Effect of a Nano‐Hydroxyapatite Paste on Bleaching‐Related Tooth Sensitivity

Abstract

Bleaching-related tooth sensitivity has been shown to be facilitated by the presence of enamel defects. A nano-hydroxyapatite (n-HAP) paste has been shown to repair these defects. Using a randomized clinical trial, an n-HAP paste was investigated to determine its efficacy in reducing bleaching-related tooth sensitivity. An n-HAP paste (Renamel AfterBleach, Sangi Co., Ltd., Tokyo, Japan) and a placebo (zero-HAP) were randomly assigned for use in 42 participants. A 7% hydrogen peroxide gel was used twice daily for 14 days, with use of assigned desensitizer for 5 minutes immediately following. A diary was completed daily for 4 weeks to note: use of the agents and sensitivity on a visual analog scale (VAS). Three aspects of tooth sensitivity were investigated: percentage of participants; number of days; and intensity level. Color change was assessed. For Groups zero-HAP and n-HAP, respectively, 51 and 29% of participants reported tooth sensitivity (p = 0.06). Days of sensitivity were 76 and 36, respectively (p = 0.001). Change in VAS score from baseline trended higher for group zero-HAP (p = 0.16). Color change was equivalent. The data trend indicated group n-HAP experienced less sensitivity over all three measures. Only the number of days of sensitivity was statistically significant. Within the limits of the study it can be concluded that the use of the n-HAP paste was associated with a statistically significant reduction in the number of days of tooth sensitivity experienced during active bleaching. For those using a tooth whitener without a desensitizing agent, this study indicates that a paste containing nano-hydroxyapatite crystal can effectively reduce the duration of tooth sensitivity.