Moreover, the sensitivity caused by tooth bleaching tends to increase within a few hours following the bleaching procedure, when most patients described the pain as a "twinge" or "shock-like." It has been demonstrated that the oxidizing agents used during the bleaching procedure cause a reduction on metabolism, viability, and cell proliferation20, allowing to increase the expression of inflammatory mediators, such as substance P and bradykinin, which is a vasoactive peptide released by nerves resulting in a neurogenic inflammation.6 The gene discussed is TAC1; the disease is inflammation.