Tooth bleaching is one of the most requested esthetic dental procedures, as many patients seek whiter and brighter teeth to enhance the appearance of their smile [1]. Despite its effectiveness, tooth bleaching is often associated with undesirable side effects, the most common being tooth sensitivity [1]. Tooth sensitivity usually occurs immediately after bleaching and is attributed to hydrogen peroxide’s low molecular weight, which enables it to diffuse through enamel and dentine and reach the pulp, potentially inducing inflammation [2], oxidative stress, and cellular damage [3,4]. Clinically, bleaching-induced sensitivity presents as sharp, transient pain or generalized hypersensitivity, with severity correlating with the concentration of the hydrogen peroxide used [5].

Previous studies have reported the incidence of tooth sensitivity following bleaching to range from 37% to 90% [1,6,7]. Sensitivity is generally more intense with in-office bleaching due to the higher peroxide concentration [3] which may discourage patients from undergoing treatment. Despite that many approaches have been proposed to decrease bleaching-induced sensitivity such as reducing the peroxide concentration [8] and decreasing application time [9]. Desensitizing agents continue to be the most widely adopted and practical method for reducing sensitivity without compromising the bleaching outcomes [3,10,11]. Desensitizing approaches target either nerve depolarization (e.g., potassium nitrate) or tubule occlusion (e.g., fluoride, hydroxyapatite, or bioactive glass (BG)) [12]. Potassium nitrate is a commonly used desensitizing agent found in toothpaste and gels. It acts by inhibiting the repolarization of sensory nerve endings, thereby preventing pain transmission, however, the desensitizing effect of potassium nitrate is subtle and clinically questionable [3].

The other modality for managing bleaching-induced sensitivity involves physically occluding dentinal tubules to reduce fluid flow and subsequent nerve stimulation [13]. Agents such as calcium carbonate, fluorides, hydroxyapatite, and oxalates promote the formation of acid-resistant mineral barriers [12]. Recently, BGs have gained interest for their potential to effectively occlude dentinal tubules and remineralize tooth surfaces. When exposed to saliva, BG releases calcium, phosphate, and sodium ions, which precipitate as hydroxycarbonate apatite (HCA) layer, sealing the tubules and enhancing enamel remineralization [14].

Bioactive glass possesses unique properties, acting as a biomimetic mineralizer that replicates the natural mineralization processes occurring in vivo, while also influencing cellular signals to support tissue restoration and the restoration of their function [15]. Bioactive glass is composed of sodium, calcium, phosphorus, and silica (calcium sodium phosphosilicate), all of which are naturally present in the human body. When exposed to saliva or water, BG particles release sodium, calcium, and phosphorus ions, which help remineralize the dental surfaces [16]. Bioactive glasses have shown promising effectiveness in managing dentine hypersensitivity [14]. A recent systematic reviews reported that bioactive glass–based desensitizers outperform other agents in reducing hypersensitivity-related pain [17] .

Moreover, bioactive-glass desensitizers, especially those based on calcium sodium phosphosilicate have shown promise in reducing dentine hypersensitivity following dental bleaching without interfering with the tooth bleaching process [10]. A meta-analysis by Favoreto et al [18] reported that calcium-containing bioactive desensitizers produced a small but statistically significant reduction in bleaching-induced sensitivity, although the certainty of the evidence was judged very low due to small sample sizes, study heterogeneity, and risk of bias. Therefore, clinical evidence is still limited, especially concerning their application in minimizing tooth sensitivity associated with in-office bleaching procedures.

Therefore, the aim of this randomized controlled clinical trial was to evaluate the efficacy of a BG desensitizer (Predicta®) in reducing tooth sensitivity associated with in-office vital bleaching using 40% hydrogen peroxide. The null hypothesis was: 1. There would be no effect of the BG desensitizer (Predicta®) on the risk and intensity of tooth sensitivity, and 2. There would be no effect of the BG desensitizer (Predicta®) on the bleaching efficacy.