Colour change of ceramic brackets with the use of coloured beverages in adolescent patients: A randomized clinical trial

Abstract

To clinically evaluate colour change of ceramic orthodontic brackets with the use of coloured beverages as ceramic brackets' resistance to discoloration has become a major concern. A prospective two parallel groups-split mouth randomized trial with a 1:1 allocation ratio. Two equal groups including 40 adolescent patients from the orthodontic department (Faculty of Dentistry, Mansoura University, Egypt), scheduled for maxillary premolar extractions were bonded with 2 types of mono-crystalline ceramic brackets: Type 1 (Inspire ICETM) and Type 2 (Radiance PlusTM). Participants in each group were asked to rinse with either black tea or Cola. After extraction, the colour of the 80 debonded brackets was compared to that of 20 control brackets from each type by spectrophotometer according to the international standard CIELAB colour space (CIE L*a*b*). The latter consists of three coordinates: L* (lightness value), a* and b* (the colour channels). The total colour difference ΔE* is the distance between two colours in this three-dimensional colour space. The colour change was also assessed by digital image analysis according to the RGB model. Type 1 brackets showed mean ΔE* values of 2.24±0.25 in black tea and 1.76±0.1 in Cola groups (P<0.001), while Type 2 brackets showed means of 1.99±0.15 in black tea and 1.56±0.1 in Cola groups (P<0.001). The mean RGB values were 174.3±12.02 in black tea and 185.6±6.9 in the Cola groups of type 1 brackets (P<0.001), while were 166.5±17.8 in black tea and 190.8±8.9 in Cola groups of type 2 brackets (P<0.001). Black tea showed more significant effect than Cola on the two bracket types. Bracket type affected the colour change in each beverage group.