Artificial Saliva Conditions Research Articles

In Vitro Preparation and Evaluation of Chitosan/Pluronic F-127 Hydrogel as a Local Delivery of Crude Extract of Phycocyanin for Treating Gingivitis

Abstract The phycocyanin (PC) in the crude extract is one of the main active compounds that has significant anti-inflammatory properties and the potential to treat gingival inflammation, the common oral disease. This work reports the preparation and characterization of chitosan/pluronic F-127 hydrogels entrapping the crude extracts of PC from Arthrospira platensis (C005H and C005L) as a local drug delivery system aiming to prolong PC release for the treatment of gingivitis. The results showed that the total phenolic content (TPC) values of the crude extracts were in the range of 2 to 5 μg GAE/100g and presented above 85% inhibition in the protein denaturation test and over 65% using a lipoxygenase (LOX) inhibition test. The hydrogels incorporating the crude extracts from C005H and C005L were perfectly prepared via the electrostatic interaction between chitosan and pluronic F-127 with very high encapsulation efficiency. The crude extracts of PC C005H and C005L were released over 70% from the loaded hydrogel within 6 hours under artificial saliva conditions. The anti-inflammatory activity of the released supernatant from the hydrogels after 6 hours was around 32-47% by LOX inhibition. The hydrogel vehicles and loaded-hydrogels did not show any cytotoxic effects against mouse fibroblast cell lines (L929) and human gingival fibroblast cells. Our current work shows that the crude extract PC-loaded chitosan/pluronic F-127 hydrogel is biocompatibility with human cells and shows prolonged crude extract release properties, suggesting it as an alternative treatment approach for gingivitis. Keywords: Phycocyanin, Gingivitis, Hydrogel, Chitosan, Pluronic F-127

Development of Innovative Chewable Gel Tablets Containing Nutmeg Essential Oil Microcapsules and Their Physical Properties Evaluation.

Chewable gel tablets are a dosed pharmaceutical form, which can have an active substance, pharmacological effect, or value of nutrition. The texture of these tablets is soft, springy, flexible, and elastic—this is influenced by the chosen ingredients. The aim of this study was to prepare chewable gel tablets with nutmeg essential oil-loaded microcapsules and determine the volatile compounds released from this pharmaceutical form. Gel tablets were prepared by using gelatin as basis, nutmeg essential oil as active compound, and natural ingredients: thyme-sugar syrup, thyme extract, and citric acid as taste and color additives. Texture properties were measured by a texture analyzer. The release of volatile compounds from nutmeg essential oil and gel tablets were analyzed by headspace-gas chromatography with mass spectroscopy in control and artificial saliva conditions in vitro. Nutmeg essential oil microcapsules had influence on the gel tablet’s physical properties (p < 0.05, by comparing tablets without glycerol and relative sample with glycerol); glycerol protects the tablets from the formation of sugar crystals on top and keeps good physical parameters (p < 0.05). A total of 12 volatile compounds were identified in nutmeg essential oil, and the six compounds with the highest amounts were selected as controls. Gel tablets prolong the release time of volatile compounds and reduce the amount of the compounds compared to the microcapsules (p < 0.05).

Controlled release of flavor oil nanoemulsions encapsulated in filled soluble hydrogels

The goal of this project was to create hydrogels, a type of soluble biopolymer delivery system to encapsulate flavored nanoemulsions that are released under artificial saliva conditions. Low methoxyl (LM) pectin and whey protein isolate (WPI) at pH 4.0 were used to form the hydrogels at a ratio of 4:1 (w/w), respectively. Orange oil, medium-chain triglyceride (MCT) oil, and WPI were used to make stable nanoemulsions loaded with flavor oil. The nanoemulsions were encapsulated into hydrogels with a mean diameter of 768 ± 36 nm. The ability of the hydrogels to encapsulate the orange oil and release the flavor in the presence of artificial saliva was determined using size distribution data, confocal microscopy, and the release of limonene as assessed by solid-phase microextraction using gas chromatography mass spectrometry. Results showed that the encapsulation of flavor nanoemulsions in filled hydrogels reduces the release of limonene.

Effect of Surface Texture Molded by a Stainless Steel Mesh on the Invisalign Material Friction Coefficient

Objective: This study aimed to evaluate the effect of surface texture mold by stainless steel (SS) mesh on Invisalign material friction coefficient. Materials and methods: Ten kinds of SS mesh were used to mold surface texture on Invisalign material. Experiments were conducted using a zirconia ball that slid against Invisalign material plates with different surface textures. In the experiments, the coefficients of friction under normal loads of 100, 200, and 300 g under dry and artificial saliva conditions were recorded. Results: The coefficient of friction was relative to the pore size and wire diameter of SS mesh. Conclusions: The Invisalign material coefficient can be effectively managed by the surface texture mold by SS mesh.

THE MICROMECHANICAL AND TRIBOLOGICAL FEATURE OF MILD MOTTLED ENAMEL

The relationships between the basic mechanical and wear properties of mottled enamel, especially during the mastication process, are important factors and must be explored. This study evaluated mottled enamel's micro-tribological behavior under artificial saliva conditions in vitro. The basic mechanical properties were determined by nanoindentiation testing. A conical diamond nanoindenter tip was used to scratch mottled enamel and normal enamel. The scratches were sliding with a constant normal load of 2 mN, with different cycles during the tests. The hardness, elastic modulus and friction coefficient were obtained to analyze the mechanical properties. The results showed that the hardness and elastic modulus of mottled enamel were 10% and 14.6% less, respectively, than those of normal enamel. Mottled enamel showed a lower friction coefficient and a higher wear rate, compared to normal enamel. The friction coefficient did not appear to be related to the wear rate for either type of enamel. The wear mechanism for normal enamel was plastic deformation for early wear, while the combination of plastic deformation and delamination was the main damage feature of mottled enamel.

Comparación de fuerza de adhesión de dos sistemas ortodóncicos con afinidad a la humedad en dos condiciones de superficie del esmalte

The purpose of this study was to compare the shear bond strength of orthodontic brackets with two systems of hydrophilic adhesives: (I) a cyanoacrylate adhesive (Smarbond, International Gestenco) and (II) a composite system (Transbond XT and Transbond™ IPM) in two enamel conditions: dry and artificial saliva contaminated. Materials and methods100 extracted premolars were stored in distilled water at 4 degrees Celsius. The teeth were cleaned, polished, and convenience distributed into 5 groups: (1) composite resin in enamel under dry conditions, (2) cyanoacrylate adhesive in dry enamel condition, (3) composite resin in enamel condition contaminated with artificial saliva before the primer, (4) composite resin enamel condition contaminated with artificial saliva after the primer, and (5) cyanoacrylate adhesive in artificial saliva contaminated enamel condition. The results showed that the adhesive system Transbond XT™ and Transbond MIP obtained the highest values of resistance to debonding in the dry enamel surface. ConclusionsThe adhesive system Transbond XT™ and Transbond MIP I provide an adequate in vitro resistance to debonding in every enamel condition. The system based on cyanoacrylate adhesive Smartbond obtained proper values of resistance to debonding in dry enamel, however it obtained the lowest values in contaminated with enamel artificial saliva conditions, unsuitable for orthodontics, and even some samples were not cemented successfully in vitro under these conditions.

Comparison between the adhesion forces of two orthodontic systems with moisture affinity in two enamel surface conditions

The purpose of this study was to compare the shear bond strength of orthodontic brackets with two systems of hydrophilic adhesives: (I) a cyanoacrylate adhesive (Smartbond, International Gestenco) and (II) a composite system (Transbond XT and Transbond™ IPM) in two enamel conditions: dry and artificial saliva contaminated. Materials and methods100 extracted premolars were stored in distilled water at 4 degrees Celsius. The teeth were cleaned, polished, and convenience distributed into 5 groups: (1) composite resin in enamel under dry conditions, (2) cyanoacrylate adhesive in dry enamel condition, (3) composite resin in enamel condition contaminated with artificial saliva before the primer, (4) composite resin enamel condition contaminated with artificial saliva after the primer, and (5) cyanoacrylate adhesive in artificial saliva contaminated enamel condition. The results showed that the adhesive system Transbond XT™ and Transbond MIP obtained the highest values of resistance to debonding in the dry enamel surface. ConclusionsThe adhesive system Transbond XT™ and Transbond MIP I provide an adequate in vitro resistance to debonding in every enamel condition. The system based on cyanoacrylate adhesive Smartbond obtained proper values of resistance to debonding in dry enamel, however it obtained the lowest values in contaminated with enamel artificial saliva conditions, unsuitable for orthodontics, and even some samples were not cemented successfully in vitro under these conditions.

A representative ex-situ fretting wear investigation of orthodontic arch-wire/bracket contacts

Recent studies show that resistance to friction and wear between the arch-wire and the bracket are of great importance for the quality of orthodontal treatment. To optimize these phenomena specific surface treatments have been developed, but a major difficulty is the methodology for comparing and improving the given palliatives. A specific ex-situ fretting test has been developed which permits the micro-slidings generated by the occlusion movements to be superimposed on macro-slidings generated by the teeth displacement. In this study the friction force between brackets and arch-wires during combined macro-/micro-slidings has been investigated. Various stainless steel bracket/arch-wire contacts have been analyzed. The wear and friction properties of different PEPVD deposited coatings such as SiC and SiN have been studied under dry and wet artificial saliva conditions.

Wear behaviour of human teeth in dry and artificial saliva conditions

Wear tests on human teeth, opposing 52100 steel and pure titanium ball, have been carried out in dry and artificial saliva conditions. To better simulate friction of a pair of teeth, small amplitude (500μm) reciprocating sliding wear tests, instead of traditional pin-disc friction tests, have been performed with a modified fretting machine. Friction coefficient, wear depth, wear mechanism have been analysed and compared. Experimental results show that the friction pair composed of pure titanium and natural tooth has a better tribological behaviour. This preliminary investigation should be very useful for clinical applications.