###### Abstract
Additionally, a physicochemical action may take place when specific absorbers, such as titanium dioxide (TiO\({}_{2}\)) or caroten (a range of photosynthetic pigments), are incorporated within the bleaching gel [14]. When exposed to light irradiation, they have the capacity to undergo modifications, resulting in changes in their electrical charges [16]. Consequently, this can lead to the destabilization of peroxides, or disruption of the pH balance of the whitening gel and hence to the generation of more reactive ROS, such as hydroxyl radical (\({}^{\bullet}\)OH) and/or mono-deprotonated peroxide (HO\({}_{2}\)\({}^{-}\)), the latter only formed at significantly elevated pH values [14,16,17]. Evidently, laser-activated bleaching primarily relies on a photothermal reaction [1,15]. While optimizing the reaction rate and minimizing the risk of sensitivity reactions, it is crucial to exercise control over the heat transmitted to the dental pulp [15]. In consequence of the above, laser-activated bleaching may be considered a safe and effective option for achieving enhanced results [1,4,12,15]. However, it is important to emphasize that laser-activated bleaching may have the potential to alleviate the adverse effects commonly associated with this procedure [18,19]. The elements investigated in bleaching studies refer mainly to the color outcome and the sensitivity appearing coincident to, or following, the bleaching treatment [20]. The color outcome is a measure of the effectiveness of the procedure, and it remains the most critical factor for the applied treatment's success, because of the growing aesthetic expectations of patients and dental practitioners [21]. The change in shade (\(\Delta\)E) as defined by the Commission Internationale de I'Eclairage (CIE) L\({}^{\bullet}\)a\({}^{\bullet}\)b\({}^{\bullet}\) color system is commonly used to evaluate shade changes objectively. The shade change value \(\Delta\)E is calculated using the equation:  
\[\Delta\mathrm{E}=([\Delta\mathrm{L}^{\bullet}]^{2}+[\Delta\mathrm{a}^{\bullet }]^{2}+[\Delta\mathrm{b}^{\bullet}]^{2})^{\frac{1}{2}} \tag{1}\]  
where L\({}^{\bullet}\) represents lightness, a\({}^{\bullet}\) corresponds to the red-green, and b\({}^{\bullet}\) corresponds to the yellow-blue axes [22,23]. In this regard, a mean color change value (\(\Delta\)E) exceeding 3.3 is regarded as clinically significant. This threshold underscores the importance of achievingsubstantial color improvements to meet the demands of modern dental care [22; 23]. The evaluation by instruments such as spectrophotometers, in addition to subjective visual assessments, is supported by the scientific literature since they offer a reliable and repeatable method for measurement [24]. Tooth sensitivity is a main concern, however, and may arise through selected pathways: (1) as a direct activation of neuronal receptors, or (2) through fluid shifts within the odontoblasts caused by desiccation or penetration of free radicals [25]. The exposure of pulp tissue to HP remains a subject of consideration. This occurs by inward diffusion through the odontoblasts [26]. The presence of HP and, further, more reactive ROS, may induce oxidative stress in the dental pulp tissue [25; 26]. Oxidative stress is associated with various cellular alterations, which have the potential to induce apoptosis, and can result in cell death [27]. Fortunately, defense mechanisms such as enzymes within the pulp and the positive pulp pressure may reduce these phenomena [25]. The quantity of HP identified in the pulp chamber typically shows a tendency to rise proportionately with both the duration of exposure, and the concentration of HP in the bleaching gel [25; 26; 27]. Additionally, direct overheating of the pulp tissue may play a crucial role in the occurrence of bleaching sensitivity [25; 28; 29]. The critical threshold for a temperature increase is 5 \({}^{\circ}\)C for a duration of one minute, after which pulp vitality may be jeopardized [30].