Mariusz Cierech

Significance of polymethylmethacrylate (PMMA) modification by zinc oxide nanoparticles for fungal biofilm formation

The objective of this study was to obtain a material composite with antifungal properties for dentures to be used as an alternative protocol in denture stomatitis treatment and prevention. Denture stomatitis is still a clinical problem in patients particularly vulnerable to this disease. Composites of PMMA and doped ZnO-NPs (weight concentrations, 2.5%, 5%, 7.5%) and PMMA with sprayed solvothermal and hydrothermal ZnO-NPs were tested. The following investigations of newly formed biomaterials were undertaken: influence on Candida albicans solution, biofilm staining, XTT analysis and a quantitative analysis of adhered C. albicans. These studies evidenced the antifungal activity of both nanocomposites PMMA-ZnO-NPs and the efficacy of sputtering of zinc oxide nanoparticles on the PMMA. The study of the biofilm deposition on the surface showed that antifungal properties increase with increasing concentration of ZnO-NPs. The XTT assay in conjunction with testing the turbidity of solutions may indicate the mechanism by which ZnO-NPs exert their effect on the increased induction of antioxidative stress in microorganism cells. The denture base made of the aforesaid materials may play a preventive role in patients susceptible to fungal infections. Based on the results obtained a modified treatment of stomatitis Type II (Newtons classification) complicated by fungal infection was proposed.

Preparation and characterization of ZnO-PMMA resin nanocomposites for denture bases

PURPOSE The aim of the paper was to investigate the antifungal activity of zinc oxide nanoparticles (ZnONPs) against Candida albicans. Some attempts have been made to find out the best way to introduce ZnONPs into polymethyl methacrylate (PMMA) resin material and to determine some parameters of a newly formed composite. MATERIAL AND METHODS Zinc oxide nanoparticles were manufactured and their basic physical parameters were determined (average particle size, density, specific surface area). Minimal inhibitory concentration (MIC) of ZnONPs was determined for the Candida albicans standard strain. The average size of ZnO conglomerates in the monomer solution of PMMA resin was measured using a dynamic light scattering instrument. PMMA resin samples with incorporated ZnONPs were produced. The morphology of nanopowder and the newly formed composite was examined under a scanning electron microscope (SEM). In addition, the roughness parameter of PMMA resin material was investigated before and after ZnONPs modification. RESULTS Nanopowder with the average particle size of 30 nm, density of 5.24 g/cm3 and surface area of 39 m2/g was obtained. MIC was determined at the level of 0.75 mg/mL. The average size of ZnO conglomerates in the monomer solution of acrylic resin dropped by 11 times after ultrasound activation. SEM examination of a newly formed composite showed a successful introduction of ZnONPs confirmed by the energy dispersive X-ray spectroscopy (EDS) analysis. There were no statistically significant differences in the biomaterial roughness before and after the modification of ZnONPs. CONCLUSION Zinc oxide nanoparticles were successfully incorporated into acrylic resin used for the production of denture bases. The presence of nanoparticles with sizes below 100 nm was confirmed. Nevertheless a newly created composite needs to be further investigated to improve its homogeneity, and to check its microbiological properties, strength and biocompatibility prior to its possible clinical use.

Mechanical and Physicochemical Properties of Newly Formed ZnO-PMMA Nanocomposites for Denture Bases

Aim: The aim of this study was to investigate the selected properties of zinc oxide- polymethyl methacrylate (ZnO-PMMA) nanocomposites that can influence the microorganism deposition on their surface. Materials and Methods: Non-commercial ZnO-NPs were prepared, characterized and used for the preparation of PMMA nanocomposite. Roughness, absorbability, contact angle and hardness of this new nanomaterial were evaluated. PMMA without ZnO-NPs served as control. Outcomes: Compared to unenriched PMMA, incorporation of ZnO-NPs to 7.5% for PMMA nanocomposite increases the hardness (by 5.92%) and the hydrophilicity. After modification of the material with zinc oxide nanoparticles the roughness parameter did not change. All tested materials showed absorption within the range of 1.82 to 2.03%, which meets the requirements of International Organization for Standardization (ISO) standards for denture base polymers. Conclusions: The results showed no significant deterioration in the properties of acrylic resin that could disqualify the nanocomposite for clinical use. Increased hydrophilicity and hardness with absorbability within the normal range can explain the reduced microorganism growth on the denture base, as has been proven in a previous study.

Methods of laboratory diagnostics of oral candidosis in removable denture wearers

Streszczenie Celem pracy jest przedstawienie różnych metod diagnostyki kandydozy jamy ustnej na podstawie dostępnego piśmiennictwa. W pracy uwzględniono następujące metody diagnostyczne kandydozy: klasyczne (wymaz z błony śluzowej jamy ustnej, preparat bezpośredni oraz hodowla), szybkie (test Dentocult CA i szybka identyfikacja za pomocą testu PCR) oraz replika protezy. Dobór powyższych metod miał na celu przedstawienie standardowego postępowania w przypadku podejrzenia kandydozy oraz mniej znanych testów mogących być alternatywą dla praktykujących lekarzy stomatologów. Najbardziej czasochłonną metodą okazało się pobranie wymazu bezpośredniego z błony śluzowej jamy ustnej pacjenta. Przy pomocy testu PCR identyfikuje się materiał genetyczny 10 gatunków grzybów z rodzaju Candida. Jest on w stanie wykluczyć infekcję grzybiczą już w 5 godzin od pobrania materiału diagnostycznego. Test Dentocult CA jest szybką i prostą metodą wykrywania kandydozy, jednakże ma dla lekarza stomatologa znaczenie jedynie orientacyjne. Metoda repliki pozwala nie tylko na jakościowe oraz ilościowe oznaczenie grzybów z rodzaju Candida, ale także wskazuje na rozmieszczenie ich na powierzchni błony śluzowej. Pomimo istnienia wielu nowoczesnych metod identyfikacji grzybicy jamy ustnej, najwłaściwszym postępowaniem pozostaje pobranie wymazu bezpośredniego z błony śluzowej oraz sporządzenie antymikogramu celem ustalenia oporności na leki przeciwgrzybicze. Metody diagnostyki laboratoryjnej grzybicy w obrębie błony śluzowej jamy ustnej u pacjentów użytkujących ruchome uzupełnienia protetyczne