WO2008020052A1 - Dental treatment lamp and method for generating a light field for treatment with a light-curable dental material - Google Patents

Abstract

The dental treatment lamp comprises several illumination elements (2) adjoining each other with different wavelength spectrums of the radiated light, the illumination intensity of said elements being individually adjustable or adjustable in groups by adjusting means (7) in such a way, that the cones of light (5) thereof overlap to form a white light field (6) with a predetermined illumination intensity and color temperature. In a lighting mode, a color rendering index R<SUB>a </SUB>of a whole spectrum (10) of the light field (6) is larger than 85. To prevent early hardening of a light-curable dental material during processing, the intensity in a treatment mode of a chosen wave length spectrum having the curing wave length ?<SUB>A</SUB>,is 50 % of the maximum intensity of the whole spectrum (20) at the most. Said dental treatment lamp can be used in the illumination mode for color adaptation and in the treatment mode for treatment with a light-curable dental material. The invention also relates to a method for creating a light field for treatment with a light-curable dental material.

Description

 Dental treatment light and method for generating a light field for treatment with a light-curable dental material. Technical field

The invention relates to a dental treatment light and a method for generating a light field for treatment with a light-curable dental material, comprising a plurality of adjacently arranged to each other bulbs with different wavelength spectrum of the emitted light. The illuminants are individually or in groups in their intensity adjustable and the light cones overlap in an object plane and produce a white light field with predetermined properties. The illumination intensity of the individual lighting means is adjusted by adjusting means so that the necessary illuminance is given and the color rendering index R _{a of} the total spectrum in an illumination mode is greater than 85%. This produces a light field which illuminates the patient's oral cavity for the dentist during the dental treatment and thereby fulfills the prescribed properties.

State of the art

Dental treatment lights are usually equipped with a halogen lamp as a lighting fixture. A halogen lamp provides a light field with an illuminance above 25000 Ix and with a spectrum that covers the visible range from 380 nm to 760 nm and has a color temperature of 3500 K to 6000 K. The ultraviolet and infrared wavelengths of the spectrum are mostly filtered out. The requirements for a dental treatment lamp according to ISO 9680 are fulfilled. For color matching of crowns, fillings and inlays, it is necessary that the color rendering index R _{a of} the spectrum of the treatment light to be determined according to CIE 13.3-1995 is at least 85%.

The disadvantage is that halogen lamps with higher power are often high-pressure halogen lamps in which there is a danger of explosion and therefore only operation in an explosion-proof housing is possible. A strong development of heat during operation of the halogen lamp requires constant cooling. The short life of max. 2000 hours requires frequent replacement of the halogen lamp.

It is also desirable to have the patient's oral cavity during treatment with a photocurable dental

Material for the purpose of filling cavities or for gluing inlays optimally illuminate. A cure wavelength of this material is typically within the spectrum of the treatment lamp with a halogen lamp. Even during the processing of this material, it comes to curing processes on the tooth. Consequently, there is poor processing of the material, pre-curing and lack of attachment to the tooth. This leads to a risk of secondary caries under the filling and poor durability of inlays. The dentist must either work faster or the treatment light must be switched off or dimmed below 8000 Ix to prevent hardening during processing of the material. Dimming the halogen bulb by reducing the supply voltage, however, causes the color temperature to be lowered. The processing of the material is the Dentist thus complicated by a reduced illuminance and a color distortion.

DE 20 2005 003 802 U1 discloses an OR lamp for a dental treatment chair, wherein the light source consists of several high-performance LEDs with collimators in a dust-tight housing. A switchable filter should be able to be introduced into the beam path in order to block out a curing wavelength of a light-sensitive composite used from the spectrum and thus harden during treatment with the light-sensitive layer

Prevent composites. Preferably, LEDs with a power of at least 3 W and a light color of 5500 K are to be used.

DE 100 34 594 A1 discloses a dental treatment light, wherein the light source consists of a plurality of LEDs arranged adjacent to one another and whose light cones are formed such that a light field having a predetermined size, illuminance, uniformity and color temperature is produced. DE 20 2004 001 189 U1 discloses a dental handpiece with a light source emitting white light, wherein the light source generates its radiation by means of at least one LED and an emission maximum of the light source is in the range from 400 to 515 nm. In the exemplary embodiments, a spectrum is generated which contains a high proportion of blue in the wavelength range from 400 nm to 615 nm. This is achieved by combining white and colored LEDs.

The object of this invention is to provide a dental treatment lamp, with which all the disadvantages mentioned are avoided. In particular, a sufficient number of be given light treatment even with a treatment with a light-curable dental material.

Presentation of the invention

This object is achieved by the features specified in claim 1.

According to the invention, the dental treatment light comprises a plurality of illuminants arranged adjacent to one another with different wavelength spectrum of the radiated light, which can be adjusted individually or in groups in their intensity and superimpose their light cones in an object plane and produce a white light field which has an overall spectrum with a predetermined color temperature between 3600 K. up to 6500 K and an illuminance of at least 8000 Ix. The treatment light can be adjusted between a lighting mode and a treatment mode. The illuminance of the individual lamps is adjusted by adjusting means so that the color rendering index R _{a of} the total spectrum in the illumination mode is greater than 85. This has the advantage that a secure color balance for

Crowns, fillings and inlays is guaranteed in a daylight-like lighting.

In the treatment mode, however, the intensity of a selected wavelength range within the total spectrum is at most 50% of the maximum intensity of the entire spectrum, the selected wavelength range containing a cure wavelength of a photocurable dental material used for the treatment.

This has the advantage that premature curing of the dental material during processing is prevented. Advantageously, the wavelength of the selected wavelength range may be from 460 nm to 500 nm. In general, as a polymerization initiator for composites, camphorquinone complex having a cure wavelength of 468 nm is used.

Advantageously, LEDs can be used as the lighting means. LED's have the advantage that they are compact, have a long life, and have a relatively good light output with low heat generation. Advantageously, white LEDs and colored LEDs can be used as the lighting means. The spectrum of a common white LED's has two increases. The first peak has its maximum at 460 nm and provides the primary radiation of a blue LED, which is part of the white LED based on gallium nitride (GAN), which is a semiconductor with wider

Energy gap is. The second increase with a maximum at 600 nm represents the yellow emitted light of a fluorescent dye covering the blue LED. The gap between the two ridges is in an illumination mode with- means of green LED's completed, so that the color rendering index R _a greater than 85%. When switching to the treatment mode, the green LEDs are dimmed or turned off so that the intensity of the selected wavelength range with the cure wavelength, for example at 468 nm, drops below 50% of the maximum intensity of the entire spectrum.

Advantageously, only colored LEDs can be used as lighting means. Several colored LEDs, for example red, green and blue LEDs, form a complete spectrum in combination with color addition. By adjusting the illuminance of the individual LED, the demanded characteristics of the total spectrum achieved in the two modes.

Another object of the invention relates to a method for generating a light field for the dental treatment with a light-curable dental material. The light field is generated by superimposing light cones provided by light sources with different wavelength spectrum and with adjustable illuminance of the emitted light.

The light cones are superimposed in the object plane and generate by adding the individual spectra a light field with an overall spectrum, the illuminance of the individual bulbs is set so that in an illumination mode, the color rendering index R _{a of} the entire spectrum greater than 85 and in a treatment mode, the intensity of a or multiple selected wavelength ranges within the total spectrum is at most 50% of the maximum intensity of the entire spectrum. An advantage of this method is that no auxiliary means, such as, for example, the optical path of the curing wavelength in the beam path, is necessary in order to adjust the overall spectrum between the illumination mode and the treatment mode. Advantageously, the total spectrum can be generated by adding the individual spectra of LEDs. LED's usually supply narrow-band spectra, which form a complete spectrum.

Advantageously, by switching off one or more colored LEDs, the entire spectrum is switched from the illumination mode to the treatment mode. A selected wavelength range can thus be faded out by switching off the respective LEDs. Thus, the entire spectrum of the illumination mode enters the treatment mode. Advantageously, by reducing the illuminance of one or more colored LEDs, the overall spectrum can be switched from the illumination mode to the treatment mode.

A selected wavelength range can therefore be attenuated by dimming the respective LEDs and thus attenuating their intensity.

Brief description of the drawings

Embodiments of the invention are illustrated in the drawing. 1 shows an exemplary embodiment for generating a light field

Fig. 2 is a diagram of the total spectrum in the illumination mode with the relative intensity as ordinate and wavelength as abscissa. Fig. 3 is a diagram of the total spectrum in the treatment mode with the relative intensity as ordinate and wavelength as abscissa

EXEMPLARY EMBODIMENTS OF THE INVENTION FIG. 1 shows the exemplary structure of a dental treatment lamp 1 with a direct beam path. A plurality of LED's 2 are fixed in a plane on a base plate 3 adjacent. The LEDs can be individually designed as white or colored. The treatment light is arranged at a distance a from an object plane 4. The individual LEDs 1 emit light cone 5, which are aligned so that they overlap in the object plane and produce a white light field 5. In this case, the white light field 6 can be generated, for example, by a combination of white and green LEDs or by a combination of blue, green and red LEDs. The light field 6 has a size with a diameter d and a predetermined illuminance of at least 8000 lx. The adjustment of the illuminance of the individual LEDs 1 is realized by a regulation of a supply voltage U _v . The supply voltage U _{v of} the individual LEDs 1 is adjustable by a corresponding adjusting means 7 in the present embodiment by a voltage divider in the form of a potentiometer, wherein an input voltage U _{e by means of} the respective potentiometer is divided. The illuminance of the individual LEDs 2 is adjusted so that the light field 6 fulfills the predetermined conditions in a lighting mode and in a treatment mode.

FIG. 2 shows an overall spectrum 10 in the illumination mode, which results from addition of the spectra of the individual light cones 4. In the present embodiment, a spectrum of a white LED 11 and a spectrum of a green LED 12 are added based on the semiconductor indium gallium nitride (InGaN), wherein the total spectrum 10 is generated. This total spectrum should have a given color temperature of 3600 K to 6500 K. A color temperature of a light source is the temperature that a black body that completely absorbs the impinging electromagnetic radiation should have, so that its light gives the same color impression as the actual light source. The middle sunlight has a color temperature of 5500 K. In the present embodiment, a color impression of the dental treatment light is sought, which comes close to a color impression in medium sunlight. The total spectrum 10 should thus approach a spectrum 13 of a blackbody at 5500 K within the visible wavelength range between 400 nm and 700 nm. A color rendering index R _a is a photometric quantity with which the quality of the color reproduction of light sources of the same correlated color temperature can be described. If the total spectrum 10 coincided with the spectrum 13, the color rendering index R _{a would be} 100. This color rendering index R _a should be at least 85 according to ISO / DIS 9680: 2005 in accordance with paragraph 5.2.8 for dental treatment lamps for diagnostic purposes. In the present exemplary embodiment, this standard is satisfied by adding the individual spectra 11 and 12 and the overall spectrum 10 has a color rendering index R _a of at least 85.

FIG. 3 shows a total spectrum 20 in the treatment mode. In the present exemplary embodiment, the overall spectrum 20 is achieved in that, in contrast to the illumination mode, the green LEDs are switched off and the white LEDs remain switched on. In the exemplary embodiment, the total spectrum 20 thus corresponds to the spectrum 11 of white LEDs. It is essential that in the treatment mode, the intensity of a selected wavelength range within the total spectrum, which in the present embodiment, a curing wavelength λ _A of 468 nm of a composite used with camphorquinone complex as a polymerization sationser, at most 50% of the maximum intensity Imax of the total spectrum. This prevents the early curing of the composite during treatment. prevents, wherein the color rendering index F _a insignificantly reduced compared to the illumination mode.

LIST OF REFERENCE NUMBERS

1 dental treatment light

2 lamps in the form of LED 3 base plate

4 object level

5 light cones

6 light field

7 adjustment means 10 total spectrum in the illumination mode

11 spectrum of a white LED

12 spectrum of a green LED

13 Spectrum of a black spotlight at 5500 K 20 Total spectrum in the treatment mode a Distance between treatment light 1 and object level 4 d Diameter of the light field 6

I max Maximum intensity of the total spectrum 20 in treatment mode U Supply voltage

U e input voltage

λ A curing wavelength

Claims

1. A dental treatment light, comprising a plurality of adjacently arranged lamps (2) with different wavelength spectrum of the emitted light, which are individually or in groups in intensity adjustable and whose light cone (5) in an object plane (4) and superimpose a white light field (6 ), which has an overall spectrum (10, 20) with a predetermined color temperature of 3600 K to 6500 K and an illuminance of at least 8000 Ix, wherein the illuminance of the individual luminous means (2) by adjusting means (7) is set so that the Color rendering index R _{a of} the total spectrum (10) in an illumination mode is greater than 85, characterized in that in a treatment mode, the intensity of a selected wavelength range within the total spectrum (20) is at most 50% of the maximum intensity I _{max of} the total spectrum (20) , wherein the selected wavelength range is an Au shunt wavelength λ _{A of} a light-curable dental material used for the treatment. 2. treatment lamp according to claim 1, characterized in that the wavelength of the selected wavelength range of 460 nm to 500 nm. 3. treatment lamp according to claim 1 or 2, characterized in that as the light source (2) LED's are used. 4. treatment lamp according to claim 3, characterized in that as the light source (2) white LEDs and colored LEDs are used. 5. treatment lamp according to claim 3, characterized in that as the light source (2) exclusively colored LEDs are used. 6. A method for generating a light field (6) for the dental treatment with a photocurable dental material by superimposing light cones (5), which are provided by bulbs (2) with different wavelength spectrum and with adjustable illuminance of the emitted light and are superimposed in the object plane (4) and generate a light field (6) with an overall spectrum (10, 20) by the addition of the individual spectra (11, 12), characterized in that the illuminance of the individual light sources (2) is adjusted in a lighting mode the color rendering index R _{a of} the total spectrum (10) is greater than 85 and in a treatment mode the intensity of a selected wavelength range within the total spectrum (20) is at most 50% of the maximum intensity I _{max of} the total spectrum (20), the selected wavelength range a curing wavelength λ _{A of} a Treatment used includes light-curable dental material. 7. The method according to claim 6, characterized in that the total spectrum is generated by adding the individual spectra of LEDs. 8. The method according to claim 6 or 7, characterized in that by switching off one or more color Biger LED 's the entire spectrum is switched from the lighting mode to the treatment mode. 9. The method according to any one of claims 6 or 7, characterized in that the total spectrum is switched from the illumination mode to the treatment mode by reducing the illuminance of one or more colored LED's.