Fluorescence is the absorption of light by a substance and
the spontaneous emission of light in a longer wavelength
within 10
−
8
s of activation
[4]
. Natural teeth emit a blue flu-
orescence under the action of UV light, which makes teeth
whiter and brighter in daylight
[5]
. When human dentin was
irradiated with 365nm UV light, fluorescence was observed
withapeakat440
±
10nm
[6]
.Fluorescenceinamaterialtends
to give a bright iridescence effect, and can be used to brighten
dark teeth without negatively affecting the translucency
[7]
.