scholarly journals Experimental Study on the Mechanical Behavior of Orthodontic Arches Exposed to the Environment in the Oral Cavity

Children ◽  
2022 ◽  
Vol 9 (1) ◽  
pp. 107
Author(s):  
Zalana Ștefan Alexandru ◽  
Maria Dămășaru ◽  
Edgar Moraru ◽  
Ciprian Ion Rizescu ◽  
Simina Neagoe (Chelărescu) ◽  
...  
Keyword(s):  
Experimental Study ◽  
Oral Cavity ◽  
Artificial Saliva ◽  
Three Dimensions ◽  
Deformation Force ◽  
Force Time ◽  
Different Diameters ◽  
Physical And Chemical ◽  
Final Degree

Background. The arches used in orthodontic therapy are subject to increasing physical and chemical stresses. Purpose of the study: This in vitro experimental study aims to highlight and compare the main mechanical properties of orthodontic arches. Materials and Methods: We used 40 springs, 2 materials, 20 of Ni-Cr and 20 of Co-Cr, of different diameters, 0.7 mm 0.8 mm and 1.2 mm, subjected to the environment of artificial saliva and artificial saliva with cola for one month and two months, respectively. Five springs of each material were tested at different times: T0, before application in the oral cavity, then at time T1, T2, T3, T4. Three lengths of the lever arm were considered for bending forces acting on the springs (dental wires). These lengths were 15, 10 and 5 mm. The wires were tested under the action of bending forces on a Hans Schmidt HV 500N stand, obtaining the characteristics of the wires: deformation-force-time. Results: Graphical determinations show that the degree of deformation of the wires is influenced by the applied force, diameter and obviously by the immersion time, respectively by the type of solution in which the springs were immersed. Conclusions: The final degree of bending is higher for Co-Cr arcs than for Ni-Cr at all three dimensions.

scholarly journals Physicochemical Characteristics of Arginine Enriched NaF Varnish: An In Vitro Study

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2998
Author(s):  
Mohammed Nadeem Bijle ◽  
Manikandan Ekambaram ◽  
Edward Lo ◽  
Cynthia Yiu
Keyword(s):  
Molecular Dynamics ◽  
Physical Properties ◽  
Artificial Saliva ◽  
Chemical Properties ◽  
In Vitro Study ◽  
Physicochemical Characteristics ◽  
Vitro Study ◽  
Physical And Chemical ◽  
Stable Matrix

The in vitro study objectives were to investigate the effect of arginine (Arg) incorporation in a 5% sodium fluoride (NaF) varnish on its physical and chemical properties including F/Arg release. Six experimental formulations were prepared with L-arginine (L-Arg) and L-arginine monohydrochloride at 2%, 4%, and 8% w/v in a 5% NaF varnish, which served as a control. The varnishes were subjected to assessments for adhesion, viscosity, and NaF extraction. Molecular dynamics were simulated to identify post-dynamics total energy for NaF=Arg/Arg>NaF/Arg<NaF concentrations. The Arg/F varnish release profiles were determined in polyacrylic lactate buffer (pH-4.5; 7 days) and artificial saliva (pH-7; 1 h, 24 h, and 12 weeks). Incorporation of L-Arg in NaF varnish significantly influences physical properties ameliorating retention (p < 0.001). L-Arg in NaF varnish institutes the Arg-F complex. Molecular dynamics suggests that NaF>Arg concentration denotes the stabilized environment compared to NaF<Arg (p < 0.001). The 2% Arg-NaF exhibits periodic perennial Arg/F release and shows significantly higher integrated mean F release than NaF (p < 0.001). Incorporating 2% L-arginine in 5% NaF varnish improves its physical properties and renders a stable matrix with enduring higher F/Arg release than control.

Multifunctional artificial saliva preparation – challenges and needs

2021 ◽  
Vol 8 ◽  
pp. 37-46
Author(s):  
Katarzyna Niemirowicz-Laskowska ◽  
Joanna Mystkowska ◽  
Dawid Łysik ◽  
Sylwia Chmielewska ◽  
Łukasz Suprewicz ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Artificial Saliva ◽  
Salivary Secretion ◽  
Biological Properties ◽  
Pharmacological Therapy ◽  
Oral Microbiome ◽  
Dry Mouth ◽  
Rheological Parameters ◽  
Saliva Substitutes

Saliva plays a crucial role in maintaining homeostasis not only within the oral cavity but also in further sections of the gastrointestinal tract. Pleiotropic properties of saliva include participation in the digestion of carbohydrates, cleansing and moisturizing the oral cavity, and maintaining the composition of the oral microbiome. The result of impaired function of the salivary gland is reduced salivation – hyposalivation, leading to dry mouth – xerostomia. It is established that numerous physiological factors (age, sex, weight change) and pathological factors (polytherapy, head and neck cancer, coexisting diseases such as diabetes, depression, cardiovascular diseases) lead to the reduction in saliva secretion, and in effect, causing a dry mouth. Treatment of salivary secretion disorders involves pharmacological therapy (including hormone therapy) or replacement therapy which based on the use of saliva substitutes. In the case of disturbances in the secretion of natural saliva, the application of the artificial saliva preparations should support the chewing processes, moisturize the oral cavity, and fulfill the biological functions of saliva. However, to date, on the pharmaceutical market, there are no saliva substitutes that meet the biological criteria and maintaining favorable physicochemical properties and rheological parameters. Taking into account the problems of the patients which are burden by impaired salivary secretion, the aim of our research was to attempt to develop an artificial saliva preparation that reflecting as much as possible the properties of natural saliva, both in terms of mechanical and biological properties. As part of the research, the chemical composition was developed and a detailed study of the physicochemical and rheological parameters of artificial saliva preparations containing mucins as well as their microbiological and biocompatibility assessment, at in vitro level were carried out.

Force decay of intermaxillary orthodontic elastics: in vitro study

2019 ◽  
Vol 88 (2) ◽  
pp. 91-95
Author(s):  
Hubert Kardach ◽  
Aneta Olszewska ◽  
Ewa Firlej ◽  
Agnieszka Bogdanowicz ◽  
Ewelina Golusińska-Kardach ◽  
...  
Keyword(s):  
Artificial Saliva ◽  
Low Cost ◽  
In Vitro Study ◽  
Ease Of Use ◽  
Force Decay ◽  
Artificial Environment ◽  
Negative Effect ◽  
Progressive Force ◽  
Different Diameters

Introduction. Orthodontic elastics are widely used in orthodontic treatment. It’s been proved that they have advantages such as low cost, ease of use, but also disadvantages, mainly force decay in time and increased entrapment of biofilm. Amount of the force is of extreme significance. This force can be altered by physical or chemical factors. Material and Methods. Latex elastics in 3 different diameters were selected for this study. Each elastic was stretched and placed on hooks that are at specified distances that equal 3 times the diameter of each elastic. The forces produced by stretching was measured using tension gauge and the measurement were taken at specific time intervals of 0h, 3h, 12h, 24h. The same process was repeated for elastics in dry and artificial environment. Results. Elastics in the dry environment showed progressive force decay cause by stretching over time. Just after 3 hours force decay between 6,07% and 8,75% was observed. The biggest loss of force between 13,61 — 16,13 % was measured after 24 hours. Compared to the dry environment, an even more significant force decay was observed in the artificial saliva. After first 3 hours force loss was between 4,99% — 9,22%. The biggest force decay was observed after 24 hours and it was 5 % higher compared to dry environment. Conclusions. 1) The artificial saliva environment and time of exposure to it, have a negative effect on the properties of elastomeric. 2) To maintain the effective orthodontic strength of elastics, they should be replaced every 12 hours.

An experimental study of nonlinear rate-dependent behaviour of skeletal muscle to obtain passive mechanical properties

2020 ◽  
Vol 234 (6) ◽  
pp. 590-602
Author(s):  
Sanaz S Hashemi ◽  
Masoud Asgari ◽  
Akbar Rasoulian
Keyword(s):  
Mechanical Properties ◽  
Skeletal Muscle ◽  
Experimental Study ◽  
Biological Tissues ◽  
Experimental Results ◽  
Three Dimensions ◽  
Nonlinear Behaviour ◽  
Muscle Properties ◽  
Dependent Behaviour

Accurate modelling of biological tissues has been a significant need for analysis of the human body. In this article, a comprehensive in vitro experimental study has been done on the fresh bovine skeletal muscle before the onset of rigour mortis in order to provide an experimental description of passive skeletal muscle properties in three dimensions. Different situations including various deformation modes, different loading rates and loading directions are tested to consider all features of skeletal muscle behaviour. Based on the nonlinear continuum mechanics, a three-dimensional visco-hyperelastic model is introduced which considers all aspects of skeletal muscle’s features such as nonlinear hyperelastic, time-dependent behaviour, anisotropy and quasi-incompressibility. Visco-hyperelastic material constants are obtained for passive behaviour of the muscle based on genetic algorithm optimization method via comparing the theoretical and experimental results. Experiments show that the rate of loading affects the configuration of experimental curves considerably. It could be also concluded that compression–tension asymmetry, as well as anisotropic behaviour, of the muscle is due to fibres orientation. Obtained experimental results help to achieve a better understanding of mechanical properties and nonlinear behaviour of the skeletal muscles.

scholarly journals An In Vitro Study of Different Types of Greek Honey as Potential Natural Antimicrobials against Dental Caries and Other Oral Pathogenic Microorganisms. Case Study Simulation of Oral Cavity Conditions

2021 ◽  
Vol 11 (14) ◽  
pp. 6318
Author(s):  
Chrysoula (Chrysa) Voidarou ◽  
Maria Antoniadou ◽  
Georgios Rozos ◽  
Athanasios Alexopoulos ◽  
Elpida Giorgi ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Antibacterial Effect ◽  
Artificial Saliva ◽  
In Vitro Study ◽  
Distilled Water ◽  
Manuka Honey ◽  
Other Substances ◽  
Reference Strains

To study the antibacterial effect of different Greek honeys, samples of citrus honey, Saturja spp. Honey, and oregano and sage honey were collected directly from producers. Manuka honey and artificial honey were used as controls. The honeys were diluted in various concentrations to determine the minimum inhibitory concentration (MIC) and were also placed in agar wells to determine the inhibitory zones of growth. The bacteria tested were two reference strains and five pathogens isolated from patients with various dental ailments. A series of samples were diluted with artificial saliva instead of distilled water to simulate the conditions in the oral cavity. The results show that in most cases the Greek honeys, and particularly the citrus honey and the oregano and sage honey, outperformed the antibacterial activity of manuka honey against all tested bacteria. This performance was due to the hydrogen peroxide as well as to other components of the honeys, that is, peptides and other substances such as phenolic compounds and flavonoids. Artificial saliva enhanced the antibacterial effect of the honeys in comparison to distilled water.

scholarly journals Brewed Robusta Coffee Increases Nickel Ion Release from Dental Alloys: An In Vitro Study

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7069
Author(s):  
Dessy Rachmawati ◽  
Devanti Ayu Cahyasari ◽  
Ardin Tito Febiantama ◽  
Lusi Hidayati ◽  
Cornelis Johannes Kleverlaan
Keyword(s):  
Oral Cavity ◽  
Dietary Habits ◽  
Artificial Saliva ◽  
In Vitro Study ◽  
Ion Release ◽  
Nickel Ion ◽  
Robusta Coffee ◽  
Oral Environment ◽  
History Of

Alloys in oral cavity always interact with dynamic oral environment, such as pH, temperature, salivary conditions, and dietary habits. Coffee can further decrease pH in the oral cavity. Thus, coffee may increase the release of metal ions that may lead to various health diseases. This study aimed to quantitively investigate the effect of brewed Robusta coffee on the nickel ion release and their morphological structures; Methods: 20 alloy specimens were divided into 4 groups and placed in solutions for 48 and 168 h: (1) distilled water, (2) artificial saliva, (3) Robusta coffee, and (4) mixture of artificial saliva and Robusta coffee. AAS, XRF, and SEM were used for examinations; Results: The release of Ni2+ was found in all groups and robust release were found in the coffee only and mixture of coffee + artificial saliva solution after 168 h. Likewise, SEM showed that internal oxidation was high after 168 h of immersion; Conclusions: The concentration of nickel increased in saliva of low pH due to brewed coffee. Though the release of these ions is still within the tolerable amount in human body, it should be realized that it usually lasts for months or years. Dentists should be cautious when using instructions for patients with a history of allergies especially for dietary with low acidity.

Study of Electrochemical Behavior of Some Dental Alloys

2018 ◽  
Vol 69 (6) ◽  
pp. 1598-1602
Author(s):  
Alice Arina Ciocan Pendefunda ◽  
Constanta Mocanu ◽  
Doriana Agop Forna ◽  
Cristina Iordache ◽  
Elena Luca ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Electrochemical Behavior ◽  
Base Alloy ◽  
Artificial Saliva ◽  
Surface Condition ◽  
Continuous Process ◽  
Metal Alloys ◽  
Alloy Surface ◽  
Dental Alloys ◽  
Dental Restorations

The purpose of the study is to investigate the electrochemical behavior of two dental alloys: palladium alloy (Palidor) and Ni-Cr alloy (Verasoft) in three types of artificial saliva. Determination of corrosion potential and recording of linear and cyclic polarization curves were performed with PGP201 potentiostat (VoltaLab 21- Radelkis Copenhagen. In order to study the modifications produced on the surface of the electrodes, a complex optical microscope MC 1 research type (IOR, Romania) was used, adapted to a digital camera, which was connected to a computer for the digital acquisition of images . Two metal alloys based on Ag-Pd and Ni-Cr were used for the experiments. The materials used came from different types of dental restorations removed from the oral cavity of the patients after a 5-15 years period. As corrosion environments, three artificial saliva were used: Fusayama, Afnor and Rondelli. The Pd-Ag dental alloy exhibits a very good corrosion resistance and the treatment in the Afnor saliva does not affect the surface of the alloy. Electrochemical behavior in Fusayama-Meyer�s saliva of the alloy surface results in a series of spots representing deposits of insoluble salts resulting from the oxidation process, while in the Rondelli saliva there is a series of small corrosion points on the alloy surface. The behavior of the Verasoft alloy in the Afnor and Rondelli saliva is similar; In both solutions, the potential breakthroughs are very close, but in Fusayama-Meyer�s saliva, the potential for initiation of corrosion points is very low (206 mV), a potential that can be encountered in the oral cavity. All metals and metal alloys, even the noble and semi-precious ones, are susceptible to corrosion, forming compounds with properties different from those of the metal or base alloy, which change their surface condition. Metallic dental restorations are permanently affected by the factors of the oral environment (physical-mechanical, chemical and biological), being subjected to a continuous process of degradation.

scholarly journals In Vitro Effects of Resin Infiltration on Enamel Erosion Inhibition

2015 ◽  
Vol 40 (5) ◽  
pp. 492-502 ◽  
Author(s):  
GC Oliveira ◽  
AP Boteon ◽  
FQ Ionta ◽  
MJ Moretto ◽  
HM Honório ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
Artificial Saliva ◽  
In Vitro Study ◽  
Adhesive System ◽  
Dental Erosion ◽  
Deep Penetration ◽  
Resin Infiltration ◽  
Fluorescence Confocal Microscopy ◽  
In Vitro Effects

SUMMARY Resin-based materials that show promising effects for preventing the progression of erosion have been studied. This in vitro study evaluated the effects of applying resin-based materials, including resin infiltration, on previously eroded enamel subjected to erosive challenges. The influence of enamel surface etching prior to application of the material was also studied. Bovine enamel blocks were immersed in hydrochloric acid (HCl), 0.01 M (pH 2.3), for 30 seconds in order to form a softened erosion lesion. The blocks were then randomly divided into nine groups (n=12) and treated as follows: C = control without treatment; Hel = pit & fissure resin sealant (Helioseal Clear); Adh = two-step self-etching adhesive system (AdheSe); Tet = two-step conventional adhesive system (Tetric N-bond); and Inf = infiltrant (Icon). The Helno, Adhno, Tetno, and Infno groups received the same materials without (or with no) surface conditioning. The depth of the material's penetration into softened erosion lesions was qualitatively analyzed using reflection and fluorescence confocal microscopy. After application of the materials, the blocks were immersed in HCl for two minutes; this step was followed by immersion in artificial saliva for 120 minutes four times a day for five days (erosive cycling). Both the enamel alteration and material thickness were analyzed using profilometry, and the results were submitted to Kruskal-Wallis and Dunn tests (p&gt;0.05). Images from the confocal microscopy showed minimal penetration of Adh/Adhno and deep penetration of Inf/Infno into the erosive lesions. The groups Hel, Adh, Inf, Tetno, and Infno resulted in the formation of a layer of material over the enamel, which was effective in inhibiting the progression of erosion. In conclusion, the infiltrant, with or without etching, was able to penetrate and protect the enamel against dental erosion. The other resin-based materials, except for the two-step conventional adhesive, were able to penetrate and inhibit the progression of erosive lesions only when they were applied after enamel etching.

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