WO1998046194A1

WO1998046194A1 - Etch detector

Info

Publication number: WO1998046194A1
Application number: PCT/SE1998/000678
Authority: WO
Inventors: Leif Hagne
Original assignee: Dental Therapeutics Ab
Priority date: 1997-04-16
Filing date: 1998-04-14
Publication date: 1998-10-22
Also published as: SE9701403D0; AU7093498A; EP0975304A1

Abstract

Etching and detection composition for conditioning dental cavities in a single step, comprising a component a) which is an etching compound and a component b) which is a caries detector. Use of the etching and detection composition for the manufacture of a treatment agent for conditioning dental cavities.

Description

ETCH DETECTOR

The present invention relates to a composition for treatment of caries and also relates to the use of said composition for the production of a treatment agent that conditions dental cavities.

Today, most experts agree that the so-called total-etch technique is the best method to use for applying adhesive fillings to teeth. In the total-etch technique, both enamel and dentin are etched with, for example, a 35% phosphoric acid, known through SE, C2, 503 150 and US. A, 5,385,728. The tooth surface is etched in order to:

1. Remove the smear-layer from the dentin. thereby opening dentinal tubules for the bonding material. Closing these dentinal tubules with a bonding material provides a tighter filling than that which would have been obtained if the smear-layer, i.e. grinding dust and the like, had been left in place during filling.

2. Obtain better bonding to the enamel by superficially removing the organic part from the enamel, leaving in place enamel prisms that project from the tooth surface. Around these enamel prisms, which are invisible to the naked eye, the bonding material can then gain a firm purchase in the tooth enamel.

It is recommended that the dentin be etched throughout a somewhat shorter interval than the enamel.

To obtain a strong bond to the dentin, it is important to remove all decayed tooth substance. If softened, decayed dentin is left in place beneath the adhesive filling, the bond with the tooth will be weaker, and the filling may even loosen since fewer mechanical retention points are provided in adhesive filling therapy than in, for example, amalgam therapy.

The problem encountered in this technique is knowing when all infected or decayed dentin has been removed. If too much is removed, the tooth may have to be root-filled. If not all of the infected or decayed dentin is removed, there is substantial risk that the patient will encounter post-operative difficulty attributable to the restored tooth. Experience has shown that, among other things, lactobacilli can survive in decayed dentin and produce acid that irritates the pulp in the tooth, and this can lead to pain in the tooth. It is also understood that this type of caries attack can continue to develop beneath a filling under which caries remains in place. To obtain a strong bond with the dentin, it is important to remove all decayed tooth substance. If softened, decayed dentin is left in place beneath the adhesive filling, a weaker bond to the tooth is obtained and the filling can even loosen since fewer mechanical retention points are provided by adhesive filling than by amalgam therapy for example. It is thus important to remove all decayed dentin. but it is also important not to remove too much dentin.

To check that all caries and only caries has been removed, the use of special substances called caries detectors is recommended. These consist of special dyes that colour the caries, i.e. demineralized dentin, red for example. There are different dyes. Others colour demineralized - dentin dark-blue/purple. Fuchsin is an example of a substance that colours decayed dentin red. Caries detectors are known through US, A, 4,347,233 and Quintessence International, Vol. 23. No. 6. 1992, pages 439-444. Caries detectors are applied to the area being attacked, after which excess detector is removed. The colour of dentin attacked by caries differs from the colour of healthy dentin after the detection agent has been applied, thus making it possible to remove the dentin attacked by caries. Removal is carried out using conventional drilling methods. When caries are excavated in the normal way using a circular drill, one can observe the drillings to see whether drilling is taking place in decayed or healthy dentin. Drillings obtained from healthy dentin resemble fine powder. Drillings from decayed dentin are coarser-grained. There will be a greater need for caries detectors as new preparation techniques for teeth are developed, such as high-speed blasting with aluminium oxide powder which is said to be considerably more agreeable to patients than drilling. With high-speed blasters it will be possible to make smaller cavities than with traditional drilling equipment. When high-speed blasters are used no drillings are obtained, and if the cavity is very small it may even be difficult to ascertain whether or not all caries has been removed. An agent that colours and indicates decayed dentin. i.e. a caries detector, can be essential in such situations for checking to see that all infected/decayed tooth substance has actually been removed before filling the tooth. Thus far. it has been possible to solve the above problem by. after excavating the decayed tooth substance, using a dye that colours the decayed dentin to make certain that no caries has been left in place. To enable the dye to colour any caries left in place, the dye must be allowed to seep into any remaining decayed tooth substance for a certain period of time, about 10-15 seconds. Thereafter, the caries detector is removed using water and compressed air. and a visual check can be made to see that no infected/decayed tooth substance has been left in place. Thereafter, the dentin is etched for a period of time approximately equal to that recommended for leaving the caries detector in the cavity, i.e. approximately 15 seconds.

The detector and etching gel must each be flushed away with water and compressed air for at least 45 seconds so that the surface of the tooth will be free of these substances. It is understood that the use of these different solutions is time consuming. Moreover, it is sometimes impractical because of the time factor since, for example, some children become fidgety and some patients find it difficult to keep saliva out of the cavity for a relatively long period. If saliva enters a cavity where an adhesive filling is to be applied, no bond will be obtained between the filling and the tooth.

Additional costs will also be incurred if it becomes necessary to purchase, manage and disinfect different solutions.

The aforesaid disadvantages are probably the determinant reasons why a majority of all dentists do not use a caries detector.

The present invention comprises a solution to the aforesaid problems, which have been solved through the present etching and detection composition defined in the characterizing clause of the main claim. Through said composition it is possible to etch and detect in a single step, thus eliminating the aforesaid problems while simultaneously gaining time and cutting costs.

The present invention also entails the use of said etching and detection composition for the manufature of a treatment agent that conditions dental cavities.

Detailed description of the invention

The main purpose of the present invention is to provide a composition that etches and detects in a single step while treating dental cavities, without removing healthy dentin. Another purpose of the present invention is to produce a treatment agent that will condition dental cavities.

These and other purposes will become evident in the following description. The present invention relates to a composition intended for use in conditioning dental cavities through etching and detection, wherewith the composition incorporates the following main components:

Component a) is an etching compound such as phosphoric and/or citric acid, preferably orthophosphoric acid.

Component b) is a caries detector selected among one or more of the following compounds:

1. The sodium salt of 9-(3,4,5,6-tetrachloro-ortho-carboxyphenyl)-6-hydroxy-2,4,5,7- tetrabromo-3 -isoxanthone .

2. The dipotassium salt of 9-(3,4,5,6-tetrachloro-ortho-carboxyphenyl)-6-hydroxy-2,4,5.7- tetrabromo-3-isoxanthone. 3. The sodium salt of 9-(4-sulfo-2-sulfoniumphenyl)-6-diethylamino-3-(N,N-diethylimino)- 3-isoxanthene.

4. The disodium salt of 8-amino-2-phenylazo-l-naphthol-3,6-disulfonic acid.

5. The disodium salt of 4-[[4-(N-ethyl-meta-sulfobenzylamino)-phenyl]-(4-hydroxy-2- - sulfonium-phenyl)-methylene]-[l -(N-ethyl -N-meta-sulfobenzyl)Δ ^" -cyclohexadienimine].

6. 9-(2-carboxyphenyl)-3,6-bis(diethylamino)xanthylium chloride.

A preferred embodiment of the composition comprises, in addition to the components mentioned above, a viscosity-enhancing agent such as derivatized polysaccharides.

The preferred polysaccharides include ethyl celluloses, hydroxyethylcelluloses, carboxymethylcelluloses and hydroxiethyl starches. Sodium carboxymethylcellulose is particularly preferred.

The compositions in accordance with the invention have a pH in the 0 - 3 range, preferably 0.5 - 2.5, in particular 0.5 - 1.5. A preferred composition contains:

phosphoric acid 15 - 40% by weight propylene glycol 60 - 80% by weight caries detector 0J - 2% by weight preservative 0 - 2% by weight buffer 0 - 2% by weight viscosity-enhancing agent 1 - 5% by weight water to 100% by weight

A particularly preferred composition contains:

phosphoric acid 15 - 37% by weight propylene glycol 65 - 75% by weight caries detector (3) (Acid Red) 0.5 - 1% by weight benzalkonium chloride 0.5 - 1% by weight sodium carboxymethylcellulose 2 - 3% by weight water to 100% by weight The present invention will be further illustrated below with reference to concrete examples which, however, must not be considered restrictive with regard to the invention in any way not defined in the appended claims.

Example 1

Production of an etching and detection composition

A water-based composition was made up by dissolving 0.5 g of the sodium salt of 9-(4- sulfo-2-sulfoniumphenyl)-6-diethylamino-3-(N,N-diethylimino)-3-isoxanthene (Acid Red), which was dissolved in 73.2 g of propylene glycol and 26.2 g of orthophosphoric acid. 1.0 g of benzalkonium chloride was stirred in. and 2.2 g of sodium carboxymethylcellulose was added to the solution thus formed, yielding a viscous, gel-like composition.

Example 2 Test of etching and detection composition on teeth having dental cavities

A composition was produced as set forth in Example 1 and applied to teeth having dental cavities. After about 10 to 20 seconds, the colours of the cavities changed due to the fact that the attacked dentin was first coloured and then etched away. The etching was concluded by flushing the tooth with water, and the etching and detection composition was neutralized and sucked away.

The result obtained in Example 2 shows that it is possible to both etch and detect attacked dentin quickly in a single step using a composition produced as set forth in Example 1.

The very important check to see that no decayed dentin is left in place thus takes place automatically and simultaneously with the etching of the tooth.

Removal of too much tooth substance while excavating decayed dentin, thereby adding to the risk of necessitating root treatment, can be alleviated by improving the checking procedure undertaken to ascertain the extent to which the decay has spread.

Because the composition both etches and detects in a single step, the determinant disadvantages which have thus far prevented caries detectors from being used to a sufficient extent are eliminated.

Claims

1. An etching and detection composition for conditioning dental cavities in a single step, characterized in that the composition comprises one component a) which is an etching compound and one component b) which is a caries detector.

2. The etching and detection composition according to claim 1, characterized in that component a) is an acid such as phosphoric and/or citric acid, preferably orthophosphoric acid and component b) is one or more of the following compounds: the sodium salt of 9-(3,4,5,6- tetrachloro-ortho-carboxyphenyl)-6-hydroxy-2,4,5,7-tetrabromo-3-isoxanthone, the dipotassium salt of 9-(3,4,5,6-tetrachloro-ortho-carboxyphenyl)-6-hydroxy-2,4,5,7-tetrabromo-3- isoxanthone, the sodium salt of 9-(4-sulfo-2-sulfoniumphenyl)-6-diethylamino-3-(N,N- diethylimino)-3-isoxanthene, the disodium salt of 8-amino-2-phenylazo-l-naphthol-3,6- disulfonic acid, the disodium salt of 4-[[4-(N-ethyl-meta-sulfobenzylamino)-phenyl]-(4- hydroxy-2-sulfonium-phenyl)-methylene]-[ 1 -(N-ethyl-N-meta-sulfobenzyl)╬ö²'⁵- cyclohexadienimine], or 9-(2-carboxyphenyl)-3,6-bis(diethylamino)xanthylium chloride.

3. The etching and detection composition according to claim 1 or 2, characterized in that the composition also comprises a viscosity-enhancing aging such as derivatized polysaccharides.

4. The etching and detection composition according to claim 3, characterized in that the viscosity-enhancing agent comprises one or more of the following: ethyl celluloses, hydroxyethylcelluloses, carboxymethylcelluloses or hydroxyethyl starches, preferably sodium carboxymethylcellulose.

5. The etching and detection composition according to any of claims 1 - 4, characterized in that the composition also comprises a preservative and/or buffer.

6. An etching and detection composition for conditioning dental cavities in a single step, characterized in that the composition comprises components having the following contents:

acid 15 - 40% by weight propylene glycol 60 - 80% by weight caries detector 0J - 2% by weight preservative 0J - 2% by weight buffer 0 - 2% by weight viscosity-enhancing agent 1 - 5% by weight water to 100% by weight

7. The etching and detection composition according to claim 6, characterized in that the composition comprises components having the following contents:

phosphoric acid 15 - 37% by weight propylene glycol 65 - 75% by weight the sodium salt of 9-(4-sulfo-2- sulphoniumphenyl)-6-diethylamino-3-

(N,N-diethylimino)-3-isoxanthene 0.5 - 1% by weight benzalkonium chloride 0.5 - 1% by weight sodium carboxymethylcellulose 2 - 3% by weight water to 100% by weight

8. The etching and detection composition according to any of claims 1 - 6. characterized in that the composition comprises components with the following contents:

acid 15 - 40% by weight propylene glycol 60 - 80%> by weight caries detector 0J - 2% by weight preservative 0J - 2% by weight buffer 0 - 2% by weight viscosity-enhancing agent 1 - 5% by weight water to 100% by weight

9. The etching and detection composition according to any of claims 1 - 7. characterized in that the composition has a pH in the 0 - 3 range, preferably 0.5 - 2.5. most preferably 0.5 - 1.5.

10. Use of an etching and detection composition according to any of claims 1 - 9 for the manufacture of a treatment agent for conditioning dental cavities.