US3846542A - Acrylic tooth-filling composition containing boric acid-releasing compound - Google Patents

Abstract

A tooth-filling composition non-toxic to tooth pulp comprising an acrylic-based filling composition containing boric acid or a compound of boron, such as tributyl borate, that liberates boric acid.

Description

United States Patent [191 Gross 5] Nov. 5, 1974 1 1 ACRYLIC TOOTH-FILLING COMPOSITION CONTAINING BORIC ACID-RELEASING COMPOUND [75] Inventor: Albert Gross, Frankfurt/Main,

Germany [73] Assignee: Kulzer & Co., GmbH, Bad

Homburg, Germany [22] Filed: Jan. 4, 1972 [21] App1.No.: 215,406

Related US. Application Data [63] Continuation of Ser. No. 56,646, July 20, 1970, abandoned, and a continuation-in-part of Ser. No. 751,714, Aug. 12, 1968, abandoned.

[52] US. Cl 424/81, 32/15, 260/893,

' 260/895 R, 260/895 A, 424/148, 424/185 [51] Int. Cl A6lk 5/00 [58] Field of Search 106/35; 32/15; 260/893,

[56] References Cited UNITED STATES PATENTS 2,887,199 3/1959 Taub 106/35 X 3,449,293 6/1969 Burzynski et a1. 260/893 UX 3,452,437 7/1969 Chang 32/15 3,531,282 7 9/1970 Miller et a1. 204/159.23 X FOREIGN PATENTS OR APPLICATIONS 14,318 8/1967 Japan 106/35 OTHER PUBLICATIONS Primary ExaminerAllan Lieberman Attorney, Agent, or Firm-Burgess, Dinklage & Sprung [57] ABSTRACT A tooth-filling composition non-toxic to tooth pulp comprising an acrylic-based filling composition containing boric acid or a compound of boron, such as tributyl borate, that liberates boric acid.

3 Claims, No Drawings RELATED APPLICATION This application is a continuation of application Ser.

' No. 56, 646 filed July 20, 1970 and now abandoned.

Said application Ser. No. 56, 646 is a continuation -in -part of Tooth Pulp-Protecting Agent, Ser. No. 751, 7l4 filed Aug. 12, 1968 and abandoned August 11, I970.

PREAMBLE It has been known to use synthetic plastic materials for filling tooth cavities, in the form of mixtures of polymers in powder form and monomeric liquids, which contain various types of additives, in particular catalysts and/or accelerators for rapid curing at low temperatures. These filling materials have become widely used and have proved generally satisfactory because of their desirable properties, but do, however, frequently have disadvantages When not expertly used, damage of the tooth pulp may occur during the introduction of the uncured mixtures into the cavity and during the curing of the mixtures. Such irritation of the pulp, which starts with damage to the odontoblasts, may

cause death of the pulp. This irritation occurs primarily because an ineffective sub-filling is used, which fails to keep the toxic monomeric liquid out of contact with the viable pulp. Thus, with incorrect or inexpert subfilling the possibility is always present that the monomeric liquid will diffuse, together with the sometimes also toxic catalyst constituents, through the layer of dentine covering the pulp and lead to damage or death of the pulp, either immediately or maybe after the filling has cured.

This damage of the living tooth texture isbelieved not to be the result of acidity, as occurs with other tooth filling materials, but probably is the result of a protein precipitating effect by the strongly fatdissolving monomer in the polymerizable liquid. Since the development of synthetic fillings in the dental field, there have been many experiments to protect the pulp from damage by the monomer liquid. It is known to cover the cavity with a synthetic film prior to inserting the filling material, which film is intended to prevent the monomer liquid from diffusing through into the living tooth pulp. However, these so-called cavity varnishes have not been able to give effective protection of the pulp, possibly because of the organic solvents introduced during application of these synthetic films causing the same texture damage also observed without the application of such a film.

, BIBLIOGRAPHY Acrylic-based tooth restorations have been used for some time:

The Science of Dental Materials; Skinner and Phillips, W. B. Saunders Company, Philadelphia, Fifth Edition, page 200 et seq., Chapter 13, Tooth Restorations with Acrylic Resins Clinical tests have shown that fast hardening acrylicbased filling materials show statistically a pulp necrosis rate greater than 4 percent:

1. Auto-polymerizing Resin Fillings, Coy, Bear and Kreshover, Journal of the American Dental Association, Volume 44, No. 3, March 1952, page 255 2. Spreter von Kreudenstein Deutsche Zahnaerztliche Zeitschrift, 10, (1955), page 1619 3. Pulp Reactions to Restorative Materials Stanley, Swerdlow and Buonocore, Journal of the American Dental Association, Volume (1967) Some results of the case of filling material according to this invention are given in:

l. Fischer, Grosz and Masuhara Deutsche Zahnaerztliche Zeitschrift, 23 (1968), page 209 et seq.

2. Fischer, Knolle and Tan Das Deutsche Zahnaerzteblatt, 23 (1969), page 251 et seq.

THIS INVENTION It has now been found that this type of damage of the pulp can be prevented by using boric acid or, under the filling conditions compounds supplying boric acid, when working with the synthetic fillings.

This invention consists of the use of boric acid (or under the filling conditions of boron compounds supplying boric acid) in the application of known synthetic filling materials, particularly acrylic ones, which consist of a pulverulent polymer and a monomer liquid and contain catalysts and/or accelerators which provide for the fast hardening of the mixture at low temperatures. As is known, these mixtures of polymer powder and monomer liquid are usually based on compounds of the acrylic acidand methacrylic acid series, especially on the acrylic acidand methacrylic acid esters, homopolymers as well as copolymers being used. The monomer liquid does not have to be a single monomer, but may be a mixture of different monomers. But such monomer liquids are toxic to the tooth pulp, as are the numerous compounds that may be used as catalysts and accelerators. This has been known in the dental field for a long time, i.e., that such materials undesirably affect the pulp.

The boron compounds are preferably used in amounts of 0.01 to 5 percent by weight, advantageously 0.05 to 3 percent by weight, and in particular 0.1 to lpercent by weight, based on the liquid constituents of the agent.

As well as boric acid itself, boron compounds, in particular borates, for example tributyl borate or trioctyl borate, have been proved to be effective boron compounds for protecting the pulp. These effective boron compounds can be used either directly in a suitable liquid, for example dissolved in water or an organic solvent, or can be dissolved in a monomeric polymerisable liquid for brushing out the tooth cavity before inserting the filling. They can be and preferably are added to the EXAMPLES Examples 1 and 2 A plastic mixture suitable for the filling of tooth cavities consisted of a fill composition containing pulverulent methyl methacrylate polymer or copolymer, which was mixed with monomeric methyl methacrylate to form a pasty mixture and was cured under the influence of a Redox System as known per se after introduction into a tooth cavity to form a filling. The monomeric liquid contained 0.1 percent free boric acid. A filling material which was of similar composition but which contained percent of tributyl borate in the monomeric liquid also formed a satisfactory filling. With both compositions it was impossible to determine any damage to the pulp by the plastic filling or by the constituents thereof, which are toxic in the uncured state.

Examples 3, 4 and 5 These filling materials are prepared in accordance with known methods whereby the pulverulent polymers and monomeric liquids are mixed in a suitable ratio and are brought into the tooth cavity wherein the mixture polymerizes or hardens into the filling in a few minutes under the influence of the catalysts and accelerators at mouth temperature. In general, there are mixed about two parts powder with one part liquid; however, these quantities can vary, depending on the portion of the filler.

3. Powder: A pearl polymer of 95 percent methacrylic acid methylester and 5 percent butylphthalylbutylglycolate (Santicizer B-l6-Monsanto Chemical), particle size 50 p. is ground with l percent dibenzoylperoxide with small additions of inorganic pigments to give the mixture a tooth-like color.

Liquid: 92 percent methacrylic acid methyl ester, 4.5 percent glycol-dimethacrylate, 0.5 percent dimethyl-p-toluidine, 3 percent tributylborate.

4. Powder: This powder corresponds to that of Exampie 3, but contains in addition 0.6 percent di-p- 4 toluene-sulfonylmethylmethylamine.

Liquid: 99 parts by weight methacrylic acid methylester, 0.5 parts by weight B-phenylethyldimethylcarbethoxymethyl-ammoniumchloride, 0.03 parts by weight copperacetylacetonate. Directly prior to mixing, there are dissolved in the liquid 3 parts by weight of tri-n-butyl-boron.

5. Powder: First, percent quartz flower having a particle size of 50 u are mixed with 25 percent of a copolymer of percent methacrylic acid methylester and 5 percent butylacrylate in pearl form having a particle size of 50 ;1.. To this mixture there is added, besides pigments, 1 percent dibenzoylperoxide and 2 percent boric acid. The liquid component corresponds to that of Example 3.

I claim:

1. In a tooth-filling composition comprising a monomeric acrylic polymerizable liquid toxic to tooth pulp and suited for use in dental filling materials, and a Redox System curing agent, the improvement which comprises adding a boric acid alkyl ester, said compound being dissolved in said monomeric acrylic polymerizable liquid in a non toxic amount sufficient to protect the tooth pulp of a prepared tooth when using said toothfilling composition therein.

2. The tooth-filling composition of claim 1 wherein said ester is present in a quantity in the range of 0.01 to 5 weight percent, calculated on the polymerizable liquid of said composition.

3. The tooth-filling composition of claim 2- wherein said ester supplying boric acid is selected from the group consisting of tri-butyl borate and tri-octyl borate. l =l Attesting'0fficer 2233; 0mm) SI'A'I'ES PATENT omen CERTIFICATE OF CORRECTION P tent No. 3,846,542 Q Dated November 5, 1974 Inventofls) I ALBERT GROSS It is certified that error appears- 1n the aboye-identified patent and that said Letters Patent are hereby corrected as shown below:

Page 1 of the pa tenI; deed, under'iter n'[21] Insert the following:

-- [30] FOREIGN APPLICATION PRIORITY DATA I August 18, 1967 German y...... 1 3134 IV/a30h Col. 2, line 58, cancel "hydrolysiscan" and substitute hydrolysis can Signed and sealed this 1st day of April 1975.

(SEAL) Attest:

C. MARSHALL DANN Commissioner of Patents and Trademarks RUTH C. I'IASOII

Claims (3)

1. IN A TOOTH-FILLING COMPOSITION COMPRISING A MONOMERIC ACRYLIC POLYMERIZABLE LIQUID TOXIC TO TOOTH PULP AND SUITED FOR USE IN DENTAL FILLING MATERIALS, AND A REDOX SYSTEM CURING AGENT, THE IMPROVEMENT WHICH COMPRISES ADDING A BORIC ACID ALKYL ESTER, SAID COMPOUND BEING DISSOLVED IN SAID MONOMERIC ACRYLIC POLYMERIZABLE LIQUID IN A NON TOXIC AMOUNT SUFFICIENT TO PROTECT THE TOOTH PULP OF A PREPARED TOOTH WHEN USING SAID TOOTHFILLING COMPOSITION THEREIN.

2. The tooth-filling composition of claim 1 wherein said ester is present in a quantity in the range of 0.01 to 5 weight percent, calculated on the polymerizable liquid of said composition.

3. The tooth-filling composition of claim 2 wherein said ester supplying boric acid is selected from the group consisting of tri-butyl borate and tri-octyl borate.