Effects of common beverage colourants on colour stability of dental composite resins: The utility of a thermocycling stain challenge model in vitro
Available online 27 April 2012
Abstract
Objectives
To
study the colour stability of dental composite resins using a
thermocycling stain challenge model accounting for the complex effects
of oral environment and tooth brushing.
Methods
Composite
resin discs were made from Filtek Supreme Ultra (FiltekSU), TPH3 and
Renamel, and subjected to thermocycling challenges in warm coffee
(55 °C/pH 5.2) and a cold tea and fruit juice mixtures (5 °C/pH 3.6) for
a total of 1000 cycles with 30 seconds dwell time in each solution per
cycle. Colour was assessed in the CIELAB colour space using a Crystaleye
dental spectrophotometer before and after thermocycling, and after
brushing vigorously for 3 min. The thermocycling stain challenge was
repeated for a second 1000 cycles and the discs were brushed again.
Colour changes were compared among the 3 groups using Kruskal–Wallis
test.
Results
All 3 groups showed statistically significant colour changes after stain challenge, with ΔE*
as 5.74 for FiltekSU, 3.21 for TPH3 and 2.52 for Renamel. Colour change
was more significant in FiltekSU than in TPH3 and Renamel (p < 0.05).
After brushing, colour recovered mostly to its original CIELAB values
in TPH3 and Renamel but less so in FiltekSU. The second round of
thermocycling stain challenge resulted in colour changes in FiltekSU
that largely could not be removed by vigorous brushing.
Conclusions
Colour
stability of FiltekSU is inferior to that of TPH3 and Renamel. The
thermocycling stain challenge model can potentially differentiate
surface staining that can be removed by brushing from true
discolouration of the material that is refractory to oral hygiene
procedures.
Comments