Effect of Candida albicans Suspension on the Mechanical Properties of Denture Base Acrylic Resin

Abstract

Yeast-like fungi such as Candida albicans (C. albicans) are the primary pathogenic microorganism in the oral cavity of denture wearers. The research available so far, conducted according to a protocol based on the exposure of specimens to a C. albicans suspension and their cutting with water cooling, shows that hard polymethyl methacrylate (PMMA) prosthetic materials are not only surface colonized, but also penetrated by microorganisms in a short time. This justifies the hypothesis that exposure to a suspension of the C. albicans strain causes the changes in mechanical properties due to surface colonization and/or penetration of the samples. In the current study, the chosen mechanical properties (flexural strength, flexural modulus, tensile strength, impact strength, ball indentation hardness, and surface Vickers hardness at 300 g load) of the PMMA denture base material Vertex RS (Vertex-Dental, The Netherlands) exposed for 30, 60, and 90 days to a suspension of C. albicans were investigated. The potential penetration of yeast was examined on the fractured surfaces (interior of specimens) to eliminate the risk of the contamination of samples during cutting. There was no influence on the flexural strength, flexural modulus, tensile strength, impact strength, or ball indentation hardness, but a significant decrease in surface hardness was registered. Microscopic observations did not confirm the penetration of C. albicans. On the surface, blastospores and pseudohyphae were observed in crystallized structures and in traces after grinding, which indicates that in clinical conditions, it is not penetration but the deterioration of surface quality, which may lead to the formation of microareas that are difficult to disinfect, causing rapid recolonization.

Patient satisfaction and oral health‐related quality of life for four implant‐assisted mandibular overdentures fabricated with CAD/CAM milled poly methyl methacrylate, CAD/CAM‐milled poly ether ether ketone, or conventional poly methyl methacrylate: A crossover clinical trial

“…On the contrary, the psychological and social disabilities scores (OHIP-EDENT- 13,14,15,16,17) not differ statistically between the study groups. Also, the first score of the handicap score (OHIP-EDENT-18) not differ between conventional and CAD/CAM constructed dentures, while the second score of handicap score (OHIP-EDENT-19), felt that life in general was less satisfying, was better statistically in both CAD/CAM constructed dentures, versus the conventional constructed denture.…”

“…The inability to easily create an optimal duplicate denture is another disadvantage. 14 In addition, polymerisation shrinkage, low impact strength and fatigue resistance, micro porosities, microbial adherence and colonisation 15 and residual monomer that affect the mechanical and biological properties of the material 14,16 are considered as main disadvantages of the commonly used PMMA material.…”

Changes in the Surface Texture of Thermoplastic (Monomer-Free) Dental Materials Due to Some Minor Alterations in the Laboratory Protocol—Preliminary Study

“…Although polyamide materials are characterized by a high level of mechanical properties, a modification [ 16 ] of the technological parameters [ 17 , 18 ] of their injection could be attempted to achieve an optimal texture. This modified surface needs to be resistant to impacts that would increase roughness [ 19 , 20 ] or deteriorate the quality of the material [ 20 , 21 ].…”

“…With minimal alteration to both the temperature (5 °C) and the pressure (0.5 Bar) in ThermoSens, the surface roughness of the material is significantly changed [ 31 ] in terms of roughness reduction [ 32 ]. This positive change in the surface texture is likely to result in: an improvement [ 33 ] in the mechanical strength and physical properties, a lack of microflora [ 34 ] or minimal changes [ 21 ], as well as a reduction in the conditions for colony formation [ 35 , 36 ]. To ascertain the presence or absence of such changes, further studies are necessary, including not only in vitro, but in vivo tests as well.…”

Composite and Polymeric Materials for Dentistry: Enhancing Antimicrobial and Mechanical Properties

“…Colonization and penetration of prosthetic materials by Candida albicans is a frequently considered problem. Chladek et al [ 14 ] conducted a 90-day experiment with a different methodology to those previously used to verify whether PMMA is penetrated by Candida albicans and to investigate its mechanical properties after exposure to yeast-like fungi. Microscopic observations have not confirmed the penetration of fungi into the material.…”