RU2428165C1 - Zinc-phosphate cement for fixation of undetachable constructions of dental prostheses with addition of silicon nanoparticles - Google Patents

Abstract

FIELD: medicine, pharmaceutics. ^ SUBSTANCE: invention relates to medicine, namely to orthopedic dentistry and can be used for fixation of undetachable constructions of dental prostheses. Composition for fixation of undetachable constructions of dental prostheses contains mixing liquid in percent by weight: phosphorus oxide -41%, zinc oxide - 10%, aluminium oxide - 4.5%, the remaining part - water to 100%, and mixture of powders, which contains in percent by weight: magnesium oxide - 10-11%, bismuth oxide - 3-3.5%, silicon oxide - 3-3.5%, aluminium oxide - 0.5%, chromium - 0.5%, silicon nanoparticles - 0.1-0.3%, zinc oxide - to 100%. ^ EFFECT: application of composition makes it possible to increase quality of fixation of undetachable constructions of dental prostheses due to increase of strength, increase of adhesive ability, resistance to oral fluid impact, reduction of film thickness and reduction of heat emission. ^ 1 tbl

Description

The invention relates to medicine, namely to prosthetic dentistry, and can be used to fix fixed structures of dentures.

An analysis of the literature on the fixation of fixed structures of dentures shows that for all indirect restorations, the presence of a gap between the structure and tooth tissues remains common, which must be reliably closed with the corresponding material for fixation. Since the fact of the presence of a gap remains a weak point, stringent requirements are imposed on cements. The gap between the denture and tooth tissues, which is usually 30-50 microns, should not increase during cementation [1].

Fixing cements must meet the following requirements: be chemically stable in the oral cavity; do not cause irritation of dentin and pulp; maintain volume constancy and not deform during solidification; have a coefficient of thermal expansion close to the coefficient of expansion of tooth tissues; be well compatible with tooth tissues, metals, plastics and porcelain in terms of physical and chemical characteristics [2].

One of the widely used cements is zinc phosphate cements. Their advantages are easy kneading, quick hardening and sufficiently high strength and cohesion. The disadvantages of zinc-phosphate cements include: pulp irritation, explained, on the one hand, by the acidic environment of the cement paste, on the other hand, by the exothermic hardening reaction; lack of antibacterial effect and adhesion; quite noticeable destruction in the oral cavity [3]. Another disadvantage of zinc-phosphate cements is a rather large film thickness (about 30 microns) compared with, for example, glass ionomer cements (10-12 microns) [1].

Known zinc-phosphate material Wisfat (company "Medpolymer", Russia TU-64-2-159-72), which is used for dental filling and cementing of dentures. The composition includes a mixing liquid containing phosphoric acid, partially neutralized by aluminum and zinc to the required density, which is dictated by the curing rate of the material, and a mixture containing zinc whitewash, magnesium oxide, bismuth oxide and quartz sand.

The disadvantages of the material are insufficient strength, low adhesive ability, increased solubility, temperature increase during solidification by 20-25 degrees, significant film thickness (45 μm).

A known composition for filling teeth and cementing dentures, including a mixture containing white zinc ZnO, magnesium oxide MgO, bismuth oxide Bi ₂ O ₃ , quartz sand SiO ₂ and ammonium molybdate (NH ₄ ) ₂ MoO ₄ (patent RU No. 1725895 from 15.04 .92). The material has high physical and mechanical properties and the necessary adhesive ability, guaranteeing reliable fixation of dentures.

The disadvantages of the known composition are the lack of regenerative properties that contribute to the restoration of dentin and enamel of the abutment tooth, an increase in temperature during hardening by 20-25 degrees, a significant film thickness (25 μm), insufficient strength, low adhesive ability, increased solubility.

A known composition for filling teeth and cementing dentures (patent RU No. 2097015 from 11/27/1997), including a mixture containing zinc white, magnesium oxide, bismuth oxide, quartz sand, ammonium molybdate. According to the invention, the mixture further comprises calcium hydroxide and sodium fluoride. The use of the composition provides the material with regenerative properties while maintaining high physical and mechanical properties.

The disadvantages of the composition are the irritating effect on the pulp of the tooth, due to the exothermic hardening reaction, and a large film thickness (30 μm).

The closest to the proposed composition is the material “Viscin” (manufactured by “Rainbow R”, Russia TU 9391-004-10611791-97) for dental fillings and fixation of dentures, containing zinc oxide, magnesium oxide, silicon oxide, alumina, bismuth oxide .

The disadvantages of the material are the irritating effect on the pulp of the tooth, due to the exothermic reaction, a large film thickness, low adhesive ability.

The aim of the invention is to develop a composition for fixing fixed structures of dentures based on zinc phosphate cement that meets the following requirements: high strength, high adhesive ability, resistance to oral fluid, small film thickness not exceeding 15 microns, which is higher than GOST R 51744 -2001 1.5 times, the absence of irritating effects on the pulp of the supporting teeth.

The technical result is achieved in that the composition of the powder mixture for fixing fixed structures of dentures, containing in percentage by weight:

Magnesium Oxide - 10-11

Bismuth oxide - 3-3.5

Silica - 3-3.5

Alumina - 0.5

Chrome - 0.5

Zinc oxide up to 100,

supplemented with silicon nanoparticles in the amount of 0.1-0.3%.

Nanosilicon is 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.

According to electron microscopy, the particle size is 50-200 nm.

The mixing liquid contains (in percent by weight): phosphorus oxide - 41; Zinc oxide - 10; Aluminum oxide - 4.5; the rest is water up to 100.

When mixing the material, a liquid, which is an aqueous solution of phosphoric acid, partially neutralized by aluminum and zinc, interacts with silicon nanoparticles, thereby cement after crystallization acquires the following properties: the exothermic effect decreases, the adhesive properties increase, and the film thickness decreases.

Another positive result of using the proposed composition was a change in physical and mechanical properties, namely an increase in strength. This is because in the course of a chemical reaction with the participation of silicon nanoparticles, a larger amount of bound water is formed.

The choice of the limits for the introduction of silicon nanoparticles is due to the fact that it should give positive effects without negatively affecting the physicomechanical and biological properties of the material.

Immediately before use, the material is prepared as follows: 2.5 grams of powder is placed on a dental glass, 0.5 ml of liquid is added and, with thorough mixing with a spatula, the composition is brought to a creamy consistency. The curing time of the composition depends on the density of the mixing liquid and the ratio of the amount of liquid and powder fractions.

To confirm the improvement of the properties of cements when the composition was supplemented with silicon nanoparticles, experimental studies were carried out on adhesiveness, compressive strength, heat dissipation, dissolution resistance, hardening time and film thickness research in accordance with GOST R 51744-2001 (see table), as well as the assessment of biological actions according to GOST R ISO 10993-2009.

Table Physico-mechanical characteristics Characteristics proposed material zinc phosphate cements Adhesive ability 10.5-11.2 kg / cm ² 2.8-10.1 kg / cm ² Film thickness 12-14 microns 25-40 microns Compressive strength 140 MPa 80-100 MPa Heat dissipation 35-38 ° C 45-55 ° C Dissolution resistance 0.15 mm / h 0.25-0.2 mm / h Hardening time 4,5 min 4-6 min

The experimental results of studying the biological effect of cements have confirmed the absence of deterioration of the toxic-hygienic properties of cements when silicon nanoparticles are added.

Thus, the proposed cement for fixing fixed structures of dentures with the addition of silicon nanoparticles in a ratio of 0.1-0.3% by weight of dry matter allows you to: increase strength, increase adhesion, resistance to oral fluid, reduce film thickness 12-14 microns, reduce heat to 35-38 ° C.

Which, in general, improves the quality of fixation of fixed structures of dentures.

Information sources

1. Christoph M. Precision fit and marginal fit in prosthetics - the role of cement for fixation // New in dentistry. - 1999. - No. 3. - S.53-55.

2. Abdurakhmanov A.I. Materials and technologies in orthopedic dentistry / A.I. Abdurakhmanov, O.R. Kurbanov. - M .: Medicine, 2000 .-- 206 p.

3. Trezubov V.N. Orthopedic dentistry. Applied Materials Science / V.N.Trezubov, M.Z. Shteyngart, L.M. Mishnev. - St. Petersburg: SpetsLit, 2003 .-- 384 p.

Claims (1)

Composition for fixing fixed structures of dentures, containing mixing fluid in percent by weight: phosphorus oxide - 41%; zinc oxide - 10%; aluminum oxide - 4.5%; the rest is water up to 100%, and a mixture of powders, characterized in that silicon nanoparticles are added to the powder mixture in the following proportions, wt.%:
Magnesium oxide 10-11% Bismuth oxide 3-3.5% Silica 3-3.5% Aluminium oxide 0.5% Chromium 0.5% Silicon nanoparticles 0.1-0.3% Zinc oxide up to 100%