Effectiveness of Low-Level Laser Therapy in Reducing Orthodontic Pain: A Systematic Review and Meta-Analysis

Table 3

Description of the principal findings for the control group and the group irradiated with LLLT, with pain assessment method and interval after orthodontic activation.

Author	Evaluation method	Evaluation interval after start of orthodontic treatment	Outcomes	Evaluation of pain level
				Laser group (LG)	Control group (CG)/placebo
Abtahi; et al. [33]	VAS	Pain levels were measured for 5 days	No statistically; significant difference between the; placebo and; experimental groups	(1) Days 1, 3, 4, and 5: no statistically; significant difference between groups.; (2) Day 2: pain level significantly; lower in LLLT group ().	(1) The maximum level of pain; was recorded 1 day after placement; of separators and gradually; declined until day 5.
Almallah; et al. [28]	VAS	1, 6, 24, 48, and 96 hours	LLLT reduced; the orthodontic pain; caused by elastomeric separators	(1) Peak pain occurred after 24 hrs in the group which received a single irradiation; and after 48 hrs in the group which received double irradiation.; (2) No differences were found between pain intensity with single or double irradiation.
AlSayed Hasan; et al. [30]	VAS	1, 6, 12, 24, 48, and 72 hours	A single application; of LLLT was not; effective in reducing; pain caused by; elastomeric separators	(1) Peak pain occurred 24 hrs after application of orthodontic force in both the placebo; group and the experimental group.; (2) Both LLLT protocols (4 J and 16 J) failed to reduce pain.
Angelieri; et al. [9]	VAS	12, 24, 48, and 72 h after LLLT; Repeated in the 2nd month	The laser protocol; used in the study; was not effective; in reducing pain; sensitivity	(1) No statistically significant difference in pain reduction was found between the; irradiated and the control sides.
Artés-Ribas; et al. [26]	VAS	5 m, 6 h, 24 h, 48 h, and 72 h	The LLLT parameters; used can reduce; pain in patients; following placement; of orthodontic; rubber separators	(1) Significant pain reduction as compared with; the control/placebo side ().	(1) Peak pain in 24 hours.; (2) Pain reached its peak after 6–24; hours and decreased thereafter; between 48 and 72 h.
Bayani; et al. [34]	VAS	2 h, 6 h, bedtime, 24 h, 2, 3, and 7 days	A single irradiation; of LLLT was effective; in reducing pain; following initial; archwire placement	(1) Peak pain occurred 24 hrs after application of orthodontic force.; (2) Low power red laser could not be recommended for pain control following; placement of orthodontic appliances.; (3) VAS presented similar mean values to those in patients treated with ibuprofen,; LLLT, and bite wafer.
Bicakci; et al. [31]	VAS	5 m, 1 h, 24 h	Significant reduction in; pain and PGE2 after; 24 hours in the; group irradiated; with LLL	(1) Significant pain reduction was observed; with laser treatment 24 h after application.; Significant differences in pain level were observed between LG and CG after 24 h ().; (2) The mean PGE2 levels showed a gradual decrease. (3) Significant differences in pain level were observed between LG and CG after 1 and 24 h ( and , resp.)	(1) The mean PGE2 levels were; significantly elevated.
Dalaie; et al. [39]	Wong-Baker; Faces Pain Rating Scale was utilized	Days 1, 33, and 63	No solid evidence was; found to support; the effectiveness of; laser for pain; reduction	(1) There was no statistically significant difference in pain reduction; between LG and CG.
Deshpande; et al. [36]	Scale used by Tortamano et al. modified (Harazaki + Number Rating Scale)	1, 24, 48, and 72 h after LLLT	LLLT reduced pain; duration and intensity; fixed orthodontic; therapy patients	(1) Peak pain occurred 1 day after; application of orthodontic force.; (2) The pain disappeared 3 days after; application of orthodontic force.	(1) Peak pain occurred 2; days after application of; orthodontic force.; (2) The pain disappeared 3; days after application of orthodontic; force.
Domínguez and; Velásquez [37]	VAS	2 h, 6 h, and 24 h; Days: 2, 3, and 7	LLLT is effective; for pain reduction throughout; orthodontic treatment	(1) Pain was significantly less in the LLLT group at all the intervals; measured ().; (2) Peak pain in 24 hours.
Doshi-Mehta; and Bhad-Patil [38]	VAS	Days: 1, 3, and 30	Pain level reduced significantly with; the use of LLLT	(1) Significant pain reduction on days 3 and; 30 as compared with the first day ( and , resp.).; (2) Significant pain reduction in the irradiated; group as compared with the CG on days 3 and; 30 (, , resp.).	(1) Significant pain reduction; after 30 days as compared with; day 1 ().
Eslamian; et al. [32]	VAS	6 h, 24 h, and 30 h; Days: 3, 4, 5, 6, and 7	LLLT reduced pain perception in the; first 3 days after; orthodontic separation	(1) After 6, 24, and 30 h and on day 3; the pain was significantly less in LG (, , , and , resp.).; (2) Pain intensity peaked at 6 and 30 h; after placing elastomeric separators.; (3) Greatest pain was recorded in the mandible; at 24 and 30 h.	(1) Pain intensity peaked between; 6 and 30 h after placing; elastomeric separators.; (2) Greatest pain was recorded; in the mandible at 24 h.
Farias; et al. [24]	VAS	5 min., 24 and 120 hours	AlGaAs diode LLLT; (810 nm) is an; effective therapeutic method to; control or reduce; pain in the early; stages of orthodontic treatment	(1) After 24 h a 13.89% reduction in pain; was promoted.; (2) LLLT (810 nm) was effective in pain; reduction from the first 24 hours up to the; fifth day (120 hours) after separator placement.; (3) Lower pain intensity was recorded in the; group treated with LLL after 5 minutes,; 24 hours, and 120 hours.	(1) After 24 h there was a 44.39%; increase in pain.; (2) A significant pain reduction was; observed 120 hours after; installation of elastomeric; separators.
Furquim; et al. [29]	VAS	6 h, 12 h; Days: 1, 2, and 3	LLLT did not; produce significant effects on the; perception of pain caused by; orthodontic separation	(1) The pain peak perceived by patients occurred between 12 hours and 1 day.
Heravi; et al. [40]	VAS	Days 0, 4, 7, 11, 15, 28, 32, 35, 39, 43, and 56	LLLT with the parameters used in; this studio did; not influence the; pain perceived; by the patients	(1) No significant difference was found in VAS scores between the laser and; the placebo groups.
Lim; et al. [25]	VAS	Before and after LLLT for 5 days	No statistically significant; difference between; the placebo; and experimental groups	(1) Pain intensity was lower in the experimental group than in the placebo group; however, no statistically significant difference was observed.
Marini; et al. [22]	VAS	0, 12, 24, 36, 48, 72, and 96 h	LLLT is effective; in reducing pain intensity and; duration	(1) No significant difference between the arches.; (2) Statistically significant differences between groups at 12, 24, 36, 48, 72, and 96 h; (); the mean VAS values of the laser groups were lower than placebo and; control groups.; (3) The pain never disappeared in 10% of subjects in the laser group, 70% of subjects; in the placebo group, and 80% of subjects in the CG.; (4) No significant differences were found between the placebo and CG.; (5) The intensity and duration of pain were lower in the LG than in the; placebo and CG.; (6) The intensity of pain was lower in the placebo group than the CG.
Nóbrega; et al. [27]	VAS	2, 6, 24, 72, 120 hours	Laser irradiation controlled the; original pain; when the elastomeric separators were fitted	(1) The levels of spontaneous and; occlusion pain were significantly lower; in patients treated with LLL as compared; with the placebo group at 2, 6,; and 24 hours, and 3 and 5 days.; (2) Two hours after installation of the; elastomeric separators, 10% of the patients; presented spontaneous pain and 16.7%; occlusion pain. After 24 hours, 50%; of the patients presented spontaneous; pain and 66.7% occlusion pain. After; 5 days, 10% of the patients presented; spontaneous pain and 23.3% occlusion pain.	(1) Two hours after installation of the; elastomeric separators, 63.3% of the; patients presented spontaneous pain and; 70% occlusion pain. After 24 hours,; 86.7% of the patients presented; spontaneous pain and 100%; occlusion pain. After 5 days,; 30% of the patients; presented spontaneous pain; and 60% occlusion pain.
Qamruddin; et al. [23]	Numerical Rating Scale	24 hours, for the next 7 days	A single dose of LLLT reduced spontaneous and chewing pain	(1) Peak pain in 24 hours.; (2) Significant reduction in the intensity of; chewing pain on the third day.; (3) Lesser intensity of spontaneous and chewing; pain in the LG as compared with the CG on days 1, 2, 3, 4, 5, 6, and 7.; (4) Although significantly less, some degree; of pain was present even on day 7.	(1) Peak pain in 24 hours.; (2) The highest intensity of pain was; associated with chewing on the; placebo side.; (3) Although significantly less,; some degree; of pain was present; even on day 7.
Tortamano; et al. [35]	Harazaki + Numeric Rating Scale	Pain start, most painful day, and end of pain	LLLT efficiently controls pain caused by the first archwire	(1) Lower intensity of oral pain compared to the placebo and control groups.; (2) Lower intensity of pain on the day of greatest pain compared to the placebo; and control groups.; (3) No differences found between maxilla and mandible.; (4) The pain ceased more quickly in the experimental group (day 3) than in the placebo; and control groups.; (5) LLLT can control pain from placement of the first archwire.; (6) The day of greatest pain was similar for both groups. It occurred between 24; and 48 hours; after activation of the orthodontic appliance.; (7) The patients in the experimental group generally report oral pain only; on touching, while in the control and placebo groups they reported; continuous and also chewing pain.