Stable tooth whitening gels containing high percentages of hydrogen peroxide

Abstract

An aqueous gel useful for bleaching teeth comprising: (i) water; (ii) polyacrylic acid thickening agent; (iii) hydrogen peroxide bleaching agent; and (iv) aminocarboxylic acid/salt stabilizing agent. Preferably the polyacrylic acid is an easy to disperse carbomer and the gels contain high concentrations (20 to 40% by weight) of hydrogen peroxide. The gels exhibit room temperature stability, both with respect to gel stability and hydrogen peroxide decomposition, sufficient to eliminate the need for constant refrigeration. A method for using the gels to bleach teeth is also disclosed.

What is claimed is:  
     
         1 . A method for bleaching teeth comprising the following steps: 
 (a) protecting the soft tissue surrounding the teeth with a covering;    (b) applying an aqueous dental bleaching gel to the teeth that comprises: 
 (i) water;  
 (ii) a polyacrylic acid thickening agent;  
 (iii) at least one bleaching agent selected from the group consisting of hydrogen peroxide and compounds that release hydrogen peroxide in water; and  
 (iv) a stabilizing agent selected from the group consisting of EDTA, CDTA, and a salt thereof,  
 wherein said bleaching agent is present in an amount ranging from about 20% to about 50% by weight, and wherein said polyacrylic acid thickening agent and said stabilizing agent are added in a weight ration within the range of about 3.3:1 to about 3.5:1 that maintains said aqueous gel in a suitable gel form for 4 to 12 weeks oat room temperature in a syringe plunger without self-expelling; and  
   (c) removing the dental bleaching gel.    
     
     
         2 . The method of  claim 1  wherein the dental bleaching gel remains in contact with the teeth for a period of 5 to 60 minutes.  
     
     
         3 . The method of  claim 2  wherein the dental bleaching gel is applied to the teeth and then treated with a laser light or heat lamp prior to removal.