## 4 Discussion  
The current study was conducted to compare the desensitizing efficacy of casein phosphopeptide-amorphous calcium phosphate and potassium nitrate with sodium monofluorophosphate after in-office vital bleaching. The results of the study show that both desensitizing gels (i.e., CPP-ASP and sodium monofluorophosphate) had a similar effect on reducing postoperative sensitivity after in-office vital teeth bleaching. The results of the current study are in agreement with the findings reported by [PERSON] et al. [10] and [PERSON] et al. [13]. They reported a remarkable decrease in postoperative sensitivity following an in-office vital bleaching after using CPP-ASP. Moreover, [PERSON] et al. revealed that CPP-ACP can compensate for the loss of flexural strength of enamel and dentine that may occur during the bleaching [14]. The desensitizing effect of potassium nitrate (KNO3) has been established for decades, and it is a core component in various desensitizing toothpastes and mouthwashes. [PERSON] et al. have reported that the required concentration of K+ ions around the axons should be around 8 mM to 16 mM to achieve depolarization [15]. Potassium nitrate in combination with Na-monofluorophosphate has been claimed to significantly reduce postoperative sensitivity [7; 8; 9]. However, others observed no additional benefits of this combination on reduction in postoperative sensitivity [16]. Moreover, by stratifying gender and age, it became more evident that the postoperative pain experience was generally the same among participants from each gender and age group, although more females than males tend to seek bleaching treatment and more young people than older people tend to seek it rather. In this regard, stratification helped in reducing the risk of overestimating our results. Furthermore, it can be seen in the results presented that the majority of the participants in either trial group only experienced \"mild\" to \"moderate\" postoperative pain in relation to the DIS. This shows that using either desensitizing agent significantly reduces postoperative pain irrespective of their mechanism of action. Furthermore, if we consider the pricing of both of these products, it can be said that CPP-ACP is more expensive to purchase and use, whereas potassium nitrate with sodium monofluorophosphate is a more cost-effective option. However, this can be completely left to the discretion of the dental practitioner to choose either. Concerning our clinical study, statistical analysis has shown no evidence of either product being superior to the other one or vice versa. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Study Groups**} & **Baseline** & **24 h after** & **36 h after** \\  & **(before Application of the Agent)** & **Application of the Agent** & **Application of the Agent** \\  & **Mean \(\pm\) SD** & **Mean \(\pm\) SD** & **Mean \(\pm\) SD** \\ \hline
**Group 1** & 2.34 \(\pm\) 1.531 & 1.72 \(\pm\) 0.731 & 0.44 \(\pm\) 0.521 \\ \hline
**Group 2** & 2.26 \(\pm\) 1.481 & 1.57 \(\pm\) 0.631 & 0.42 \(\pm\) 0.421 \\ \hline
**Group 3** & 2.29 \(\pm\) 1.631 & 2.74 \(\pm\) 1.642 & 2.99 \(\pm\) 1.666 \\ \hline
**ANOVA _p_-value** & 0.069 & 0.048 & 0.017 \\ \hline \multicolumn{4}{c}{**Group wise comparison (_p_-value)**} \\ \hline
**1 and 2** & 0.726 & 0.851 & 0.472 \\ \hline
**1 and 3** & 0.684 & 0.037 & 0.004 \\ \hline
**2 and 3** & 0.834 & 0.043 & 0.001 \\ \hline \hline \end{tabular} ANOVA and post hoc Turkey’s test, \(p\leq\) 0.05 was taken as statistically significant. SD: standard deviation, DIS: discomfort interval scale.  
\end{table} 
Table 2: Comparison of mean DIS score between the groups. Additionally, like every other study, this study also had its limitations. Although great care was taken to carefully explain to the participants how to complete the DIS, it can be said that there could have been errors on their part to correctly assess the severity of postoperative pain after in-office vital bleaching of teeth, which may have led to an overestimation of (DIS) pain scores.