WO2006100371A1

WO2006100371A1 - Prosthetic teeth with reconstituted dentine, method for applying such dentine and set of compositions for implementing said method

Info

Publication number: WO2006100371A1
Application number: PCT/FR2006/000604
Authority: WO
Inventors: Michel Seguier
Original assignee: Michel Seguier
Priority date: 2005-03-23
Filing date: 2006-03-17
Publication date: 2006-09-28
Also published as: FR2883466B1; FR2883466A1

Abstract

The invention concerns a prosthetic tooth (10) with reconstituted dentine, in particular ceramic- and/or resin-based, characterized in that said reconstituted dentine is formed by the superimposition, from inside outward of the tooth, of a first dentine (13) and at least a second dentine (14) each enclosing a fluorescent component, the first dentine being more opaque and less coloured than the second dentine. The first dentine (13) is preferably of equal or higher fluorescence than the second dentine (14). The method for applying said dentine includes a step which consists in successively applying on a support such as an armature (11) the first dentine (13), then the second dentine. The invention also concerns a set of compositions for reconstructing the dentine for implementing said method.

Description

Prosthetic teeth with reconstituted dentin, method of applying such dentin and set of compositions for its application

The present invention relates to a prosthetic tooth with reconstituted dentin, in particular based on ceramic or resin, a method of applying a reconstituted dentine on a support, as well as a set of compositions for reconstituting dentin.

When repairing or restoring a tooth, the technician or dentist uses various compositions based on ceramic or resin, to reconstitute the missing parts. These compositions also contain constituents, such as opacifiers and pigments, making it possible to give the prosthetic tooth an appearance which is as close as possible to the appearance of neighboring natural teeth.

Until now, the manufacturers of dental materials offer, for the reconstruction of prosthetic teeth, a single basic dentine having the role of masking the underlying metal framework in the area of the free edge of the tooth, while respecting the basic shade of the tooth. However, the final aesthetic result, even if the chosen shade is respected, does not bring the expected mimicry. These achievements give an artificial aspect mainly due to:

- a uniform and too high light reflection mainly due to too high opacity, - a lack of contrast,

- a completely artificial appearance in fluorescent light due to a uniform reflection of the tooth.

In order to allow the dental technician to carry out more elaborate work and even closer to natural teeth, compositions such as:

- basic dentins (which contain opacifying, coloring, and fluorescent compounds) - intensive opaque dentins (which contain opacifiers and colorants in higher concentrations)

- intensive dentin (very colorful and not very opaque) ι

- incisors (very little colored and little opaque) - make-up or stains (based on dyes).

To obtain a contrasting artificial tooth, the technician can use several dentins of different shades and with more or less intense coloring.

However, it is very difficult to reproduce the translucency of the natural tooth, It is often necessary to make several prosthetic teeth before manufacturing one which is close to the neighboring natural teeth, under a given light. This method is very laborious and expensive.

In addition, the current requirements for aesthetic rendering are very high. The prosthetist is now working on digital photos, of the patient's teeth, enlarged (sometimes up to 10 times) revealing in detail the effects and the nuances, which obliges him to final achievements of more and more elaborate prosthetic teeth.

It is known from EP 1 400 232 a dental restoration process based on ceramic incorporating a standard dentin and a more opaque dentin in an undercoat, of identical coloration, covering the opaque which itself masks the metallic framework. This set has the disadvantage of making teeth more opaque than natural teeth, with an artificial rendering caused by too much light reflection on standard dentin (therefore very little light penetration in the layers of the tooth). The presence of the fluorescent element in the deep opaque layer covering the frame brings a slight improvement in brightness, without resolving the defects of the too opaque dentines.

The present invention aims to overcome the aforementioned drawbacks by providing a dental material allowing, while masking the framework, to create contrast effects both of color, of translucency and of fluorescence, which can be applied in a simple and inexpensive, in giving the prosthetic tooth a natural appearance.

To this end, the prosthetic tooth with reconstituted dentin, in particular based on ceramic and / or resin is, according to the invention, characterized in that said reconstituted dentin is formed from the superposition, going from the inside towards the exterior of the tooth, at least a first dentin and at least a second dentin, each containing a fluorescent component, the first dentin being more opaque and less colored than the second dentin.

The first dentin is advantageously with fluorescence equal to or higher than the second dentin.

Thus, the prosthetic tooth with dentin reconstituted according to the invention, reproduces as closely as possible the structure and appearance of a natural tooth comprising a dentin, with a clear opaque zone, situated around the pulp and a colored translucent zone (called amelo-dental layer) covering it.

Thanks to a reconstitution by means of the superposition of these two dentins, in the intermediate layers of the tooth, the effects of contrast, reflection or absorption of light are markedly improved, and reproduce the natural gradient of the tooth. Indeed, the first dentin, less opaque, lets light penetrate into the deep layers.

Thanks to the presence of these two different dentines in opacity and coloring, we can create multiple contrasts by varying their relative thicknesses.

Advantageously, the contrast ratios between the first dentine and the second dentine are such that the opacity contrast ratio (R ₀ O) is greater than or equal to 1.01, preferably between 1.02 and 2, 00 approximately and that the fluorescence contrast ratio (R _c f) is greater than or equal to 1.00, preferably between 1, 10 and 2.70 approximately. With regard to color, the color contrast ratio R ₀ C between the second dentin and the first dentin is advantageously greater than or equal to 1.10, preferably between 1, 20 and 3.00 approximately. The present invention also relates to the method of applying a reconstituted dentin to a support in order to produce a prosthetic tooth as described above, comprising at least one step consisting in successively applying to said support at least one first dentin and at least a second dentin covering the first dentin, the first dentin being more opaque and less colored than the second dentin, in order to impart a natural appearance to said dentin, the two dentins containing a fluorescent constituent. The first dentin is advantageously with fluorescence equal to or higher than the second dentin. The contrast of opacity (R _C O), fluorescence (R ₀ T) and color (R _C C) ratios are advantageously as defined above.

This process has the advantage of being simple to implement, following traditional application methods, while allowing the natural layering of the tooth to be reproduced.

The presence of bumps or depressions in the first layer of dentin according to the invention will create zones where the second dentin will be more or less thick, giving rise to color contrasts which appear to be greater. The fluorescence, preferably weaker from the second dentin, promotes the penetration of light and simulates natural fluorescence.

The support can be a material based on metal, zirconia, alumina, pressed ceramic, or a composite thereof.

The present invention also relates to a set of compositions for reconstituting dentin, in particular based on ceramic and / or resin, for the implementation of the method described above. The set of compositions according to the invention comprises at least two dentin compositions having different opacity, color and fluorescence properties, with a view to imparting a natural appearance to said dentin. In particular, this set comprises at least a first dentin composition and at least a second dentin composition, the first dentin composition being more opaque and less colored than the second dentin composition, the two dentins containing a fluorescent component.

The first dentin composition is advantageously with fluorescence equal to or higher than the second dentin composition. Advantageously, the contrast ratios of opacity (R _C O), fluorescence (R _c f) and color (R _C C) are as defined above.

In addition, said dentin compositions can form, in the mixed state in a determined proportion, a so-called basic dentin composition corresponding to the shade chosen for the prosthetic tooth. Thus, it is possible to mix these dentin compositions to obtain a new basic dentin, of the shade to be produced, but preferably less opaque, usable for example in certain areas of the prosthetic tooth. The opacity can, for example, be adjusted with opaque dentin (DOI) of the shade to be produced.

The basic material of the dentin composition is either a ceramic, or a photopolymerizable resin (for example of the acrylic type), or a composite material (ceramic + resin) which combines the advantages of the two materials, in particular limiting the shrinkage.

The opacifiers are generally oxides such as zirconium oxide, titanium oxide, or the like.

The dyes are either organic molecules or oxides. The fluorescent constituents are, for example, type Z compounds sold by the company LUMILUX and having emission peaks ranging from 480 nm to 550 nm.

All these materials or constituents are approved for use in the development of prosthetic teeth.

By prosthetic teeth is meant here:

- crowns and bridges made by dental technicians,

- artificial teeth manufactured in industry, - partial reconstructions (veneers, inlays, onlays ...) carried out by dentists in offices.

The present invention will be better understood in the light of the following illustrative examples, with reference to the attached diagrams, in which:

FIG. 1 represents a sectional view of a natural maxillary central incisor,

FIGS. 2a and 2b show views in transverse and longitudinal sections, respectively, of a prosthetic tooth according to a first variant of the invention,

FIGS. 3a and 3b show views in transverse and longitudinal sections, respectively, of a prosthetic tooth according to a second variant of the invention,

FIGS. 4a and 4b show views in transverse and longitudinal sections, respectively, of a prosthetic tooth according to a third variant of the invention.

When one examines natural teeth and in particular a maxillary central incisor 1, one is surprised by its extreme translucency. Seen in longitudinal section (Figure 1), it reveals several very distinct zones distributed in the form of strata. Starting from the heart outwards, the following main areas are distinguished: - the pulp 2.

- the lobes 3 in very opaque dentin (DOI) placed on the vestibular and lingual surfaces and continuing in a thin thickness up to the free edge of the tooth sandwiched between the vestibular enamel and the lingual enamel. - a dentin having an opaque and dense zone 5 rather present around the pulp 2, ending in the form of irregular fibrils 6 crossing, up to the enamel 8, a more translucent zone 7 (called amelo-dentin layer) covering the crown 9, thick in the line of the large contour of the emergence profile and very fine in the free edge. This dentin, of variable thickness depending on the tooth and the patient, gives, by reflection and absorption of light, the basic shade of the tooth. - The enamel 8, too, structured in various zones of variable opacity, covers the entire crown 9 with a thick layer of constant value.

The tooth undergoes, over the years, an aging which causes wear of the free edge due to abrasion and a modification of the shade by the intensification of the opaque and translucent areas of the dentin. In order to facilitate the shade analysis work, these variations in the aging of the teeth are referenced according to known shade guides (such as Vita, Ivoclar, Biodent) which give the average value of a shade by comparing the shade guide positioned next to the tooth natural and viewed from a distance of 35 to 40 centimeters.

Until now, artificial reconstruction of prosthetic teeth has never taken into account the different natural areas of dentin.

The examples presented below show in detail how the present invention makes it possible to take this into account.

Example 1 (Prior art)

An example of the composition of a conventional opaque basic dentine of a given shade, chosen from a color chart, is indicated in table 1 below (parts by weight):

Table 1

Basic dentin of shade B4

Ceramic base 100 parts Opacifier (x) Z _r O ₂ pure 0.280 Frit 30% Z _r O ₂ 0.950

Colorant (y)

Yellow frit 10% B 930 1,000 Ocher frit 10% B 152 1,500 Bluish gray frit 10% 1702 0.140

Fluorescent (z) ZW 0.250

The opacity of the above composition, measured with a spectrophotometer which compares, over the entire range of visible wavelengths, the difference in opacity on a white background and on a black background measured on a 2.5 mm pellet thick. In this example, the opacity is 94.30%, that is to say very high because it only lets in 5.70% of the light. This basic opaque dentin composition perfectly hides the metal framework, but does not give a natural appearance to the prosthetic tooth.

EXAMPLE 2 General Composition of Dentins According to the Invention From an DDB base dentin opaque with a shade of a commercial color chart, having an opacity of x% and comprising concentrations of dye and fluorescent of y respectively and z, two types of dentin were produced according to the invention, by varying the concentrations of these three constituents (opacifier, dye and fluorescent), in the ranges presented in table 2 below.

Table 2

These ranges are valid whatever the base material (ceramic, resin or composite). x = the opacity of conventional basic dentin generally varies between 80 and 95 approximately. Preferably, the first dentin is more opaque than this basic dentin, and the second dentin more translucent.

On the other hand, with regard to color, the first dentin is preferably less colored, and the second dentin more colored than the conventional basic dentin.

Example 3

From a shade B4 of the color chart of the Vita Company, having an opacity of 94.3% presented in Example 1, two types of dentin were produced by adjusting the concentrations of opacifiers, dyes and fluorescers, of the same nature than those in base shade B4. The compositions of these two dentins are presented in Table 3 below.

From these two dentins D1 and D2, it is also possible to reconstitute what is called a new basic dentine (NDDB), by mixing these two dentins in given proportions, for example here 70% of D1 and 30 % of D2. The characteristics of this new NDDB basic dentin are also presented in Table 3. Table 3

2S.

Example 4

After preparation of the two dentins D1 and D2 in accordance with Examples 2 or 3, and of the new basic dentine NDDB, according to the invention, a prosthetic tooth 10 (for example a maxillary incisor) is constructed or reconstructed, by stratification on a support. or a framework 11 of different layers of dentin in two stages:

- the first stage in the vestibular face

- the second step on the lingual side.

After application of a thin opaque layer 12 intended to hide the reinforcement 11 completed with a very opaque dentin layer 19 (DOI) at the free edge of the reinforcement 11, it is deposited successively (see FIGS. 2a, 2b , 3a and 3b, 4a and 4b):

- a first dentin 13, a light opaque DOC, which covers the entire vestibular surface and represents between 25 and 50% approximately of the thickness of the total dentin. Depending on the desired effect: saturation, hue or lightening, the appropriate undulation is created. The role of this DOC is to:

• create the internal structure; "create fluorescence effects;

• illuminate the inside of the tooth to lighten the embrasures and the cervical border;

"vary the response of the light, under different lighting, favoring mimicry. This interior relief will gently reflect the light on the bumps and retain it in the depressions.

- A second dentin 14, called translucent colored DTC. This is also applied in a thick layer on the first dentine 13, starting from the neck of the tooth (50 to 75% of the thickness of the total dentine) and stretching up to the crown of the lobes. This layer will thus make the light penetrate and diffuse almost up to the reinforcement 11, in the area of large contour of the emergence profile, and be reflected by bumps and lobes. This decreasing thickness up to the free edge will create the natural saturation gradient of tooth 10 causing in depressions of DOC 13 a greater thickness of DTC, creating a gentle shade contrast.

- A new basic NDDB 15 dentine can, in certain areas, replace all or part of the second DTC dentine, in particular in the lingual surface (cf. FIGS. 3b and 4b).

- A semi-translucent DST 16 dentine. At this stage of the stratification, we can reproduce, if necessary, the clear horizontal lines going up from the heart of the tooth towards the enamel. These fibrils can be more or less dense and more or less long giving clear areas next to saturated areas. To reproduce them, depending on the desired effect, you can use pure DOC or associate it in unequal parts with DTC, creating a semi-translucent DST dentin.

It suffices to make oblique cuts in the scalpel, in general above and below the line of large contour of the emergence profile, in the direction of the cervical edge, to bury these mixtures in fine films, then to fold down the dentine raised. These lines also cause more or less attenuated fluorescent effects depending on the DOC / DTC associations.

- Enamel. The construction or reconstruction of the tooth is completed by a stratification of incisal 17 (containing very little dye and very little opacifier) in the vestibular and lingual free edge, according to a conventional method and covered with a layer of material " translucent "neutral 18 (containing neither coloring nor opacifying) on all the crown.

After the stratification, the tooth is baked in a vacuum oven between 750-980 ° C according to the usual process. After cooking, it is machined and shaped. By a stage, called "frosting", we finish the last adjustments of shade and we cook again to fix the dyes and vitrify the surface to give the natural look.

Claims

1. Prosthetic tooth (10) with reconstituted dentin, in particular based on ceramic and / or resin, characterized in that said reconstituted dentin is formed by superposition, going from the inside towards the outside of the tooth, d 'at least a first dentin (13) and at least a second dentin each containing a fluorescent component (14), the first dentin being more opaque and less colored than the second dentin.

2. Prosthetic tooth (10) according to claim 1, characterized in that the first dentin (13) has a fluorescence equal to or higher than the second dentin (14).

3. Prosthetic tooth (10) according to claim 1 or 2, characterized in that the opacity contrast ratio (R _C O) between the first dentin (13) and the second dentin (14) is greater than or equal to 1 , 01, preferably between 1.02 and 2.00 approximately.

4. Prosthetic tooth (10) according to any one of the preceding claims, characterized in that the color contrast ratio (R _C C) between the second dentin (14) and the first dentin (13) is greater than or equal to 1, 10, preferably between 1, 20 and 3.00 approximately.

5. Prosthetic tooth (10) according to one of claims 2 to 4, characterized in that the fluorescence contrast ratio (R _c f) between the first dentin (13) and the second dentin (14) is greater than or equal at 1.00, preferably between 1.10 and 2.70 approximately.

6. Method for applying dentin reconstituted on a support for producing a prosthetic tooth (10) according to any one of claims 1 to 5, comprising at least one step consisting in successively applying to said support at least a first dentin (13) and at least a second dentin (14) covering the first dentin (13), the first dentin (13) being more opaque and less colored than the second dentin (14) in order to impart a natural appearance to said tooth, the two dentins containing a fluorescent component.

7. Method according to claim 6, characterized in that the first dentin (13) has a fluorescence equal to or higher than the second dentin (14).

8. Method according to claim 6 or 7, characterized in that the opacity contrast ratio (R _C O) between the first dentin (13) and the second dentin (14) is greater than or equal to 1.01, of preferably between 1.02 and 2.00 approximately.

9. Method according to any one of claims 6 to 8, characterized in that the color contrast ratio (R _C C) between the second dentin (14) and the first dentin (13) is greater than or equal to 1, 10, preferably between 1, 20 and 3.00 approximately.

10. Method according to any one of claims 7 to 9, characterized in that the fluorescence contrast ratio (R _c f) between the first dentin (13) and the second dentin (14) is greater than or equal to 1, 00, preferably between 1, 10 and 2.70 approximately.

11. Method according to any one of claims 6 to 10, characterized in that the support is a material based on metal, zirconia, alumina, pressed ceramic, or a composite thereof.

12. Set of compositions for reconstituting dentin, in particular ceramic and / or resin base, for carrying out the method according to one of claims 6 to 11, characterized in that it comprises at least a first dentin composition and at least a second dentin composition, the first dentin being more opaque and less colored than the second dentin in order to impart a natural appearance to said dentin, the two dentins containing a fluorescent constituent.

13. Set of compositions according to claim 12, characterized in that the first dentin composition has a fluorescence equal to or higher than the second dentin composition.

14. Set of compositions according to claim 13, the opacity contrast ratio (R ₀ O) between the first and the second dentin composition is greater than or equal to 1.01, preferably between 1.02 and 2, 00 approximately.

15. Set of compositions according to claim 12 or 13, characterized in that the color contrast ratio (R _C C) between the second dentin composition and the first dentin composition is greater than or equal to 1, 10, preferably between 1, 20 and 3.00 approximately.

16. A set of compositions according to any one of claims 12 to 15, characterized in that the fluorescence contrast ratio (R _c f) between the first dentin composition and the second dentin composition is greater than or equal to 1, 00, preferably between 1, 10 and 2.70 approximately.

17. Set of compositions according to any one of claims 12 to 16, characterized in that said dentin compositions form, in the mixed state in a determined proportion, a so-called dentin composition new basic dentin corresponding to the shade chosen for the prosthetic tooth.

18. A set of compositions according to claim 17, characterized in that the dentin composition called new basic dentin is less opaque than the shade chosen for the prosthetic tooth.