Equipment and method for measuring dental shade

Abstract

The invention relates to a device for measuring dental shade.

1 . A measuring instrument, comprising:
 illumination for successively illuminating at least one part of a tooth with light of different colors;   at least one monochrome sensor sensitive to intensity of light coming from the tooth part, in response to the illumination, to generate for each different color of illumination, at least one measurement signal;   means for converting the measurement signals corresponding to the tooth part, into coordinates of a measurement point, in a shade space in which reference points are also defined, corresponding to the preset shades of a dental shade guide;   automatic shade search means for automatically searching a shade corresponding to the reference point closest to the measurement point, in the shade space, for the tooth part; and   an illumination head provided with a plurality of light emitting sites linked to the light sources.   
     
     
         2 . The measuring instrument according to  claim 1 , wherein the sensor is housed in the illumination head and wherein the light emitting sites are arranged around the sensor. 
     
     
         3 . The measuring instrument according to  claim 1 , wherein the light emitting sites are coupled with light sources by means of optical fibers. 
     
     
         4 . The measuring instrument according to  claim 3 , wherein the light emitting sites are coupled in common to a set of light sources, to emit simultaneously light of the same spectral range, when at least one light source is activated. 
     
     
         5 . The measuring instrument according to  claim 1 , comprising a plurality of subassemblies of light emitting sites, each subassembly of light emitting sites being coupled respectively to a light source taken among a plurality of light sources of various spectral ranges, so that the light emitting sites of each subassembly simultaneously emit light of the same spectral range, the light emitting sites of each subassembly being distributed substantially regularly around the sensor. 
     
     
         6 . The measuring instrument according to  claim 1 , wherein the light emitting sites are the free ends of a bundle of optical fibers, coupled to the light sources. 
     
     
         7 . The measuring instrument according to  claim 1 , comprising a grip housing at least one from among: a set of light sources, the signal conversion means, and a data transmission interface, and in which the illumination head is mounted in a removable way on the grip. 
     
     
         8 . The measuring instrument according to  claim 1 , comprising a first shield opaque to the illumination light, held close to the illumination head to be able to insert a tooth between the illumination head and the shield. 
     
     
         9 . The measuring instrument according to  claim 1 , comprising a second shield solid with the illumination head and surrounding the light emitting sites, to prevent ambient light from directly reaching an illuminated tooth part, when the illumination head is applied to a tooth. 
     
     
         10 . The measuring instrument according to  claim 1 , comprising a means for forming an image on the sensor.