## 3 Results  
A total of 201 patients participated in this double-blind randomized controlled trial; patients were randomly and equally divided into three groups of 67 patients in each. There were three dropouts: one subject from each group. One subject from group 1 dropped out for an unknown reason and subjects from groups 2 and 3 dropped out due to severe sensitivity. The other 66 participants were available for the recall at 24 and 36 h of the study. Patients in group 1 applied CPP-ASP as the desensitizing agent, while group 2 used PNSMP, and group 3 applied placebo gel after in-office vital bleaching (Figure 1). Overall, the mean age of participants who consented to participate in this study was calculated as 25.74 \(\pm\) 5.155, with a standard error of \(\pm\)0.445. This means that the average age for all participants who were part of this clinical trial was between 25 and 26 years of age. The gender distribution of patients showed equal representation (99 were males and were 99 females). Furthermore, at the baseline, i.e., after bleaching but before the application of the desensitizing agent, it was observed that 54 (81.8%) of the total patients in group 1 experienced moderate pain, while 6 (9.09%) had severe pain, 4 (6.06%) showed mild pain, and 2 (3.03%) had no pain. In group 2, at the baseline 54 (81.81%) patients had moderate pain, 5 (7.57%) had mild pain, 4 (6.06%) had severe pain, and 3 (4.54%) had no pain at all. However, in group 3, 57 (86.36%) patients had moderate pain, 3 (4.54%) had mild pain, 3 (4.54%) had severe pain, and 3 (4.54%) no pain, as shown in Table 1.  
The decrease in pain was observed 24 h after the application of the desensitizing gels in groups 1 and 2. Out of the total patients, it was observed that in group 1, 40 (60.60%) patients had mild pain, while 18 (27.27%) had no pain at all. In seven (10.60%) patients, the moderate amount of pain persisted, while one (1.51%) still had severe pain. Almost similar results were found in group 2 patients, where 41 (62.12%) patients had mild pain, while 19 (28.78%) had no pain at all, and in 6 (9.09%) patients the moderate level of pain persisted. In group 3, 46 (69.69%) patients had moderate pain and 14 (21.21%) developed severe pain, while 3 (4.54%) had mild pain, and 3 (4.54%) had no pain, as shown in Table 1.  
Lastly, after 36 h, the pain further decreased in group 1 and group 2 patients. In group 1, 57 (86.36%) patients were pain-free, followed by 7 who had only mild pain (10.60%) and 2 in which moderate pain persisted (3.03%). Meanwhile, in group 2, 57 patients (86.36%)  
Figure 1: CONSORT flow diagram of the study. were pain-free, followed by 8 patients (12.12%) who had only mild pain and only 1 who had moderate pain (1.51%). However, in group 3, 33 patients developed severe pain (48.48%) and 28 had moderate pain (42.42%), while 3 had mild pain (4.54%) and 3 had no pain (4.54%), as shown in Table 1. There was a significant difference in discomfort level with time within group 1 (\(p\) = 0.015) and group 2 (\(p\) = 0.036). However, no significant difference was found in group 3 (\(p\) = 0.085). The pain severity was worse in group 3 in comparison with groups 1 and 2, as illustrated in Figure 2.  
However, no significant difference (independent \(t\)-test; \(p\) = 0.391) was found between both sexes when desensitizing agents were applied on teeth, demonstrating that the postoperative discomfort was the same in both sexes. There, was a strong correlation (Pearson correlation \(p_{r}\) = 0.75, \(p\) = 0.651) between age and desensitizing or pain reduction, post bleaching amongst the participants in this study, indicating that the level of discomfort was higher with increase in age and vice versa. The majority of the participants from both groups experienced \"mild pain\" postoperatively in the first 24 h. In group 1, 30 females (88.23%) reported no or mild pain postoperatively after application of CPP-ASP; whereas only 3 females (8.82%) observed moderate pain, and 1 female developed severe pain (2.94%).