JPH0780738B2 - Resin composition for dental impression taking tray material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin composition for a dental impression taking tray material.

More specifically, it is a low melting point thermoplastic polycaprolactone resin having a softening point of 50 to 60 ° C., which is prepared by blending two kinds of resins having different relative viscosities (that is, having two kinds of different molecular weight distributions). The present invention relates to a resin composition for a tray material for dental impression taking, which uses a resin having a performance that cannot be exhibited by a resin having a single molecular weight.

The resin composition for a tray material used when taking a dental impression of the present invention is a known powdered polymethylmethacrylate resin and a liquid methylmethacrylate monomer that are conventionally used at room temperature or It can be used for the same purpose as the method using a heating polymerization range.

(Prior Art) Conventionally, in a dental prosthesis, as a dental impression taking tray that has been used when performing a dental impression taking operation, a blend of a polymer and a monomer called “range” described above is used. It was

The most common polymers and monomers that make up this so-called "range" are powdery polymethylmethacrylate resins containing a polymerization initiator such as benzoyl peroxide and a colorant in the case of a room temperature curing type. A liquid methyl methacrylate monomer containing a cross-linking agent (such as EDTA), a polymerization accelerator (such as dimethyl paratoluidine), and a polymerization inhibitor (such as hydroquinone), which were mixed and kneaded. .

In addition, in the above composition, there is also a heat-curing type in which a polymerization initiator such as benzoyl peroxide is decomposed by heating without adding a polymerization accelerator (such as dimethylparatoluidine).

Immediately, the powdery polymethylmethacrylate resin containing this polymerization initiator and liquid methylmethacrylate monomer were blended immediately before the impression taking work, and the curing reaction was caused at room temperature or by heating to perform the impression work. .

The procedure is outlined below.

First, for example, a kneaded alginate impression material is pressed against the gums that have no teeth in the patient's mouth or only a small portion of the teeth, and the shapes of the gums and the uneven parts of some teeth are copied. As a negative mold, pour a solution of gypsum in water into it to harden it, and use this as a positive model to press the above-mentioned softened “resin” to form a tray.

When performing an impression taking operation, a separately prepared elastic impression material such as condensed silicone rubber is adhered to the uneven upper surface, inserted into the mouth of the patient, and chewed by the upper and lower gums.

Through the above work, the shape of the upper or lower gum is precisely used for the condensed silicone rubber and used.

In the above work, instead of using a mixture of powdered polymethylmethacrylate resin and liquid methylmethacrylate monomer as the "resin", a natural resin called "modeling compound" and a stearic acid which is plastic are mixed in advance. A method of preparing a thermoplastic material having a melting point of 70 to 80 ° C and heating and softening it at the time of mold making work is also partially used.

However, the method using the "resin" or "modeling compound" as described above has the following drawbacks.

(Problems to be solved by the invention) The problem is that in the above materials, "range" must be used by mixing two types of substances, a polymer and a monomer, before the work. It takes time to mix uniformly, and it takes a long time for the mixture to cure, specifically about 30 minutes from the start of work to curing, and it is a liquid monomer. Poor workability due to having to use methylmethacrylate, and because they are relatively unstable substances, care must be taken in the storage state so that they do not deteriorate, and there is a peculiar odor during work. Is.

On the other hand, the "modeling compound" has the disadvantage that it is brittle and cracks when a large force is applied due to its low strength.

The present inventor has disclosed a method for taking a dental impression using a tray made of a polycaprolactone resin composition as an improvement over these drawbacks in Japanese Patent Laid-Open No. 171554/1988.

However, the use of polycaprolactone resin as a tray for obtaining a dental impression has the following problems.

That is, the polycaprolactone resin disclosed in Japanese Patent Laid-Open No. 171554/1988 is a case where a polycaprolactone resin having various molecular weight distributions is used alone, and has a molecular weight of 10,000 to 70,000, and is simply the blended resin described in the present invention. From the viewpoint of the average molecular weight, those belonging to the same range are included.

However, as described below, it was found that special performance is exhibited when the morphology of the molecular weight distribution is different.

That is, the polycaprolactone resin having a high relative viscosity (that is, a high molecular weight) alone has a problem that the bending strength of the tray when used as a tray is insufficient and the viscosity at the time of melting is high. There is.

In view of such a situation, the present inventors have completed the present invention as a result of intensive studies.

(Structure of the Invention) That is, the present invention is characterized in that "a polycaprolactone resin having a relative viscosity of 1.50 to 2.80 and a polycaprolactone resin having a relative viscosity of 1.15 to 1.50 are blended at a weight ratio of 85/15 to 30/70. Resin composition for dental impression taking tray material ".

The relative viscosity referred to in the present invention is a viscosity measured using a capillary viscometer (Ubbelohde viscometer).

The measuring method was performed according to JIS K6726.

However, the value is measured at a solvent concentration of 1% and a temperature of 25 ° C plus or minus 0.05 ° C.

The point of the resin composition for the tray material used when taking the dental impression of the present invention is that the resin is safe in the mouth of the patient instead of the above-mentioned "resin" or "modeling compound", that is, at a temperature that does not cause burns. Needless to say, it can be used as a method of softening and hardening at room temperature.
The properties which cannot be exhibited when the polycaprolactone resins having various molecular weights disclosed in JP-A-171554 are not used alone are exhibited by polymer blending.

When the polycaprolactone resins having various molecular weights disclosed in JP-A-63-171554 are used alone,
It is sufficient as a substitute material for "resin" and "modeling compound", but when it is made as a tray, it is still insufficient in terms of bending strength.

Moreover, it is not affordable to faithfully transfer the state of unevenness with fine viscosity during melting.

These points have been solved by using a blend of two polymers having different relative viscosities (that is, two polymers having different molecular weight distributions).

Among the polycaprolactone resin blends described in the present invention, the polycaprolactone resin having a relative viscosity of 1.50 to 2.80 has a molecular weight distribution as shown in the GPC chart of FIG. 2 as a representative example.

Further, among the polycaprolactone resin blends described in the present invention, the polycaprolactone resin having a relative viscosity of 1.15 to 1.50 is a typical grade having a molecular weight distribution as shown in the GPC chart of FIG. is there.

A thermoplastic polycaprolactone resin which has a softening point of 50 to 80 ° C. and is solid at room temperature, which is used in a resin composition for a tray material used when taking a dental impression of the present invention, is produced as follows. To be done.

That is, it can be obtained by subjecting a lactone monomer such as ε-caprolactone monomer to ring-opening addition polymerization in the presence of an initiator having an active hydrogen group and a catalyst.

As the catalyst used in this reaction, organotin compounds, organotitanium compounds, organohalogen compounds are generally used, and the amount used is 0.1 to 5000 pp with respect to the starting material.
m, preferably 10-100 ppm.

A suitable reaction temperature is 100 to 230 ° C, and it is advisable to carry out the reaction in an inert gas.

It is not preferable to set the reaction temperature to 230 ° C or higher. This is because the depolymerization temperature of polycaprolactone is about 220-230 ° C.
Therefore, if the reaction is carried out at a higher temperature than this, the polymer is decomposed and the molecular weight does not increase.

On the contrary, when the reaction temperature is 100 ° C or lower, the reaction rate is slow and the efficiency is poor.

This thermoplastic polycaprolactone resin has various molecular weights (that is, relative viscosities) ranging from liquid to solid at room temperature, and is used for various purposes. Taking the dental impression of the present invention In order to use as a material for the tray in the tray material resin composition used in the case of, it is preferable to blend a polycaprolactone resin having a relative viscosity of 1.50 to 2.80 and a relative viscosity of 1.15 to 1.50 by the following method. Most preferred.

A polycaprolactone resin having a relative viscosity of 1.50 to 2.80 is commercially available for various purposes. For example, a boosting operation object (JP-A-60-240692), plastic clay (JP-A-61-42679), Medical cast (JP-A-58-8104)
2), splint materials, face masks for radiation irradiation, wig patterning (JP-A-60-215018), etc.

Specific examples of the polycaprolactone resin having a relative viscosity of 1.50 to 2.80 include caprolactone H-7 manufactured by Daicel Chemical Industries, Ltd. and commercially available.

Polycaprolactone resins having relative viscosities of 1.15 to 1.50 are also commercially available for various purposes and are used as general resin modifiers.

Specific examples thereof include caprolactone H-1 manufactured by Daicel Chemical Industries, Ltd. and commercially available.

Therefore, these commercially available products may be purchased and used.

The GPC chart of FIG. 1 shows the molecular weight distribution pattern of the resin composition when the polycaprolactone resins having the two different relative viscosities (that is, the two different molecular weight distributions) as described above are blended in a predetermined ratio. It becomes something like.

As shown in the GPC chart shown in FIG. 1, the characteristic of the molecular weight distribution pattern of the blended resin composition is that the main peak is divided into a plurality of peaks as compared with the case of a single case.

It can be proved that the peaks are blended by being divided into a plurality of peaks.

In addition, Fig. 4 shows GPC of a grade having the same viscosity (that is, molecular weight distribution) as the blended resin composition.
It is a chart.

FIG. 5 shows three types of GPC charts of a single resin in which the positions on the horizontal axis are aligned with each other.

The following method is used to blend the above-described two types of polycaprolactone resins having different relative viscosities (that is, molecular weight distributions) at a predetermined ratio.

That is, commercially available resin pellets or flakes, powders, etc. may be purchased and blended in an extruder. Alternatively, when each resin is discharged from the polymerization vessel after polymerization, each high-viscosity product The resin in the state may be mixed in an extruder.

These methods are appropriately selected depending on the difference between the resin manufacturer and the processor who purchases and processes the raw material.

It is appropriately selected by the raw material resin manufacturer in relation to the production volume.

When the resin composition thus blended is applied to the method of the present invention, the following method may be used.

That is, it may be distributed in the form of a bag in the form of pellets, immersed in warm water or softened with hot air at the main place of use, such as a dental clinic or dental laboratory, and molded into a desired shape before use. .

In addition, at the resin molding manufacturer, the blended resin pellets as described above can be used in a heart shape or horseshoe thickness of 1
A plate-shaped product having a size of up to 5 mm, for example, a product called a flat blank and shipped to the market may be softened and used as described above.

An example of what is called a flat blank is that disclosed in JP-A-58-38544.

However, it is preferable to use a blended resin pellet in the form of a bag as it is circulated in a bag rather than a flat molded product called a flat blank because it can handle various situations.

It is economical because (1) only the necessary amount can be used for the following reasons.

(2) In particular, when making a tray for the lower jaw, it is faster to press a thicker rod-shaped product than a plate-shaped molded product called a blank for quicker work.

In the case of pellets, it can be formed into a rod shape having an arbitrary thickness.

(3) When a sheet-shaped blank is pressed against the jaw model, it becomes extremely thin, making it difficult to form.

Next, a specific work procedure when using the resin composition of the present invention will be described.

(1) How to make a personal tray Remove the spacer such as paraffin wax from the work model beforehand Put the required amount of resin in a container and pour boiling water at 90 ° C or higher,
When all the resin particles are transparent, throw away the hot water, hold the lump in your palm and squeeze it tightly a couple of times to dispel the water.

If it is hot at this time, quickly pass it through water and then take it on your palm.

At this time, if the container is covered with gauze, the adhesion of the resin can be prevented.

Next, the outer shape of the individual tray is created on the working model and immersed in cold water to cure it.

(If the water temperature is 15 ° C or higher, it will harden in a short time using ice water.) After confirming the hardening, remove the tray from the work model.

(If there is a semi-transparent part on the inner surface of the tray, it is better to harden it with cold water.) (2) Method for streaking when impression of dentures 2mm margin of the individual tray created by the above method
Heat only to a degree to soften (until transparent).

Then, soak it in water and touch it to the extent that it is not hot to the touch (45
When the surface temperature reaches about ℃), muscle formation is performed in the oral cavity.

After completing the streaking, the tray is hardened with cold water.

The polycaprolactone resin used in the resin composition of the present invention may be white, but may be colored pink or the like.

When using this for impression taking work, prepare hot water having a temperature around the softening point or soften the resin with a hair dryer-like warmer that uses electric heat, and use the "resin" or " Used in place of "Modeling Compound".

Although the resin produced by the above method can be stored or transported for several months, the polycaprolactone resin is a polyester resin, so that the molecular weight due to hydrolysis peculiar to the ester bond is high. A decline occurs.

In order to prevent this, a part of the epoxy resin is added in place of a small amount of water serving as the above-mentioned initiator and polymerized, and the resin obtained is remarkably improved in hydrolysis resistance.

(Effect of the invention) The resin composition for a tray material used for taking a dental impression using the tray made of the blended thermoplastic polycaprolactone resin of the present invention has a significantly shortened working time and The strength is remarkably improved, the viscosity at the time of melting is reasonable, the management is easy, there is no change with time, and the patient is not uncomfortable, which is preferable.

In addition, the tray made of the blended thermoplastic polycaprolactone resin used in the present invention has excellent dimensional stability.

The effects of the present invention will be described below with reference to examples.

Example -1 commercial polycaprolactone resin polycaprolactone -H ₇
(Daicel Chemical Industry Co., Ltd .: Relative viscosity 2.34) and commercially available polycaprolactone-H ₁ (Daicel Chemical Industry Co., Ltd .: Relative viscosity 1.28) were blended at the following ratios to produce a resin blend.

The blending operation was performed using a Brabender-Plastograph.

The respective characteristics and melt viscosities at the respective blend ratios are as follows.

Example-2 Commercially available polycaprolactone resin polycaprolactone-H ₅
(Daicel Chemical Industry Co., Ltd .: Relative viscosity 1.77) and the same commercially available polycaprolactone-H ₁ (Daicel Chemical Industry Co., Ltd .: Relative viscosity 1.28) were blended in the following ratios to produce a resin blend.

The blending operation was performed using a Brabender-Plastograph.

The respective characteristics and melt viscosities at the respective blend ratios are as follows.

[Bending strength measurement method] According to JIS K7203.

However, the stress at the time of bending by 5 mm was obtained by measuring the distance between fulcrums 4 cm, the test speed 5 mm / min, the temperature 20 plus or minus 2 ° C, and the humidity 65 plus or minus 5% RH.

The sample piece is 8 cm long, 3 cm wide, and 3 mm thick.

[Measurement method of melt viscosity] Using a Koka type flow tester, temperature 80 ℃, residual heat time 5
Min, orifice nozzle 1 mmφ, load 100 kg.

[Brief description of drawings]

FIG. 1 is a GPC chart of a composition prepared by blending two kinds of polycaprolactone resins having different relative viscosities used in the resin composition of the present invention. FIGS. 2 to 4 are GPC charts of polycaprolactone resins each having a single relative viscosity. FIG. 5 is a synthesized GPC chart of the polycaprolactone resin having the relative viscosity shown in FIGS. 2 to 4.

Claims (3)

[Claims] 1. A tray for taking a dental impression, characterized in that a polycaprolactone resin having a relative viscosity of 1.50 to 2.80 and a polycaprolactone resin having a relative viscosity of 1.15 to 1.50 are blended at a weight ratio of 85/15 to 30/70. Resin composition for materials. 2. A resin composition for a dental impression taking tray material according to claim 1, wherein the polycaprolactone resin is polymerized by using an epoxy resin as a part of the initiator. 3. A resin composition for a dental impression taking tray material according to claim (2), wherein the epoxy resin is an EP-type epoxy resin.