Grobler, Sias RenierOsman, Yusuf Ismail2020-11-062020-11-062017Grobler, S.R . and Osman, Y. I . ( 2017) Insights into the clinical effectiveness of whitening products. Dentist-supervised-at-home bleaching product . Whitening of darker teeth in contrast to the effects on relatively whiter teeth, 328-329 . The Journal of the Dental Association of South Africa . DOi: 10.17159/2519-0105/2017/v72no7a8http://doi 10.17159/2519-0105/2017/v72no7a8http://hdl.handle.net/10566/5385This 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.enWhitening darker teethHydrogen peroxideCosmetic dentistryArticle