Evaluation of fungal adherence to plasma‐modified polymethylmethacrylate

Abstract

There is a propensity for fungal adherence to the polymethylmethacrylate used for making denture bases. Therefore, this study investigated whether surface modifications with plasma treatments would reduce the adherence of Candida albicans to a denture base resin. Samples (n = 180) with smooth and rough surfaces were made and divided into five groups: control - non-treated; experimental groups - submitted to plasma treatments to obtain surfaces with different hydrophobicities (Ar/50 W; ArO(2) /70 W; AAt/130 W) or with incorporated fluoride (Ar/SF(6) 70 W). Contact angles were measured immediately after treatments and after samples were immersed in water for 48 h. For each group, half the samples were incubated with saliva before the adherence test. The number of adhered C. albicans was evaluated by counting after crystal violet staining. The plasma treatments were effective in modifying the polymethylmethacrylate surface. However, there was a significant alteration in the contact angle measured after immersion in water. No statistically significant difference in the adherence of C. albicans was observed between the experimental and control groups, irrespective of the presence or absence of saliva, and surface roughness.

Time-related surface modification of denture base acrylic resin treated by atmospheric pressure cold plasma

“…Surface characteristics of denture base acrylic resin, such as surface roughness, hydrophilicity, surface topography, and surface charge have all been reported to involved in the adherence of Candida, which is the essential step for development of Candida-associated denture stomatitis [7][8][9][10][11] . There has been a large body of evidence indicating that atmospheric pressure cold plasma technique may affect these surface characteristics on the surface layer without affecting their bulk properties 7,11,12,[20][21][22][23] . The results of the present study revealed that cold plasma treatment of acrylic resin specimens significantly increased the surface hydrophilicity when comparing with the control group thus confirmed the findings of published investigations 7,11,12,21,23) .…”

“…Surface characteristics, such as surface roughness, hydrophilicity, and surface charge have all been reported to involve in the adherence of Candida [7][8][9][10][11] . Therefore, the development of methods that could modify these denture base surface properties to prevent the adherence of C. albicans would be a significant advancement in the prevention of Candida-associated denture stomatitis 8,9,12) . Atmospheric pressure cold plasma is a complex mixture composed of ions, energetic free radicals, electrons, atoms, and molecules generated by gas discharge.…”

“…It has been used in various applications, such as tooth whitening 13,14) , sterilization [15][16][17] , blood coagulation 18) , and inducing tumor cells apoptosis 19) . This technique has also been considered a potential method for surface modification of PMMA without inducing bulk alteration 7,11,12,[20][21][22][23] . Some authors have demonstrated that the plasma treatment can improve the hydrophilicity 7,11,12,20,21,23) and modify the chemical composition of the PMMA 11,[20][21][22][23] .…”

“…This technique has also been considered a potential method for surface modification of PMMA without inducing bulk alteration 7,11,12,[20][21][22][23] . Some authors have demonstrated that the plasma treatment can improve the hydrophilicity 7,11,12,20,21,23) and modify the chemical composition of the PMMA 11,[20][21][22][23] . However, information on the adherence of C. albicans to atmospheric pressure cold plasma modified denture base acrylic resin is scarce and there is no agreement until now 7,11,12) .…”

“…Some authors have demonstrated that the plasma treatment can improve the hydrophilicity 7,11,12,20,21,23) and modify the chemical composition of the PMMA 11,[20][21][22][23] . However, information on the adherence of C. albicans to atmospheric pressure cold plasma modified denture base acrylic resin is scarce and there is no agreement until now 7,11,12) . Moreover, the relationship between surface modification of denture base acrylic resins and plasma treatment time remains to be investigated.…”