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Stable, cationically polymerizable/crosslinkable dental compositions having high filler contents

a dental composition and polymerization technology, applied in dental prosthetics, dental preparations, applications, etc., can solve the problems of affecting the mechanical reinforcement function assigned, the filler level of such compositions rarely exceeds 45%, and the absorption capacity of resin is limited, so as to achieve economic viability, easy to implement, and substantial stability of compositions

Inactive Publication Date: 2005-03-17
RHODIA CHEM SA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention thus features novel cationic dental compositions, polymerizable and / or crosslinkable in an oral environment, which not only are stable and highly charged (e.g., ≧50%) but which also have markedly improved qualities, particularly as concerns the very clear reduction in the shrinkage phenomenon of dental compositions which are used for producing dental prostheses or dental restoration materials.
In the field of dental restoration, the dental composition according to the invention may be used as material for filling the anterior and posterior teeth in different colors (for example, “VITA” colors), and is rapid and easy to use.

Problems solved by technology

This is because the absorption capacity of the resin is limited.
The result is that the filler levels of such compositions rarely reach more than 45% by volume.
This is therefore to the detriment of the mechanical reinforcement function assigned to the particulate filler.
This particulate filler may also interact with the reactive functions of the (photo)polymerizable / crosslinkable species and may therefore underlie problems of instability of the dental composition.
These resins have the drawback of not being perfectly transparent to the actinic activating radiation of the UV-visible actinic polymerization, which is detrimental to the reaction kinetics and hence limits the possibilities of obtaining very thick photocrosslinked materials.
Silicone formulations of this kind are therefore unstable on storage of the compositions.
This is because the R—[—CO—(CH2)5—O—]n—PO3H2 dispersants are not suitable for the cationic compositions, in particular since they contain a significant acid residue, RPO3H2, which reacts in the presence of oxirane functions and is detrimental to the stability of the composition.
It is therefore apparent that the prior art provides no satisfactory solution to the twin problem of stabilizing dental compositions based on units which are polymerizable cationically under UV (oxiranes, for example) and dispersing sizable amounts of fillers in the resin.

Method used

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  • Stable, cationically polymerizable/crosslinkable dental compositions having high filler contents
  • Stable, cationically polymerizable/crosslinkable dental compositions having high filler contents
  • Stable, cationically polymerizable/crosslinkable dental compositions having high filler contents

Examples

Experimental program
Comparison scheme
Effect test

example 1

1.1 Preparation of a Control Formulation 1 without Dispersant:

A Hauschild® centrifuge mixer is charged with 25 g of quartz (SiO2>99%) with a particle size of 5 μm, sold by Schott, 3 g of ytterbium trifluoride, 10 g of siloxane resin having a monomer (A) content >90%, obtained by hydrosilylating VCMX according to a preparation process as described above.

Stirring is carried out for 16 s with the centrifuge mixer and then 1.25 g of photoinitiator system are added, containing 30% of photoinitiator P1 and 0.23% of a photosensitizer based on chloropropoxythioxanthone CPTX, sold by Lambson, all in solution in the resin (A) without solvent. Stirring is carried out for 16 s with the centrifuge mixer. Then 5 g of fumed silica (SiO2>99%) are added and the mixture is stirred for 16 s. 5.75 g of fumed silica are added and the mixture is then stirred for 16 s.

The fumed silica is a silica sold by Degussa under the name OX-50, with a specific surface area of 40 m2 / g.

The curve of change in ...

example 2

2.1. Preparation According to the Invention:

The dispersant Byk® 164 (8 g) is dissolved in the resin (A) at 4% and the solution is subsequently devolatilized so as to remove the butyl acetate present in the dispersant, by heating under a vacuum of 10 mmHg at 60° C. for 3 hours in a rotary evaporator.

The active substance concentration is 2.4%.

2.2 Preparation of a Formulation 1 with Dispersant:

A Hauschild® centrifuge mixer is charged with 25 g of quartz (SiO2>99%) with a particle size of 5 μm, sold by Schott, 3 g of ytterbium trifluoride, 1.25 g of the solution of dispersant Byk® 164 devolatilized in the resin (A) as described above, and stirring is carried out for 16 s with the centrifuge mixer. 9 g of resin (A) are added.

Stirring is carried out for 16 s with the centrifuge mixer and then 1.25 g of photoinitiator system in (A) are added, containing 30% of photoinitiator P1 and 0.23% of photosensitizer CPTX. Stirring is carried out for 16 s with the centrifuge mixer. Then 5 ...

example 3

Photopolymerization of Dental Restoration Formulations 1, 2 and 3 (§ 2.2, 2.3 and 2.4 Above):

The formulations crosslink over a thickness of 3 mm in 40 of irradiation with an Optilux® Demetron lamp. The Vickers hardness measured after photocrosslinking is 50 for each of the three formulations. The flexural modulus and flexural strength measured in accordance with standard ISO4049 are 5 GPa and 80 MPa respectively.

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Abstract

Stable, highly filled cationic dental compositions useful for the production of dental prostheses and dental restoration materials contain: (1) at least one compound which is reactive cationically when activated, advantageously at least one UV-and cationically reactive oxirane-functionalized silicone; (2) at least one dental filler, advantageously SiO2; (3) at least one organic polymer or copolymer dispersant having an amine index less than or equal to 100 mg of potassium hydroxide per gram of dispersant, advantageously a polyurethane / acrylate copolymer or alkylammonium salt thereof; (4) at least one cationic photoinitiator, advantageously iodonium borate; and (5) optionally, at least one photosensitizer.

Description

BACKGROUND OF THE INVENTION 1. Technical Field of the Invention The present invention relates to dental compositions. More precisely, the dental compositions according to the present invention are useful for producing dental prostheses and for dental restoration. 2. Description of Background and / or Related and / or Prior Art The conventional dental compositions are typically epoxy resins or photopolymerizable silicones or free-radically polymerizable acrylate resins. These compositions further include particulate reinforcing fillers (e.g., of hydrophobicized silica), photoinitiators and optionally photosensitizers in the case of cationic compositions or free-radical initiators for the free-radical compositions, and indeed other functional additives such as pigments or stabilizers. After they have been mixed, these compositions are shaped and then photocrosslinked to a mass whose structure is like that of the teeth. The fact that the filler is composed of very fine particles (≈0....

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): A61K6/083A61K6/891A61K6/896
CPCA61K6/0052A61K6/093C08L83/12Y10S522/908A61K6/62A61K6/896
Inventor FRANCES, JEAN-MARC
Owner RHODIA CHEM SA
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