AU605330B2 - Autodisinfecting impression material - Google Patents

Description

I

AUSTRALIA

PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

53 FOR OFFICE USE Application Number: Lodged: 0. 09 0 0 09 0 0 0'040 0i 0 Complete Specification Lodged: Accepted: Published: Priority: Related Art: This document contains the amendments made under Section 49 and is correct fori printing.

TO BE COMPLETED BY APPLICANT °04# TO BE COMPLETED BY APPLICANT 0 00 00 0 0 66 0 00 o 00 0 0 0 0 0 ft Bf *0008 Name of Applicant: Address of Applicant: Actual Inventors: Address for Service: BAYER AKTIENGESELLSCHAFT D-5090 Leverkusen, Bayerwerk, Germany 1) Dr. Peter Schwabe 2) Dr. Reiner Voigt ARTHUR S. CAVE CO.

Patent Trade Mark Attorneys Level 10 Barrack Street SYDNEY N.S.W. 2000

AUSTRALIA

-j Complete Specification for the invention entitled AUTODISINFECTING IMPRESSION MATERIAL.

The following statement is a full description of this invention including the best method of performing it known to me:- 1 ASC 49 The invention relates to impression materials basea on hydrocolloids, preferably irreversible types, such as, for example, alginates, which contain disinfectants.

In the production of inlays, crowns, bridges and prostheses in the dental sector, a negative of the region in question is produced with the aid of impression compositions and is then cast with modelling gypsum. The desired dental work can then be carried out on the gypsum model (positive).

1l11 Irreversible hydrocolloids are preferably used as impression materials. ALginates and agar-agar are used in particular for impressions in dental practice.

Impression materials of irreversible hydro- ,15 colloids have been used for a Long time for the product t- S Stion of impressions in the dental sector (US 23 45 255).

The use of agar-agar in impression materials is also known Rehberg, Die Quintessenz der zahnarztlichen AbformmitteL (The quintessence of dental impression agents), Verlag "Die Quintessenz" Berlin 1971, pages 18, 57-61).

SgHydrocolloids form a nutrient medium for pathogenic germs, such as viruses, bacteria, fungi and spores.

There is a considerable risk that these germs are transmitted and spread from sick dental patients via the impressions.

This problem is known and is dealt with in detaiL in Dentalecho 1/87, pages 51 to 54 (1987). The publication states that no suitable disinfectant for the hydrocolloid category has yet been found. Practical measures for disinfection should not result in a Loss in the precision of the impression.

Dentalecho 1/87, pages 51 to 54 (1987) sees a further difficulty in the disinfection of impressions in a Le A 25 378 Sla Lack of hygiene in the dental practice. In the opinion of the publication, the risk of infection in dental practices is often wrongly estimated. This is also related to the fact that patients at risk are often difficult to detect.

To guarantee that the contamination chain is broken, it must be ensured that the impressions produced are in atl cases disinfected by destroying the pathogenic germs.

10 Active compound combinations based on glutaralde- *o hyde and buffered aqueous phenolate solutions are known S(US 41 03 001, company publication on Sporicidin by Breitschmidt AG, CH 6020 Kriens) and can be used for disinfection of alginate impressions in the cold.

15 According to the company publication, the impressions are disinfected by being dipped briefly into a 1 to 16 aqueous Sporicidin solution and are packed without being 'rinsed.

S.This method of disinfection has a number of disadvantages. Thus, the degree of disinfection largely depends on the period for which the impression is dipped into the aqueous disinfection solution. Too brief a dipping into the disinfection solution leads to incomplete destruction of the germs. Dipping for too long, on 25 the other hand, Leads to a change in the surface of the impression and thus to an influence on the fit.

This known type of disinfection of impressions furthermore does not guarantee that disinfection is carried out without gaps in every case. There will always remain the uncertainty of whether or not disinfection has been regarded necessary after production of the impression.

Autodisinfecting impression materials based on hydrocolloids have been found, which are characterized in that they contain a disinfectant.

The autodisinfecting impression materials accord- Le A 25 378 2 ~2ih: r~ ing to the invention ensure destruction of the pathogenic germs on the material following contamination. A change in the accuracy of the fit of the impression by subsequent sterilization is no longer possible. The uncertainty of whether disinfection has been carried out also no longer applies. The autodisinfecting impression materials according to the invention guarantee interruption of the contamination chain.

Additionally the impression materials of invention exhibit unobviously a higher storage stability. Even after a long storage the high quality of the impression will be maintained.

Preferred disinfectants according to the invention are phenol derivatives and ammonium salts.

Phenol derivatives which may be mentioned are compounds such as cresols, chlorocresols, xylenes, chloroxylene, isopropylcresol, 15 chlorothymol, phenylphenols and bis-phenols.

Ammonium salts which may be mentioned are compounds of the formula 4 4 4.44 Q. 4 4 4 4 r 44 44 4 4) 44 4* *4 3 1I R R 4

R

or 1

X

x *4*4 in which 20 R 1

R

2

R

3 and R 4 are identical or different and denote methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, hexadecyl, octa, decyl or benzyl and X stands for chlorine or bromine.

The following phenol derivatives may be mentioned as examples: 4-chloro-2-methyl-phenol, 4-chloro-3,5dimethyl-phenol, 4-chloro-2-isopropyl-5-methyl-phenol, 4-chloro-3isopropyl-6-methyl-phenol, 2,2'-methylene-di-(4-chlorophenol), 2phenol-phenol and Na 2-phenol-phenolate.

The following ammonium salts may be mentioned as examples: hexadecyl-pyridinium chloride, hexadecal-tri- Le A 25 378 3 0 00 00 9 O 0 00 0 0 *00000 tt 9 a 0 0 e o o f 0 0 0 0O 0 40 00 o ot o o6 o o *f methylammonium bromide, hexadecyL-trimethylammonium chloride and benzyL-dodecyL-dimethyl-ammonium chloride.

Preferred disinfectants which are used according to the invention are 4-chloro-2-methyL-phenoL, 4-chLoro-3,5-dimethyL-phenoL, 2,2'-methyLene-bis(4-chLorophenoL), 2-phenyLphenol and its Na salt and hexadecyLpyridinium chloride.

2,2'-methylene-bis-(4-chLorophenoL) is particu- Larly preferred.

10 The disinfectants preferably used according to the invention are solids and are present as a constituent of the impression material of the hydrocoLLoid.

The disinfectants according to the invention are in general in powder form.

15 The disinfectants used according to the invention in general have a particle size of 1 to 100 pm, preferably 5 to 40 im.

The impression materials according to the invention contain the disinfectants in an amount of 0.05 to 20 1.0 part by weight, preferably 0.1 to 0.5 part by weight, per 100 parts by weight of the formulation.

The hydrocolloids can be irreversible or reversible. ALginates and agar-agar are preferred.

The impression materials according to the invention in general contain a soluble hydrocolloid (for example the sodium and/or potassium salt of alginic acid) in an amount of preferably 8 to 25% by weight, in particular 10 to 17% by weight, a metal compound which forms a water-insoluble salt with alginic acid (preferably calcium compounds, such as calcium sulphate) in an amount of preferably 5 to 40% by weight, in particular 10 to by weight, a retardant for the hardening process (for example an alkali metal phosphate, diphosphate or polyphosphate) in an amount of preferably 0.5 to 10% by weight, in particular 1 to 5% by weight, and fillers (for example gypsum, silicic earth, diatomaceous earth or Le A 25 378 4

A

alumina) in an amount of preferably 25 to 85% by weight, in particular 40 to 75% by weight. If appropriate, the impression composition can contain further additives, such as, for example, dyestuffs and flavouring substances, and compounds which improve the compatibility with gypsum (for example potassium fluorotitanate or potassium fLuorozirconate). Further additives, for example those which prevent dust formation in the material, are of course also possible.

I e 10 A process has also been found for the preparation of autodisinfecting impression materials, which is characterized in that the pulverulent disinfectant is Spremixed with 1 to 50 times, preferably 10 to 20 times, ese o the amount of fillers, the mixture is added via a sieve 15 of 150 to 400 pm mesh width to the other starting substances in a mixer and the components are mixed.

Sieves of 150 to 400, preferably 200 to 300 pm mesh width are in general used.

Plough blade mixers are preferably used as the mixers.

Ia The autodisinfecting impression materials according to the invention are formulated for use in the customary manner. The pulverulent material is made into a Spaste with the required amount of water and is applied 25 to the appropriate dental region for the impression.

The autodisinfecting impression materials according to the invention have a broad action spectrum and attack virtually all pathogenic germs. Pathogenic germs which may be mentioned are all known viruses, bacteria, fungi and spores. The following pathogenic germs may be mentioned as examples: Staphylococcus aureus, Escherichia coli and Candida albicans.

The autodisinfecting impression materials according to the invention have outstanding impression properties.

Le A 25 378 5 99L 99 9 99 9O 9 99 9 9 9 99 9 9 *O 9 Example 1 (Preparation of an aLginate impression composition) 58.00 parts by weight of diatomaceous earth, 8.00 parts by weight of aluminium silicate, 15.45 parts by weight of calcium dihydrate, 14.00 parts by weight of sodium alginate, 3.00 parts by weight of potassium fLuorotitanate, 1.20 parts by weight of tetrasodium diphosphate, 0.30 part by weight of coloured pigment and 0.05 part by weight of fragrance are processed to a homo- 10 geneous mixture in a plough blade mixer.

The disinfectants are ground down to a particle size of 40 pm in a bead mill. The powdered disinfectants are premixed in an amount of 0.1 or 0.3 part by weight with 2 or 5 parts by weight of the abovi mixture and the resulting mixture is passed through a sieve of 200 pm mesh width and mixed with the remaining 98 or parts by weight of the above mixture in a plough blade mixer.

Example 2 to 14 a) The microbiological activity of the disinfectants in the impression material according to Example 1 is determined as follows: The components are introduced into mixing beakers and are mixed with a mixing spatula in the course of 25 seconds. Sample pieces of 6 cm in diameter and 0.5 cm in height are produced. Test pieces of 3 cm are stamped out of these discs.

Petri dishes 9.5 cm in diameter are filled with mL of contaminated agar. The germ seed is 1 x germs/1 ml of agar. After solidification of the nutrient medium, the test specimens are placed centrally on the nutrient medium and pressed lightly so that there is intensive contact with the nutrient medium.

The test specimens are stored at 27 0 C for a period of 4 days.

9 f* Le A 25 378 6 e rrb) The results of testing are shown in Table 1. In addition to the microbioLogical data, the table contains the results of testing of the alginate impression compositions in accordance with Specification No. 18 of the American DentaL Association (ADA).

we 00 0o 0 0 00 o 0 00 0 o 00D o 00 o 0 00 *00004 Le A 25 378 7 00 0 O 0 0 0 0 0 Table 1 Example Disinfectant Concentration in by weight Mlic rob ioIog ica I evaluation Testing in acco-dance with ADA Specification No. 18 Setting Permanent Compressive time deformation st ren th M% (N/mind) 2 no active substance 3 2,2'-methyLene-bis- (4-chtorophenoL) 4 2,2'-methylene-bis- (4-chLorophenoL) 2-phenyLphenol 6 2-phenyLphenoL 7 4-chLoro-2-methyLphenoL 8 4-chLoro-2-methyLphenoL 9 2-isopropyL-5-methyLphenoL 2-isopropyL-5-methyLphenoL 11 2-phenyLphenoL, Na salt 12 2-phenylphenot, Na salt 13 hexadecyLpyridinium chloride 14 hexadecyLpyridinium chloride 6-9 2-3 4-5 1-1.5 Il-5 0 2-3.5 1 3-4 0 1-2 1 '10"1 1 '25'" 1 '30" 1 loll 1 10"l 1 15" 1 '20" 1 '15'' 1 '20" 1 '25" 1 '30" 1' 10ll 1 15" 0.90 0.98 0.85 0.92 0.88 0.89 0.90 0.92 0.86 0.92 1.00 0.95 0.95 The values for the microbiological evaluation represent the inhibiting area around the aLginate test specimen in the contaminated agar mass in mm.

To provide more depth to the results from Table 1, the alginate impression compositions in untreated form (Example 2 as a comparison) and treated with 0.1 and 0.3% by weight of 2,2'-methylene-bis-(4-chlorophenoL) (Examples 3 and 4) and with 0.1 and 0.3% by weight of 2-phenyLphenol (Examples 5 and 6) were subjected to the specification test in accordance with ADA 18 again after storage for 3 months and 6 months, 1 and 2 years in order to demonstrate that the disinfectant additives have no influence on the storage t Sstability of the impression materials. The microbiological activity of the two disinfectants against the test germs 0 15 Escherichia coli, Staphylococcus aureus and Candida albicans was furthermore determined by the method described.

The results of the tests are summarized in o o Tables 2 and 3.

0 00 0 00 0 0 0 'Ott AtA t t Le A 25 378 9 Zr 0* 4 0 00 00* 0 0 0 0 0 0 0 4 0 0 4 0 0 4 Table 2 Example Disinfectant Concentration in by weight Activity [scheri chi a cal i against Staphylococcus aureus Candi da al bicans no active substance 2,2'-methylene-bis- (4-chlorophenol) 2,2'-methyl ene-bi s- (4-chioro-phenol) 2-phenyl phenol 2-phenyl phenol 0 13 7 Table 3 Example Disinfectant Concentration in by weight Testing in accordance with ADA Specification No. 18 immediate/3 months after/6 months after/i year after/2 years after Setting time Permanent deformation

M%

Compressive 2 strenght (N/mm) 2 no active substance (compari son) 3 2,2'-methylene-bis- (4-chiorophenol) 4 2,2'-methylene-bis- (4-chiorophenol) 2-phenyiphenol 6 2-phenyl phenol 1'10''/1'30''/1'45- 1-55' 2,5/-/2,5/3,3/5,2 1'25"'/1'35'' 1'40' 1'30' 1-35' 2.5/-/2.5/2.8/2.9 3.4/-/2.5/2.5/2.9 0,90/-/0.83/0. 79/0.53 0. 86/0. 82/0. 76 0.85/-/0.82/0.83/0.78 0.92/-/0.85/0.80/0.73 0.88/-/0.83/0.78/0.78 1'10''/1'25''/1'30' 1'35' 1'10' '/1'30' 113011'/11401 12.5/-/2.6/3.0/3.3 2.5/-/2.6/3.0/3.2

Claims (2)

1. An autodisinfecting dental impression material capable of being hardened into a dental impression compr '-ing a hydrocolloid, a retardant for the hardening process, fillers and 0.05 1.0 parts by weight of a pulverulant disinfectant per 100 parts by weight of the impression material, said disinfectant having a particle size of 1-100 pm, said disinfectant capable of destroying pathogenic germs and having no influence on the storage stability of the impression material, the disinfectant being selected from the group consisting of 2,2'-methylene-bis-(4-chlorophenol) and

4-chloro-2-methylphenol. 2. A process for the preparation of autodisinfecting dental impression materials according to claim 1 comprising mixing o" 0.05 1.0 parts by weight of a pulverulant disinfectant o* 4 selected from the group consisting of 2,2'-methylene-bis-(4-chlorophenol) and 4-chloro-2-methylphenol i with 1 50 times the amount of filler, adding the filler-disinfectant mixture via a sieve of 150 to 400 pm mesh width to a hydrocolloid and mixing the so formed mixture in a mixer to provide a dental impression material. 3. An autodisinfecting dental impression material, substantially as herein described, with reference to Table 1, Examples 3, 4, 7 and 8 and Table 2, Examples 3 and 4. DATED this 4th day of October, 1990. BAYER AKTIENGESELLSCHAFT By Its Patent Attorneys ARTHUR S. CAVE CO. 12