Resumen de The effect of sodium hexametaphosphate on sensitivity and whitening effectiveness of an at-home bleaching gel: 
a randomized, triple-blinded clinical trial

Hamideh Mohamadipour, Hosein Bagheri, Majid Akbari, Shima Behzadi, Navid Ramezanian, Sajad Javanshir, Mehrzad Khorshid

• Objective: Bleaching sensitivity (BS) is the most common adverse effect of tooth bleaching treatments. This study evaluated the effect of adding 1% sodium hexametaphosphate (SHMP) on BS and the whitening effectiveness of a bleaching gel.

  Method and materials: Two maxillary quadrants from 26 patients were randomly assigned to the experimental and control groups in a split-mouth design. In the control group the at-home bleaching gel containing 3% hydrogen peroxide, and in the experimental quadrant the same gel with 1% SHMP, were applied in individual trays for 6 hours per night for 2 weeks. The patients’ sensitivity to cold and touch as well as spontaneous sensitivity were recorded based on a visual analog scale (VAS). Changes in shade guide units (ΔSGU) and ΔE were measured using a spectrophotometer. Data were analyzed using the Kolmogorov-Smirnov, Mann-Whitney U, Wilcoxon signed-rank test, and independent sample t test.

  Results: Twenty-four patients completed the study. After 2 weeks, the sensitivity to cold and touch was significantly lower in the intervention group compared to the control (P = .015 and P = .039, respectively). The spontaneous sensitivity revealed no significant alteration between these two groups and during the bleaching period in each group (P > .050). Regarding both color measurements, the bleaching effectiveness in both groups was comparable, with no noticeable difference (P > .050).

  Conclusion: The application of 1% SHMP was able to reduce the BS with no detrimental effect on the at-home bleaching effectiveness. (Quintessence Int 2021;52:596–605; doi: 10.3290/j.qi.b1098303)