Tooth bleaching compositions

A tooth bleaching gel comprising:

• at least 70% by weight of water,
• hydrogen peroxide in an effective tooth whitening amount,
• a thickening agent in an amount required to form a viscous gel,
• an alkaline pH adjusting agent, and
• a calcium chelating agent selected from the group consisting of EDTA, citric acid, gluconic acid, alkali metal pyrophosphates and alkali metal polyphosphates,
• wherein the gel is packaged as a single component, and wherein the pH of the gel when in contact with a tooth surface in an oral cavity is substantially constant within a range of 6.0 to 10.0.

A tooth bleaching gel comprising:

• at least 70% by weight of water,
• hydrogen peroxide in an effective tooth whitening amount,
• a Carbopol® polyacrylic acid in an amount required to form a viscous gel,
• sodium acid pyrophosphate,
• sodium stannate trihydrate, and
• an alkaline pH adjusting agent, wherein:
• the water, hydrogen peroxide, Carbopol® polyacrylic acid, sodium acid pyrophosphate and sodium stannate trihydrate are present in descending amounts by weight percent in the order listed herein,
• the alkaline pH adjusting agent is present in an amount that provides a pH above 5.5 proximate to a tooth surface in the oral cavity of a human in contact with the gel, and
• the gel is packaged as a single component for application to a tooth surface in the oral cavity of a human.