GB2209563A

GB2209563A - Syringe for the preparation of casting patterns

Info

Publication number: GB2209563A
Application number: GB8819884A
Authority: GB
Inventors: Akira Hasegawa
Original assignee: GC Dental Industiral Corp
Current assignee: GC Corp
Priority date: 1987-09-09
Filing date: 1988-08-22
Publication date: 1989-05-17
Anticipated expiration: 2008-08-22
Also published as: JPS6471549A; GB2209563B; DE3827963A1; GB8819884D0

Description

1J1 1 -7 225956j SYRINGE FOR THE PREPARATION OF CASTING PATTERNS The

present invention relates to a syringe for the preparation of various types of deLtal casting patterns (clasp, inlay, lingual bar, palatal bar, skeleton, casting plate, crown bridge and like patterns), which can easily define the sectional shapes thereof and makes dies placed at its extreme end easily replaceable.

Various types of linear casting wax having various sectional shapes (e.g., Ready-Casting Wax manufacted by GC Dental Industrial Corp.) have currently been used for casting clasps, lingual bars, palatal bars, skeletons, sprues and so on. Such castings are prone to deformation at room temperature because of the castings being formed of wax. For that reason, castings of improved fit-accuracy have been prepared by the so-called entire-mold-investing method technique comprising the steps of taking an impression of a working model, replacing it by a modeling investment and carrying out waxing-up to invest it in a casting investment, followed by casting. This technique eliminates the need of using any syringe for the preparation of casting patterns such as one contemplated in the present invention, since linear casting wax, to which the desired shape is previously imparted, is already provided in that case.

The aforesaid entire-mold-investing method technique making use of a paraffinic wax pattern is costly as regards the materials to be used, for instance, the impression material for impression-taking and the modeling material, and involves a troublesome and timeconsuming step of preparing dental castings. Further, the use of the -Zconventional paraffinic wax pattern essentially requires to use an exclusive bonding agent (e.g., one manufactured by GC Dental Industrial Corp. and available in the trade name of Preform Bond). Since a film of about 50 pm is then formed between wax pattern and modeling investment, it is impossible to obtain any dental casting of satisfactory fit- accuracy. Still further, the paraffinic wax pattern has an adverse influence upon the shape and surface nature of the model, since it is pressed against the modeling investment by hand and fingers, thereby causing peeling-off of the investment particles. Still further, the wax of the paraffinic wax pattern expands so rapidly at the time of incineration that the investment may crack or roughen on its surface. In order to solve these problmes, there has been developed lightpolymerizable casting pattern resin as a new replacement to the paraffinic wax pattern (Japanese Patent Application No. 15610111987 and 'corresponding U.K. Patent Application No. 8813643.7).

Since this material is polymerized upon exposure to light (activated energy rays), it is vital to use a container which does not transmit light. The -following possible forms of container have been considered by the inventor: 1. Syringe, 2. Box, 3. Sheet,and 4. Jar.

Of these, the box container needs to prepare various casting patterns which have previously been molded. Difficulty is encountered in keeping the casting patterns from being exposed to light before use, and the light polymerizable pattern resins for casting are very poor in storage stability. In.the case of the sheet container, it is only possible to make casting patterns in the form of a sheet, and it is hence impossible to obtain casting patterns capable of meeting various purposes. As is the case with the box container, the jar container cannot prevent the transmission of light. Not only are 1 1 1 -3light polymerizable pattern resins for casting poor in storage stability, but it is also impossible to previously make casting patterns suitable for various purposes. Whenever need arises, a caster has to make a casting pattern. For that reason, dental castings take time and labor to prepare. Taken altogether, of these containers, the syringe is taken as being the most suitable to contain a light polymerizable pattern resin for casting in view of its storage stability with respect to the transmission of light and by reason that it is easy to obtain a casting pattern suitable for the intended purposes.

The present invention is based on the following considerations.

1. A syringe for the preparation of a casting pattern can nave a die which has a through-hole designed such that, when such a content as a light polymerizable pattern resin for casting is extruded through said syringe, the sectional shape of the thus extruded content can conform to the sectional shape of the end casting pattern.

2. A dental casting pattern takes on about 16 sectional shapes for different purposes. However, there is unavailable any single syringe capable of meeting such all purposes. Therefore, wat is provided is - a syringe for the preparation of a casting pattern, which allows dies having through-holes conforming to various sectional shapes to be replaceably attached to its extreme end.

As a result of extensive and intensive studies, it has tnusbeen found that the foregoing problems can be solved by the provision of the following syringes for the preparation of casting patterns, which are designed to be used with light polymerizable resins.

1. A syringe for the preparation of a casting pattern, characterized in that dies having various through-holes are replaceably attached to its extreme end according to purposes to extrude its content therethrough, thereby imparting the desired sectional shape to said casting pattern.

2. A syringe for the preparation of a casting pattern, characterized in that dies having through-holes of various shapes are replaceable at its extreme end.

Table 1 sets out definite shapes, dimensions. and main applications of possible dies.

Table 1 unit (m) Shape of Width (Dian-eter)IHeightl Through- Main Purposes Holes 0.5 Resin retaining wires and bents 0.7 of rretal plates 1.0 1.5 Sprue wires of crowns, bridce-s, 2.0 and inlays 2.5 3.2 Sprue wires of metal plates 4.0 5.0 1.4 1.1 Clasps 1.9 1.0 2.2 1.2 2.8 1.1 Side 1. 7) Border beb.k--en n-p-tal and resin plates 4.0 1. 0 Palatal bars 3.1 1. 4 Lingual bars 1 -5.- These through-holes of varied shapes, widths (diameters), and heights may be used according to purposes. It is noted, however, that the dimensions and shapes of such through-holes are not limited to those set out in Table 1.

In the accompanying drawings:

FIGURE 1 is an exploded perspective view of parts of one syringe for the preparation of a casting pattern according to the present invention, and FIGURE 2 illustrates dies having various through-holes.

The materials forming the syringe for the preparation of casting patterns according to the present invention may optionally be selected from thermosetting resins, thermoplastic resins, hard rubber, metals, ceramics and so on.

The thermosetting resins used may include melamine, phenolic, unsaturated polyester, alkyd, epoxy, urea, polyurethane, polyamide, furan, silicone and other resins. The thermoplastic resins used may include polyethylene, polypropylene, polystyrene, polymethyl methaerylate, polyvinyl chloride, nylon, polytetrafluoroethylene, polycarbonate and so on. The hard rubber used may include butadieneacrylonitrile rubber, butadiene-styrene rubber, acrylonitrilestyrenebutadiene rubber, high-impact polystyrene and so on. The most suitable metal is stainless steel, and ceramics used may include sintered alumina, zirconia, silicon nitride, silicon carbide, magnesia, silica and so on. Composite materials comprising these substances filled with fibers or particles may also be used.

The syringe for the preparation of casting patterns molded of such materials should be of such mechanical properties as represented in terms of the resistance that permits it to sufficiently stand up to an internal pressure produced at the time when its content is extruded from dies having varied through-holes and of the rigidity that prevents its temporal or permanent distortion. The present syringe should also be of such chemical properties that its content is not degraded over an extended period of time, its content does not react with it, and it is not deteriorated by environmental substances such as ozone.

Since the content, i.e. a casting pattern,is polymerized by light (activated energy rays), the syringe for the preparation of casting pat terns according to the present invention should not transmit light (activated energy rays) therethrough. For that reason, a syringe for the preparation of casting pattern made of a thermosetting or thermoplastic resin needs to be filled with a pigment to shield light (activated energy rays), since that resin can easily transmit light. As the pigment, use may be made of any substance that can shield light (activated energy rays) such as organic or inorganic pigments and metal oxides.

Example

Fig. 1 is a perspective view of the syringe for the preparation of casting patterns according to the present invention, wherein reference numeral 1 stands for a cap; 2, a die having various throughholes; 3, a syringe body; 4, an intermediate plug; 5, a threaded cap; 6, a plunger; and 7, a through-hole.

Refer-ring to the assembling of the syringe according to the present invention, a light polymerizable pattern resin for casting that is the content thereof is first filled in the syringe body 3, and the intermediate plug 4 is forced thereinto from the side of the plunger 6. Next, the threaded cap 5 is threadedly fitted onto the syringe body 3 and the plunger 6 is inserted into the cap 5. The die 2 having a through-hole of the desired shape is then selected and positioned at an outlet portion of the syringe body 3, which is in Y 1 turn capped with the cap 1 in such a manner that light is not incident upon the resin. In order to obtain the end casting pattern, the cap 1 is removed ana the sy'rirj-gz bo.ly 3 hild by one hand while turning the plunger 6 clockwise by the other hand. Once a casting pattern having the required length has been obtained, it is cut in conformity with the through-hole 7 by a wax instrument. When this syringe is not used while its content still remains, it should be immediately capped with the cap 1. Since the die 2 having the through-hole 7 is replaceable and internally threaded, its attachment to or detachment from the syringe body 3 is easily achieved without admitting light.

Fig. 2 illustrates the dies having various through-holes, which find different applications depending upon the shapes and dimensions of their through holes. Through-holes of (a) 0. 5 mm (b) 0. 7 mm and (c) 1.0 mmo are primarily used for resin retaining wires and bents of metal plates; (d) 1.5 mmo, (e) 2.0 mmo and (f) 2.5 mmo for sprue lines of crowns, bridges and inlays; and (g) 3.2 mmo, (h) 4.0 mmo and (i) 5.0 mmo for sprue lines of metal plates. A through-hole for clasps takes on four semicircular shapes of, in width and the largest height, (j) (1.4 mm and 1.1 mm), (k) (1.9 mm and 1.0 mm), (1) (2.2 mm and 1.2 mm) and (m) (2.8 mm and 1.1 mm). A through-hole in the form of a regular triangle (-n), each side of 1.7 mm, is mainly used for a border of a metal plate and a resin plate. A through-hole for palatal bars is in the form of a rectangle (o) of 4 mm x 1 mm, and a through-hole for lingual bars (p) in the form of a rectangle of 3. 1 mm X 1. 4 mm.

In this example, the syringe for the preparation of casting patterns was made of black polypropylene which incorporated iron oxide (red oxide of iron MTB-10) manufactured by Morishita Bengara. Molding was injection molding.

-a- With the syringe for the preparation of casting patterns disposed Arjove, it is possible to rapidly and easily obtain, from a light polymerizable pattern resin for casting, a pattern according to the purpose.

Since the desired die is selected from 16 dies having varied throughholes and can be easily attached to or detached from the syringe body of the syringe for the preparation of casting patterns as -described above, it is unnecessary to keep dies having variously shaped through-holes at hand, and it is thus possible to obtain variously shaped casting patterns with a single syringe.

While the present invention has been described with reference to the specific embodiment illustrated in the drawings attached hereto, it is understood, however, that many changes and/or modifications may be possible within the scope of the present invention as defined in the appended claims.

n i

Claims

Claims:-

A syringe for the preparation of casting patterns, comprising a material incapable of transmitting activated energy rays, to which dies having through-holes of sectional shapes suitable for different purposes are replaceably attached.
2. A syringe for dispensing a casting pattern of light polymerizable material, comprising a hollow body for containing the said material, extrusion means, and a die having a through-hole through which the pattern is to be dispensed, the syringe being non-transmissive to light and the die being exchangeable.
3. A syringe as claimed in claim 2, including a removable cap closing the exit of the through-hole.
4. A syringe as claimed in claim 2 or 3, in which the extrusion means comprises a plug which is fitted in the body and can be forced towards the die.
5. A syringe as claimed in claim 4, including a screw-threaded plunger for forcing the plug towards the die.
6. A syringe as claimed in any of claims 2 to 5. in which the hollow body contains a light polymerizable material.
7. Apparatus for dispensing casting patterns, comprising a syringe according to any of claims 2 to 6 and a plurality of interchangeable dies having through-holes of various shapes.
8. A syringe substantially as described with reference to. and as shown in, Figure 1 of the accompanying drawings.
9. Apparatus for dispensing casting patterns. substantially as described with reference to, and as shown in, the accompanying drawings.

1:

Published 1988 at The Patent Oflice. Stwe House. 6671 Higb Holborn. London WC1R 4TP Airther copies may be obtained from The Patent office, Sales Branch, St Mapy Cray. Orpington, Kent BR5 3RD Printed by Multiplex techniques ltd, St Mary Oray, Kent. Con 1 181 -. -1-, -j. ------------ --- __--------- --- --- ---0 ------ M'