scholarly journals Effects of repeated use of tungsten carbide burs on the surface roughness and contact angles of a CAD-CAM PMMA denture base resin

Author(s):  
Perihan Oyar ◽  
Mutahhar Ulusoy ◽  
Rukiye Durkan
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Mohammed M. Gad ◽  
Reem Abualsaud ◽  
Shaimaa M. Fouda ◽  
Ahmed Rahoma ◽  
Ahmad M. Al-Thobity ◽  
...  

Statement of Problem. Novel polymethyl methacrylate (PMMA) containing zirconium dioxide nanoparticles (nano-ZrO2) was suggested as a denture base material but there is a lack of information regarding denture cleanser effects. Objectives. This study aimed to evaluate denture cleanser effects on color stability, surface roughness, and hardness of PMMA denture base resin reinforced with nano-ZrO2. Materials and Methods. A total of 420 specimens were fabricated of unreinforced and nano-ZrO2 reinforced acrylic resin at 2.5% and 5%, resulting in 3 main groups. These groups were further subdivided (n = 10) according to immersion solution (distilled water, Corega, sodium hypochlorite, and Renew) and immersion duration. Surface roughness, hardness, and color were measured at baseline (2 days-T0) in distilled water and then after 180 and 365 days of immersion (T1 & T2) in water or denture cleansing solutions. Data was collected and analyzed using two-way ANOVA followed by Bonferroni post hoc test (α = 0.05). Results. Surface roughness increased significantly after denture cleanser immersion of unmodified and nano-ZrO2-modified PMMA materials while hardness decreased ( P < 0.001 ). The denture cleansers significantly affected the color of both PMMA denture bases ( P < 0.001 ). The immersion time in denture cleansers significantly affected all tested properties ( P < 0.001 ). Within denture cleansers, NaOCl showed the highest adverse effects ( P < 0.05 ) while Renew showed the least adverse effects. Conclusion. Denture cleansers can significantly result in color change and alter the surface roughness and hardness of denture base resin even with ZrO2 nanoparticles addition. Therefore, they should be carefully used.


2020 ◽  
Vol 12 (5) ◽  
pp. 67
Author(s):  
Ranganathan Ajay ◽  
Karthigeyan Suma ◽  
Vikraman Rakshagan ◽  
Elumalai Ambedkar ◽  
Vellingiri Lalithamanohari ◽  
...  

2013 ◽  
Vol 5 (2) ◽  
pp. 174-183 ◽  
Author(s):  
Maki Sato ◽  
Tomoko Ohshima ◽  
Nobuko Maeda ◽  
Chikahiro Ohkubo

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4331
Author(s):  
Shaimaa M. Fouda ◽  
Mohammed M. Gad ◽  
Passent Ellakany ◽  
Maram A. Al Ghamdi ◽  
Soban Q. Khan ◽  
...  

Background: Denture base resin has some drawbacks. This study investigated the impact of nanodiamonds (ND) and autoclave polymerization on the surface characteristics, translucency, and Candida albicans adherence in polymethyl methacrylate (PMMA) denture base resin after thermocycling. Methods: Heat-polymerized PMMA discs (15 × 2 mm) with a total sample size n = 160 were studied. Specimens were categorized into two main groups (N = 80): conventional water-bath-polymerized PMMA (CP/PMMA) and autoclave-polymerized PMMA (AP/PMMA). Each group was subdivided according to the ND concentration into four groups (n = 20): unmodified PMMA as a control, and 0.1%, 0.25%, and 0.5% ND–PMMA. Scanning electron microscopy (SEM) was used to inspect the morphology of the ND and the ND–PMMA mixtures before heat polymerization. The specimens were exposed to thermal cycling (5000 cycles at 5 and 55 °C), then surface roughness was measured with a non-contact optical interferometric profilometer, contact angle with an automated goniometer, and translucency using a spectrophotometer. Colony-forming units (CFU) were used to determine the adherence of Candida albicans cells to the specimens. ANOVA and Tukey post hoc tests for pairwise comparison were utilized for the statistical analysis (α = 0.05). Results: Surface roughness was significantly reduced with ND addition to CP/PMMA (p ˂ 0.001), while the reduction was not statistically significant in AP/PMMA (p = 0.831). The addition of ND significantly reduced the contact angle, translucency, and Candida albicans count of CP/PMMA and AP/PMMA (p ˂ 0.001). The incorporation of ND in conjunction with autoclave polymerization of PMMA showed significant reduction in all tested properties (surface roughness, contact angle and Candida albicans adherence) except translucency (p = 0.726). Conclusions: ND addition to PMMA and autoclave polymerization improved the surface properties with respect to antifungal activities, while the translucency was adversely affected.


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