GB2159167A

GB2159167A - Combination packaging for the production of dental compositions

Info

Publication number: GB2159167A
Application number: GB08512216A
Authority: GB
Inventors: Peter Schwabe; Reiner Voigt
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1984-05-26
Filing date: 1985-05-14
Publication date: 1985-11-27
Also published as: DE3419829A1; GB2159167B; IT8521895V0; IT8520839A0; DE3419829C2; JPS614A; FR2564730A1; CH665350A5; BE902488A; GB8512216D0; FR2564730B1; IT1183654B

Abstract

Two part silicone casting compositions for dentistry are colour coded for different classes of viscosity; for example, by dyeing the base paste a colour assigned to the respective class of viscosity and filling part of the catalyst paste dispenser (1) with a paste of the same colour (J), the remainder (K) being undyed or of a contrasting colour. The illustrated arrangement will produce a catalyst paste with stripes of the same colour as the base paste. <IMAGE>

Description

SPECIFICATION Combination packaging for the production of dental compositions This invention relates to a combination packaging for the production of a dental composition, based on polysiloxane, with a given viscosity class which is curable at room temperature. Modern systems of such vinyl silicone pastes cross-link by the addition system and conventionally contain organopolysiloxanes with 2 or more vinyl groups in the molecule, organohydrogenpolysiloxane, a catalyst for accelerating the addition reaction, hydrophobic fillers and optionally further conventional additives and dyes.

These components are prepared in the form of a catalyst paste which contains the catalyst, silicone oil, fillers and optionally dyes and in the form of a base paste which contains the cross-linking agent, silicone oil, fillers and optionally dyes. Both pastes are filled into tubes, cartridges or similar dispensing means and are presented as combination packagings. The ready-to-use dental composition is produced in that the cross-linking agent-containing base paste is mixed with a corresponding quantity of catalyst paste. The cross-liking reaction is then completed after 2 to 5 min at room temperature.

In this case, the silicone oil is a vinyl terminated polydimethylsiloxane. The cross-linking agent contains the reactive SiH groups and the catalyst consists of a platinum complex. Both pastes are preferably suited to each other in that they have the same viscosity and can be processed in the mixing ratio 1:1. The following principle may be similarly applied to known silicone systems in which condensation cross-linking takes place. However, the mixing ratios vary in these systems.

As various methods are used in dentistry for casting jaws with full sets of teeth, partial sets of teeth and no teeth at all, and the mucous membrane, casting compositions of various classes of viscosity have to be offered. Thus, in double casting methods, kneadable compositions are required as preliminary casting material and casting compositions of low viscosity are required as correction materials, while in double mixing methods, highly-viscous compositions are required as spooning materials and compositions of medium viscosity are required as injection materials. Compositions are required in the single phase method which have medium to high viscosity.

The catalyst paste and the base paste are of different colours on the one hand to distinguish between the individual classes of viscosity. On the other hand, a different dye is used for the base paste than for the assigned catalyst paste in order to facilitate a visual mixing control. The base paste and the catalyst paste have to be intensively mixed together until a homogeneous mixture with a uniform colour is obtained.

While the kneadable compositions are generally packed in plastic containers, compositions of low, medium and high viscosity are filled into tubes or cartridges. In view of the various casting methods, casting compositions of corresponding classes of viscosity are kept in stock in the dental surgery.

Although the related tubes of one class of viscosity should be characterised in terms of colour in that the catalyst paste assigned to the respective base paste is immediately recognised, confusion of the tube and thus mixing of base and catalyst paste of different classes of viscosity cannot be completely ruled out. To confuse the tubes in this manner would modify the physical properties and thus cause a deterioration in the casting results. This is where the present invention comes into play.

An object of the present invention is to prevent the confusion of pastes of different classes of viscosity by a suitable colour coding of the two pastes.

This object is achieved in that one of the two pastes is dyed in a colour assigned to the respective class of viscosity and that a small proportion of the filling volume of the other paste is filled with a pasty inert substance or with the other paste and is dyed the same colour, while the paste contained in the remainder of the filling volume is not dyed or is dyed white or a contrasting colour.

Preferably the base paste is dyed with a colour assigned to the respective class of viscosity and a small proportion of the filling volume of the catalyst paste is filled with the pasty inert substance which has been correspondingly dyed or with the catalyst paste which has been correspondingly dyed, while the remaining catalyst paste is not dyed or is dyed white or a contrasting colour.An embodiment of the combination packaging has proved very successful in which the catalyst paste is filled into a tube, cartridge or the like which has, in the interior as the extension of the outlet opening, a tubular section with slit-shaped openings in the surface which is shorter than the length of the tube and the dyed proportion of the catalyst paste or the dyed inert substance is coated around the tubular section, while the remaining tube-free part of the tube is filled with the white or undyed catalyst paste. These tubes or cartridges are filled so that the catalyst paste which has been dyed the colour of the base paste or the inert substance which has been correspondingly dyed is metered in up to the height of the end of the tube and the undyed catalyst paste is coated over this. The tube end is subsequently sealed in a conventional manner.If the tube is now pressed with the screw cap open a strand of paste is obtained which substantially consists of white paste and flows through the tubular section and the outlet opening. A small quantity of the dyed paste simultaneously emerges through the slits in the tubular section during this process so that several stripes of dye are produced on the surface of the white strand of paste. If such a strand of catalyst paste is mixed with a strand of the same length of base paste from a normal tube or cartridge which has been correspondingly dyed, there is at first a substantial contrast in colour between the pastes which gradually disappears as the mixing progresses. The uniformity of colour ensures that a homogeneous finished mixture is obtained.

Starting materials for the vinyl silicone compositions are silicone oil, fillers, cross-linking agents, catalysts and coloured pigments. The silicone oil is preferably a trimethylsilyl terminated or a vinyl terminated polydimethylsiloxane with a viscosity of from 200 to 100,000 mPa.s, depending on which class of viscosity is required. Quartz and cristobalite powders, calcium sulphate, diatomaceous earth and precipitated and pyrogenic silicon dioxide are used as fillers.

The cross-linking agent is a polydimethylsiloxane which has hydrogen atoms at at least two silicon atoms in its molecule. The siloxane copolymers with different degrees of polymerisation which are terminated bytrialkylsilyl or dialkylhydrosilyl groups are known.

The catalyst is a platinum complex which is produced from hexachloroplatinic(lV) acid. These compounds are also known as such.

The aforementioned inert substance serving to produce a stripe of dye, preferably contained in the partial volume of the tube with the catalyst paste, consists of the aforementioned silicone oil and fillers. Inorganic or organic coloured pigments are preferably used as dyes.

The colour coding according to the invention ensures that the various viscous casting compositions conventionally used for different casting methods in dentistry are characterised by colours, and by matching the colour of the solidly coloured strand of base paste with the colour of the coloured stipe on the strand of catalyst paste in the same class of viscosity, the confusion of the tubes or cartridges and thus the mixing of the base and catalyst paste of different classes of viscosity can almost be excluded.

Thus, this prevents, for example, the blue coloured base paste and the white-blue striped catalyst paste of the "highly viscous" class from being confused with the green coloured base paste and the whitegreen striped catalyst paste of the "medium viscosity" class. This also provides the possibility of a mixing control as a homogeneous mixture is only obtained when the base and catalyst paste are mixed if the mass has a uniform colour without stripes or streaks.

Embodiments of the present invention are described in the following. The drawing shows the tube preferably used for the catalyst paste.

A screw-type cap 2 with an outlet opening 3 is located at the top of the tube 1. Arranged centrally in the interior of the tube 1 as an extension of the screw-type cap 2 is a shorttubularsection 4, which section is open at the bottom and has slit-like openings 5 distributed over the surface area. The length of the tubular section 4 is from about 1/15 to 1/20 of the total length of the tube 1. The large volume located below the tubular section 4 is filled with the colourless or white-coloured catalyst paste K. The remaining partial volume around the tube 4 contains a catalyst paste J which has been dyed to the colour of the base paste or a pasty inert substance which has been dyed correspondingly.

The dyed composition contained in the small partial volume is therefore coated onto the undyed or white mass K contained in the large partial volume. Of course the catalyst paste K contained in the large partial volume can also be dyed with a completely different (contrasting) colour, that is with a colour other than that of the base paste.

If the tube is pressed, a white or colourless strand is obtained which has coloured stripes on its surface.

These stripes are produced in that small quantities of the paste located around the tube 4 penetrate into the slit-like openings 5 and are applied to the white paste flowing through the tube 4. The stripes ensure that there is a clear correlation of the catalyst paste to the base paste of the same colour. When the two pastes are mixed, there is first of all a pronounced contrast in colour which then disappears as mixing continues, so that it is easy to assess visually if the mixture is homogeneous.

In the following embodiments, the parts given are to be understood as being parts by weight.

EXAMPLE I The base paste is produced by mixing in a kneading apparatus 330 parts of vinyl terminated polydimethyl-siloxane with a viscosity of 10,000 mPa.s at 25"C, 80 parts of dimethylhydrogensilyl terminated polydimethyl-siloxane with a viscosity of 50 mPa.s. at 25"C, 545 parts of quartz fines, 40 parts of pyrogenic silica with a specific BET surface area of 50 m2/g and 5 parts of inorganic green coloured pigment.

The catalyst paste is produced by mixing in a kneading apparatus 400 parts of vinyl terminated polydimethylsiloxane with a viscosity of 10,000 mPa.s at 25"C, 558 parts of quartz fines, 125 parts of calcium sulphate, 40 parts of pyrogenic silica with a specific BET surface area of 50 m2/g, 0.2 parts of platinum siloxane complex and 1.8 parts of titanium dioxide. 100 parts of the 1000 parts of catalyst paste are removed and mixed with 0.5 parts of inorganic green coloured pigment.

While the green base paste of the "medium viscosity" class of viscosity is filled into a normal tube, the catalyst paste of the "medium viscosity" class of viscosity is filled into the above-described special tube. Filling is carried out in that the green part of the catalyst paste is firstly coated around the tubular section 4 provided with slits 5 and then the white paste is metered into the remaining part of the tube.

If two strands of paste of the same length are pressed from the two tubes onto a mixing block, a green strand of base paste and a white strand of catalyst paste with green stripes are obtained. When these are mixed this produces at the outset a green-white striped composition, which after further mixing produces a homogeneous light green colour, and after 3 mins (calculated from the beginning of mixing) begins to cross-link to produce a rubber which after a further 7 mins has a Shore A hardness of 52".

EXAMPLE2 The base paste is produced in a kneading apparatus by mixing 495 parts of vinyl terminated polydimethyl-siloxane with a viscosity of 10,000 mPa.s at 25"C, 300 parts of dimethylhydrogensilyl terminated polydimethylsiloxane with a viscosity of 50 mPa.s at 25"C, 200 parts of pyrogenic silica, the surface area of which has been partially treated, and which has a specific BET surface area of 50 m2/g and 5 parts of inorganic blue coloured pigment.

The catalyst paste is produced in a kneading apparatus by mixing 799 parts of vinyl terminated polydimethylsiloxane with a viscosity of 10,000 mPa.s at 25"C, 200 parts of pyrogenic silica, the surface area of which has been partially treated, and which has a specific BET surface area of 50 m2/g, 0.3.

parts of platinum-siloxane complex and 0.7 parts of titanium dioxide.

100 parts of the 1000 parts of catalyst paste are removed and mixed with 0.5 parts of inorganic blue coloured pigment.

While the blue paste of the "low-viscosity" class of viscosity is filled into normal tubes, the catalyst paste is filled, as described above, into the special tube. If two strands of paste of the same length are pressed from the two tubes onto a mixing block, a blue strand of base paste and a white strand of catalyst paste with blue stripes are obtained. A blue-white striped composition is firstly produced on mixing, which are further mixing, produces a homogeneous blue composition, and which after 3 mins 30 secs (after the beginning of mixing) begins to cross-link to produce a rubber which after a further 6 mins 30 secs has a Shore A hardness of 40 .

EXAMPLE 3 A green strand of base paste of the "medium" viscosity" class of viscosity (according to Example 1) and a white strand of catalyst paste of the same length with blue stripes of the "low viscosity" class of viscosity are placed on a mixing block. A greenwhite-blue striped composition is firstly produced on mixing, which, after further mixing, produces a homogeneous green mass which begins to crosslink to produce a rubber after 2 mins 30 secs after the beginning of mixing, and after 7 mins 30 secs has a Shore A hardness of 35 . In contrast to the rubbers obtained according to Examples 1 and 2, this rubber does not meet the specifications for silicone casting composition, as prescribed for example, by the ADA specification No. 19.

EXAMPLE 4 A blue strand of base paste of the "low viscosity" class of viscosity (according to Example 2) and a white strand of catalyst paste of the same length with green stripes of the "medium viscosity" class of viscosity are placed on a mixing block. A blue-whitegreen striped mass is firstly produced on mixing, which produces a homogeneous blue composition on further mixing, which after 4 mins begins to cross-linkto produce a rubber and after a further 6 mins has a Shore A hardness of 38". In contrast to the rubbers obtained from Examples 1 and 2, this rubber does not meet the specifications for silicone casting compositions as prescribed, for example, by the ADA specification No. 19.

Claims

1. A combination packaging for the production of a polysiloxane-based dental composition which is curable at room temperature, has a predetermined class of viscosity and is cross-linkable by the addition system, the packaging comprising a first dispensing system containing a base paste comprising an organopolysiloxane with two or more vinyl groups in the molecule, an organohydrogenpolysiloxane, and a hydrophobic filler, and a second dispensing system containing a catalyst paste comprising an organopolysiloxane with two or more vinyl groups in the molecule, a hydrophobic filler and a catalyst for accelerating the addition reaction, wherein one of the two pastes is dyed a colour assigned to the respective class of viscosity and a small part of the filling volume of the dispensing system for the other paste is filled with a pasty inert substance or with the other paste and is dyed the same colour, while the paste contained in the remaining part of the filling volume is either not dyed or is dyed white or with a contrasting colour.

2. A combination packaging according to claim 1,wherein the base paste is dyed a colour which is assigned to the respective class of viscosity and a small part of the filling volume of the dispensing system for the catalyst paste is filled with the pasty inert substance which has been correspondingly dyed or with the catalyst paste which has been correspondingly dyed, while the catalyst paste contained in the remaining part of the filling volume is either not dyed or is dyed white or a contrasting colour.

3. A combination packaging according to claim 2, wherein the catalyst paste is contained in a dispensing system, which has in the interior as an extension of an outlet opening a tubular section with slit-shaped openings in the surface area, which section is shorter that the length of the dispensing system and the dyed part of the catalyst paste or the coloured inert substance is coated around the tubular section while the remaining tube-free section of the dispensing system contains the white undyed catalyst paste or the catalyst paste which has been dyed a contrasting colour.

4. Acombination packaging according to any one of claims 1 to 3, wherein the dispensing system is a tube or a cartridge.

5. A combination packaging according to any one of claims 1 to 4, wherein the dyed inert paste comprises a trimethylsilyl terminated polydimethylsiloxane with a coloured pigment and a filler.

6. A combination packaging substantially as herein described with reference to any of Examples 1 or 2 orthe accompanying drawing.