JP2999111B2 - Dental casting material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding material in the dental field.

[0002]

[Prior art and its problems]

(1) About dentures Partial dentures use a so-called clasp (a metal hook made by bending a wire or alloy casting and generally called a spring) as a maintenance device for installing it in the oral cavity. I use a lot. This is because the metal part extends from the artificial tooth part or the denture base adjacent to one side of the remaining tooth so as to cover the buccal side and the lingual side of the remaining tooth in a “crossed” manner, and the tip is the other of the remaining tooth. The undercut is located on the side of the left side, and the pinching force of the two wings of the remaining teeth is used for the maintenance of the denture.

[0003] Therefore, the clasps present on both wings of the remaining teeth impair the aesthetics of the oral cavity, wear the teeth, and cause the remaining teeth to sway.

[0004] In addition, since it is made of metal, there is a problem in that in a short period of time, loss of pinching force on the remaining teeth due to metal fatigue or loss of the function of maintaining the denture due to breakage of the hook blade causes a major cause of dissatisfaction when wearing the denture. Has become. There are also attachments (metal connecting tools), but most of them have a metal crown over the remaining teeth, one of the attachments is fixed to the remaining teeth by means such as soldering, the other is embedded and fixed in the denture, and both are fixed. The space is mechanically connected to each other, so that the two can be attached and detached. There is also a so-called telescope similar to the relationship between a tea caddy and a lid. This is done by placing the inner crown of a metal double crown over the remaining teeth, connecting the outer crown to the denture,
The frictional resistance of the outer crown is used for maintaining the denture.

[0005] When these attachments and telescopes are used, there are problems such as the massive removal of dentin and the technical difficulty in the operation, and the use of precision parts made of precious metals and the necessity of advanced and precise techniques are expensive. It is not a universal technology because of the high cost of treatment.
In addition, there are many problems such as a problem of breakage due to a noble metal precision part having insufficient hardness and strength and difficulty of maintenance.

(2) Denture base A denture is generally installed in the oral cavity with its stability depending on the attraction force and its maintenance force (resistance to denture detachment) depending on the remaining teeth. In the case of a complete denture with no remaining teeth, the denture base is set as wide as possible and the denture base is extended to the undercut of the ridge to enhance the attraction and maintenance. In recent years, attempts have been made to improve the retention of dentures by embedding ceramic granules under the ridge ridge mucosa and artificially constructing an undercut.

The conventional denture base designed to cover the undercut with the denture base resin is apt to damage the ridge at the time of attachment / detachment, and often results in the denture base extending to the angle undercut part being deleted. .

(3) Molding Material One of the basic techniques of dental technology is a casting technique by a lost wax method, and wax is usually used as the molding material. However, the conventional molding material wax has a high plasticity at room temperature and is liable to be deformed. In particular, the tip portion expands when the molding material is removed from the gypsum model at the time of molding. Cause a decrease in the accuracy.

(4) Basic Concept for Solving Problems Recently, attention has been paid to synthetic resins having shape memory properties, and techniques for using shape memory resins in special modes are being developed in various fields. This shape memory resin is
Utilizing a large change in elastic modulus before and after the glass transition point, heating and softening to a temperature above the glass transition point, deforming into a desired shape, maintaining this deformation and cooling to a temperature below the glass transition point, This deformed shape is fixed, and the fixed shape can be easily erased (recovered) by heating to a temperature higher than the glass transition point.

The present invention has been made by paying attention to the properties of the shape memory resin, and aims to solve the above-mentioned problems of the denture, the denture base and the molding material by effectively utilizing the properties. .

[0011]

In order to solve the above-mentioned problems, the present invention provides the following dentures, denture bases, and molding materials.

1) A denture characterized in that the denture base is made of a shape memory resin.

[0013] 2) A denture characterized in that the denture base portion located at the remaining tooth undercut is made of a shape memory resin.
tooth.

3) It is characterized in that at least a portion of the denture base located at the ridge undercut is made of a shape memory resin.
The denture base to be marked.

4) A molding material characterized in that a low-melting-point resin is overlapped on a shape-memory resin molded product and joined.

[0016]

[Action and effect]

(1) Denture The denture according to the present invention has the following operation and effects. When the denture base is made of a shape memory resin, the denture base is heated to a temperature higher than the glass transition point when worn in the oral cavity to be deformable, and fitted while deforming according to the intraoral shape,
In this state, it can be stably mounted by lowering the temperature to the intraoral temperature. At the time of detachment, the denture base can be easily removed by heating to soften and deform the denture base.

According to the denture in which the portion of the denture base located at the remaining tooth undercut is made of a shape memory resin, when the denture is attached, the remaining tooth undercut portion made of the shape memory resin is heated above the glass transition point. Deformable rubber state, deforming it along the narrowing part of the remaining tooth, fitting it in, and then lowering the temperature to the body temperature below the glass transition point. It can be firmly fixed, and the denture can be prevented from falling off and a good maintenance state can be obtained. On the other hand, when removing the denture, the undercut portion is softened and deformable by heating it to a temperature equal to or higher than the glass transition point, so that the denture can be easily removed.

(2) Denture base In the denture base according to the present invention, since at least the portion located in the ridge undercut is made of a shape memory resin, it is heated and softened to a temperature higher than the glass transition point when the denture is detached. This allows the denture to be removed by opening the part that covers the ridge undercut. By fitting to the cut portion, the device can be stably mounted, and by directly lowering the temperature to body temperature, the undercut can be covered without damaging the ridge.

(3) Molding Material Since the molding material according to the present invention is formed by laminating a low-melting resin on a shape memory resin, precision molding by the low-melting resin and shape memory of the shape memory resin are performed. It has both.
Therefore, this is heated and the low-melting-point resin is applied to the mold to perform molding, and the temperature is lowered as it is to bring the shape memory resin into a glass state, thereby maintaining the molding state, and performing high-precision molding. It can be carried out.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 relate to partial dentures,
In particular, FIGS. 3 to 5 show changes in the shape of the maintenance device when the denture is worn. In each figure, (1) is a denture in which an artificial tooth (2) and a denture base (3) are integrally formed. (4) is a remaining tooth, and (5) is a gum. FIG.
5 to 5 show partial dentures having a large floor area applied to a case in which the remaining teeth are isolated, and FIGS. 6 and 7 show intermediate dentures having a small floor area when the remaining teeth are located at both ends of the denture. The partial denture was shown.

The denture base is made entirely of a shape memory resin, or the base portion is made of an acrylic resin or another resin, and the undercut portion (3a) of the remaining teeth (4) is made of a shape memory resin. The remaining portion (3a) made of shape memory resin is replaced with the remaining tooth undercut portion (3a) of the denture base.
It is manufactured separately as b) and embedded in or adhered to the denture base.

The attachment / detachment of the denture when the denture retaining portion (3b) is used will be described below.

When the denture (1) is mounted, the shape memory resin holding portion (3b) is heated to a temperature higher than its glass transition point to be in a deformable rubber state. This heating may be performed on the entire denture including the maintenance part (3b) by immersing the denture in warm water, or a part including only the maintenance part (3b) or its surroundings by blowing heated air or the like. May be performed for In this state, the void portion of the denture is fitted to the remaining tooth (4) in the order shown in FIGS. At this time, as shown in FIGS. 3 to 5, the maintenance portion (3b) of the denture base is fitted while being deformed and fitted along the undercut portion of the remaining tooth, and the state shown in FIG. 5 is maintained.
By setting b) to be equal to or lower than the glass transition point, the maintenance portion (3b) is deformed and fixed to a glass state, so that the denture can be firmly held.

On the other hand, when removing the denture (1), the maintenance portion (3b) is heated to a deformable rubber state,
If the tooth is pulled out from the remaining teeth, the maintenance part (3b) is deformed, so that the denture can be easily removed. Maintenance part (3
The heating of b) can be performed by, for example, containing hot water having a temperature equal to or higher than the glass transition point in the oral cavity, for example, hot water of 60 ° C. to 65 ° C., and sufficiently bringing hot water into the maintenance portion. Alternatively, the maintenance can be performed by blowing hot water or hot air at an appropriate temperature on the maintenance portion. These heating methods for attaching and detaching dentures can be used in the same manner in the case of the following denture base.

Alternatively, when the entire denture base is formed of a shape memory resin, and when the portion located at the remaining tooth undercut is formed of a shape memory resin, the denture can be similarly attached and detached. That is, when attaching and detaching the denture, the shape memory resin portion or the entire denture including the same is heated to a temperature higher than the glass transition point of the shape memory resin constituting the denture to make the elastic material elastic, and the ease of deformation is utilized. In the state of wearing in the oral cavity, curing at a temperature below the glass transition point allows the denture to be attached so that the narrowed portion of the remaining tooth is sandwiched from both adjacent surfaces of the denture base, so the maintenance power is compared with the clasp It is strengthened so as not to become. as a result,
The area of the denture base can be made sufficiently small, the temperature and taste of food can be felt, and it is easy to design and manufacture a so-called non-palatal denture with no pronunciation disorder, and the feeling of wearing a denture is improved.

Further, since there is no rubbing of the tooth surface at the time of wearing a denture like a clasp, there is no problem of dentin wear,
Unlike clasps that can protect the dentin of the remaining teeth and clamp the remaining teeth on the surveyor line from both sides, the occlusal stress of the denture is less transmitted to the remaining teeth, and the maintenance part applies the remaining teeth to the remaining teeth. Damage can be prevented.

Furthermore, it is a synthetic resin, which is extremely inexpensive, has almost no risk of breakage or deformation like a metal clasp, and is extremely easy to replace even if its function is deteriorated or damaged for some reason after use. There is no need to remove dentures for days for maintenance. By using a shape memory resin, these can be made the same color as the tooth color or the gum color, so that a part of the tooth surface is not covered with a metal color like a metal clasp, and the natural feeling is not impaired. Performance can be improved.

Next, an example of a denture having a denture base according to the present invention will be described with reference to FIGS.

The denture (1) includes an artificial tooth (2) and a denture base (3), and a portion (7a) near the ridge undercut of the denture base (3) is formed of a shape memory resin. 7
b) is composed of an ordinary acrylic resin or the like. Both parts (7) and (8) are firmly connected by adhesion or fusion.

As described above, the portion near the undercut of the ridge is made of a shape memory resin, so that when the denture leaves the oral cavity, the denture is heated to a temperature higher than the glass transition point to soften the denture. Can be opened and removed. On the other hand, at the time of installation, the chin ridge undercut is opened in the open state, then heated and deformed so that it fits the chin ridge, and attached to the chin ridge. Can cover the undercut portion and stably mount the denture. Therefore, even if the denture base is manufactured to be extended to the undercut portion of the ridge, there is no risk of damaging the ridge when attaching and detaching. In addition, since the floor area of the denture base can be increased, it is possible to improve the maintenance force when the denture is worn.

In the above embodiment, an example was described in which only the portion near the undercut of the ridge was made of a shape memory resin. However, the same applies when the entire denture base was made of a shape memory resin.

FIGS. 10 to 13 show an embodiment of a molding material according to the present invention. The molding material (8) is formed by laminating a shape memory resin (9) and a low melting point resin (10) having a melting point of about 60 ° C.
Both are bonded or fused. This molding material (8) is used for making a casting model of the metal fitting (12) for maintaining the denture (11) as shown in FIG. 11, and is used as follows. First, using the molding material (8), a part (15) corresponding to the maintenance metal fitting (12) is molded from the gypsum model (3) as shown in FIG. At this time, the molding material (8) is heated above the melting point of the low-melting resin, and the low-melting resin (10) side is pressed against the tooth surface to mold. In this case, since the shape memory resin (9) is also heated and softened to a temperature higher than the glass transition point, it is easily deformed. After molding in this way, the temperature is lowered to fix the shape of the shape memory resin (9). In this state, the sprue (14) is implanted in the part (15), and the sprue is pulled out of the model (13) by holding the sprue. The casting model thus obtained is buried in foundry sand and used for casting in a usual manner. According to this molding material (8),
Precise molding can be performed due to the good molding material of the low melting point resin and the ease of deformation of the shape memory resin during heating.

Further, according to the present molding material, even a complicated one as shown in FIG. 13 can be directly molded from a gypsum tooth mold.
The manufacturing process of the cast body can be shortened. In addition,
Examples of the shape memory resin that can be used for the above-described denture maintenance device, denture base, and molding material include urethane-based, styrene-butadiene-based, crystalline diene-based, and norbornene-based polymers.

Among them, polyurethane is preferable, and more specifically, a difunctional isocyanate: polyol: chain extending agent is used in a molar ratio of a bifunctional diisocyanate, a difunctional polyol, and a bifunctional chain extender containing an active hydrogen group. Agent = 2.0
~ 1.10: 1.00: 1.00-0.10 and polymerized by a prepolymer method, containing approximately equal amounts of NCO and OH groups at the terminals, and having a glass transition point of-
Those having a temperature of 50 to 60 ° C. and a crystallinity of 3 to 50% by weight are suitably used.

Since this polyurethane does not have an excess NCO group at the terminal of the molecule, the cross-linking reaction does not proceed, and it is a chain-like molecule. Molding can be performed easily and well.

The raw material of the above-mentioned polyurethane, 2
The functional isocyanates of the general formula is represented by OCN-R-NCO, R is - (CH ₂₎ - means an _n group one or two phenylene groups. Specifically, 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, carbodiimide-modified 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate and the like can be used.

Further, as the bifunctional polyol, general formula is represented by OH-R'-OH, R 'is - (CH ₂₎ - means an _n group one or two phenylene groups. Further, a reaction product of a bifunctional polyol and a bifunctional carboxylic acid or a cyclic ether can be employed. Specifically, polypropylene glycol, 1,4-butane glycol adipate, polytetramethylene glycol, polyethylene glycol, a reaction product of bisphenol A and propylene oxide, and the like can be used.

As the bifunctional chain extender containing an active hydrogen group, the general formula is represented by OH—R ″ —OH, where R ″ represents a — (CH ₂ ) _—n group, one or two phenylene groups. And the reaction products of the chain extenders with bifunctional carboxylic acids or cyclic ethers. Specific examples include ethylene glycol, 1,4-butane glycol, bis (2-hydroxyethyl) hydroquinone, and bisphenol. A reaction products with ethylene oxide, bisphenol A and propion oxide, and the like can be used.

The polyurethane of the present invention synthesized from these raw materials can be represented by the following general formula.

HOR "OCONH (RNHCOOR'OCONH) nRNHCOO-R" OCONH (RNHCOOR'OCONH) mRNHCOOR "OH m = 1 to 16 n = 0 to 16 Table 1 shows an example of preparation of the shape memory polyurethane elastomer. For example, by using No. 40 in Table 1, one having a glass transition point of 48 ° C. can be produced.
The glass transition point can be freely set by changing the type, blending ratio, and the like of the above-described isocyanate, polyol, and chain extender.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

[Table 4]

[Brief description of the drawings]

FIG. 1 is a rear view of an embodiment of a denture according to the present invention as viewed from a lingual side.

FIG. 2 is a plan view of the embodiment of the denture according to the present invention as viewed from the lingual side.

FIG. 3 is a rear view sequentially showing a process of mounting a denture.

FIG. 4 is a rear view sequentially showing a process of mounting a denture.

FIG. 5 is a rear view sequentially showing a process of mounting a denture.

FIG. 6 is a rear view showing an embodiment of a denture in the case of a missing intermediate tooth.

FIG. 7 is a rear view showing the mounted state of the denture of FIG. 6;

FIG. 8 is a plan view of a denture provided with a denture base according to the present invention.

FIG. 9 is a longitudinal sectional front view of the denture base of FIG. 8;

FIG. 10 is a perspective view of a molding material for clasp casting according to the present invention.

11 is a plan view of a denture manufactured using the molding material of FIG.

FIG. 12 is a front view showing a molding state using the molding material of FIG. 10;

FIG. 13 is a perspective view of a molding material after the molding according to FIG. 12;

[Explanation of symbols]

 (1) ... denture (2) ... artificial tooth (3) ... denture base (3a) ... undercut part (3b) ... maintenance part (4) ... remaining teeth (5) ... gingiva (6) )… Ridge (7)… Undercut part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61C 9/00 A61K 6/10

Claims (1)

(57) [Claims] 1. A dental molding material wherein a low-melting-point resin is superimposed on a shape-memory resin molded product and bonded.