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What makes permanent seal on the teeth?
09-09-2009
In physical properties of the permanent filling materials can be divided into three groups: cements, materials for metal seals and polymers.
Cements
As a material for the permanent seals used silicate cements, silikofosfatnye and ionomer.
Silicate Cements. Domestic industry produced Silitsin, Silitsin-2. Foreign analogues: Silikap, Alyumodent, Friteks. The main ingredient of the powder is silicon dioxide. Liquid silicate cement – an aqueous solution of phosphoric acid solution containing additional zinc, aluminum and magnesium phosphate. Introduction to the composition of silicate cement fluoride gives it protivokarioznye properties and reduces the likelihood of development of secondary caries.
Filling mass is prepared by mixing the powder with a liquid on a smooth glass plate plastic spatula. Optimum ratio of powder and liquid varies for different grades of 1,25 to 1,55 g of powder to 0.4 ml of liquid. When mixing the powder made into a liquid in large chunks. Just enter a half dose of powder, then 2-3 portions – the remainder. Setting time of cement slurry – up to 1 min.
Silicate cements have significant toxic effect on the tooth pulp, have weak adhesion and lack of mechanical strength (brittle), so they are used to seal cavities I and III classes. Requires mandatory imposition of the insulating gasket.
Silikofosfatnye cements. According to its physical and chemical properties silikofosfatny cement occupies an intermediate position between the phosphate and silicate cement. Silikofosfatny cement has better adhesion than silicate; less pronounced its toxic properties. Used for sealing of cavities I and III classes. In the treatment of medium and deep cavities silidont used with an insulating gasket.
Industry produces silikofosfatnye cements: silidont and silidont-2. Foreign analogues silikofosfatnogo cement: Aristos, Lumicon, Fluoro-Thin.
Steklononomernye cements represent a system of powder – liquid. The powder is made up of aluminosilicate glass with a certain ratio of silicon, aluminum and fluorine. Liquid – usually 50% solution of polyacrylic acid. Also produced steklononomernye cements, knead in water, in this case as a liquid for cement use distilled water.
Steklononomernye cements are harmless to the tissues of the tooth, do not have irritating to the pulp. In the process of hardening of the material formed free carboxyl groups that can bind with calcium dental hard tissues, resulting in a high adhesion of the material.
Fluoride constituent GLASS cements provide a flow of fluorine in the adjacent to the seal of dental hard tissues, providing protivokarioznoe action.
Steklononomernye cements have high sensitivity to acids. This property is used to improve the connection with the laying of a composite of cement GLASS, why do its acid etching.
Kneaded GLASS cement on special paper plates within 30-40 with. Time zatverzhdeniya material – an average of 3 min.
Of glass are chemical, light and combined hardening.
Depending on the purpose steklononomernye cements are divided into the following groups:
For sealing of cavities, wedge-shaped defects and erosion of enamel – «Jonofil», «Aqua lonofil», «Chem Fil Superior», «Chem Flex», «Chelon Fil», «Glasionomer», «Legend», «Ketas Fil», « Ketac-Molar »,« Legend Silver »,« Fuji II »,« Fuji HLC »,« Fuji IX GP »,« Argion Molar »,« Jonofil Molar ».
For the sealing of all classes of cavities of deciduous teeth and sealing fissures of permanent teeth – «lonofil», «Aqua lonofil», «Argion», «Ionobond», «lonoseal», etc.
To apply insulating gaskets and laying the foundations for the restoration – «Fuji-I», «Argion», «Aqua Ionobond», «Base Line», «Ionobond», «lonoseal», «Chem Rex», «Lining Cement».
For the fixation pins and prosthetic – «OrtofiksS», «lonofil», «Fuji-1», «Fuji Plus», «Aqua Meron», «Metop», «Aqua Cem», «Aqua lonofil», «Ionofix».
For the filling of root canals – «Stident», «Ketac-Endo».
When working with GLASS cements should strictly observe the following rules:
• the correct ratio of liquid and powder;
• vial of powder tightly close the lid, as it is very hygroscopic;
• Before you take a scoop right amount of powder, shake the bottle well to loosen the powder, because it has a tendency to compaction;
• avoid contact with evgenolsoderzhaschimi drugs;
• strictly observe the ratio of the powder – liquid, because its violation may cause a reduction in the strength of the seal and increase its solubility in the oral fluid;
• After sealing of the material GLASS cover it with a special varnish Final Varnish, which protects the seal during the curing of the impact of oral fluid and improves the quality of the seal.
Polymeric filling materials
Composite filling materials (composites). The mechanism of curing of composite materials is a process of converting monomer into polymer (polymerization). The mechanism of polymerization, or curing and sealing of composite materials can be chemically or light, and therefore distinguish between composites of chemical and light curing.
In materials of chemical curing process begins by mixing the polymerization catalyst – benzoyl peroxide and the activator – aromatic quaternary amine. Therefore, chemical cure composite materials – is always a two-component system (paste – paste or powder – liquid), one of which is a catalyst in another – an activator.
Light-curing composite materials – a single component system, consisting of activator and catalyst. The activation of the polymerization process causes a beam of light fotopolimerizatora, which are sent to the surface of the seal.
Light-curing composites due to the lack vremennbgo limitations when working with them have an advantage compared with chemical cured materials, as they allow a doctor to simulate a seal within the time required to obtain the desired result.
Most of the existing composite material basically contain monomeric matrix BISGMA, synthesized by the compound bisphenol-A and gliiidila methacrylate. Some modern composites as a basis contain uretandimetakrilaty.
The most important component of composite materials, determining their basic properties, is a mineral or inorganic filler, which is represented by microparticles of crystalline quartz, silicon compounds, different types of glass, diamond dust.
Depending on the size of the particles of mineral filler composite materials are divided into the following groups.
Makronapolnennye composites, or makrofily. They contain an inorganic filler particle size from 2 to 30 microns. The materials in this group are characterized by adequate strength, but they are not well polished, which leads to a change in color of fillings and the formation of microbial plaque, causing secondary caries and gingivitis. Therefore makrofily used only to seal the cavities I and II classes posterior teeth. For the restoration of dental hard tissues makrofily not use. The materials in this group include Evicrol, Adaptic, Consise, Heliomolar, Sure Fil and others
Mikronapolnennye composites, or mikrofily. Have the size of particles of mineral filler 0,02-0,04 microns. Mikrofily well polished and can achieve a good cosmetic effect a seal, but they are not strong. They are used for the restoration of the front teeth in the presence of small defects in solid tissues. By mikrofilnym composites are materials: Isopast, Helioprogress, Silux Plus, etc.
Hybrid composites, or hybrids. Universal composite materials used for all kinds of restoration work. Hybrid composites contain ¬ zhat mikronapolnennuyu matrix with the addition of macro-and micro-filler size from 0,05 to 2,0 micron. The group of hybrids composed of the following materials ¬ ly: DeguftH, Compodent, Brilliant, Prisma-Fill, Den-Mat, Alfacomp, Charisma, Tetric, Prisma TPH, Polofil, Arabesk, Herculite XR, Hereulite XRV, Z-100, Spectrum TPH, Prodigy , Apollo, etc.
Among the hybrid materials constitute a separate group of hybrids with fine ceramic filler, which accounts for about 80% of the volume. The materials are very strong, plastic, well-modeled. It has good color gamut, radiopacity. In the process of polymerization in the surrounding hard tissues allocated fluorides, providing kariesprofilaktichesky effect. This Tetric-Ceram. Te-Econom. Recommended for all types of restoration work.
Compomers – materials that are a combination of a hybrid composite-tion of glass and cement. Representatives of this group are Dyract, Dyract AP and Compoglass. Compomers have good adhesion, as well as form a chemical bond with hard tissues, convenient and easy to use, have good aesthetic quality, biologically compatible with tooth structure. In the process of polymerization emit fluorides entering the adjacent to the seal of dental hard tissues, preventing the formation of secondary caries. The technology works with Compomers fundamentally different from working with composite materials: does not require acid etching, as the material comes in a chemical bond to tooth structure.
Compared with the composite materials Compomers less durable. They are recommended for the restoration of cavities, sealing erosion, wedge-shaped defects, as well as insulating gaskets.
Dyract AP has improved mechanical properties compared with Dyract, so it can be applied to all types of restoration work.
Metal Sealing materials
Amalgam – an alloy metal with mercury. There are silver and copper amalgams.
Silver amalgam is an alloy, with ¬ standing mainly of silver and tin with a small amount of copper. Used to seal the cavities I, II and V classes. Silver amalgam has high strength, ductility, and resistant to moisture, does not collapse under the action of saliva in the mouth. Among its drawbacks include poor adhesion, high thermal conductivity, volume change (shrinkage) and the presence of mercury in its composition, in violation of technologies capable of making the material to have a toxic effect on the patient and dental office staff. However, compliance with the necessary requirements of storage, cooking and working with amalgam eliminates the possibility of its toxic action. The most important condition for the safe handling of amalgam is the RPA ¬ Vilna dosing of mercury and a powder that is guaranteed by the industrial production of the drug in capsules (two-chamber or unicameral). Mixed with the powder and liquid in special amalgamosmesitelyah. To work with amalgam use special tools: leveling head-amalgam, amalgam-plugger, trowel, etc.
Improvement of the silver amalgam is on ways to improve the content of copper in it and the creation of fine spherical particles of silver alloy, which reduces determined mainly by corrosion and toxic effect of Amal-Gamow seals.
In the dental practice of using silver amalgam domestic production: FTAA-01, FTAA-43, as well as silver amalgam capsules SSC-68, 5-01, amadent minimum-phase gamma-2 (v2).
Foreign companies produce silver amalgam (Amalcap) in an encapsulated form. Amalcap used to seal the cavities of small size.
Amalcap plus non-gamma-2, used to seal the cavities of medium and large sizes, produced by «Vivadent». Silver amalgam Septalloy non-gamma-2 NG 50 NG 70 produces a firm «Septodont».
Copper amalgam is produced by domestic industry: UITA-56.
Copper amalgam has high strength, ductility, dense marginal adaptation. However, it has some drawbacks: painted black, and corrosion under the influence of acids in the mouth.
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