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Dental adhesive systems

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Enamel adhesives. Acid-etching of the enamel, that was first introduced by М.G.Вuonосоrе (1955) is desirable before the application of enamel adhesive. Acid selectively dissolves peripheral and central zones of enamel prisms, and the surface of the enamel under the electronic microscope resembles the bee cells. As the result of mechanical cutting of enamel prisms and acid-etching of the enamel active surface of bonding to the composite widens, and hydrophobic adhesives can easier penetrate into the outer layer of the enamel.

Unfilled or lightly-filled mixes of diacrilates are used as enamel adhesives, that are included in composite’s matrix. Due to their high viscosity they penetrate into the etched enamel slowly. The set adhesive forms retentive tags within the enamel, similar to an interlocking jigsaw, thus providing microretention of a composite on the surface of the enamel.

Enamel etching includes etching enamel with 37% phosphoric acid (solution or gel), that is placed on the enamel surface for 20–30 sec. Gel is more convenient, because it is visible on the enamel and the quality of application and rinsing may be controlled, it may also prevent contact of the acid with mucosa and skin.

Remember, that organic formations on the tooth surface (plaque, pellicle) interfere with enamel etching. That is why the surface cleanliness is paramount for the development of adhesion. Clean the tooth surface with rubber cup or rotary brush, stripes and fluoride-free polishing paste.

Dentine adhesives (primers) differ significantly from the enamel adhesives; they are applied on wet surface, which comprises a great part of organic material. That is why dentine adhesives must be water compatible, to be hydrophilic unlike enamel adhesives.

IV-generation ofadhesive systems– multi-component adhesive systems that form a hybrid layer (Pro Bond (Dentsply), Scotchbond MP Plus (3M), OptiBond (Kerr)).

IV generation adhesive systems usually consist of 3 components:

- etching gel – is a phosphoric acid as a gel, used for etching of enamel and dentin;

- primer – a mix of hydrophilic low-molecular polymerizeable compounds;

- adhesive – a resin, that bonds composite to hybrid layer and tooth enamel.

V generation adhesive systems are one-component, light-cured, no-mixing systems (Single Bond (3M), Optibond Solo (Kerr)). The combine properties of primer and adhesive. Their composition includes special low-molecular hydrophilic resins and elastomers, diluted in water, alcohol or acetone.

VI generation adhesives are self-etching multi-component adhesives (Adper Prompt L-Pop и Adper Prompt (3M ESPE), Xeno III (Dentsply), Contax (DMG, Germany), Se-bond (Kuraray).

VII generation of adhesive systems –are one-step adhesives, which combine etching, application of primer and adhesive in one step. I Bond (Heraeus Kulzer) is a VII generation adhesive.

Adhesive systems of VI и VII generations are the most convenient for use in pediatric dentistry, because of “impatience” of most of patients, and low mineralization of hard tooth tissues. The safe adhesion is very important also during period of tooth tissue formation.

Compomers — is a new class of filling materials that somehow combines properties of composites and glass ionomer cement.

Particles of reactive fluoride-aluminium-silicate glass with additives serve as a filler. That can be silanized barium-fluoride-silicium or stronyium-alluminium-fluoride-sillicium glass (Dyract) with particle size 0,2-2,5 mcm. Filler’s ratio is 52-60%. Initiators, stabilizers and dye are also included in the composition. Organic matrix is a monomer that has polimerizable groops of composite resin and acid carboxyl groups of glass ionomer polymer.




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Вимоги до знань та вмінь. | Геологічна зйомка навчального полігону | Застосування геофізичних та гідрогеологічних досліджень при геологічній зйомці | CONTENTS | Peculiarities of class III and IV cavity preparation in deciduous and permanent teeth | Class III cavity preparation | Class IV cavity preparation | Glass-ionomer cements. | Modern endodontic instruments | Filling materials for temporary and permanent obturation of root canal. The techniques of temporary and permanent filling of root canal concerning the stage of tooth development. |


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