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Polymers Nov 2019Polycaprolactone (PCL) and polylactide (PLA) are the two most common biodegradable polymers with potential use in oral applications. Both polymers undergo mainly slow...
Polycaprolactone (PCL) and polylactide (PLA) are the two most common biodegradable polymers with potential use in oral applications. Both polymers undergo mainly slow hydrolytic degradation in the human body. However, specific conditions of the oral cavity, like elevated temperature, low pH, and presence of saliva affect the rate of hydrolysis. The study examined the properties of solid samples of PCL and PLA subjected to degradation in phosphate buffered saline (PBS) and artificial saliva (AS) at temperatures of 37 or 42 °C, and pH values 2 or 7.4. A number of tests were performed, including measurement of the degree of swelling, weight loss, molecular weight, differential scanning calorimetry, and thermogravimetry of polymers, as well as hardness and tensile strength. Additionally, topography and stiffness of surfaces using atomic force microscopy are presented. It has been noticed that in the artificial saliva, the processes of polymer degradation occur slightly more slowly, and the effects of temperature and pH are less pronounced. We believe that a layer of porcine gastric mucin from artificial saliva that adsorbed on the surface of polymers may have a key role in the observed differences; this layer resembles protective mucin coating tissues in the oral cavity.
PubMed: 31739431
DOI: 10.3390/polym11111880 -
Caries Research 2016The aim of this study was to evaluate the erosion-preventive effect of different artificial saliva formulations and human saliva in vitro compared to human saliva in...
The aim of this study was to evaluate the erosion-preventive effect of different artificial saliva formulations and human saliva in vitro compared to human saliva in situ. In the in vitro experiment, bovine enamel and dentin specimens were stored in artificial saliva (4 different formulations, each n = 20), deionized water (n = 20) or human saliva (n = 6 enamel and dentin specimens/volunteer) for 120 min. In the in situ experiment, each of the 6 enamel and dentin specimens was worn intraorally by 10 volunteers for 120 min. The specimens were then eroded (HCl, pH 2.6, 60 s). Half of the specimens were subjected to microhardness analysis (enamel) and the determination of calcium release into the acid (enamel and dentin), while the other half were again placed in the respective medium or worn intraorally, respectively, for 120 min before a second erosion was performed. Knoop microhardness of enamel and the calcium release of enamel and dentin into the acid were again determined. Statistical analysis was conducted by two-way repeated-measures ANOVA or two-way ANOVA (α = 0.05). Enamel microhardness was not significantly different between all test groups after the first and the second erosive challenge, respectively. Enamel calcium loss was significantly lower in situ compared to the in vitro experiment, where there was no significant difference between all test groups. Dentin calcium loss was significantly lower than deionized water only after the first and than all except one artificial saliva after the second erosion. Under the conditions of this experiment, the use of artificial saliva formulations and human saliva in vitro does not reflect the intraoral situation in dental erosion experiments adequately.
Topics: Animals; Cattle; Dental Enamel; Dentin; Saliva; Saliva, Artificial; Tooth Erosion
PubMed: 26870948
DOI: 10.1159/000443188 -
Journal of Pharmacy & Bioallied Sciences Feb 2019To provide an update on artificial saliva used to maintain the health of the oral cavity of patients with severe hyposalivation. (Review)
Review
AIM
To provide an update on artificial saliva used to maintain the health of the oral cavity of patients with severe hyposalivation.
MATERIALS AND METHODS
A literature search was conducted in April 2018 in three electronic databases (The Cochrane Central Register of Controlled Trials [CENTRAL], PubMed, and Embase) by combining key words and terms related to the population and intervention of the topic.
RESULTS
The databases search resulted in 455 titles and abstracts. Of these, 21 were judged to meet inclusion criteria and full texts were read. Finally, 10 clinical trials were included for qualitative synthesis.
CONCLUSION
Published evidence suggests that all the artificial saliva products tested in included studies reduced symptoms of xerostomia. These products should specifically be selected according to the patients' concerns and needs. However, the included studies presented a wide range of products and suffered from high risk of bias. Therefore, long-term randomized controlled trials on effects of various products are required.
PubMed: 30923424
DOI: 10.4103/jpbs.JPBS_220_18 -
Materials (Basel, Switzerland) Aug 2020Exposure of denture base acrylic resins to the oral environment and storage media for extended periods of time results in sorption of saliva or water, leading to a...
Exposure of denture base acrylic resins to the oral environment and storage media for extended periods of time results in sorption of saliva or water, leading to a reduction in physical properties and thus clinical service life. The purpose of this in vitro study was to assess the sorption and solubility of high-impact heat-polymerised denture base acrylic resin (HI PMMA) impregnated with zirconia nanoparticles after being stored for 180 days in distilled water (DW) and artificial saliva (AS). The specimens were divided into six groups for each storage medium, according to the concentration of zirconia nanoparticles (0, 1.5, 3.0, 5.0, 7.0, and 10.0 wt.%). Data were statistically analysed for sorption and solubility using one-way and two-way ANOVA statistical tests. Sorption in DW and AS for all groups containing zirconia showed sorption values lower than the control group at 90 days, though not significantly different ( > 0.05) compared to the control group. For both the DW and AS groups, the lowest solubility value was measured in the group containing 3 wt.% zirconia, however, there was no significant difference compared to the control group except when observing 10 wt.% zirconia in AS, which showed a significantly higher solubility ( < 0.05). High-impact PMMA, impregnated with low concentrations of ZrO, showed the lowest sorption and solubility in both media, but was not significantly different compared to pure HI PMMA.
PubMed: 32847026
DOI: 10.3390/ma13173732 -
ACS Central Science Jul 2023
PubMed: 37521799
DOI: 10.1021/acscentsci.3c00803 -
Materials (Basel, Switzerland) Feb 2022There is limited information on the effect of melatonin on the cytotoxicity of dental materials. The study evaluated the cytotoxic effects of heat- and auto-polymerized...
There is limited information on the effect of melatonin on the cytotoxicity of dental materials. The study evaluated the cytotoxic effects of heat- and auto-polymerized acrylic resin, particulate filler composite resin and a thermoplastic material on L-929 fibroblast cell viability at different incubation periods in artificial saliva without and with melatonin. Disk-shaped specimens were prepared according to each manufacturer's instructions and divided into two groups to be stored either in artificial saliva (AS) and AS with melatonin (ASM). The measurements were performed using an MTT (3-(4,5)-dimethylthiazol-2-yl)-2,5-diphenyl tetrazoliumbromide) assay, in which the L-929 mouse fibroblasts cell culture was used. For the MTT test, extracts were examined at 1, 24, 72 h and 1 and 2 weeks. Data were analyzed using 3-way ANOVA and Tukey's tests. No significant difference was found between groups AS and ASM (F = 0.796; = 0.373). Incubation period significantly affected all materials tested ( < 0.001). Storing resin-based materials in artificial saliva with melatonin solution for 24 h may reduce cytotoxic effects on the fibroblast cells for which the highest effect was observed. Soaking resin prosthesis or orthodontic appliances in artificial saliva with melatonin at least 24 h before intraoral use or rinsing medium containing melatonin may be recommended for decreasing the cytotoxicity of dental resin materials.
PubMed: 35208000
DOI: 10.3390/ma15041457 -
Journal of Texture Studies Jun 2021Xersotomia is associated with food avoidance and low nutritional assessment. This review seeks to document whether products called "saliva substitutes" or "artificial...
Xersotomia is associated with food avoidance and low nutritional assessment. This review seeks to document whether products called "saliva substitutes" or "artificial saliva" can really replace saliva in food oral processing. Pubmed and Science Direct were searched for articles using the keywords "saliva substitutes" and "artificial saliva." An advanced search was applied using the terms "xerostomia" and/or "food oral processing" and/or "eating" and/or "mastication" and/or "chewing" and/or "swallowing." The analysis methods and the inclusion criteria were documented in a protocol published in the International prospective register of systematic reviews (PROSPERO with the registration number CRD42019124585). The search included 43 articles, published between 1979 and 2017. Among the included studies, 17 were observational studies, 5 were pilot studies, 21 were crossover studies, and 14 of these studies were blinded. The Strobe score for the included articles varied from 7.5 to 20. The possible effects of the use of saliva substitutes on the ingestion function were poorly investigated. No evidence was based on physiological studies. It is unknown whether using a saliva substitute has an effect on the composition and rheological properties of the food bolus, on the lubrication of the oral and laryngeal mucosa or on both phenomena. Moreover, saliva substitutes were not formulated to improve food oral processing and most of them are flavored. New saliva substitutes and artificial saliva should be designed and formulated to improve food oral processing.
Topics: Humans; Lubrication; Saliva; Saliva, Artificial; Xerostomia
PubMed: 33587294
DOI: 10.1111/jtxs.12591 -
Viruses May 2022Surface to hand transfer of viruses represents a potential mechanism for human exposure. An experimental process for evaluating the touch transfer of aerosol-deposited...
Surface to hand transfer of viruses represents a potential mechanism for human exposure. An experimental process for evaluating the touch transfer of aerosol-deposited material is described based on controlling surface, tribological, and soft matter components of the transfer process. A range of high-touch surfaces were evaluated. Under standardized touch parameters (15 N, 1 s), relative humidity (RH) of the atmosphere around the contact transfer event significantly influenced transfer of material to the finger-pad. At RH < 40%, transfer from all surfaces was <10%. Transfer efficiency increased markedly as RH increased, reaching a maximum of approximately 50%. The quantity of material transferred at specific RHs above 40% was also dependent on roughness of the surface material and the properties of the aerosol-deposited material. Smooth surfaces, such as melamine and stainless steel, generated higher transfer efficiencies compared to those with textured roughness, such as ABS pinseal and KYDEX® plastics. Pooled human saliva was transferred at a lower rate compared to artificial saliva, indicating the role of rheological properties. The artificial saliva data were modeled by non-linear regression and the impact of environmental humidity and temperature were evaluated within a Quantitative Microbial Risk Assessment model using SARS-CoV-2 as an example. This illustrated that the trade-off between transfer efficiency and virus survival may lead to the highest risks of fomite transmissions in indoor environments with higher humidity.
Topics: Aerosols; COVID-19; Humans; Humidity; SARS-CoV-2; Saliva; Saliva, Artificial; Viruses
PubMed: 35632793
DOI: 10.3390/v14051048 -
Clinical Oral Investigations Feb 2022The aim of the study was to evaluate the influence of filler content, degradation media and time on the mechanical properties of different dental composites after in...
OBJECTIVE
The aim of the study was to evaluate the influence of filler content, degradation media and time on the mechanical properties of different dental composites after in vitro aging.
MATERIALS AND METHODS
Specimens (1 mm) of three commercially available composites (GrandioSO®, Arabesk Top®, Arabesk Flow®) with respect to their filler content were stored in artificial aging media: artificial saliva, ethanol (60%), lactic acid (pH 5) and citric acid (pH 5). Parameters (Vickers microhardness, compressive strength, elastic modulus, water sorption and solubility) were determined in their initial state (control group, n = 3 for microhardness, n = 5 for the other parameters) and after 14, 30, 90 and 180 days (n = 3 for microhardness, n = 5 for the other parameters for each composite group, time point and media). Specimens were also characterized with dynamic-mechanical-thermal analysis (compression tests, F = ± 7 N; f = 0.5 Hz, 1 Hz and 3.3 Hz; t = 0-170 °C).
RESULTS
Incorporation of fillers with more than 80 w% leads to significantly better mechanical properties under static and dynamic compression tests and a better water sorption behavior, even after chemical degradation. The influence of degradation media and time is of subordinate importance for chemical degradation.
CONCLUSION
Although the investigated composites have a similar matrix, they showed different degradation behavior. Since dentine and enamel occur only in small layer thickness, a test specimen geometry with very small dimensions is recommended for direct comparison. Moreover, the use of compression tests to determine the mechanical parameters for the development of structure-compatible and functionally adapted composites makes sense as an additional standard. Clinical relevance Preferential use of highly filled composites for occlusal fillings is recommended.
Topics: Composite Resins; Dental Materials; Elastic Modulus; Hardness; Materials Testing; Saliva, Artificial; Stress, Mechanical; Surface Properties
PubMed: 34453210
DOI: 10.1007/s00784-021-04122-0 -
Materials (Basel, Switzerland) Jun 2022The aim of this study was to tackle the topic of appropriate recommendations for artificial-saliva and mouthwash usage. The contact angle, pH, and conductivity of two...
The aim of this study was to tackle the topic of appropriate recommendations for artificial-saliva and mouthwash usage. The contact angle, pH, and conductivity of two artificial saliva solutions, four mouthwashes, and their mixtures on enamel, glass-ionomer, and composite dental materials were measured. The measurements were conducted with a MATLAB algorithm to minimize human error. The obtained values for the contact angle were in the range from 7.98° to 52.6°, and they showed completely nonlinear and nonuniform behavior for all investigated liquids and on all investigated substrates. Results reveal statistically significant differences among all tested liquids on all investigated substrates (p < 0.05). pH values ranged from 1.54 to 7.01. A wide range of conductivity values were observed, from 1205µS/cm in the saliva-stimulating solution to 6679 mS/cm in the artificial saliva. Spearman’s test showed a moderate positive correlation between the pH and conductivity of the tested fluids (R = 0.7108). A comparison of the data obtained using Image J software and the MATLAB algorithm showed consistency, not exceeding 5% error. When an experiment uses human material and bioactive materials THAT are used in biomedicine as substrates, an additional definition of protocols is highly recommended for future research on this topic.
PubMed: 35806658
DOI: 10.3390/ma15134533