Discussion
Usage-time compliance behavior
SECONDARY, TOOTH SENSITIVITY
This blinded, parallel, randomized clinical trial with similar allocation between treatment groups aimed to evaluate different aspects of bleaching treatment, such as daily compliance behavior, dental color change and tooth sensitivity. The main objective of this study was to assess compliance behavior daily—secondary outcomes are additional dependent variables, hierarchically less important.Based on the results of the present study, the first null hypothesis was rejected, because less usage time promoted more compliance of patients during at-home bleaching. Usage-time compliance behavior variations could possibly compromise the effectiveness of bleaching treatments. The effectiveness of an at-home dental bleaching procedures depends on tray usage time, which is entirely under the responsibility of the patient. Therefore, the clinician must guide the patient on the importance of properly following the recommended usage time in order to obtain effectiveness out of the treatment.A wide variability in usage time within some of the volunteers was observed. Drastic differences were found, with values ranging from 0 hours (Score 0) up to 12 hours and 15 minutes (Score 3), when the actual recommended usage time was 2 hours. This usage time pattern was a characteristic of patients who tried to compensate for little or no use time in a few days, or for those who used the trays while sleeping, for longer than recommended. Schott and LudwigAlthough an 8-hour usage time is associated with use during sleep, a 2-hour usage time is more effective since it can be easily made at any time of the day. This finding is consistent with the medical literature, which suggests that less frequent dosing regimens are associated with better adherence.It was possible to observe, through subjective visual evaluation, higher color change for G8 than G2 at most of the evaluation time. For G2, even with higher patient compliance (score 1), reduced color change was observed, certainly due to the shorter usage time (2 hours). After 2 hours, more than 50% of the active agent is available in bleaching trays with reservoirs, and 19% in the ones without reservoirs.Spectrophotometry is an objective evaluation method capable of expressing minimal color differences in numerical form.Cardoso, et al.In the objective analysis, the difference between the upper arch means of groups G2 and G4 at T4 (0.86) can be correlated with the acceptability and perceptibility values proposed by Paravina, Pérez and GhineaTooth sensitivity may be related not only to bleaching gel concentration, but also to its time of contact with dental structures.However, in T2 and T3 the sensitivity means showed the same level of intensity, with results becoming practically null in T4, observations that are in agreement with other studies.