Clinical response of three whitening products having different peroxide delivery: comparison of tray, paint-on gel, and dentifrice.

In head-to-head 14-day testing, a low concentration (5% carbamide peroxide) barrier-based tray system yielded superior tooth color improvement compared to two barrier-free delivery systems-an 18% carbamide peroxide paint-on gel and a 1% hydrogen peroxide dentifrice with a metal activator.