Insights into the clinical effectiveness of whitening products. Dentist-supervised-at-home bleaching product (Opalescence PF). Whitening of darker teeth in contrast to the effects on relatively whiter teeth
Abstract
This study evaluated the success of the whitening of
darker teeth by comparing the results of a tooth whitening
programme in two groups, subjects with darker (A2 and
darker) teeth and patients with whiter teeth. Opalescence
PF 10% was applied for 14 days (nightly for 6-8 hours) and
the colour changes followed over a six month period. The
overall effect (∆E*ab) showed a much higher improvement
(p<1%) in the whitening of darker teeth (~40%) relative
to teeth which at the outset had been whiter than A2.
Overall (∆E*ab) a deterioration of about 19% for darker
teeth and ~9% for whiter teeth was seen after six months,
but a significant improvement in colour was still evident.
Conclusion: The effect of Opalescence PF 10% treatment
was significantly better in all components (L*, a*, b* and
∆E*ab) for A2 and darker teeth relative to whiter teeth.
Despite a significant colour relapse after a six-month
period, there was still an improvement compared with
before treatment. Thus, it can be expected that bleaching
treatment of darker teeth would result in more aesthetic
observable colour changes. The significant loss of the
whitening effect found after six months may suggest the
recommendation to re-bleach.