In vitro tooth whitening effect of two medicated chewing gums compared to a whitening gum and saliva

BACKGROUND: Extrinsic staining of teeth may result from the deposition of a variety of pigments into or onto the tooth surface, which originate mainly from diet or from tobacco use. More recently, clinical studies have demonstrated the efficacy of some chewing gums in removing extrinsic tooth staining. The aim of this study was to assess the effectiveness of two nicotine medicated chewing gums (A and B) on stain removal in an in vitro experiment, when compared with a confectionary whitening chewing gum (C) and human saliva (D). METHODS: Bovine incisors were stained by alternating air exposure and immersion in a broth containing natural pigments such as coffee, tea and oral microorganisms for 10 days. Stained enamel samples were exposed to saliva alone or to the test chewing gums under conditions simulating human mastication. The coloration change of the enamel samples was measured using a spectrophotometer. Measurements were obtained for each specimen (average of three absorbances) using the L*a*b scale: lightness (L*), red-green (a) and yellow-blue (b). RESULTS: Medicated chewing gums (A and B) removed a greater amount of visible extrinsic stain, while the confectionary chewing gum with a whitening claim (C) had a milder whitening effect as evaluated by quantitative and qualitative assessment. CONCLUSION: The tested Nicotine Replacement Therapy (NRT) chewing gums were more effective in the removal of the extrinsic tooth stain. This visible improvement in tooth whitening appearance could strengthen the smokers' motivation to quit smoking.