Preliminary evaluation of the utility of optical coherence tomography in detecting structural changes during photobiomodulation treatment in patients with atrophic-erosive oral lichen planus.

INTRODUCTION: Oral lichen planus (OLP) is a common oral inflammatory condition. Against symptomatic atrophic-erosive OLP, topical steroids, or photobiomodulation (PBM) are deployed. Optical coherence tomography (OCT) provides a real-time, non-invasive, tissue investigation. Aim of this study was to evaluate modifications of OCT pattern in patients with painful atrophic-erosive OLP, before and after treatment with PBM, comparing those results with patients treated with topical steroid.METHODS: Two groups of 20 OLP patients were evaluated. Group A underwent two daily application of 0.05% clobetasol propionate for 8 weeks; group B was treated with eight weekly PBM sessions using a 980/645nm diode laser. OCT scans were performed before and after treatment, and six months after end of the proposed protocol. Changes of width of stratified epithelium (EP) and lamina propria (LP) were quantified.RESULTS: After 8-weeks, both groups experienced a significant increase of EP width (p<0.05), and a significant decrease of LP width (p<0.05), with Delta-EP in Group A significantly higher than Group B (p=0.0015); conversely, Delta-LP was not significantly different (p>0.05). After six months, significant increase of EP width remained only in group B (p=0.01), with no significant decrease of LP mean width in both groups (p>0.05).CONCLUSIONS: Increase of EP and decrease of LP might be explained as consequence of clobetasol and PBM ability to promote epithelial healing, and to reduce interface inflammation. When investigated with OCT, clobetasol appears to provide more significant short-term structural changes, whereas PBM might guarantee long-term alterations.