Whitening Effect by Stain Inhibition from a Chewing Gum with Sodium Hexametaphosphate in a Controlled Twelve-Week Single-Blind Trial

Objective: A twelve-week clinical study was conducted to assess the effect of a chewing gum containing sodium hexametaphosphate (4%) on the inhibition of stain formation. Methodology: Fifty-four subjects were entered and completed all aspects of the study. Twenty-seven of the subjects were smokers, and the other half did not smoke. Subjects were randomly assigned to the test gum or no-gum group. Each participant received a full oral prophylaxis at the beginning of each period of observation. Those chewing the test gum agreed to chew four times a day, for five minutes each time, over twelve weeks. Those assigned to the no-gum group agreed not to chew any gum. After twelve weeks, participants were scored for stain deposits (Lobene Index), received a second oral prophylaxis, and joined the alternate group in this cross-over format. At the end of the twenty-fourth week, all subjects were again scored for stain deposits and the study was completed. In order to enhance stain formation during the entire 24-week study period, all participants received a supply of a chlor-hexidine (0.12%) dentifrice without anionic agents to use three times a day. Stain levels were scored by the same examiner for all measurements and recorded on computer. The examiner was blinded to all treatment assignments. Results: There were no reported problems associated with the chewing gum. The Lobene Index mean score for stain extent was 0.54 (± 0.36) in the test-gum group and 0.81 (± 0.47) for the no-gum group. The difference between the mean scores was highly significant with paired sample t-test (p < 0.001). Mean stain intensity was 0.57 (± 0.38) in the test group and 0.95(± 0.72) in the control group, with a statistically significant difference at p < 0.01. Conclusion: The results indicated that chewing gum containing sodium hexametaphosphate reduced induced stain formation by 33% compared to a no-gum treatment.