RU2594255C1 - Method of improving adhesion and strength characteristics of polymer filling materials and bonds - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, specifically to dentistry, and can be used in practical health care in sealing cavities of teeth and for preventing caries. Method of improving adhesion and strength characteristics of polymer filling materials and bonds involves their irradiation in constant electromagnetic field with magnetic field strength of 20·10^4-24·10⁴ A/m for 15-25 minutes with subsequent curing with polymerising lamp blue light at wavelength not less than 420 nm and not more than 490 nm and power of not less than 5 W for not less than 40 s.

EFFECT: method provides high strength of polymer filling materials and improved adhesion physical and chemical properties, which significantly increases service life of seals.

1 cl, 5 dwg, 2 tbl

Description

The invention relates to medicine, namely to dentistry, and can be used in medical practice when filling carious cavities of teeth and to prevent caries.

Known methods for increasing the strength and bactericidal properties of dental materials [US Pat. RU 2080853]. The filling material is prepared by phased mixing of the powder and liquid to a certain consistency, while before mixing the liquid is treated with a constant electric field of up to 75 V / cm with the help of metal electrodes and the obtained gel-like mass is treated with current under the same conditions. The proposed method allows to obtain cements with improved properties.

The prior art method for producing adhesive joints with increased strength and thermal conductivity by exposing an uncured adhesive to a magnetic or electric field [US Pat. RU 2327717]. The method includes introducing a filler into a polymer matrix and subsequent curing, using a ferromagnetic material in the form of a powder as a filler, and curing is carried out in a cyclic magnetic field.

The disadvantages of the above methods: the effects of the influence of electromagnetic fields on modern polymer-based dental materials have not been studied. There is no information about the duration of conservation of the obtained effect of changes under the influence of the electromagnetic field of the structural properties of polymeric materials.

The technical result is the development of a method of influencing polymer dental materials, allowing to modify the structure of the substance, to obtain a modification of the polymer with improved adhesive and strength characteristics.

Qualities that an ideal dental material should possess: be biocompatible; resist the effects of the environment of the oral cavity; provide a strong and permanent connection with the structure of hard tissues of the tooth; fully reproduce their appearance; possess a set of physical and mechanical properties corresponding to the properties of restored natural tissues and, moreover, contribute to their recovery and regeneration.

The invention is based on the results of our research on the development of dental material with increased strength characteristics.

The studies were performed on 20 samples of the Latebond-LC adhesive system (Profident LLC, Kharkov, Ukraine), which has all the features of existing bonds, 60 samples of filling materials from Heraeus Kultzer, Germany, namely Solitaure, Charisma, Durafil VS and 20 samples of filling material, company Dentsply, USA.

Each sample was placed in the installation for processing polymer materials in a constant electromagnetic field for a period of not less than 15 and not more than 25 minutes at an apparatus performance of 20 * 10 ⁴ -24 * 10 ⁴ A / m. After exposure, a sample with a volume of at least 0.5 cm was cured with light of a blue polymerization lamp at a wavelength of at least 420 nm and not more than 4 90 nm and a power of at least 5 W for at least 40 seconds. Then, at the widest point of the sample, a notch was made with a diamond disk to a depth of not less than 0.2 mm. Using a dental trowel, a specimen was cracked along the marked notch so that a cleavage of the filling material with a diameter of at least 0.4 mm was obtained. A study was made of the structure and substructure of samples of composite materials and an adhesive system using a scanning electron microscope from JEOL JSM-6380LV, Japan at magnifications of × 2000, × 30000, × 50,000 and × 100,000. As a control, the same material, which was not subjected to preliminary treatment with an electromagnetic field, was split and investigated using a similar technique.

In the course of our research, changes in the structure of polymeric materials were discovered, namely, its compaction in comparison with samples of the same material not exposed to electromagnetic fields.

So, for example, before exposure to an electromagnetic field, the particle density per unit area of the Latebond bond (Fig. 1) is 12, and after exposure to 25. Certain changes were observed after exposure to the electromagnetic field and in the filling material. So, in the filling material Charisma and Durafil, the company Heraeus Kultzer (Fig. 2, 3), coarsening of the particles of the material took place 2-3 times.

Thus, the use of an electromagnetic field improves the physicomechanical properties of polymer-based dental materials. This means that the material has become more resistant to mechanical and physical influences, that is, its strength and hardness have increased, which contributes to a longer service life of the seals. The effect obtained lasts for 4 months.

In addition to density, we studied the strength characteristics of the material after exposure to an electromagnetic field, namely, the chemical adhesion at the fill-tooth border in intact teeth removed by orthodontic indications. The adhesive properties and shrinkage of the irradiated Latebond, filling material Charisma, Solitaure and Durafil VS, Heraeus Kultzer in the tooth were evaluated. For this, samples of 12 filled teeth with an artificially created carious cavity of medium size on the chewing surface were studied. The adhesion was evaluated by x-ray spectral analysis with a JEOL JSM-6380LV microscope, Japan at a magnification of × 250 at certain points in the spectrum, namely, at the fill-tooth border and at three to four points in the spectrum from the border toward the fill and tooth, respectively (Fig. 4 )

It was found that when examining samples by X-ray spectral analysis after exposure to an electromagnetic field on dental materials of polymer nature, there is an increase in the concentration and interpenetration zone of micro and macrocells at the fill-tooth border (Table 1., Fig. 5).

In figure 5, the border of the filling-tooth (5) in the unirradiated sample (I) is clearly delineated, in the irradiated sample (K) - blurred.

To confirm the change in the structure of the light-cured composite filling material after exposure to an electromagnetic field and to determine the change in the strength properties of the material, the compressive strength was determined [GOST R 51744-2001. Water-based dental cements. Technical requirements. Test methods].

As a result of the tests, the result is an increase in compressive strength after exposure to electromagnetic fields on the filling material by 1.5 times (Table 2).

Thus, we have developed a new way to improve the characteristics of polymer filling materials for the treatment and prevention of dental caries by exposure to an electromagnetic field, which allowed us to obtain a new result unknown from the prior art — a change in the ultrastructure of polymer filling materials, accompanied by an increase in strength and adhesive physical and chemical properties. Such changes can significantly increase the service life of seals.

Description to figures

FIG. 1. Latebond bond, Kharkov, Ukraine, with an increase of × 30,000 before (A) and after (B) exposure to an electromagnetic field

1 - a separate particle,

2 - area for calculating the number of particles.

FIG. 2. Filling material Charisma, the company Heraeus Kultzer, Germany, with an increase of × 100,000 before (V) and after (D) exposure to an electromagnetic field

1 - a separate particle,

2 - area for calculating the number of particles.

FIG. 3. Filling material Durafil, Heraeus Kultzer, Germany, with an increase of × 100,000 before (D) and after (E) exposure to an electromagnetic field

1 - a separate particle,

2 - area for calculating the number of particles.

FIG. 4. The content of micro-macrocells at the fill-tooth border of Charisma material and bond at × 250 magnification before (G) and after (H) exposure to an electromagnetic field

3 - seal

4 - tooth

5 - the seal-tooth border.

Claims (1)

A method of improving the adhesive and strength characteristics of polymer filling materials and bonds by irradiation in a constant electromagnetic field, characterized in that the irradiation is performed at a magnetic field strength of 20 · 10 ⁴ -24 · 10 ⁴ A / m, the exposure time of at least 15 and not more 25 min, followed by curing with light of a blue polymerization lamp at a wavelength of at least 420 nm and not more than 490 nm and a power of at least 5 W for at least 40 s.

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