Bakhtiari 2017.

Methods	Study design: RCT Conducted in Iran Number of centres: 1 Recruitment period: unclear Funding source: unspecified
Participants	Inclusion criteria: clinically and histopathologically diagnosed with reticular and erosive LP, seeking medical management Exclusion criteria: presence of histological signs of dysplasia, use of drugs which caused lichenoid reactions, therapy for OLP in 2 months prior to the study, pregnant or breastfeeding women, uncontrolled systemic disease, lesions adjacent to amalgam fillings and people with photosensitivity Group A: randomised 15; analysed 15 Group B: randomised 15; analysed 15
Interventions	Group A: dexamethasone mouthwash (0.5 mg in 5 mL of water) 4 times daily + 1 nystatin mouthwash 4 times daily for 2 weeks Group B: methylene blue as photosensitiser and light source of LED 630 nm (Fotosan, Denmark). Device was used according to manufacturer's instructions. Output power was 7.2–14.4 J/cm² and probe diameter was 8 mm. Participants gargled methylene blue 5% for 5 minutes and 10 minutes prior to irradiation. Each lesion was irradiated for 30 seconds up to 2 minutes with spot technique
Outcomes	Pain (VAS), clinical score (Thongprasom), clinical severity index, EI Measured at days 15, 30, 60 and 90 after beginning of the treatment
Notes	VAS results were reported graphically; data extraction was not possible
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: insufficient information to permit judgement.
Allocation concealment (selection bias)	Unclear risk	Comment: insufficient information to permit judgement.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: blinding not feasible.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Comment: participants (self‐assessed, pain was primary outcome) were not blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: no missing data. All randomised participants included in analysis.
Selective reporting (reporting bias)	High risk	Comment: ≥ 1 outcomes of interest were reported incompletely (standard deviations were missing) so data could not be entered in a meta‐analysis.
Other bias	Low risk	No other sources of bias identified.