Clinical evaluation of in-office tooth whitening with violet LED (405 nm): A double-blind randomized controlled clinical trial

Although there is little evidence showing the effectiveness of violet LED on in-office tooth whitening, there are some studies which have reported satisfactory results. This double-blind randomized controlled clinical trial aimed to evaluate the effect of a violet light emission diode (LED) (405 nm) system, used in-office, on tooth whitening, sensitivity, use of medication after whitening and quality of life.Eight patients were randomized into 4 groups (n = 20): G1 - violet LED, G2 - 35% carbamide peroxide (CP) and violet LED, G3 only CP 35% and G4 35% hydrogen peroxide (HP). The color was measured using a spectrophotometer at the following times: baseline, 15 and 180days. The colorimetric changes were analyzed using measurements from the CieLab System ΔE (ΔL, Δa and Δb) and the WID (Whiteness Index for Dentistry) for the 4 groups. Tooth sensitivity was recorded via a visual analog scale (VAS). Additionally, the Psychosocial Impact of Dental. Aesthetics Questionnaire (PIDAQ) was used to evaluate quality of life.For the analysis of ΔL, G4 and G2 presented more brightness than G1 and G3 (p<0.05), implying that G2 is at least as good as G4 (p>0.05). For measure of Δa, G4 presented better results, standing out from the other groups. (p<0.05). For Δb, both G4 and G2 showed a greater tendency for blue color than groups G1 and G3 (p <0.05). When analyzing ∆E at the 180-day follow up, G4 produced the highest ∆E, while G3 showed the lowest ∆E. The other 2 whitening groups produced intermediate ∆E values. For ∆W, G1 and G3 significantly differed from G2 and G3. When analyzing the 180-day follow up, G2 produced the highest ∆W, while G3 showed the lowest ∆W. The other two whitening treatments produced intermediate ∆W values. As for sensitivity, only G4 patients showed dental sensitivity within 24 h of the bleaching, with pain ceasing after 48 h. For G4, 33% of the patients needed to take analgesics within the first 24 h after the first 3 whitening sessions. For PIDAQ, there was no overall decrease in score over time for any of the groups and there was no difference between them (p>0.05).Our results showed that violet LED was not able to whiten teeth at the same intensity, when used alone, as it was when associated with 35% CP, contrary to our initial hypothesis. However, given that pain was not consistently reported in G2, one could suggest that treatment with LED + 35% CP is quite similar to that of 35% HP when used for tooth whitening, but with better pain outcomes. All treatments suggested an improvement in quality of life.Clinical Trial Registry: This trial is registered at ClinicalTrials.gov; the registration number is NCT03192852 https://clinicaltrials.gov/ct2/show/NCT03192852.