scholarly journals Comparative Analysis of Abrasive Materials and Polishing System on the Surface Roughness of Heat-Polymerized Acrylic Resins

Author(s):  
Stanley Chibuzor Onwubu ◽  
Phumlane Selby Mdluli

Abstract Objective The aim of this in vitro experiment was to see how the operator's manual skills, polishing equipment, and abrasive materials affected the surface roughness of denture base resins. Materials and Methods Forty polymethyl methacrylate (PMMA) specimens were created and polished by using two different polishing systems, namely hand and automatic polishing machines. Three operators hand-polished 30 of specimens with eggshell powder and pumice, while 10 were automatically polished (n = 5). A profilometer was used to determine the average surface roughness (Ra) after polishing. The Ra values for the specimens hand-polished were analyzed by using paired sample testing. The Ra values for all polished specimens were analyzed by using a one-way ANOVA. Differences between the two abrasive materials as well as the polishing system were determined by using the Bonferonni tests (p = 0.05). Results and Conclusion For the PMMA specimens hand-polished, there was a strong connection in the Ra values. There were also significant variations in the Ra values across the three operators (p < 0.001). The automated technique created a substantially smoother surface than the traditional technique (p = 0.001). The greatest Ra values (0.20 µm) were found in specimens polished traditionally by using pumice, whereas the lowest Ra values (0.04 µm) were found in specimens polished mechanically with eggshell powder. The automated polishing system was the most effective polishing method when the Ra values were connected to the level of smoothness.

2006 ◽  
Vol 15 (3) ◽  
pp. 180-186 ◽  
Author(s):  
Julie C. Berger ◽  
Carl F. Driscoll ◽  
Elaine Romberg ◽  
Qing Luo ◽  
Geoffrey Thompson

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3305
Author(s):  
Pablo Kraemer Fernandez ◽  
Alexey Unkovskiy ◽  
Viola Benkendorff ◽  
Andrea Klink ◽  
Sebastian Spintzyk

(1) Background: To date, no information on the polishability of milled and 3D-printed complete denture bases has been provided, which is relevant in terms of plaque accumulation. (2) Methods: three groups (n = 30) were manufactured using the cold-polymerization polymethilmethacrilate, milling (SM) and 3D printing (AM). 10 specimens of each group were left untreated (reference). 10 more specimens were pre-polished (intermediate polishing) and 10 final specimens were highgloss polished. An additional 20 specimens were 3D printed and coated with the liquid resin (coated), 10 of which were additionally polished (coated + polished). For each group Ra and Rz values, gloss value and REM images were obtained. (3). The “highgloss-polished” specimens showed statistically lower Ra and Rz values in the SM, followed by AM and conventional groups. In the AM group statistically lower surfaces roughness was revealed for highgloss-polished, “coated + polished”, and “coated” specimens, respectively. (4) Conclusions: The milled specimens demonstrated superiors surface characteristics than 3D printed and conventionally produced after polishing. The polished specimens demonstrated superior surface characteristics over coated specimens. However, the surface roughness by both polished and coated specimens was within the clinically relevant threshold of 0.2 µm.


2012 ◽  
Vol 3 (2) ◽  
pp. 171-175 ◽  
Author(s):  
Farideh Bahrani ◽  
Mahroo Vojdani ◽  
Anahita Safari ◽  
Ghasem Karampoor

ABSTRACT Purpose The aim of this study was to evaluate mechanical property hardness and surface roughness (Ra) of different polymerization acrylic resins used for denture bases. Materials and methods A total of 30 specimens were prepared and divided in two groups. A total of 15 samples were processed by the compression molding technique using Meliodent (heatcured). Another 15 samples were processed with cold-cured resin Futura Gen via the injection molding technique. Hardness testing was conducted using a Vickers hardness tester. The Ra test was performed by a profilometer. Data were analyzed using the independent sample t-test and differences were statistically significant at the 0.05 level. Results The Vickers hardness numbers (VHN) were 20.8 ± 2.39 for Meliodent and 21.18 ± 1.42 for FuturaGen, which was not significantly different (p > 0.05). The Ra of Meliodent was 0.92 ± 0.23 µm and for FuturaGen it was 0.84 ± 0.37 µm. There were no significant changes in roughness. Conclusion The hardness and Ra of Meliodent and FuturaGen were not significantly different. Therefore, we recommend the use of FuturaGen for manufacturing denture base materials. How to cite this article Bahrani F, Safari A, Vojdani M, Karampoor G. Comparison of Hardness and Surface Roughness of Two Denture bases Polymerized by Different Methods. World J Dent 2012;3(2):171-175.


2012 ◽  
Vol 13 (3) ◽  
pp. 389-393
Author(s):  
Deepthi Kalahasti ◽  
Smitha Sharan ◽  
Harish Konde

ABSTRACT Aims To evaluate the effect of chemical disinfectant on the transverse strength of heat-polymerized acrylic resins subjected to mechanical and chemical polishing. Materials and methods A total of 256 rectangular specimens (65 × 10 × 3 mm) 128 per resin (Lucitone-199 and Acralyn-H) were fabricated. One side of each specimen was not polished and the other was either mechanically (n = 96) or chemically (n = 96) polished and immersed for 10, 30 and 60 minutes in 2% alkaline glutaraldehyde. Mechanically polished (n = 32) and chemically polished (n = 32) control specimens were immersed only in distilled water. The transverse strength (N/mm2) was tested for failure in a universal testing machine, at a crosshead speed of 5 mm/min. Data were statistically analyzed using 2-way ANOVA and Student t-test. Results chemical polishing resulted in significantly lower transverse strength values than mechanical polishing. Lucitone- 199 resin demonstrated the highest overall transverse strength for the materials tested. Heat-polymerized acrylic resins either mechanically or chemically polished, did not demonstrate significant changes in transverse strength during immersion in the disinfecting solution tested, regardless of time of immersion. Conclusion Lucitone-199 resin demonstrated the highest overall transverse strength for the materials tested and significantly stronger than Acralyn-H with either type of polishing following immersion in 2% alkaline glutaraldehyde. Clinical significance There is a concern that immersion in chemical solutions often used for cleansing and disinfection of prostheses may undermine the strength and structure of denture base resins. In this study it was observed that, the transverse strength of samples of Lucitone-199 was higher than that of the samples of Acralyn-H. The chances of fracture of the denture made of Lucitone-199 are less than that of dentures made of Acralyn-H. The chemically polished dentures may be more prone to fracture than mechanically polished dentures. How to cite this article Sharan S, Kavitha HR, Konde H, Kalahasti D. Effect of Chemical Disinfectant on the Transverse Strength of Heat-polymerized Acrylic Resins Subjected to Mechanical and Chemical Polishing: An in vitro Study. J Contemp Dent Pract 2012;13(3):389-393.


Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 221
Author(s):  
Avi Meirowitz ◽  
Arkadi Rahmanov ◽  
Eti Shlomo ◽  
Helena Zelikman ◽  
Eran Dolev ◽  
...  

Denture stomatitis is a common manifestation of oral candidiasis affecting some 65% of denture wearers. This condition is initiated by the adherence of Candida albicans to denture base acrylic resin. The present study aimed to test the in vitro effect of traditional and novel fabrication methods on Candida albicans adhesion to denture base samples. Denture based acrylic discs were fabricated using: (i) computerized milling, (ii) 3D printing, (iii) heat curing, and (iv) cold curing. Discs were tested for surface roughness (Ra), hydrophobicity (contact angle), mucin adsorption (Bradford assay), and Candida albicans adhesion. 3D printing significantly increased microbial cell adhesion as compared with heat curing, and computerized milling significantly decreased it. These results were associated with mucin adsorption levels rather than surface roughness. Results suggest that 3D printing may increase the risk for developing denture stomatitis, whereas computerized milling may decrease it as compared with traditional heat curing denture base fabrication.


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