Ricerc@Sapienza

The aim of this in vivo study was to evaluate the colourimetric
changes between sound enamel and post orthodontic WSLs and to
correlate these findings with human eye colour perception threshold
using spectrophotometry. Experimental approach Seventy-six
permanent teeth with post orthodontic WSLs in 12–16 years old
patients were evaluated in this in vivo study at “Sapienza”University
of Rome. The spectrophotometric differences in colour (ΔL*, Δa*,
Δb*; Color Difference ΔE00; Whiteness Index ΔWIO) between
sound enamel and clinically detected WSLs in each tooth were calculated.
A correlation between Acceptability Threshold (AT = 3.3)
and the calculated CIEDE2000 colour difference was performed.
The L* value is measure of the lightness ranging from 0 (black) to
100 (white), the a* value of redness/greenness (a* ><0), and the b*
value of yellowness/blueness (b*> <0). The colour change between
sound and affected enamel for each tooth was defined by the CIEDE2000
colour space (ΔE00). WIO Index is the most up to date
and appropriate index to measure tooth whiteness. Spectrophotometric
differences in colour between sound enamel and clinically
detected post orthodontic WSLs show a decrease in ΔL* (–1.06)
and ΔWIO (–11.88) and an increase in Δa*(0.43) and Δb*(2.94).
Overall colour change ΔE (4.38) was always higher than the Acceptability
Threshold. In conclusion white spot lesions due to
orthodontic fixed therapy affect colourimetric properties of teeth
and the amount of the calculated colour difference is on average
always higher than 3.3, indicating a detectable and aesthetically
unacceptable, colour difference.