Table 1.

The specifications of the included studies

Study ID	Study design	Number of participants/age/gender	Tooth type	Endodontic diagnoses	Endodontic treatment	Pain evaluation method	Pain evaluation interval
Nabi et al.[18]	RCT (Randomized clinical trial)	120 participants	Permanent teeth with fully formed apex	Symptomatic irreversible pulpitis with no periapical radiolucency	RCT (Root canal therapy), single visit	Heft and parker pain rating scale	4, 8, 12, 24, and 48 h of posttreatment
		68 males and 52 females
		18–64 years
Morsy et al. (2018)[29]	Parallel RCT (Randomized clinical trial)	56 participants	Anterior teeth (maxillary central incisors permanent teeth)	Necrotic teeth with chronic periapical lesions	RCT (Root canal therapy), two-visit by a single endodontist	NRS	Pretreatment, and 6, 12, 24, 48 h and 7 after treatment
		24 males and 32 females
		18–35 years
Doğanay Yıldız and Arslan[16]	Randomized placebo-controlled clinical trial	42 participants	Mandibular molar	Symptomatic apical periodontitis	RCT (Root canal therapy), single visit by a single endodontist	VAS	1, 3, 5, 7, and 30 days of posttreatment
		19 males and 23 females
		18–64 years
Ramalho et al. (2016)[32]	Randomized placebo-blind clinical trial	60 participants		Irreversible pulpitis		VAS	Immediately and 15 min after treatment
		21 males and 39 females
		Mean age
		Control group: 33.7±11.6
		Placebo group: 31.1±13.8
		Laser at 4 J/cm2 group: 34.6±13.04
		Laser at 40 J/cm2 group: 30.3±11.8
Arslan et al.[15]	Preliminary placebo-controlled, triple-blind, RCT (Randomized clinical trial)	36 participants, whom 3 participants dropped out 21 males and 12 females	Mandibular molars	Teeth with periapical lesions and pain VAS <50 and a percussion pain VAS <50	RCT (Root canal therapy), two-visit	VAS	1, 2, 3, 4, 5, 6, and 7 days of posttherapy
		Mean age
		Placebo group: 25.76±8.14
		PMB group: 32.62±9.27
Coelho et al. (2019)[33]	Prospective, randomized, double-blind clinical trial	60 participants	Single-rooted teeth with fully developed apices and healthy periodontal tissue	Asymptomatic necrotic pulp	RCT (Root canal therapy), single visit	VAS	24 h, 72 h, and 1-week after treatment
		22 males and 38 females
		Mean age
		Control group: 46.97±13.23
		PDT group: 46.73±16.30
Lopes et al., (2019)[17]	Randomized, controlled, clinical study	60 participants	Mandibular first or second molar	Irreversible pulpitis	RCT (Root canal therapy), single visit	VRS, NRS	6, 12, and 24 h after treatment
		23 males and 37 females
		18–60 years
Barciela et al. (2019)[34]	Prospective RCT (Randomized clinical trial)	40 participants	Single-root	Pulp necrosis, showing apical periodontitis visible on periapical radiography, without spontaneous painful symptoms	RCT (Root canal therapy), single visit by a single experienced endodontist	VAS	24 h, 72 h, and 1 week after treatment
		18–76 years

RCT: Randomized clinical trial; RCT: Root canal therapy; NRS: Numerical Rating Scale; VAS: Visual Analog Scale; PMB: Photobiomodulation; PDT: Photo Dynamic Therapy