Assessment of changes in enamel colour following fixed orthodontic therapy using an advanced spectrophotometer: An in vivo study

Abstract

BACKGROUND:

Any manipulation of the surface of natural teeth may result in a variation of their colour. The fixed orthodontic treatment (FOT) is one such procedure which alters the enamel surface during the procedure.

OBJECTIVE:

To clinically evaluate the colour changes in teeth associated with comprehensive FOT (to compare the changes in test and control groups) and to determine the relationship of age and gender on enamel colour due to FOT by using an advanced spectrophotometer.

METHODS:

The selection of sixty patients for the study was done randomly and among these thirty patients who underwent the FOT as the case group, the other thirty patients who did not need FOT, were the control group. The recordings of spectrophotometric data were done in a standardized manner for all patients in the labial circular region of every anterior tooth, following debonding and cleaning operations, and before bracket bonding. The Commission Internationale de l’Eclairage’s L*, a*, and b* (lightness, red/green, and blue/yellow) tooth-type characteristics were used to measure color, and the associated color differences (DE) between the groups were computed. One-way ANOVA (a $<$ 0.05) and the paired $t$ -test were used to evaluate any changes in these color characteristics.

RESULTS:

Fixed orthodontic treatment is associated with changes in colour parameters. L* values decreased ( $P<$ 0.001), while a* and b* values increased ( $P<$ 0.001) at the end of treatment. All measured tooth types showed significant colour change (DE); their mean differences ranged from 1.64 to 2.96 DE units.

CONCLUSIONS:

Fixed orthodontics can change the natural colour of teeth. The CIE colour parameters L*, a*, and b* of natural teeth showed statistically significant differences after debonding the orthodontic appliances. The L* values decreased making the teeth look darker. The adolescent and male patients had more tooth colour changes than the adult and female groups.