JP4592295B2 - Dental alginate impression material composition - Google Patents

Description

  The present invention relates to a dental alginate impression material. Specifically, the present invention is excellent in properties such as kneadability, strength, surface smoothness, and dimensional stability required for an impression material, and is particularly useful for taking a dental alginate impression for a complete denture. The present invention relates to a material composition.

  The alginate impression material (hereinafter sometimes abbreviated as “impression material”) is a material that utilizes the fact that alginate gels by a reaction with a gelling agent such as calcium sulfate to produce a gel-like cured product. It is a composition mainly composed of an alginate, a gelling agent, a gelation modifier, other fillers and the like. Such impression materials are frequently used in the dental field, mainly for molds used in the treatment and restoration of teeth, and other molds, such as kneadability, strength, surface lubricity, and dimensional stability. It is required to satisfy all the characteristics of

  Alginate impression materials are roughly classified into a powder type and a paste type as a commercial form. The powder type is kneaded with water at the time of use and is used as a homogeneous paste for taking an impression. For this reason, since the impression after collection contains a large amount of moisture, the impression material is gradually deformed due to subsequent evaporation of moisture, or if moisture is evaporated from the external impression material after pouring gypsum. The loss of elasticity results in the possibility of damaging the gypsum details when the gypsum is removed from the impression. Therefore, it has been proposed to add sugar alcohol as a moisturizing agent to the impression material to prevent moisture from evaporating from the impression material and prevent a decrease in elastic strain over time (Japanese Patent Laid-Open No. 10-139615).

  Furthermore, when using an alginate impression material, it is pressed against a mold (original) from which a paste-like impression material is acquired, gelled and then removed from the original, and the resulting gel-like cured product is molded with a plaster or other mold. In order to easily remove the prototype and the gel-like cured body, the impression material gel body may be distorted by external force. Desired. However, in order to obtain an accurate model, it is not preferable that the mold material such as plaster is deformed by the gravity, so that the distortion caused by the external force must be moderate. In order to satisfy such conflicting properties, a method of adding hemihydrate to the calcium sulfate component of the impression material has also been proposed (Japanese Patent Laid-Open No. 11-209219).

On the other hand, when taking an impression using such a conventionally known impression material in actual dental treatment, it is possible to cope with molds other than a complete denture, but taking an impression when creating a complete denture. However, these impression materials were not satisfactory because of their low viscosity. Therefore, there has been a strong demand for an impression material that satisfies various required characteristics as an impression material and is suitable for taking an impression for making a complete denture.
JP-A-10-139615 JP-A-11-209219

In view of the circumstances as described above, the present inventors have found an impression material useful for taking an impression for creating a denture during clinical treatment of dental treatment, particularly an impression material suitable for taking an impression for creating a complete denture. As a result of intensive studies, it was necessary to cover the entire denture area with the impression material and obtain the entire jaw in the oral cavity in order to obtain an impression when creating a complete denture. It has been found that it is necessary to have a viscosity enough to push away the mucous membrane of the part, that is, a high viscosity. And it discovered that the impression material which has the characteristic of this high viscosity was obtained by mix | blending high molecular weight alginate as the structural component, and achieved this invention.
That is, the present invention provides an impression material having a viscosity suitable for taking an impression of a denture, in particular, taking an impression at the time of making a complete denture, and having kneadability, strength, surface smoothness, and dimensional stability. The objective is to provide an impression material that is excellent in all required properties.

The present invention provides a dental alginate impression material composition based on the above findings, the gist of which is a composition comprising a high molecular weight alginate having a weight average molecular weight of 550,000 or more and 850,000 or less . The dental alginate impression material composition is characterized by containing 7 to 25% by weight based on the total amount .

  The alginate impression material having the above-described constitution of the present invention is sufficiently satisfactory for taking a complete denture impression, which has been difficult in actual dental treatment, and has the kneadability and gel required as an impression material. It is excellent in all the properties such as plasticizing time, elastic strain, permanent strain, compressive strength, dimensional stability and surface roughness, so it can be used for taking ordinary denture impressions, and is extremely useful impression material It is.

Hereinafter, the present invention will be described in detail.
It is essential that the alginate impression material composition of the present invention contains at least a high molecular weight alginate as a main component.
The kind of the high molecular weight alginate used in the present invention is not particularly limited, and examples thereof include water-soluble salts such as sodium, potassium, ammonium or triethanolamine which are generally used.

The alginate used in the present invention must have a high molecular weight, and the weight average molecular weight is preferably 550,000 or more and 850,000 or less. The high molecular weight alginate according to the present invention has a viscosity of 800 to 3000 cps (concentration: 3% by weight aqueous solution, 20 ° C.) measured using a B-type rotational viscometer, preferably 900 to 2500 cps. is there.
The content of the high molecular weight alginate in the impression material of the present invention is 7 to 25% by weight, preferably 9 to 18% by weight, based on the total amount of the composition. If the content exceeds this range and is too low, sufficient viscosity cannot be obtained, while if it is too high, the viscosity becomes high and the amount of filler added becomes too low, resulting in poor dimensional stability. Is also not preferable.

In the impression materials that have been widely used in the past, the alginate that is generally used has a viscosity of 400 to 700 cps when measured under the above conditions, and its blending amount is 5 to 15% by weight. Thus, since the conventional impression material has a lower viscosity than the alginate of the present invention, that is, a low molecular weight alginate, the viscosity of the process of taking a three-dimensional structure by the gelation reaction is low, and therefore, a denture is created. It was not possible to take an impression of the entire jaw in the oral cavity.
On the other hand, in the present invention, since a highly viscous alginate is used, as a result, the viscosity increases in the process of forming a cured body by a gelation reaction, and the degree required to displace the mucous membrane of the marginal part. Thus, it is possible to obtain an impression of the entire jaw in the oral cavity.

Other gelling agents, gelation modifiers, fillers and the like added to the alginate impression material composition of the present invention are not particularly limited, and known ones can be used as appropriate.
Examples of the gelling agent include calcium sulfate such as calcium sulfate dihydrate, calcium sulfate hemihydrate, and calcium sulfate anhydrous. These are usually used as fine powders, and the amount used is 3 to 40% by weight, preferably 5 to 30% by weight, in terms of impression material powder.

  Examples of the gelation modifier include tertiary phosphates of alkali metals such as sodium and potassium, pyrophosphates, tripolyphosphates, phosphates such as hexametaphosphate, silicates, carbonates and oxalates. It is done. These are usually used as fine powders, and the amount used is 0.1 to 5% by weight, preferably 0.2 to 4% by weight, in terms of impression material powder.

Examples of the filler include diatomaceous earth, talc, silica, calcium carbonate, mica and the like, and diatomaceous earth is preferable.
The amount of filler used is 30 to 85% by weight, preferably 40 to 70% by weight, in terms of impression material powder.

Furthermore, in addition to the above components, the impression material of the present invention may contain, for example, a fluoride or silicofluoride such as sodium hexafluorotitanate or potassium hexafluorozirconate as an agent for improving compatibility with model gypsum. Addition of surfactants, polyethylene glycol, polypropylene glycol, glycerin, liquid paraffin and other dust prevention agents, metal oxides such as magnesium oxide, zinc oxide and aluminum hydroxide, metal hydroxides, colorants, fragrances, etc. An agent can be blended as necessary.
The amount of these additives used is 0 to 10% by weight, preferably 0.5 to 8% by weight, respectively, in terms of impression material powder, for the improver and the dust prevention agent.

  The method for producing the impression material of the present invention is not particularly limited, and can be appropriately selected from known methods. For example, all the raw materials may be charged and mixed at the same time in the mixer, or divided and mixed depending on the purpose.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not restrict | limited at all by the following Examples, unless the summary is exceeded.

Examples 1-2 and Comparative Examples 1-2
Each component was mix | blended according to the mixture ratio (weight part) of Table 1, and it mixed uniformly with the blender, and prepared the alginate impression material. The resulting impression material was left overnight in a room temperature atmosphere at 23 ° C. and 50% relative humidity. The physical properties of the impression material are examined by the following evaluation methods, and the results are summarized in Table-1.

Evaluation method “Viscosity after impression material kneading” Viscosity at 1 minute 10 seconds, 1 minute 20 seconds, 1 minute 30 seconds from the start of kneading assuming 60 seconds after kneading of the impression material. And the average value was assumed to be the viscosity at the time of impression taking. The measurement was performed using a vibration type simple viscometer VM100M type (manufactured by YAMAICHI ELECTRONICS).

Measurement of “gelation time, permanent strain, elastic strain and compressive strength” The measurement was performed according to JIS T-6505 (dental alginate impression material). The powder / liquid ratio (impression material / water) was 16 g / 37.6 ml (water).

Measurement of “Dimensional Change” American Dental Association Specification No. It carried out according to the measuring method of 19. In addition, the dimensional change in air | atmosphere is the value measured after being immersed in 23 degreeC water for 1 hour, a positive value shows linear expansion and a negative value shows linear shrinkage.

Measurement of “Surface Roughness” Take an impression of a smooth acrylic plate (20 × 30 × 5 mm) with an alginate impression material, remove the acrylic plate after curing of the alginate impression material, and immediately plaster (Ryoka Dental Co., Ltd.) Manufactured by New Diamond Stone) and allowed to stand at room temperature. The cured gypsum was removed 1 hour after the gypsum injection, and measured with a surface shape measuring machine (Surfcom 50A, manufactured by Tokyo Seimitsu Co., Ltd.).

As shown in Table 1, the impression materials of Examples 1 and 2 have a high viscosity after kneading the impression material, and an impression material that is clinically satisfactory in taking an impression of a complete denture that is the object of the present invention. Moreover, it was excellent in all the properties of kneadability, gelation time, elastic strain, permanent strain, compressive strength, dimensional stability and surface roughness.
On the other hand, Comparative Examples 1 and 2 were excellent in all the properties of kneadability, gelation time, elastic strain, permanent strain, compressive strength, dimensional stability and surface roughness as in the examples. Later, the viscosity was insufficient, and in taking an impression of a complete denture, the marginal part of the jaw was missing, which was clinically unsatisfactory.

Claims (1)

A dental alginate impression material composition comprising 7 to 25% by weight of a high molecular weight alginate having a weight average molecular weight of 550,000 or more and 850,000 or less based on the total amount of the composition.