Table 1. Characteristics of the studies included in qualitative analysis.

Reference	Region	Study design	Patient no /lesion no	Confounder	Lesion type and location	Diagnosis of lesion	Gender	Age, (years)	Intervention	Comparison	Follow-up period
Dillenburg et al (2014) 21	Brazil	RCT	42 patients (21 in each group)	None	Symptomatic atrophic/erosive OLP, tongue, buccal and labial mucosa, floor of mouth, gingiva, palate	Histopathology	7 males, 35 females	Clobetasol: 61.33 ± 11.85, PBMT: 55.14 ± 15.96	PBMT was administered using a continuous wave, InGaAlP diode laser diode laser with a wavelength of 660 nm, power output of 40 mW, output density of 1,000 mW∕cm 2 , energy density of 6 J∕cm2, 6-s exposure time per point, and 0.24 J of total. PBMT was administered 3x/week for 4 weeks, totaling 12 sessions.	Clobetasol propionate gel 0.05%, 3x/day applications for 30 days, candidiasis prevention was done with nystatin application	Follow-up weekly until a month and 4 weeks and 8 weeks after completion of treatment
Mirza et al (2018) 22	Saudi Arabia	RCT	45 patients (divided into 3 equal groups)	None	Erosive-atrophic OLP; tongue, buccal mucosa	Histopathology	8 males, 37 females	Group 1 (52.6 ± 11.4), Group 2 (50.8 ± 14.7), Group 3 (49.2 ± 10.6)	• Group-2 (low level laser therapy): diode laser, 1.5 J/cm2 per session; 2 times/week for max 10 sessions	• Group-1 (toluidine blue-PDT): topical 1mg/ml toluidine blue followed by GaAlAs laser (630 nm, 1.5 J/cm2 per session); 2 sessions, 2x/week for 1 month • Group-3 (control group): Topical dexamethasone	Follow-up weekly until a month and 1 year after completion of treatment
El-Shenawy and Eldin (2015) 23	Egypt	NRCT	24 patients (12 in each group)	2 patients are hypertensive, 1 patient is diabetic, and 4 patients are diabetic and hypertensive	Erosive-atrophic OLP, site not mentioned	Histopathology	5 males, 19 females	PBMT: 53.6 ± 13.2, CORT: 52.2 ± 6.4	12 patients were subjected to laser sessions with 970 nm diode laser, continuous non-contact mode with (320 µm) diameter fiber optic, 2x/week for max 10 sessions	12 patients treated with topical corticosteroids (0.1% triamcinolone acetonide orabase)	Follow-up weekly up to 4 weeks after completion of treatment
Kazancioglu and Erisen (2015) 24	Turkey	RCT	120 patients (divided into 4 equal groups)	None	Atrophic-erosive OLP, tongue or buccal mucosa	Clinically and histopathology	56 males, 64 females	42.6 ± 8.3	Group-1 (PBMT): GaAlAs laser (808 nm, 0.1 W, continuous wave) was used as a light source. A light exposure dose of 120 J/cm2 was used for 2.5 minutes, 2x/week for max 10 sessions	• Group-2 (ozone therapy): performed by using an ozone generator with a tissue probe, applied intraorally for 10s, 2x/week for max 10 sessions. • Group-3 (positive control): dexamethasone mouthwash for 5 minutes, followed 30 minutes later by 30 drops of nystatin solution, 4x/day for 1 month • Group-4 (negative control): A special solution filled with base ointment without the corticosteroid component was prepared, gargled solution for 5 minutes, 4x/day for 1 month	Follow-up at 1, 3, and 6 months after the treatment
Jajarm et al (2011) 25	Iran	RCT	24 patients for analysis, 30 recruited, randomly allocated		Atrophic-erosive biopsy-proven OLP in the tongue or buccal mucosa	Histopathology	Not mentioned	Not younger than 20	Group 1- A diode laser was used as a light source (Mustang2000 þ, Russia, KLO3 probe, 630 nm, 10 mW, continuous wave, spot size: 11 cm). Irradiation was done 2x/week for a maximum of 10 sessions	Group 2- dexamethasone (0.5 mg in 5 ml water) mouth wash for 5 minutes, followed 30 minutes later by a mouth rinse with 30 drops of Nystatin (100,000 units) for 5 minutes. This treatment was repeated 4x/day for 1 month	Follow-up weekly up to 1 month after completion of treatment
Jain et al (2021) 26	India	RCT	30 patients, 15 in each group	None	Symptomatic OLP, site not mentioned	Clinically and histopathology	10 males, 20 females	18-30	Group-1 (Steroid + PBMT): topical 0.1% triamcinolone acetonide oral base, 5 x/day for 28 days or till the lesions heal + PBMT delivered by the photon (3W) zolar diode laser with wavelength: 810 nm, mode: continuous defocused non-contact mode, power output: 0.8–0.9 W, time duration: 10 minutes laser equipment, 2x/week for 9 sessions	Group-2 (Steroid): topical 0.1% triamcinolone acetonide oral base, 5x/day for 28 days or till the lesions heal	Follow-up once every 15 days for 2 months after completion of treatment
Bhatt et al (2022) 27	India	RCT	60 patients (divided equally in to 2 groups)	None	Oral lichen planus	Clinically and histopathology	38 females, 22 males	Mean age of 40.73	GaAlAs diode laser (980 nm wavelength twice weekly for 2 months. 0.6 W/cm2, 12 J/cm2, twice weekly for 2 months	Aloe vera extract 500 mg capsule was mixed with carboxymethylcellulose powder, applied topically for 30 minutes, for 2 months	Follow-up weekly for 9 months after completion of treatment
Ferri et al (2021) 28	Brazil	RCT	34 patients, 17 in each group	None	Reticular-atrophic-erosive OLP, buccal mucosa, gingiva, tongue, palate, lips, alveolar ridge, floor of mouth	Histopathology	32 females, 2 males	mean age of 62.2	GaAIAs diode laser, with 660nm wavelength, irradiance: 35.4mW/cm2, radiant exposure: 177J/cm2, 5 sec exposure time per point and 0.5J of total energy per point, 2x/week for 4 weeks, for 8 sessions	Clobetasol propionate gel 0.05%, covering the OLP lesions completely, applied 3 x/day for 30 consecutive days	Follow-up at 60 days, 90 days, and 120 days after the treatment

Abbreviations: GaAIAs, gallium-aluminum-Arsenide laser; InGaAlP, aluminum-gallium- indium-phosphide laser; NRCT, nonrandomized controlled trial; OLP, oral lichen planus; PDT, Photodynamic therapy; PBMT, photobiomodulation therapy; RCT, randomized controlled trial.