DE9012977U1 - Tooth color determination - Google Patents

Description

The invention relates to a device for measuring the color of a tooth for the precise color matching of artificial teeth.

Dentists have long had the problem that the artificial teeth they put in a patient do not match the color of the adjacent real teeth.

This is of course undesirable, which is why attempts have been made to determine the color of a tooth.

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When determining the color, both the artificial tooth and the original tooth must be determined.

Photographic methods are ineffective because they cannot cover all wavelengths of the visible spectrum. Efc—iso are methods in which the light sensors cannot weight all wavelengths exactly like the human eye, which is severely handicapped.

A device for measuring the colour of a fence for precise colour matching of artificial teeth is already known from WO/FR 86/00433, in which a measuring head is brought close to a tooth in order to capture the light reflected by the tooth.

However, this device has the disadvantage that the captured light still comes from light that is reflected on the surface of the tooth.

The object of the invention is therefore to create a device in which the ambient light does not have to be taken into account and only measuring light from the tooth is recorded, excluding light resulting from surface reflections.

This task is solved by a measuring head with a plurality of external waveguides for illuminating the tooth and an internal waveguide for receiving the light emitted by the tooth, which is placed directly on the tooth.

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'..> /AiM'G)TONNIES

In a preferred embodiment, the outer waveguides are arranged in a ring around the inner waveguide in a bundle.

Furthermore, it is advantageous to use a glass waveguide for illumination.

To capture the light emitted by the tooth, it is advantageous to use a quartz waveguide.

Furthermore, the device is advantageously equipped with a conical tip into which all waveguides end.

This conical tip has a flat surface at its end.

In practical tests, versions of the device in which this tip is attached to a tubular rigid extension with a pistol-like handle have proven particularly advantageous.

Finally, it is recommended to provide the device with a shutter on the waveguide suspension, which interrupts a light path from an additional light-emitting light guide and an additional light-conducting light guide when the waveguide rests on a surface in order to generate a trigger switching signal via a light detector.

The invention is illustrated below with reference to a drawing. Shown are:

Fig. 1 is a schematic representation of the measuring head on a tooth, and

Fig. 2 shows a representation in which a diaphragm device in front of the receiving light guide prevents stray light from entering.

In Fig. 1, a tooth 10, the measuring tip 12, the external light guides 14 used for illumination, the waveguide 16 used to receive the light emitted by the tooth and the flat surface 18 into which the conical tip ends can be seen.

To illuminate the tooth, xenon flash lamps can be used, e.g. using the 45/0 remission measurement method or halogen light bulb light that is transmitted using optical fiber technology.

The respective light sources are optically coupled to the lighting light guides.

The measuring head is mounted movably in a handle, with a diaphragm attached to the suspension of the measuring head or the waveguide in such a way that it interrupts the light path of an additional pair of light guides when the waveguide is placed on a surface. A photodetector amplifier attached to the light-transmitting waveguide serves to generate a pulse. The measuring head then only needs to be placed on the tooth in order to send a measurement trigger pulse to the electronics.

This makes handling the device much easier, since in practice one typically takes up to five measurements on one tooth.

To prevent reflected light from entering the measuring light guide, which does not come perpendicularly from the sample or at a maximum angle of +/- 5° from the tooth, an optical device for limiting the reflected light as shown in Fig. 2 can be used. It consists of two diaphragms 2 0 connected in series or a correspondingly conical channel.

The design proposed here ensures that light reflected from the tooth surface, which is not usable for tooth color determination, cannot enter the measuring light guide. ^;

The direct placement of the flat surface 18 on the tooth 10 has the desired side effect that saliva remaining on the tooth 10 creates an optical contact between the tooth and the light guides 14, 16.

Claims (7)

N5056 CLAIMS 1. Device for measuring the color of a tooth (10) for the precise color matching of Kunat teeth, characterized by a measuring head that can be placed directly on the tooth and has a plurality of outer waveguides (14) for illuminating the tooth (IC) and an inner waveguide (16) for receiving the light emitted by the tooth. 2. Device according to claim 2, characterized in that the outer waveguides (14) are arranged in a bundle in a ring shape around the inner waveguide (16). 3. Device according to one of the preceding claims, characterized in that glass waveguides are used for illumination. 4. Device according to one of the preceding claims, characterized in that quartz waveguides are used to receive the light emitted by the tooth (10). > j f · · · tit 5. Device according to one of the preceding claims, characterized in that all waveguides (14, 16) end in a conical tip (12) which has at its end a flat surface (18) into which the waveguides (14, 16) open. 6. Device according to claim 4, characterized in that said tip (12) is attached to a tubular rigid extension with a pistol-like handle. 7. Device according to one of the preceding claims, characterized by a diaphragm on the suspension of the waveguides (14, 16), which interrupts the light beam of a particular pair of optical fibers when the waveguides (14, 16) are placed on a surface, one of the two pairs of optical fibers leading to a photo amplifier.