Red Light Therapy for Orthodontic Pain: Scientific Evidence

A split-mouth design, 1 side of each mouth treated with photobiomodulation therapy (PBMT) and the other left as control, underpinned a 2021 randomized controlled trial in Iran of light against orthodontic pain from elastomeric separators, the rubber rings placed before molar bands. 30 patients received an 808 nm diode laser at 400 mW and 15.6 J/cm², held for 22 seconds against the gum at the neck of the 2 roots of the upper first molar on the treated side. Pain on both sides rose over the first 6 hours and peaked at 24 hours. According to the results, the pain score was significantly lower on the laser side than on the control side at every time point except immediately after placement. An 808 nm laser was found to be an effective way to reduce this pain.

120 patients had elastomeric separators, the rubber rings placed before molar bands, fitted on both sides of the first molars in a 2020 clinical trial at a dental college in India comparing 3 ways of easing the orthodontic pain that follows. They were divided into 4 groups: a control group, a low-level laser group treated at 830 nm and 200 mW for 20 seconds, a topical anesthetic gel group, and a TENS group, in which mild electrical pulses through the skin dull the pain. Pain was rated on a self-rated scale immediately after placement and on each of the next 4 days, covering how strong it was and how long it lasted. Researchers found that low-level laser therapy was the most effective of the 3 methods at reducing pain after separator placement.

Applying a single photobiomodulation (PBM) session to each newly banded molar, a 2020 randomized controlled trial in Italy tested whether light changes the intensity of orthodontic pain from bands, the metal rings cemented around the upper first molars. 26 patients with an average age of 11.8 were randomly assigned to a control group or a PBM group, in which each banded molar received light at 820 to 840 nm and 140 to 160 mW for 5 seconds at 4 points. Pain intensity was tracked over the following days. The PBM group showed significantly lower pain intensity than the controls. The authors concluded that PBM might be a promising way to reduce general pain intensity, while noting that it did not change when the pain started, peaked, or ended.

Whether low-level laser therapy (LLLT) reduces the orthodontic pain caused by bands, the metal rings cemented around the back teeth, was the question a 2020 randomized controlled trial in Italy put to children aged 10 to 14. 60 patients who needed bands on both upper first molars were randomly assigned to laser, placebo, or control, in groups of 19, 20, and 17. 56 completed the trial, of whom 29 were boys and 27 were girls, with an average age of 12.03. The laser group received 980 nm light at 1 W for 10 seconds per point, and pain was rated on a numeric scale immediately after the bands went on, at 6 and 24 hours, and daily from day 2 to day 5. The laser group felt less pain at every interval and had a lower maximum pain score than both the control and placebo groups, all statistically significant. The authors noted that their sample was Caucasian children in good social conditions and that the results may not transfer to other populations.

76 patients who had braces fitted and then received a diode laser, ozone therapy, or nothing recorded the highest pain scores of 3.6, 5.25, and 5.75, respectively, in a 2020 randomized controlled trial at a medical university in Poland. The patients, 55 women and 21 men with an average age of 35.1, were divided into a control group of 26, an ozone group of 25, and a laser group of 25. The laser ran at 635 nm and 400 mW in contact with the gum for 5 seconds and 2 J at each of 23 points over the root tips and between the teeth, with the ozone probe applied at the same points. The laser group's pain was significantly lower than the control group's, while ozone gave no pain reduction compared with the controls, the researchers reported. Crowding of the teeth did not raise pain in any group.

Tooth movement 31% to 100% faster and pain relief that lasted days rather than weeks were the 2 findings of a 2019 review from Italy of low-level laser therapy protocols during braces treatment, according to its authors. Searches of the Cochrane Library and PubMed for randomized controlled trials in humans identified 14 relevant clinical studies, using light at 780 to 830 nm. The reviewers found that laser reduced orthodontic pain only on the day after application when the eye teeth were being pulled back, and for no more than 5 days after braces were fitted in the other studies. Both LED devices and AlGaAs diode lasers appeared usable, with different protocols suited to different cases. The treatment was found to be effective for both tooth movement and pain, and it was recommended that future work look at higher-powered devices, since larger doses reaching the target tissue produced larger effects.

In 2019, a randomized controlled trial in Saudi Arabia evaluated a single application of low-level laser therapy (LLLT) for orthodontic pain in the first week after brackets were bonded to the upper teeth. 32 patients with a displaced eye tooth who needed braces were assigned to 4 groups: LLLT with self-ligating brackets, LLLT with conventional brackets, and each bracket type without LLLT. The laser groups received 940 nm light at 100 mW and 7.5 J/cm² at 5 points on each side of every tooth from first molar to first molar. In the LLLT plus self-ligating group, pain on an 11-point scale was 3.33, 3.58, 2.31, and 1.89 at 4 hours, 24 hours, 3 days, and 7 days, and the laser groups appeared to report less pain than the groups without laser. No harms were encountered.

Researchers in India evaluated a single dose of low-level laser therapy (LLLT) for orthodontic pain after braces were activated, in a 2019 randomized controlled trial. 20 patients (16 female and 4 male, aged 18 to 24) who needed both upper canines moved back received a retraction force of 200 g per side. 10 were treated at 980 nm, 2.5 W/cm², and 600 J for 30 seconds on the lip side and palate side of each tooth, and 10 received red LED light as a placebo. Pain was rated on a 0 to 10 scale immediately after activation and at 1, 3, 24, and 48 hours, and at 7 days. Pain was lower in the laser group at every point except immediately after activation, but the difference reached significance only at 24 hours. At 7 days, the laser group reported no pain while the placebo group still reported mild pain. The trial concluded that a single LLLT dose at these settings relieved orthodontic pain after activation, and the authors called for larger trials across a wider age range.

84 of the 90 patients enrolled completed a 2019 randomized controlled trial at a university in Italy asking whether low-level laser therapy (LLLT) eases orthodontic pain after the alignment archwire, the first straightening wire, is engaged, and whether crowding changes the answer. The 84 who completed the study were 41 male and 43 female, aged 13 to 30, all with at least 3 mm of crowding in the lower front teeth. They were split between braces plus LLLT, braces plus simulated LLLT, and braces alone. The laser was delivered at 980 nm and 24 to 27 J/cm² for 2.5 minutes. Pain was rated on a 0 to 10 scale at 2, 6, and 24 hours and daily from day 2 to day 7. Pain at every interval and the maximum pain score were significantly lower in the laser group, with no difference between the placebo and control groups. Crowding made no difference to pain in any group, so the authors saw no reason to reserve LLLT for the most crowded cases.

Among 40 adults aged 20 to 30, 30 women and 10 men, a 2019 randomized controlled trial in Brazil tested infrared light-emitting diode (LED) phototherapy for orthodontic pain while elastic separators, rubber rings placed between the teeth, were in place. Half received LED light at 846 nm and 180 mW for 22 seconds, 4 J and 8 J/cm² at each of 2 points around the separated teeth, in 3 sessions over 3 to 4 days, and half received no light. Pain was rated on a self-rated scale immediately after the separators went in and at 48 hours, 72 hours, and 7 days. Pain rose to a peak at 48 hours and fell after 72 hours in both groups, but the LED group appeared to have significantly less pain at every time point except the moment of insertion. Men and women did not differ in pain at any time.

A placebo-controlled parallel design with equal laser and placebo groups was used in a 2018 randomized controlled trial in China of repeated low-level laser therapy (LLLT) for orthodontic pain and the heightened sensitivity of the teeth and gums that braces provoke. 40 patients starting treatment for mild crowding, 10 male and 30 female, aged 12 to 33, were assigned to laser or placebo. The laser ran at 810 nm, 400 mW, and 2 J/cm² for 20 seconds, held about 1 cm from the gum over the upper eye tooth, in repeated applications over 7 days. Researchers found the average pain score was 1.0 in the laser group against 2.1 in the placebo group, a statistically significant difference, with pain peaking at 24 hours in both. Pressure and heat sensitivity were also significantly reduced by LLLT on the untreated side of the mouth as well as the treated side.

2018 brought a review from a university in Brazil that searched the English-language literature, with no date limit, for the best method of managing orthodontic pain. 1281 articles were recovered, and 56 randomized clinical trials were selected, of which 19 tested drugs, 16 tested low-level laser therapy, and 21 tested other methods of pain control. Ibuprofen, paracetamol, naproxen, aspirin, and 4 other anti-inflammatory drugs were reported as effective, and most of the laser trials reported favorable results for orthodontic pain. The reviewers noticed that for drugs and laser alike, there is no consensus on the doses and protocols best suited to orthodontic pain, and suggested that the alternative methods widen the options open to clinicians.

42 patients, 26 women and 16 men, took part in a 2018 split-mouth randomized controlled trial in Pakistan of a single dose of low-level laser therapy (LLLT) for orthodontic pain after each early archwire, the thin wire that straightens the teeth, was fitted. Each patient received 4 successive nickel-titanium wires in the upper jaw 4 weeks apart, with 1 side of the mouth chosen at random for laser and the other for placebo. After each wire was placed, the laser side received a 940 nm diode laser at 100 mW and 7.5 J/cm² for 3 seconds at each of 10 points per tooth from the front tooth to the first molar. Spontaneous and chewing pain were rated on a numeric scale for the following 7 days. The trial found significantly lower spontaneous pain on the laser side after the first 2 wires, and a single LLLT dose was described as considerably lessening the pain of the early straightening wires.

Published in 2017, this systematic review and meta-analysis from Chile assessed whether low-level laser therapy (LLLT) reduces orthodontic pain at 24 and 72 hours after force is applied to the teeth. Searches of 6 databases identified 467 articles, of which 20 randomized controlled trials were included, using wavelengths from 808 to 1064 nm, with 13 trials rated at high risk of bias, 5 unclear, and 2 low. Pooled against placebo, LLLT favored the laser for spontaneous pain at 24 and 72 hours after light archwires, the first thin wires fitted to braces, and for both spontaneous and chewing pain at 24 and 72 hours after elastomeric separators. LLLT was found effective in reducing spontaneous and chewing pain after orthodontic force, but the poor quality of the evidence means the results must be treated with caution.

Comparing a single laser dose with a double dose, a 2016 randomized controlled trial in Syria tested low-level laser therapy (LLLT) for orthodontic pain from elastomeric separators, the rubber rings placed on either side of a molar before a band is fitted. 36 patients aged 12 to 26 had separators placed at the first molars of 1 jaw on 1 side only, the other side serving as placebo. They were split into a single-irradiation and a double-irradiation group, both treated with an 830 nm GaAlAs laser at 100 mW and 4 J/cm². LLLT reduced pain on the laser side compared with the placebo side at every assessment in both groups. No statistically significant difference separated the single-dose and double-dose groups, so GaAlAs LLLT reduced early orthodontic pain from separators whether given once or twice.

According to a 2016 single-blind randomized controlled trial at a medical university in Pakistan, a single dose of low-level laser therapy reduced both spontaneous pain and pain on chewing after elastomeric separators, small rubber rings placed between the teeth, were fitted. 88 patients had separators placed on either side of the first molars in all 4 quarters of the mouth, with both jaws divided into a laser side and a placebo side. The laser side received 940 nm light at 200 mW in continuous mode for 20 seconds at each of 3 points on the gum over the molar, and the placebo side had the same probe held in place without the laser switched on. Spontaneous and chewing orthodontic pain were rated on a numeric scale for the next 7 days. Both kinds of pain appeared significantly lower on the laser side, and a single laser dose was described as an efficient way to reduce this pain.

In 2016, a randomized split-mouth controlled trial in Brazil evaluated low-level laser therapy (LLLT) for orthodontic pain and discomfort in the early stage of treatment. 30 volunteers of both sexes aged 18 to 40 had elastic separators, rubber rings placed beside the first molars, fitted on 1 side of the upper jaw and then, after a week's rest, on the other. 1 side received an 810 nm laser at 100 mW and 2 J/cm² for 15 seconds at each of 3 points, and the other received a simulated application, with the separators left in for 5 days. Researchers found a statistically significant reduction in discomfort on the laser side compared with the placebo side at 5 minutes, 24 hours, and 120 hours after the laser. A single LLLT application may be indicated for controlling pain in the early stages of orthodontic treatment.

Published in 2015, this split-mouth, single-blind, randomized controlled trial at a private clinic in Iran tested a single dose of helium-neon laser for orthodontic pain while the upper eye teeth are pulled back during braces treatment. The study enrolled 30 patients, and 27 completed it, of whom 16 were male and 11 female, aged 12 to 21. 1 upper quarter of the mouth was chosen at random for 632.8 nm light at 10 mW and 6 J/cm² once the retraction spring was activated, and the other quarter was treated with the same device switched off. Average pain across home ratings on days 1, 2, 4, and 7 was 2.35 on the laser side against 4.06 on the placebo side, a statistically significant difference, with pain falling over time on both sides, the researchers reported. No harm was identified during or after the study, which the authors funded themselves and did not register.

Researchers in China pooled the trials of low-level laser therapy (LLLT) for orthodontic pain after separators are placed in a 2015 meta-analysis. 5 databases, 2 of them Chinese, were searched in June 2014, and 6 studies with 333 patients met the criteria, using 635 to 910 nm light at up to 20 J/cm² and 6 to 160 mW around the first molars. According to the analysis, LLLT had a significant pain-relieving effect compared with placebo at 6 hours and on days 1, 2 and 3 after placement. At 2 hours and on days 4 and 5, the results favored LLLT without reaching significance. The reviewers concluded that LLLT can effectively reduce this pain but that the trials disagreed with each other to a high degree, so well-designed randomized trials are still needed.

40 children with an average age of 8.05, still with a mix of baby and adult teeth, who needed their molars separated before orthodontic treatment recorded less orthodontic pain for 2 days after low-level laser therapy (LLLT) in a 2015 randomized controlled trial in Germany. 20 children received a 660 nm laser at 100 mW for 20 seconds, held about 8 mm from the gum, on the day the separators were placed, and 20 received no laser. Every child recorded their worst pain on the day of separation and on each of the following 4 days. Pain was significantly lower in the laser group on day 1 and still lower on day 2, with equal pain in both groups on days 3 to 5. LLLT was described as an interesting option for pain relief even in very young patients.

Diode low-level laser therapy (LLLT) appeared to reduce orthodontic pain by 39% compared with placebo, according to a 2015 systematic review and meta-analysis from Hong Kong. A search of 4 databases for randomized controlled trials up to November 2014 returned 186 results, of which 14 trials with 659 participants from 11 countries were included, using 635 to 910 nm light at 0.5 to 80 J/cm² and 6 to 200 mW. All but 3 of the trials were rated at high risk of bias, mainly for blinding and concealment of allocation. Diode LLLT significantly reduced maximum pain intensity in trials that compared separate groups, but showed no significant effect in trials that treated 1 side of the mouth and used the other as placebo. The reviewers found the approach promising but the evidence insufficient to support or refute it, and called for better-designed trials with adequate numbers.

2015 brought a randomized controlled trial in Italy of a single superpulsed low-level laser therapy (SLLLT) session for orthodontic pain induced by elastomeric separators, the rubber rings placed beside the molars and premolars. 120 subjects averaging 23.01 years were assigned to an upper or a lower jaw group of 60, each split into laser, placebo, and control subgroups of 20, with 910 nm light at 160 mW through an 8 mm beam for 340 seconds at placement. All subjects recorded pain duration and a 100 mm self-rated score at placement and at 12, 24, 36, 48, 72, and 96 hours. Pain intensity appeared significantly lower in the laser groups than in the placebo and control groups. 70% of laser subjects felt pain at every visit, compared with the other groups, and the laser groups' pain ended earlier. A single SLLLT application seemed effective at reducing the intensity and duration of this pain.

Researchers in 2014 tested continuous-wave 810 nm low-level laser therapy (LLLT) against orthodontic pain from elastomeric separators in a randomized controlled trial in Iran. 37 patients, 12 male and 25 female, aged 11 to 32, had 4 separators placed around the first molars of the upper jaw (22 patients) or lower jaw (15), with 1 side chosen at random as the placebo side. The laser side received 10 doses of 2 J/cm² at 100 mW for 20 seconds each, 5 on the cheek side and 5 on the tongue side at the necks of the roots, and another 10 doses 24 hours later. Pain was rated on a 10 cm self-rated scale at 0, 6, 24, and 30 hours and daily to day 7, and was significantly lower on the laser side at 6, 24, and 30 hours and on day 3, the researchers reported. Pain peaked at 6 and 30 hours on both sides, was low on average with wide ranges, and was higher in the lower jaw and in adults on days 3 and 4, with no difference between the sexes.

When patients irradiated their own first molars every 12 hours for a week, a 2013 single-blind randomized controlled trial in Korea found their separator pain stayed under the level felt by placebo and untreated patients. 88 patients were assigned to a laser group, a light-emitting diode (LED) placebo group, or a control group, with elastomeric separators, rubber rings placed between the teeth, fitted at the first molars. The laser and LED groups used a portable 635 nm device for 30 seconds at each of 4 points around the molar, every 12 hours for 7 days, and pain was rated on a self-rated scale at set intervals. According to the trial, laser pain scores were significantly lower than control scores up to 1 day, while LED scores matched the laser for the first 6 hours and then matched the control group. Frequent LLLT decreased pain to a level that stayed below significance throughout the week, and the authors suggested it might be an effective method of reducing orthodontic pain.

Applying laser at the end of braces treatment rather than the start, a 2013 randomized controlled trial at a university in Colombia tested whether low-level laser therapy reduces the orthodontic pain of the final archwire, the last and stiffest wire fitted before braces come off. 60 patients, 30 with conventional and 30 with self-ligating brackets, had 1 jaw chosen at random for 830 nm laser at 100 mW, 22 seconds, and 2.2 J at 80 J/cm² along each side of the roots; the other jaw was treated with the laser off. Pain followed the same course on both sides and peaked at 24 hours, but the trial found the laser reduced it at every time point up to 7 days, whichever bracket the patient wore. Low-intensity laser was concluded to reduce pain from final archwires without interference from the type of bracket.

Among 60 orthodontic patients aged 12 to 26, a 2013 double-blind randomized controlled trial at a university in Brazil tested a single dose of 830 nm low-level laser therapy (LLLT) for orthodontic pain from elastomeric separators, rubber rings placed either side of a lower molar. The laser group, average age 17.9, received 1 spot of 2 J/cm² at the root tip and 3 spots of 1 J/cm² along the root straight after the separators went in, while the control group, average age 17.1, received a placebo light. Pain was recorded at home at 2, 6, and 24 hours and 3 and 5 days, with the mouth relaxed and the teeth together. The laser group appeared to have lower average pain on every measure, and complete absence of pain was significantly more common in that group. The authors concluded that a single LLLT dose at 830 nm efficiently controlled this pain.

Comparing laser against placebo or no treatment across 8 trials, a 2013 systematic review and meta-analysis from China assessed low-level laser therapy (LLLT) for orthodontic pain. Searches of 6 databases up to October 2011 screened 152 studies and included 4 randomized controlled trials, 2 quasi-randomized trials, and 2 controlled clinical trials, covering 641 patients in 6 countries and wavelengths from 632.8 to 1060 nm. Pooled, LLLT reduced the risk of pain by 24% and brought the most painful day forward, and the laser groups showed a trend towards an earlier end of pain that did not reach significance against either placebo or control. The reviewers concluded that because of the methodological weaknesses and risk of bias in the included trials, the evidence that LLLT delays the onset and reduces the intensity of pain is limited, and larger, better-designed trials are needed.

Pain scored 7.7 mm on a 100 mm scale in the laser-treated quarter of the mouth against 14.14 mm in the placebo quarter, in a 2013 randomized controlled trial in Spain of low-level laser therapy (LLLT) for orthodontic pain from elastomeric separators. 20 healthy volunteers, 6 men and 14 women with an average age of 26.4, had separators fitted on both sides of the upper jaw. 1 side was irradiated at 830 nm, 100 mW and 250 mW/cm² for 20 seconds per point at 5 J/cm², 6 points per tooth, and the other side was given a placebo light. Pain peaked at 6 to 24 hours on both sides, and researchers found the laser side significantly less painful at every rating from 5 minutes to 72 hours. None of the 20 needed a painkiller during the study.

This 2012 randomized controlled trial at a university in Turkey tested low-level laser therapy (LLLT) against orthodontic pain after bands were fitted, measuring both self-rated pain and a chemical marker of inflammation in the fluid around the gum. 19 patients, 11 girls and 8 boys averaging 13.9 years, had bands placed on both upper first molars, 1 side chosen at random for a single 5-second shot of 820 nm laser at 50 mW and 7.96 J/cm², and the other as placebo. Gum fluid was sampled before banding and 1 and 24 hours after the laser, and pain was rated at 5 minutes, 1 hour, and 24 hours. The trial found no difference in pain at 5 minutes or 1 hour but a significant reduction on the laser side at 24 hours, and the inflammation marker rose on the placebo side while falling on the laser side. LLLT was concluded to be efficient at reducing this pain.

A split-mouth design gave each patient a laser side and a control side in a 2012 randomized controlled trial at a dental college in India of low-intensity laser therapy for shortening treatment and reducing orthodontic pain. 20 patients needing their first premolars removed had each upper eye tooth pulled back into the gap by a coil spring. The laser side received 810 nm infrared light at 5 J/cm² on days 0, 3, 7, and 14 of the first month and then every 15 days until the tooth was fully retracted, over 135 days. Tooth movement was measured on models and pain was rated on a self-rated scale, and the laser side moved an average of 30% faster with pain scores that appeared significantly lower than on the control side. The authors concluded that low-intensity laser therapy is a good option for reducing both treatment time and pain.

60 orthodontic patients aged 12 to 18, average 15.9, took part in a 2009 double-blind randomized controlled trial in Brazil of low-level laser therapy (LLLT) for pain after the first archwire, the wire that runs through the braces, was fitted. Each patient had braces on 1 jaw and was assigned to laser, placebo, or no treatment, with the laser group receiving 830 nm light at 30 mW and 2.5 J/cm² on the cheek and tongue sides of every tooth straight after the wire went in. The placebo group had the probe held in the same places with a sound every 10 seconds, and all patients recorded their pain at home for 7 days. Researchers found that the laser group had lower scores for pain and for its intensity on the worst day, and that their pain ended sooner, though the laser changed neither when pain began nor which day was worst. Pain did not differ between the upper and lower jaw on any measure.

14 of 38 laser-treated patients reported pain 6 hours after their braces were banded, against 29 of 38 given a placebo, in a 2006 single-blind randomized controlled trial at a university in Austria of a single low level laser therapy (LLLT) session. 76 patients, 46 women and 30 men with an average age of 23.1, were assigned to LLLT at 670 nm and 75 mW for 30 seconds per banded tooth or to a placebo laser with no active light. Pain was self-rated on a standard questionnaire at 6, 30, and 54 hours. The difference held at 30 hours, 22 against 33 patients, but not at 54 hours, 20 against 25, and more than 90% of both groups described the pain as tearing. A single LLLT session straight after banding appeared to reduce how many patients felt pain at 6 and 30 hours.

Researchers in Syria tested a single dose of low-level laser therapy (LLLT) against spontaneous and chewing orthodontic pain after the first archwire, the initial straightening wire, in a 2020 single-blind randomized controlled trial. 26 patients, with an average age of 20.07, whose upper crowding of 7 mm or more required removal of the first premolars, were assigned to laser or placebo (beam off). The laser group received 830 nm light at 2 J per point at 4 points around the root of each upper front tooth, 2 on the cheek side and 2 on the palate side. Pain was scored on a 100 mm self-rated scale at 1, 6, 24, 48, and 72 hours. Laser appeared to make no difference to either kind of pain at any point, apart from chewing pain at 72 hours, 18.84 mm with laser against 38.15 mm with placebo.

Pain averaged 1.1 in the laser group against 1.6 in the placebo group immediately after elastomeric separators, rubber rings placed beside the lower first molars, were fitted in a 2019 double-blind randomized controlled trial in Brazil of single-session low level laser therapy (LLLT). 62 patients were assigned to 4 groups: laser or placebo on the right side and laser or placebo on the left, with 830 nm light at 100 mW for 30 seconds applied before separation and again 24 and 48 hours after it. The difference just after separation was statistically significant, but at 24 hours, before the next application, the groups no longer differed, and pain peaked at 24 hours with laser and placebo alike, the researchers reported. Women in the placebo group reported slightly more pain than men after the first application, and at 48 hours men in the laser group reported less pain than women, 0.6 against 1.6. The laser was effective only when applied immediately after the separators went in, which the authors read as a limited effect.

A 2017 systematic review and meta-analysis from Iran compared ibuprofen with low-level laser therapy (LLLT) for orthodontic pain during treatment with braces. A search of PubMed and Medline in August 2016, limited to English and to blinded randomized controlled trials of high quality, yielded 6 studies with 315 patients: 4 on ibuprofen and 2 on LLLT, the laser trials using 670 and 830 nm light. According to the analysis, both ibuprofen and LLLT reduced pain intensity over a 17-day follow-up, but the reduction was statistically significant only at 6 to 24 hours for ibuprofen and at 2 hours and days 3 to 7 for LLLT. The ibuprofen trials agreed closely with each other, while the LLLT trials differed widely. Ibuprofen relieves archwire pain on the 1st day with fairly strong evidence, and LLLT may reduce it later with limited evidence.

This 2016 Cochrane review from the United Kingdom assessed every non-drug approach to orthodontic pain that had been tested in a randomized controlled trial. Searches of 5 databases and 2 trial registries to October 2016 found 14 trials with 931 participants, testing low-level laser therapy (LLLT) in 4, vibrating devices in 5, chewing aids in 3, and music, talking therapy, or a text message in 1 each. Pooling 2 laser trials with 118 participants gave low-quality evidence that LLLT reduced pain at 24 hours by 20.27 mm on a 100 mm scale, and LLLT also appeared to reduce pain at 6 hours and at 3 and 7 days. Every other comparison was inconclusive because the evidence was very low quality, and no trial measured adverse effects, the reviewers reported. Laser may help reduce orthodontic pain in the short term, but the evidence is too weak to rely on, and the reviewers asked for trials with longer follow-up that measure costs and harms.

5 ways of relieving orthodontic pain: a placebo vitamin tablet, ibuprofen, a bite wafer, a red laser, and an infrared laser, were compared in a 2016 randomized controlled trial in Iran after the first archwire, the wire that runs through the braces, was fitted. The study included 100 patients aged 14 to 21 (66 female and 34 male), with 20 assigned to each group. The laser groups received a single session of 660 nm red light at 14.3 J/cm² or 810 nm infrared light at 3.6 J/cm², both at 200 mW and 1 J per point at 6 points around each tooth. Researchers found that over 7 days of self-rated pain on chewing, biting, and closing the teeth, the infrared laser, ibuprofen, and bite wafer groups scored alike, all significantly lower than the red laser and placebo groups, with the infrared laser lowest at some points. Infrared laser or a bite wafer were suggested as suitable alternatives to ibuprofen.

Across 244 articles screened, a 2016 systematic review from a university in Sweden assessed low level laser therapy (LLLT) for 3 uses during braces treatment in children and young adults: speeding tooth movement, preventing relapse and easing acute orthodontic pain. Searches of Medline, the Cochrane trials register, and 1 other database found 16 studies that met the criteria, 3 on tooth movement and 13 on pain, and none on relapse, with laser techniques varying widely and wavelengths from 632.8 to 904 nm. The included studies reported promising results, faster tooth movement and lower pain scores than controls. The review found the quality of evidence very low for tooth movement and low for acute pain, and no study met the criteria for relapse. The reviewers called for high-quality research with consistent designs before LLLT can be said to improve braces treatment.

Whether low-level laser therapy (LLLT) relieves orthodontic pain, and how good the evidence is, was the question a 2015 systematic review and meta-analysis from China put to the randomized trials. Searches of the Cochrane Library and MEDLINE to July 2014 found 11 randomized controlled trials, covering wavelengths from 523 to 980 nm at 2.3 to 5 J/cm², which were pooled and graded for quality of evidence. Pooled, LLLT lowered the score on the most painful day by 4.39 points against placebo and brought the most painful day forward against control, while the end of pain came earlier with laser but not significantly so. Every comparison for all 3 outcomes was rated very low quality once the downgrading factors were applied. The reviewers concluded that the methodological shortcomings and risk of bias left insufficient evidence to evaluate whether LLLT relieves orthodontic pain, and asked for better trials before it is recommended as routine.

2 light protocols, a 660 nm laser and a 640 nm light-emitting diode (LED), were tested against placebo and no treatment in a 2011 randomized controlled trial at a research institute in Brazil of orthodontic pain after tooth movement. 55 volunteers, 39 men and 16 women with an average age of 24.1, were divided into 4 groups, with elastomeric separators, small rubber rings placed between the teeth, used to induce the pain. The laser ran at 4 J/cm² and 30 mW for 25 seconds, and the LED at 4 J/cm² and 100 mW for 70 seconds, on the gum either side of the separated molars, with pain self-rated up to 120 hours. The LED group showed a significant reduction in pain from 2 to 120 hours compared with both the control and the laser groups, an average reduction of 56% against control, the researchers reported. The laser group did not differ significantly from the control group.

Across 388 patients in 6 randomized trials, a 2010 meta-analysis from China compared the methods used to control orthodontic pain during treatment with braces. Searches of MEDLINE, the Cochrane Library, EMBASE, and a Chinese database identified 26 randomized trials, of which 6 qualified. The analysis found that ibuprofen reduced pain at 6 and 24 hours after archwire placement compared with placebo, with no difference between ibuprofen, acetaminophen, and aspirin; however, 2 longer-acting painkillers still produced lower pain scores. Low-level laser therapy (LLLT) was also effective, with pain scores of 3.30 in the laser group versus 7.25 in the control group. The reviewers concluded that painkillers remain the main treatment despite their side effects, and that approaches such as LLLT have drawn researchers' attention.

A 2021 randomized controlled trial at a university in Turkey found no statistically significant difference in orthodontic pain at any time point among laser, chewing gum, and no treatment for pain from the first archwire (the initial straightening wire). 63 patients, 33 female and 30 male, with 3 to 6 mm of upper crowding and no extractions planned, were randomly allocated to 3 groups. The laser group had a single 820 nm dose at 50 mW, 110.3 mW/cm², and 1.76 J/cm² for 16 seconds as treatment began, and the gum group chewed sugar-free gum for 20 minutes immediately and at 24 and 48 hours. Pain was rated on a self-rated scale at 2, 6, and 24 hours and on days 2, 3, and 7, and neither low-level laser therapy nor gum showed any clinically significant effect, the researchers reported. They suggested that more participants or lasers with different settings might give different results.

According to a 2021 randomized controlled trial at a university in Turkey, ibuprofen rather than low-level laser therapy (LLLT) was the treatment that eased orthodontic pain and pain signals after elastomeric separators, the rubber rings placed before molar bands. 60 patients needing separators before bands on the upper first molars took 400 mg ibuprofen or a placebo lactose tablet 1 hour before placement, or had a single 810 nm laser session at 100 mW for 10 seconds per point straight after. Gum-crevice fluid was sampled on days 0, 1, 3, and 7 for 2 chemical signals of inflammation and pain, and pain was rated on a self-rated scale at baseline, 2 and 6 hours, and days 1, 3, and 7. The trial found that only the ibuprofen group showed lower substance P, the pain signal, on days 0 and 1 and less pain than the control group at baseline. Pain peaked on day 1 in every group, and the laser group differed from control at no point.

When laser was tested alongside a vibrating device for orthodontic pain after the first archwire, a 2019 randomized controlled trial at a university in Turkey found neither differed significantly from no treatment. 60 patients with 3 to 6 mm of upper crowding and no extractions planned were divided into 3 groups of 20, balanced by sex, with average ages of 13.98, 14.86, and 14.41. After the first thin wire was engaged, group 1 had mechanical vibration immediately, and at 24 and 48 hours, group 2 had a single low-level laser application at 820 nm, 50 mW, and 1.76 J/cm² for 16 seconds, and group 3 had no treatment. Pain was rated on a self-rated scale, and researchers found no statistically significant differences among the groups at any time point. The vibration group's scores were consistently the lowest, and the authors recommended further trials before drawing firmer conclusions.

No statistically significant difference from placebo appeared at either laser energy in a 2018 single-blind randomized controlled trial in Syria of low-level laser therapy for orthodontic pain caused by elastomeric separators, the rubber rings placed beside a molar. 26 patients needing braces were assigned to a 4 J or a 16 J group, with separators at both lower first molars and 1 molar chosen at random for a single 830 nm laser dose, while the other received the device without the beam. Pain on chewing was rated for each molar on a 100 mm self-rated scale at 1, 6, 12, 24, 48, and 72 hours, and 25 patients completed the questionnaires. Neither the 4 J nor the 16 J dose appeared to differ from its placebo side, and the authors concluded that LLLT at these 2 energies is ineffective for this pain. No side effects were reported, the provider of the laser was not blinded, and the trial was not registered.

A 2015 single-blind randomized controlled trial in Brazil investigated whether a single 6 J dose of low-level laser therapy (LLLT) changes the orthodontic pain caused by elastomeric separators, the rubber rings placed before bands are fitted. 79 patients aged 13 to 34 at the start of treatment had separators placed on either side of the upper first molars for 3 days. A third received 808 nm laser at 100 mW and 80 J/cm² for 60 seconds, a third a placebo application, and a third no treatment, in a split-mouth arrangement. No differences were found among the laser, placebo, and control groups on the self-rated scale at 6 and 12 hours or on days 1, 2, and 3. Pain from the separators varied widely between patients and was usually mild.

No statistically significant difference between laser and placebo emerged in a 1995 double-blind randomized controlled trial at a dental faculty in Singapore of low-level laser therapy (LLLT) for orthodontic pain after an adjustment. 39 volunteer dental students had elastomeric separators, small rubber rings, placed beside 1 premolar in each quarter of the mouth to induce pain. An 830 nm diode laser at 30 mW was held against the gum over the middle of each root for 15, 30, or 60 seconds, with a 30-second placebo on the 4th tooth, so each student received every treatment. Pain was rated on a self-rated scale before and after each application for 5 days. The trial found that laser-treated teeth had lower median pain scores than placebo-treated teeth, but the within-subject differences were not statistically significant, and the authors attributed the apparent relief to the students knowing they were in a trial.