Evaluation of Gingival Inflammation after Tooth Whitening In-Office with Violet LED: A Randomized Controlled Clinical Trial with a Split-Mouth Design

This split-mouth randomized study evaluated the effect of in-office tooth whitening with violet Light-Emitting Diode (LED) on gingival inflammation, assessed by gingival crevicular fluid (GCF) interleukin-6 (IL-6) level, histomorphology, and immunohistochemical analysis of Tumor Necrosis Factor (TNF-α) and Cluster of Differentiation 8 (CD8) expression, with and without gingival barrier protection. Thirteen volunteers requiring gingivoplasty were included. The whitening procedure was performed with parameters of 400 nm, 134J/cm², and 20 cycles of 30 sec with 60 sec of standby. Gingival surgery was performed 48 h post-whitening for histomorphology analysis, while GCF IL-6 levels were quantified using an Enzyme-Linked Immunosorbent Assay (ELISA). We also attempted immunohistochemical analysis of TNF-α and CD8 expression; however, the small gingival specimens, which were primarily epithelial tissue, limited the reliability of the results. No statistically significant differences were observed between sides for histomorphology or GCF IL-6. These findings suggest that LED whitening without a gingival barrier may not induce gingival inflammation. However, further studies with larger and gender-balanced samples, extended time points, and additional cytokine markers are needed to confirm these results.