological properties. Thermal analysis employed DSC revealed two different peaks of crystallization and melting revealing incompatibility in the blends. DMA showed reduction in the modulus with incorporation of LDPE and EPDM. SEM analysis confirmed the homogeneous distribution of RLD droplets with reduction in the interparticle distance indicates the partial miscibility. © 2022 Society of Industrial Chemistry.

Evaluation of Occlusal Pressure Pattern and Dimensional Changes of the Lined Dentures Subjected to Microwave Disinfection Protocol

Evaluation of Occlusal Pressure Pattern and Dimensional Changes of the Lined Dentures Subjected to Microwave Disinfection Protocol

Study of physical methods and technical means of grain disinfection: network analysis

The article discusses the results of a network analysis to determine the main classification features of physical methods of grain disinfection and parameters that affect the efficiency of the disinfection process. It has been established that the first place (according to eLibrary.ru for the period from 1957 to 2021) in terms of publication activity is occupied by works on microwave disinfection of 48.33 % of 209 publications, the second is ozonation, as well as thermal and hydrobarothermal treatment, respectively. 21.53% of publications, the remaining 8.61% are ultra-violet processing. An assessment is given to some devices that implement physical methods of disinfection. A classification of physical disinfection methods is presented, dividing them into three groups (thermal, mechanical and electrophysical). The parameters affecting the efficiency of the disinfection process are also divided into three groups (structural, mechanical and technological). A generalized concept of what an agent of influence is derived.

Evaluation the Effect of Microwave Disinfection on Soft Linear Hardness

Evaluation the Effect of Microwave Disinfection on Soft Linear Hardness

Antifungal Efficacy of Sodium Perborate and Microwave Irradiation for Surface Disinfection of Polymethyl Methacrylate Polymer

Various disinfecting agents showing variable success in disinfecting polymethyl methacrylate (PMMA) are available. The aim of our study was to evaluate the antifungal efficacy of sodium perborate (denture cleaning tablet-DC), microwave irradiation, and their combination for eradicating candida albicans (C. albicans) from polymethyl methacrylate (PMMA) denture base polymer. One hundred and sixty-eight PMMA resin specimens (30 × 30 × 15 mm) were divided into four groups, including control (no disinfection), microwave disinfection in distilled water (MW-DW), sodium perborate with distilled water (DC-DW), and a combination of MW-DC-DW (n = 10). Biofilms of C. albicans were cultured on the PMMA resin denture base specimens for 96 h. The samples were exposed to three different antifungal regimes, i.e., MW, denture cleaning agent-sodium perborate (DC) and DW, and a combination of MW-DC-DW for 1 to 5 min. Scanning electron microscopy (SEM) was performed to evaluate colony formation. The colony-forming units (CFU) among the experimental groups were assessed using ANOVA, a Kruskal–Wallis test, and a Mann–Whitney test. The mean CFU values were compared with the control for each disinfecting regime at 96 h growth time. For MW-DC-DW, the CFU were significantly low at 2 and 3 min of exposure when compared with the control (DW) (p &lt; 0.05). For the MW-DW treated group, the CFU were significantly low at 3 min of exposure when compared with the control (DW) (p &lt; 0.05). It was also found that for DC-DW, the CFU were significantly low at 5 minutes when compared with the control specimens (DW) (p &lt; 0.05). Microwave disinfection in combination with sodium perborate is a more effective disinfecting regime against C. albicans than that of microwave disinfection and sodium perborate alone.

Bacterial Disinfection of Polymethyl Methacrylate (PMMA) Resin Polymer Using Low Level Microwave Irradiation and Denture Cleaning Agent

The aim was to evaluate the disinfection of E. coli, S. aureus and S. mutans cultured on Polymethyl Methacrylate (PMMA) resin polymer using microwave disinfection and sodium perborate (DC). Biofilms of E. coli, S. aureus and S. mutans were cultured on the PMMA denture base for 24, 36, 48 and 96 h. Specimens were subjected to three disinfection protocols, including microwave disinfection in distilled water (MW-DW), sodium perborate (denture cleaning tablet) with distilled water (DC-DW) and a combination of MW-DC-DW for 1 to 5 min. Colony-forming units among the study groups were analyzed using Kruskal–Wallis and Mann–Whitney tests. For E. coli and S. aureus cultured on PMMA, the MW-DC-DW group displayed complete disinfection at 2 min of exposure. However, for both bacteria, the MW-DW disinfection group showed zero CFU at 3 min. DC disinfection for E. coli and S. aureus displayed zero CFU at 5 min of exposure (p ≤ 0.05). For S. mutans, MW-DC-DW and MW-DW displayed zero CFU count at 1 min and 2 min, respectively. In DC-treated samples, CFU were significantly zero at 4 min when compared with the control at each growth time. A combination of MW irradiation with DC (sodium perborate) showed higher disinfection percentage of bacterial species on PMMA polymer denture bases compared to MW and DC alone. PMMA disinfection using DC displayed a lower antimicrobial disinfection percentage than the combined use of MW and DC as well as MW alone at 1 min or 2 min disinfection for E. coli, S. aureus and S. mutans.