Oral Hygiene Habits of Complete Denture Wearers in Central Transylvania, Romania.

PURPOSE: To identify the oral hygiene habits and denture hygiene status (e.g. sociodemographic characteristics, general health status) of complete denture wearers in Central Transylvania, Romania. MATERIALS AND METHODS: This descriptive cross-sectional study was based on an original self-administered questionnaire. It included 162 patients who experienced complete tooth loss in one or both jaws and wore polymethylmethacrylate acrylic (PMMA) complete dentures. The exclusion criteria were partial dentures, dentures fabricated from materials other than PMMA, and the patient being unable to provide all the required information. The questionnaire solicited information regarding sociodemographic status, general health and oral hygiene-related habits. The dentures were clinically evaluated in order to assess denture hygiene. RESULTS: Most respondents were completely edentulous (38.0% wore maxillary dentures, 10.6% mandibular dentures, while 51.6% had both), with an average age above 60, all wearing dentures. The clinical evaluation of the dentures revealed that 12.3% exhibited optimal hygiene status, 40.1% good, 32.7% unsatisfactory and 14.8% bad, with more women than men having well-cleaned dentures. Cleaning frequency was found to be 2-3 times per day for 54.3% of the patients, with 93.2% of the subjects using a toothbrush and 76.5% using toothpaste. Most of the participants felt at ease with the cleaning procedures. Only 30.9% of the respondents reported denture removal overnight. The results showed that the hygiene of the patients' dentures was not correlated with their answers regarding oral hygiene habits. CONCLUSIONS: Competent oral health and denture hygiene promotion should be established, especially regarding nocturnal denture removal, denture hygiene methods, instruments and cleaning frequency.

Flexural strength, biocompatibility, and antimicrobial activity of a polymethyl methacrylate denture resin enhanced with graphene and silver nanoparticles.

OBJECTIVE: The study evaluates the effect of adding graphene-Ag nanoparticles (G-AgNp) to a PMMA auto-polymerizing resin, with focus on antibacterial activity, cytotoxicity, monomer release, and mechanical properties. MATERIALS AND METHODS: Auto-polymerizing acrylic resin (M) was loaded with 1 wt% G-AgNp (P1) and 2 wt% G-AgNp (P2). Methyl methacrylate monomer release (MMA) was measured after immersion of the samples in chloroform and cell medium respectively. Cell viability was assessed on dysplastic oral keratinocytes (DOK) and dental pulp stem cells. Oxidative stress and inflammatory response following exposure of dysplastic oral keratinocytes to the experimental resins was evaluated. Antibacterial activity against Staphylococcus aureus, Streptococcus mutans and Escherichia coli and also flexural strength of the resins were assessed. RESULTS: Residual monomer: For samples immersed in chloroform, MMA concentration reached high levels, 10.27 µg/g for sample P1; MMA increased at higher G-AgNp loading; 0.63 µg/g MMA was found in medium for P1, and less for sample P2. Cell viability: Both cell lines displayed a viability decrease, but remained above 75%, compared to controls, when exposed to undiluted samples. Inflammation: proinflammatory molecule TNF-α decreased when DOK cultures were exposed to G-AgNp samples. MDA levels indicated increased oxidative stress damage in cells treated with PMMA, confirmed by the antioxidant mechanism activation, while samples containing G-AgNp induced an antioxidant effect. All tested samples showed antibacterial properties against Gram-positive bacteria. Samples containing G-AgNp also exhibited bactericide action on E. coli. Mechanical properties: both samples containing G-AgNp improved flexural strength compared to the sample resin, measured through elastic strength parameters. CONCLUSIONS: PMMA resin loaded with G-AgNp presents promising antibacterial activity associated with minimal toxicity to human cells, in vitro, as well as improved flexural properties. CLINICAL RELEVANCE: These encouraging results obtained in vitro support further in vivo investigation, to thoroughly check whether the PMMA loaded with graphene-silver nanoparticles constitute an improvement over current denture materials.

The Influence of Graphene in Improvement of Physico-Mechanical Properties in PMMA Denture Base Resins.

The clinical performances of dental materials depend on their mechanical profiles, determining their long-term deformation and wear resistance. This paper describes a study on the mechanical properties, water absorption and morphological properties of a polymethyl methacrylate (PMMA) resin enriched with graphene-silver nanoparticles (Gr-Ag). Two different concentrations-1 and 2 wt.%-of Gr-Ag were loaded into the PMMA material. For the mechanical characterization, the compression behavior, flexural strength and tensile strength were evaluated. Optical microscopy in polarized light and scanning electron microscopy were used for filler analysis. The filler addition led to an improvement in all mechanical properties, with slight changes being derived from the filler content variation. Gr-Ag use led to an increase in the applied maximum loads. Moreover, 1 wt.% Gr-Ag determined an increase of 174% in the modulus of rupture, which indicates high flexibility.