RU2438645C2 - Glass-ionomer cement with silicon nanoparticles added - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely to orthopaedic dentistry, and can be used for fixed denture retention. What is offered is a modification of glass-ionomer cement for fixed denture retention, containing a powder and a liquid, by adding silicon nanoparticles to the powder in proportions, wt %: 0,015-0,025%.

EFFECT: modification allows providing better adhesion of glass-ionomer cement, improving strength and oral fluid stability, decreasing a film thickness to 10-15 mcm, that as a whole substantially improves quality of fixed denture retention.

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Description

The invention relates to medicine, in particular to orthopedic dentistry, and can be used to fix fixed dentures.

The effectiveness of orthopedic treatment of patients using fixed denture structures depends on the choice of fixing material and their high-quality fixation on the abutment teeth.

For fixing cements, in addition to common to all medical materials, the following specific requirements are made. These materials should not have a toxic effect on the pulp, on the contrary, having an anti-inflammatory effect and stimulating dentinogenesis. In addition, they must be good insulators for pulp from thermal, chemical and biological irritants. By the nature of application, these materials should have high shear, tensile, and compression strengths [1].

Violation of the fixation of fixed structures of dentures may be due to deficiencies in the physicomechanical properties of the fixing glass ionomer materials in combination with the microbial factor. The dissolution of cements leads to the appearance of edge permeability under the prosthesis and the penetration of bacteria.

In recent years, the scope of glass ionomer cements has expanded significantly, they belong to the group of the most widely used filling materials, are also widely used in pediatric dentistry and orthopedic dentistry for fixing fixed structures of dentures, as they have higher physicochemical parameters compared to other cements.

However, glass ionomer cements also have a number of drawbacks that can reduce the quality of fixation of fixed structures of dentures: inconsistent adhesive properties, a long final hardening time with a relatively short working time.

In addition, it is known that glass ionomer cements are not resistant to acids, and a drop in the pH of the oral fluid occurs in patients with diseases of the gastrointestinal tract. This may be an additional negative factor in the impact of oral fluid on the strength of the fixing materials [3].

In the practice of orthopedic dentistry, glass ionomer cement is required to fix fixed structures of dentures, which will meet all the requirements for fixing materials as much as possible: high strength, low brittleness, resistance to aggressive oral environment, small film thickness, lack of hypersensitivity to tissue cement components supporting teeth.

Close in composition to the proposed material is “Stion” for dental filling and fixation of fixed orthopedic structures (manufactured by “Rainbow R”, Russia, TU 9391-009-10611791-97), which is a fluoroaluminosilicate glass and an aqueous solution of polyacrylic acid, however, the disadvantage of this the fixing material is insufficient adhesion to the hard tissues of the teeth, a significant film thickness.

Known glass-polyalkenate cement "Celite Ionomer FH" (Russia, TU 9391-043-10614163-2005) fluorine-containing fluorine-containing chemical curing for fixing orthopedic structures, the shortage of which is considered to be short working time, significant film thickness (more than 30 microns).

Fuji (GC Corporation No. ФС3 2009/05239) created glass-polyalkenate cement grades for dental fillings and fixation of fixed dentures, followed by Everbond cement (Kerr), Ketac Cem (3M Espe), which have high physical and mechanical properties, biological compatibility with hard tissues of the tooth, optimal working time. Such materials make it possible to avoid a number of complications in the treatment of hard tooth tissues and fixation of fixed structures of dentures, and in many respects facilitate the work of a dentist, however, the rather high price of such foreign materials does not allow their widespread use in practice.

Known silver-containing glass ionomer cement Ketac-Silver (Germany) [4] for filling teeth and fixing fixed orthopedic structures. The introduction of silver particles increases the compressive strength, provides X-ray contrast, improves the bactericidal properties of the material. Disadvantages: when silver is added to the cement, the amount of fluoroaluminosilicate glass decreases and, accordingly, the tensile strength decreases, which explains the fragility of the material.

The purpose of the invention: the development of a formulation based on glass-ionomer fixing material for fixing fixed structures of dentures that meets the following requirements: high compressive and diametrical tensile strength, high adhesive ability, resistance to oral fluid, small film thickness not exceeding 10-15 microns, which is higher than GOST R 51744-2001, the absence of toxic effects on the pulp of the tooth.

The technical result is achieved by adding to the powder a fixing material, for example, “Stion” (Russia “Rainbow R”, Voronezh, TU 9391-009-10611791-97), “Target Ionomer FH” (Russia, TU 9391-043-10614163 -2005), Cemion F (Russia, Vladmiva, Belgorod, TU 939101445814830-2000), Glassin fix (Russia, Omega Dent, Moscow), Ketak Nem No. 56900 (3M ESPE, USA) silicon nanoparticles.

The mixing fluid contains two main components as a percentage by weight: about 45-55% polyacrylic acid, water about 40-50%, modifying additives, which can be various acids, for example, itaconic, maleic, tartaric, according to the composition declared by the manufacturer.

When mixing materials with the proposed additives during the chemical reaction of silicon nanoparticles with an aqueous solution of polyacrylic acid, a large amount of bound water is formed. Water is a necessary component of glass-ionomer cement, which plays an important role in the process of hardening. After the solidification reaction of the test material with the addition of silicon nanoparticles, there is an increase in compressive strength, diametrical tension, an increase in adhesive properties, and a decrease in film thickness.

The technology for the preparation of glass ionomer cements with the proposed additive does not differ from the standard. Immediately before use, the fixing material is kneaded. With manual kneading, a strict ratio of powder to liquid (1.5: 1) is necessary, and kneading is carried out for 30 seconds to a homogeneous consistency.

Experimental studies were carried out according to GOST R 51744-2001 on the adhesive ability, compressive strength, hardening time, dissolution resistance and film thickness research. Comparative indicators are presented in the table.

Preliminary biological tests did not reveal an increase in toxicity due to the addition of the declared amounts of silicon nanoparticles.

Comparative characteristics of the physicomechanical properties of the studied compositions of glass ionomer cements Characteristics Material according to the invention (added nanosilicon in% by weight) Analogs - glass ionomer cements <0.015 0.015-0.025 > 0.025 Adhesive ability (kg / cm ² ) 2-7 8-10 3-5 2-7 Film thickness (μm) 25 8-15 20-22 22-24 Compressive strength (MPa) 80-100 110-140 70-90 90-120 Hardening time (min) 3-5 5-8 2-3 4-3 Resistance to dissolution (mm / h) 0.8-1 0.4 0.5-1 0.8-1.5 Color light yellow light yellow dark brown light yellow white

When testing to determine the optimal concentration of nanosilicon in the preparation of the composition of the fixing material, less than 0.015% of silicon nanoparticles by weight was added to the powders of fixing materials. At such a concentration of silicon nanoparticles, no improvement in the physicomechanical properties of glass ionomer fixing materials was revealed.

When silicon nanoparticles were added to the powder of the glass ionomer fixing material in an amount of 0.015-0.025% by weight, an improvement in the physical and mechanical properties of the materials was obtained.

With an increase in the concentration of silicon nanoparticles of more than 0.025% by weight of the powder of various samples of glass ionomer cement, a significant change in color, up to black, an increase in the fragility and working time of hardening of the material used was found to be 1.5 times lower in comparison with the requirements of GOST.

Thus, it was found that when silicon nanoparticles are added in an amount of 0.015-0.025% by weight of the glass ionomer cement powder of the studied grades, a positive effect is observed on the part of the physicomechanical properties of the fixing material.

The use of nanosilicon particles, rather than ionic or other forms of the substance, is confirmed by the technology for its preparation, namely, nanosilicon obtained by electrochemical etching of crystalline silicon followed by ultrasonic treatment. Infrared spectrography made it possible to establish that the peak was recorded in the region of 600-620 cm ^-1 , which corresponds to silicon in the nanoform.

The particle size is 50-200 nm, which is confirmed by electron microscopy.

Our proposed composition of the fixing material with the addition of silicon nanoparticles in a ratio of 0.015-0.025 to the mass allows: to increase the adhesive ability, increase strength, resistance to oral fluid, reduce the film thickness to 10-15 microns, which, in general, significantly improves the quality of fixation of non-removable designs of dentures.

Sources

1. Trezubov V.N. Orthopedic Dentistry: Applied Materials Science. / V.N.Trezubov, M.Z. Shteyngart, L.M. Mishnev / St. Petersburg, 2003 - 208-224 p.

2. Bidenko N.V. Glass ionomer materials and their use in dentistry. - M., 2003.

3. Unknown G.R., Abdulov I.I., Rozov Yu.V. // Dentistry. - 1992. - No. 2. - S. 91-93.

4. Simmons J.J. Silver-alloy powder and glass ionomer cement // J. Am. Dent. Assos. - 1990. - V.120. P.49.

Claims (1)

Glass ionomer cement for fixation of fixed dentures, consisting of a powder and a liquid, characterized in that the powder contains silicon nanoparticles in a ratio, wt.%: 0.015-0.025%.