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Santhaveesuk P, Serichetaphongse P, Kiat-Amnuay S. Microwave disinfection of facial silicone prostheses, part 2: Mechanical properties. J Prosthet Dent 2024; 131:340.e1-340.e6. [PMID: 38212157 DOI: 10.1016/j.prosdent.2023.11.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/21/2023] [Accepted: 11/21/2023] [Indexed: 01/13/2024]
Abstract
STATEMENT OF PROBLEM Part 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. PURPOSE The 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 METHODS Six 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). RESULTS Following 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). CONCLUSIONS Overall, 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.
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Affiliation(s)
- Penchanok Santhaveesuk
- Former Prosthodontic Resident, Department of Prosthodontics, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand; and Former AEGD Preceptor, University of Texas Health Science Center at Houston, School of Dentistry, Houston, Texas
| | - Pravej Serichetaphongse
- Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Sudarat Kiat-Amnuay
- Professor and Section Head, Department of General Practice and Dental Public Health, Houston Center for Biomaterials and Biomimetics, University of Texas Health Science Center at Houston, School of Dentistry, Houston, Texas.
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Głowacki M, Mazurkiewicz A, Słomion M, Skórczewska K. Resistance of 3D-Printed Components, Test Specimens and Products to Work under Environmental Conditions-Review. MATERIALS (BASEL, SWITZERLAND) 2022; 15:ma15176162. [PMID: 36079539 PMCID: PMC9458170 DOI: 10.3390/ma15176162] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 08/31/2022] [Accepted: 09/02/2022] [Indexed: 05/27/2023]
Abstract
The development of additive manufacturing methods known as "3D printing" started in the 1980s. In these methods, spatial models are created from a semi-finished product such as a powder, filament or liquid. The model is most often created in layers, which are created from the semi-finished product, which is most often subjected to thermal treatment or using light or ultraviolet rays. The technology of additive manufacturing has both advantages and disadvantages when compared to the traditionally used methods of processing thermoplastic materials, such as, for example, injection or extrusion. The most important advantages are low cost, flexibility and speed of manufacturing of elements with different spatial shapes. From the point of view of the user of the product, the most important disadvantages are the lower mechanical properties and lower resistance to environmental factors that occur during the use of the manufactured products. The purpose of this review is to present current information and a compilation of features in the field of research on the effects of the interactions of different types of environments on the mechanical properties of 3D-manufactured thermoplastic products. Changes in the structure and mechanical properties of the material under the influence of factors such as humidity, salt, temperature, UV rays, gasoline and the environment of the human body are presented. The presented article enables the effects of environmental conditions on common materials used in 3D printing technology to be collated in one place.
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Affiliation(s)
- Marcin Głowacki
- Department of Mechanical Engineering, Bydgoszcz University of Sciences and Technology, Kaliskiego 7 Street, 85-789 Bydgoszcz, Poland
| | - Adam Mazurkiewicz
- Department of Mechanical Engineering, Bydgoszcz University of Sciences and Technology, Kaliskiego 7 Street, 85-789 Bydgoszcz, Poland
| | - Małgorzata Słomion
- Department of Management, Bydgoszcz University of Sciences and Technology, Kaliskiego 7 Street, 85-789 Bydgoszcz, Poland
| | - Katarzyna Skórczewska
- Faculty of Technology and Chemical Engineering, University of Sciences and Technology, Seminaryjna 3, Street, 85-326 Bydgoszcz, Poland
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Additive Manufacturing of Plastics Used for Protection against COVID19-The Influence of Chemical Disinfection by Alcohol on the Properties of ABS and PETG Polymers. MATERIALS 2021; 14:ma14174823. [PMID: 34500911 PMCID: PMC8432493 DOI: 10.3390/ma14174823] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/18/2021] [Accepted: 08/23/2021] [Indexed: 12/20/2022]
Abstract
In this paper, the influence of disinfection on structural and mechanical properties of additive manufactured (AM) parts was analyzed. All AM parts used for a fight against COVID19 were disinfected using available methods-including usage of alcohols, high temperature, ozonation, etc.-which influence on AM parts properties has not been sufficiently analyzed. During this research, three types of materials dedicated for were tested in four different disinfection times and two disinfection liquid concentrations. It has been registered that disinfection liquid penetrated void into material's volume, which caused an almost 20% decrease in tensile properties in parts manufactured using a glycol-modified version of polyethylene terephthalate (PETG).
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Santos Sousa TM, Rodrigues de Farias O, Dantas Batista AU, Souto de Medeiros E, Santiago BM, Cavalcanti YW. Effectiveness of denture microwave disinfection for treatment of denture stomatitis: A systematic review and meta-analysis. Int J Dent Hyg 2020; 19:62-77. [PMID: 33022878 DOI: 10.1111/idh.12477] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 09/25/2020] [Accepted: 09/30/2020] [Indexed: 12/25/2022]
Abstract
OBJECTIVE The aim of this systematic review was to evaluate the effectiveness of removable complete denture disinfection using microwaves for the treatment of denture stomatitis. METHODS This review identified studies comparing the efficacy of microwave prosthesis disinfection (I) to topical antifungal therapy (C) in the treatment of denture stomatitis (O), which included only individuals who used complete dentures and presented with denture stomatitis (P). The search was performed in six databases and identified 1524 records; after the removal of duplicates, 816 articles remained. Three articles were selected for qualitative synthesis and two for meta-analysis. Random-effects meta-analysis estimated the polled effects of microwave disinfection and antifungal therapy on the Candida counts and clinical manifestation of denture stomatitis. The GRADE approach was used to estimate the certainty of evidence. RESULTS All included studies reported significant reductions in Candida counts and the frequency of denture stomatitis of groups subjected to microwave disinfection of dentures and topical antifungal therapy with nystatin. Significative differences between treatments were only detected for Candida quantification in the palate, within 90 days follow-up period (SMD = 0.47, 95% CI = 0.02-0.91). Meta-analyses did not show any further differences between treatments (p > .05), considering the Candida quantification in dentures and the frequency of clinical signs of denture stomatitis. The certainty of the evidence was considered as low, according to GRADE approach. CONCLUSION Microwave disinfection of complete dentures can be considered as efficient as antifungal therapy for the treatment of denture stomatitis. However, further well-designed studies are necessary to confirm such evidence.
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Affiliation(s)
- Taisa Mara Santos Sousa
- Postgraduate Program in Dentistry, Health Sciences Center, Federal University of Paraiba, Joao Pessoa, Brazil
| | - Ohana Rodrigues de Farias
- Postgraduate Program in Dentistry, Health Sciences Center, Federal University of Paraiba, Joao Pessoa, Brazil
| | - André Ulisses Dantas Batista
- Postgraduate Program in Dentistry, Health Sciences Center, Federal University of Paraiba, Joao Pessoa, Brazil.,Department of Restorative Dentistry, Health Sciences Center, Federal University of Paraiba, Joao Pessoa, Brazil
| | - Eliton Souto de Medeiros
- Postgraduate Program in Dentistry, Health Sciences Center, Federal University of Paraiba, Joao Pessoa, Brazil.,Materials Engineering Department, Technology Center, Federal University of Paraiba, Joao Pessoa, Brazil
| | - Bianca Marques Santiago
- Postgraduate Program in Dentistry, Health Sciences Center, Federal University of Paraiba, Joao Pessoa, Brazil.,Clinical and Social Dentistry Department, Health Sciences Center, Federal University of Paraiba, Joao Pessoa, Brazil
| | - Yuri Wanderley Cavalcanti
- Postgraduate Program in Dentistry, Health Sciences Center, Federal University of Paraiba, Joao Pessoa, Brazil.,Clinical and Social Dentistry Department, Health Sciences Center, Federal University of Paraiba, Joao Pessoa, Brazil
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Effect of Pressure, Post-Pressing Time, and Polymerization Cycle on the Degree of Conversion of Thermoactivated Acrylic Resin. Int J Dent 2018; 2018:5743840. [PMID: 30186326 PMCID: PMC6114067 DOI: 10.1155/2018/5743840] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/29/2018] [Accepted: 07/18/2018] [Indexed: 11/17/2022] Open
Abstract
Herein, the effect of different post-pressing times and pressure in two cycles of polymerization on the degree of conversion (DC) of thermally activated acrylic resin (TRRA) is analyzed to optimize the polymerization of this material. After post-pressing for 0, 6, or 12 h, polymerization was performed with or without a pressure of 60 psi (0.41 MPa) in a short (4 h) or a long (11 h) cycle, totaling 12 groups. To determine the DC, PMMA specimens were analyzed by Fourier transform infrared spectroscopy. The influence of each factor alone on the DC was studied by experimental planning. The statistical tests used were three-way ANOVA, t-test, Tukey's test, and Levene's test, with a margin of error of 5%. Two groups prepared with post-pressing times of 12 h had the lowest DC (p < 0.001). Post-pressing times of 0 and 6 h did not yield statistically different results. Pressure increased the DC in only one group (long cycle +12 h, p=0.001). The short cycle resulted in a higher DC than the long cycle in 2 groups (with pressure +0 h, p=0.002; without pressure +6 h, p=0.015), while the long cycle yielded a statistically higher DC in only one group (with pressure +12 h, p < 0.001). The polymerization showed satisfactory DC in all 12 groups. Small differences found among the specimens indicate that the pressure, post-pressing time, and polymerization cycles herein were not influential factors for the DC of PMMA.
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Polychronakis N, Polyzois G, Lagouvardos P, Andreopoulos A, Ngo HC. Long-term microwaving of denture base materials: effects on dimensional, color and translucency stability. J Appl Oral Sci 2018; 26:e20170536. [PMID: 29898184 PMCID: PMC6010326 DOI: 10.1590/1678-7757-2017-0536] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 02/22/2018] [Indexed: 11/24/2022] Open
Abstract
While the combined effect of microwave irradiation with cleansing solutions on denture base materials has been investigated, the effects of only using microwave irradiation and, more importantly, in a long-term basis, was not studied yet.
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Affiliation(s)
- Nick Polychronakis
- National and Kapodistrian University of Athens, School of Dentistry, Department of Prosthodontics, Athens, Greece
| | - Gregory Polyzois
- National and Kapodistrian University of Athens, School of Dentistry, Department of Prosthodontics, Athens, Greece
| | - Panagiotis Lagouvardos
- National and Kapodistrian University of Athens, School of Dentistry, Department of Operative Dentistry, Athens, Greece
| | - Andreas Andreopoulos
- National Technical University of Athens, School of Chemical Engineering, Department of Synthesis and Development of Industrial Processes, Athens, Greece
| | - Hien Chi Ngo
- University of Sharjha, College of Dental Medicine, Department of Preventive and Restorative Dentistry, Sharjha, United Arab Emirates
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Gandhi N, Daniel S, Benjamin S, Kurian N, Varghese VS. Evaluation of Surface Microhardness Following Chemical and Microwave Disinfection of Commercially Available Acrylic Resin Denture Teeth. J Clin Diagn Res 2017; 11:ZC87-ZC91. [PMID: 28658916 DOI: 10.7860/jcdr/2017/27587.9944] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 04/24/2017] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Denture disinfection is an indispensable procedure for preventing cross contamination and the maintenance of a healthy oral mucosa in patients rehabilitated with removable dental prosthesis. Nevertheless, they are known to cause changes in the physical and mechanical properties of denture base resins and acrylic resin denture teeth following immersion of a denture in a suitable chemical disinfectant solution or by undergoing microwave irradiation. One such mechanical property indicator for artificial tooth materials is hardness. AIM To assess the surface hardness of acrylic resin teeth of three different commercial brands (Ivoclar, Newace, Acryrock) following chemical (2% glutaraldehyde, 1% sodium hypochlorite) and microwave disinfections. MATERIALS AND METHODS Ten specimens of each of the three commercial brands were made for control and each simulated disinfection type and stored in distilled water at room temperature for 24 hours. After water storage, specimens were immersed in 2% glutaraldehyde and 1% sodium hypochlorite (one and three cycles) at room temperature for 10 minutes. Irradiation with microwave (one and three cycles) was done in domestic microwave for three minutes with the specimens immersed in 150 ml of distilled water. The specimens were stored in distilled water at room temperature for seven days after each disinfection cycle. Vickers hardness measurements were made using a hardness indenter under a load of 50 g force for 10 seconds. Data was subjected to repeated measure two-way ANOVA test and Tukey's test. RESULTS There were statistically significant differences for the variables disinfection, tooth, and cycle (p<0.05 for teeth & disinfectant interaction, p<0.05 cycle and disinfectant interaction). The mean surface hardness following one microwave disinfection cycle was lower than control, glutaraldehyde and sodium hypochlorite. Comparison among cycles revealed that microhardness was significantly decreased for three cycles of microwave disinfection. CONCLUSION It was concluded that there was no significant difference in microhardness when the teeth were subjected to chemical disinfection but three cycles of microwave disinfection produced decrease in the microhardness of different types of artificial teeth.
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Affiliation(s)
- Nitasha Gandhi
- Professor and Head, Department of Prosthodontics and Crown and Bridge, Christian Dental College, Ludhiana, Punjab, India
| | - Smitha Daniel
- Postgraduate Resident, Department of Prosthodontics and Crown and Bridge, Christian Dental College, Ludhiana, Punjab, India
| | - Sushant Benjamin
- Postgraduate Resident, Department of Prosthodontics and Crown and Bridge, Christian Dental College, Ludhiana, Punjab, India
| | - Nirmal Kurian
- Postgraduate Resident, Department of Prosthodontics and Crown and Bridge, Christian Dental College, Ludhiana, Punjab, India
| | - Vinaya Susan Varghese
- Postgraduate Resident, Department of Conservative and Endodontics, Maratha Mandal Dental College, Belgaum, Karnataka, India
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Polychronakis N, Yannikakis S, Zissis A. The Effect of Repeated Microwaving Disinfection on the Dimensional Stability of Acrylic Dentures. Acta Stomatol Croat 2016; 48:279-84. [PMID: 27688376 DOI: 10.15644/asc48/4/5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
OBJECTIVE The aim of this study was to evaluate the effect of repeated microwave disinfections on the dimensional stability of acrylic dentures. MATERIALS AND METHODS Three groups of dentures made of a heat polymerized acrylic resin were tested. I: dentures kept in water (control group). II: dentures microwaved daily while being immersed into water (wet disinfection). III: dentures microwaved daily without being immersed into water (dry disinfection).
Measurements were taken across three reference points, on two occasions: after curing and immersion in water for 24 hours, and one week later.
Data obtained were analyzed using one-way analysis of variance (ANOVA) and Scheffe's multiple range test. RESULTS The results showed that the microwave disinfection provokes dimensional changes of the same pattern (shrinkage). The dentures which underwent wet disinfection exhibited the greatest shrinkage (p<0.05). CONCLUSIONS Disinfection using microwave energy may cause dimensional changes (shrinkage) of complete dentures.
The microwave "dry disinfection" method can be safely applied in everyday practice since the dimensional changes which occurred seem to be of no clinical significance.
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Affiliation(s)
- Nick Polychronakis
- Assistant Professor, Division of Removable Prosthodontics, Dental School, National and Kapodistrian University of Athens, Greece
| | - Stavros Yannikakis
- Professor, Department of Dental Technology, Division of Removable Prosthodontics, Technological Educational Institution of Athens, Greece
| | - Alcibiades Zissis
- Associate Professor, Division of Removable Prosthodontics, Dental School, National and Kapodistrian University of Athens, Greece
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Klironomos T, Katsimpali A, Polyzois G. The Effect of Microwave Disinfection on Denture Base Polymers, Liners and Teeth: A Basic Overview. Acta Stomatol Croat 2015; 49:242-53. [PMID: 27688409 PMCID: PMC4993596 DOI: 10.15644/asc49/3/7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 06/29/2015] [Indexed: 10/31/2022] Open
Abstract
The aim of this paper was to overview the current scientific knowledge concerning the effect of microwave disinfection on denture related material properties. Cross-infection control in dentistry is a significant issue in everyday clinical practice due to the recent increase in some infectious diseases such as hepatitis B, C and AIDS and therefore numerous methods of disinfection have been used. The most widespread method of disinfection used in everyday practice is chemical, however, studies have suggested that chemical disinfectants alter the physical and mechanical properties of the acrylic resins and enable the growth and proliferation of certain bacteria. Therefore, microwaves were introduced as an easy to use-and-access, low cost, chemical free alternative. The question that arose was if and in what way the microwave irradiation affected the denture related material properties. Microwaving affects the denture resin bases, liners and teeth in different ways. The results showed that microwave disinfection could be a safe alternative for the disinfection of denture bases and liners compared to the chemical one, when the procedure is carried out in dry conditions, but could possibly cause dimensional changes of clinical significance on them when the irradiation takes place in wet environment. It also seems to have no detrimental effects of clinical importance on the flexural properties, impact strength and hardness of denture resins and the bond, flexural strength, porosity and hardness of denture liners. The effects of microwave disinfection on the hardness of denture teeth and teeth/denture bond strength are still controversial and no safe conclusions can be drawn.
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Affiliation(s)
| | | | - Gregory Polyzois
- Professor, Department of Removable Prosthodontics, Dental School, University of Athens, Athens, Greece
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Eleni PN, Perivoliotis D, Dragatogiannis DA, Krokida MK, Polyzois GL, Charitidis CA, Ziomas I, Gettleman L. Tensile and microindentation properties of maxillofacial elastomers after different disinfecting procedures. J Mech Behav Biomed Mater 2013; 28:147-55. [DOI: 10.1016/j.jmbbm.2013.07.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 07/12/2013] [Indexed: 10/26/2022]
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Senna PM, Da Silva WJ, Faot F, Del Bel Cury AA. Microwave disinfection: cumulative effect of different power levels on physical properties of denture base resins. J Prosthodont 2011; 20:606-12. [PMID: 21980952 DOI: 10.1111/j.1532-849x.2011.00770.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
PURPOSE This study evaluated the cumulative effects of different microwave power levels on the physical properties of two poly(methylmethacrylate) (PMMA) denture base resins. MATERIALS AND METHODS Eight sets of four PMMA specimens each (two polymerized in a water bath and two using microwave energy) were immersed in beakers containing 200 ml of distilled water. Each beaker was subjected to microwave irradiation for 3 minutes at a power level of 450,630, or 900 W. The surface roughness, surface hardness, linear stability, flexural strength, elastic modulus, impact strength, and fractographic properties were evaluated after either 6 or 36 simulated disinfection cycles. The data were statistically analyzed using ANOVA and the Tukey post hoc test (α= 0.05). RESULTS The polymerization method did not influence any property (p > 0.05) except linear stability. The surface roughness (p < 0.001) and hardness (p= 0.011) increased after 36 irradiation cycles at 630 or 900 W. The resin polymerized using microwave energy exhibited greater linear distortion (p= 0.012), and there was a cumulative effect on linear stability for both resins (p < 0.001). No significant change (p > 0.05) was observed in flexural strength; however, the elastic modulus decreased (p= 0.008) after 36 disinfection cycles. The impact strength and crack propagation angles displayed no significant differences (p > 0.05). CONCLUSION Within the limitations of this study, it can be concluded that microwave disinfection at 450 W to 630 W for 3 minutes is safe for PMMA.
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Affiliation(s)
- Plinio M Senna
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas, Piracicaba, Brazil.
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