Perception of Long-Term Changes in Smile Aesthetics Following Dental Bleaching: A Randomized Controlled Trial.

Abstract

Objectives: To evaluate patients' perceptions of colour change induced by tooth whitening over 1 year.

Material and methods: This study included 50 participants aged 19-28. In 24 patients, teeth were whitened with photoactivated gel, whereas in 26 patients, a placebo gel with peppermint oil was applied to simulate burning. Colour changes were monitored spectrophotometrically. Patients reported procedural pain and psychosocial impact using the Orofacial Esthetic Scale (OES) and Oral Health Impact Profile (OHIP). Personality characteristics were assessed.

Results: Short-term (one week) colour change was significantly greater in the active group than in the placebo group (effect estimate 1.9; 95% confidence interval [CI] 1.1-2.8; p < 0.001), but this difference decreased in the long term (one year) due to relapse in the active group. Higher pain was reported in the active group than in the placebo group (p = 0.013). Teeth whitening significantly increased satisfaction with orofacial aesthetics (OES) in both groups in the short term (p < 0.001). Long-term satisfaction decreased in the active group, but not in the placebo group. Satisfaction in both groups was higher in the long term than before the intervention. The intervention reduced the OHIP domain scores in both groups in the short term; however, no major changes were observed in the long term. The intensity of short term colour changes in the correlated with the intensity of the change in psychosocial impact (r = -0.304; p = 0.032). A greater long-term colour change was associated with reduced psychosocial impact among introverted participants (p = 0.043).

Conclusion: Both tooth whitening and placebo appeared to confer psychosocial benefits, possibly due to colour changes, expectancy effects, and temporary satisfaction.

Trial registration: This clinical trial was retrospectively registered at ClinicalTrials.gov (Identifier NCT03380702) on 21 December 2017. The trial protocol and statistical analysis plan are available through the ClinicalTrials.gov registry. Individual de-identified participant data (including the data dictionary), statistical code and other study materials are available from the institutional repository https://repository.fdmri.uniri.hr/.