Red Light Therapy for Malocclusion: Scientific Evidence

22 growing patients aged 10 to 14 with Class II malocclusion from a lower jaw set too far back took part in a 2023 randomized controlled trial in Iran of low-level laser therapy added to a functional appliance. All wore the appliance, and after 3 to 4 weeks, the laser group also received 980 nm light at 100 mW over 100 seconds at each of 4 points around the jaw joint, in contact with the skin, once a week for 3 months, with jaw measurements taken from side-view X-rays before and after treatment. The lower jaw lengthened more, sat further forward, and had a longer vertical branch in the laser group, and the mismatch between the jaws fell further, all statistically significant differences from the appliance alone. The authors concluded that the laser at these settings improved the appliance's effect and reduced the mismatch between the 2 jaws.

3 arms: fixed bite blocks on the back teeth plus low-level laser therapy (LLLT), bite blocks alone, and no treatment, were compared in a 2022 randomized controlled trial in Syria for children whose front teeth do not meet. 42 children aged 8 to 10 were assigned equally to the 3 groups, with the laser group receiving 808 nm light at 4 J per point for 16 seconds per point at the first visit, on days 3, 7, and 14, and then every fifteen days to the end of treatment, and jaw and tooth changes were measured on side-view X-rays. The trial found the open bite closed in 7.07 months with laser against 9.42 months with bite blocks alone, a statistically significant difference, and the upper first molars moved 1.21 mm up into the bone with laser against 0.82 mm without. The untreated children's molars drifted 0.32 mm the other way, and the 2 treated groups showed similar changes in the bones and teeth.

Applying laser to the skin over both jaw joints alongside a removable appliance that holds the lower jaw forward, a 2022 3-arm randomized controlled trial in Syria tested whether low-level laser therapy (LLLT) shortens treatment of Class II malocclusion caused by a lower jaw set too far back. 48 patients (aged 10.5 to 14.5 years, 28 girls and 20 boys) were split equally into appliance plus LLLT, appliance alone, and an untreated group observed for 9 months, with 45 completing. The laser was delivered at 808 nm and 250 mW, 5 J per point over 20 seconds at each of 5 points over each of the 2 joints, twice a week in the first month, every 2 weeks in the second, and every 3 weeks after that. Treatment took 129 days with laser versus 235 without, and the lower jaw lengthened by 4.41 mm with laser, 3.66 mm with the appliance alone, and 1.07 mm untreated, the researchers reported. The improvement in how far forward the lower jaw sat was similar in the 2 treated groups, and the laser did not push the jaw joint forward.

Crowded lower front teeth straightened in 68 days on average with laser against about 110 without, according to a 2022 randomized controlled trial of low level laser therapy (LLLT) in Egypt. 32 women aged 18 to 25 with a correct back-tooth bite and 4 to 10 mm of lower crowding were randomly split into laser and control groups, both fitted with brackets and a standard sequence of wires, with the laser group receiving 940 nm light at 2.5 W and 25.7 J/cm² on the lower front teeth on days 3, 7 and 14, at 1 month and then every 2 weeks until the teeth were straight, and pain rated on a standard scale over the week after the first wire. The laser group showed a significantly higher percentage improvement in straightness and lower pain scores than the control group. The trial concluded that LLLT may speed the straightening of the front teeth and reduce pain from the first wires.

Among 30 children with an average age of 7.8, 16 girls and 14 boys, a 2021 randomized controlled trial in Italy tested whether LED photobiomodulation (PBM) eases the pain of having the upper jaw widened with an expander for a narrow upper jaw. The children, all at an early growth stage judged from neck X-rays, were assigned at random to expander plus PBM or expander alone, with the PBM group receiving 450 to 835 nm light from 4 cm away for 18 minutes at 48 to 144 J/cm², and pain rated on a 0 to 10 scale at 6, 12, and 24 hours and daily from day 2 to day 7. Pain at every time point and the worst pain reported appeared significantly lower with PBM, and it faded faster, reaching close to 0 after 2 to 3 days. The trial judged PBM effective at reducing both how much pain the children felt and how long it lasted.

In 2021, a systematic review from Chile set out to determine the benefits of low-level laser therapy (LLLT) as a complement to widening the upper jaw with an expander in patients with a narrow upper jaw. Of 32 publications found, 16 were included: 2 earlier reviews, 6 human studies of 1 to 39 patients aged 8 to 26, and 8 animal studies. The human studies used lasers between 660 and 830 nanometres at 1.5 to 140 J/cm² in 3 to 12 sessions along the join in the roof of the mouth. Every study reported faster bone regrowth at the join, and the review recommended starting LLLT early, at small doses, on at least 4 sites.

When researchers in Italy gave patients an LED session every 2 weeks during braces, a 2020 single-blind randomized controlled trial found that mild crowding in the lower teeth resolved sooner in patients with Class I malocclusion. 100 patients aged 13 to 30 with no extractions planned were enrolled, and 89 were analyzed: 50 women and 39 men, with an average age of 18.4, 43 in the braces plus photobiomodulation (PBM) group and 46 in the braces-only group. The PBM group sat in front of a 3-panel device held 4 cm from the cheeks and lips, delivering 450 to 835 nm light at 99 Hz and 144 J/cm² for 18 minutes per session, every 2 weeks from bracket fitting until the teeth were straight. The authors concluded that PBM significantly reduces alignment time, a median of 203 days against 260, and 7 monthly visits against 9, while cautioning that this covers the alignment stage only.

A single-arm design with no comparison group was used in a 2019 clinical trial in Italy of low-level laser therapy (LLLT) combined with cuts in the jawbone to widen the upper jaw on 1 side only, in adults whose upper back teeth bit inside the lower ones on that side. 15 adults, 8 women and 7 men with an average age of 21.6, were fitted with an expander and self-ligating braces, had the bone cuts made on the outer side of the affected jaw, and received LLLT monthly until the crossbite was corrected, with the 980 nm therapy laser (an erbium line of 2,940 nanometres is also listed) set at 1000 mW/cm² and 0.18 J for 1 minute 51 seconds from about 1.5 cm away, and the result measured on digital models. The team corrected every patient's crossbite and achieved a working bite, with significantly more widening on the affected side than the other at the premolars and first molars. The trial concluded that the combined technique was effective for this kind of crossbite.

Whether low-level laser therapy (LLLT) improves clinical success, wound healing, and bone regrowth after the upper jaw is widened, with or without surgery, was the question a 2018 systematic review from Iran put to the published trials in patients with malocclusion. Searches of 4 databases up to May 2017 returned 1804 records, of which 4 randomized controlled trials were sound enough in their randomization and methods to include. Across those 4 trials, the light ran from 660 to 830 nm at 40 to 100 mW, with doses from 100 to 420 J/cm² and 20 to 84 seconds at each point on the roof of the mouth. Based on these trials, LLLT appeared to offer some benefit in speeding bone remodeling, and the reviewers advised that it is better used in the initial phase of widening.

2017 brought a 2-arm randomized controlled trial of low-level laser therapy (LLLT) for speeding the straightening of severely crowded upper front teeth. 26 patients whose crowding called for removal of 2 premolars were assigned 13 to a laser group and 13 to a control group, both fitted with braces after the extractions, with the laser group receiving 830 nm light at 2 J per point at 4 points on the root of each upper front tooth straight after the first wire, on days 3, 7 and 14, and then every fifteen days from the second month until the teeth were straight, and progress measured on models at 1 and 2 months and at the end. The trial found a statistically significant difference in the total straightening time and in the percentage improvement at 1 and 2 months, both with the laser group doing better. LLLT was judged an effective way to speed tooth movement.

A 2017 randomized controlled trial in Italy evaluated whether low-level laser therapy (LLLT) makes the straightening phase of fixed braces more efficient in patients with malocclusion. 36 patients were randomly assigned to braces plus a single monthly session of LLLT inside the mouth, with a 980 nm diode laser at 1 W in continuous wave delivering 150 J/cm², or to braces alone, with age, sex, and amount of crowding balanced between the groups. The trial found the teeth were straight after 212 days on average with laser against 284 without, a statistically significant difference, and the laser group needed a median of 7 check-up visits against 9.5. Described by its authors as a pilot, the study offers its results only as a suggestion that LLLT might improve efficiency.

Researchers in the United Arab Emirates tested whether an LED device worn against the cheek speeds the straightening of crowded lower front teeth in a 2017 randomized controlled trial. 40 patients with crowded lower front teeth and self-ligating braces were split into a test group using 850 nm light at 90 mW/cm² for 20 minutes every day, an estimated 108 J/cm² at the cheek surface and about 12 J/cm² reaching the bone, and a control group, with 34 completing and average ages of 21.8 and 21.1. The lower front teeth were straight after 68 days on average with the light, compared with nearly 88 without, a 22% reduction that reached statistical significance, the researchers reported. The trial was not registered on a public registry.

In a 2016 single-blind randomized controlled trial in Spain, 39 children who had just had their upper jaw widened with an expander showed better repair of the join in the roof of the mouth after low-level laser therapy (LLLT) than after placebo. The children, aged 6 to 12 with a narrow upper jaw, were randomized to 20 receiving 660 nm light at 100 mW, 332 mW/cm² and 12 to 23 J/cm², 3 to 6 J, over 60 seconds at each of 4 points along the join and 30 seconds at each of 2 points beside it, 5 minutes in all, on days 1, 7, 14, 28, 42, 56 and 70 of the retention phase, and 19 receiving placebo, with 3D scans on the first day and at day 75. At day 75, the laser-treated children appeared to have a greater share of closed zones in the front and back upper parts of the jaw, though less closure in 1 posterior zone. LLLT appears to stimulate the repair process during retention after widening, the trial concluded.

19 patients with crowded front teeth who used an LED device inside the mouth every day reached straight teeth in 48 days against 104 without it, in a 2016 clinical trial in the United States. The 11 test patients, 18 dental arches between them, and 8 controls with 10 arches all had Class I or Class II malocclusion with at least 3 mm of crowding and no extractions, and the device delivered continuous 850 nm light to the outer gums at 42 to 60 mW/cm² for 3 minutes 48 seconds a day, an average of 9.5 J/cm² a day, with the 2 groups wearing different bracket types. Researchers found that crookedness fell by 1.27 mm per week with the light, compared with 0.44 mm per week without it, a 2.9-fold faster rate and a 54% shorter time to straight teeth, with patients using the device on 93% of days. The authors concluded that the device could shorten straightening time, but called for a large trial with random assignment given the study's limitations.

10 of the 14 children in a 2016 randomized controlled trial in Brazil received low-level laser therapy (LLLT) after their upper jaw was widened with an expander, and the other 4 received the expander alone. The children were aged 8 to 14 and had an upper jaw that was too narrow. The expander was turned twice a day until the jaw was slightly over-widened, and the laser group then had 12 sessions of 780 nm light at 70 mW and 35 J/cm² over 20 seconds at each of 4 points in contact along the join in the roof of the mouth, 140 J/cm² in all, with bone density measured on 3D scans straight after widening and 4 months later. Bone density appeared to rise significantly in the laser group but not in the control group, and it was higher in the laser group at 4 months. Both groups showed the join fully closed with bone by the 4-month scan.

Researchers at a hospital in Egypt used each patient as their own control in a 2015 clinical trial of low-level laser therapy (LLLT) after surgery that lengthens the lower jaw by slowly pulling the cut bone apart, in adults whose lower jaw sat too far back on both sides. 10 patients, 7 women and 3 men with an average age of 31, had the surgery on both sides of the jaw. The right side then received a 905 nm diode laser at 500 mW for 2 minutes, and the left side received no laser, with bone density read from panoramic X-rays after 6, 12, 24, and 54 days of healing. According to the trial, bone density on the laser side was significantly higher at days 12, 24, and 54, though not at day 6. In the trial's judgment, LLLT improved the quality and quantity of the new bone and shortened the healing period, allowing the lengthening device to be removed earlier.

9 patients aged 13 to 16 with a lower jaw more than 5 mm too narrow took part in a 2015 clinical trial in Turkey of low-level laser therapy (LLLT) after surgery that widens the jaw by slowly pulling the cut bone apart. All 9 had surgery at the midline of the lower jaw. 5 then received 830 nm light at 40 mW and 8.4 J/cm² per spot at 2 points on the midline in 8 sessions, 48 hours apart, and 4 received no laser, with new bone measured on high-resolution scans. According to the trial, the laser group had a higher rate of bone mineral density, while the control group had more new bone that was still immature. In the trial's reading, LLLT may increase mineralization and could shorten the healing period after this surgery.

Across 90 patients at several centers, a 2013 clinical trial in the United States tested whether photobiomodulation shortens the straightening phase of braces in patients with malocclusion. 73 test patients and 17 controls, adolescents and adults, wore standard brackets and wires, with the test group holding a device against the cheek that delivered continuous 850 nm light at 60 mW/cm² for 20 or 30 minutes a day or 60 minutes a week, giving 72, 108, or 216 J/cm², and crookedness of the front teeth was measured on a standard index at regular intervals. Crookedness fell by 1.12 mm per week in the light group against 0.49 mm per week in the controls, a change the authors judged meaningful in practice. The light group started with more crooked teeth, 6.35 mm against 5.04 mm on the index.

2012 brought a randomized controlled trial in Brazil of a low-level laser during widening of the upper jaw with an expander in children with a narrow upper jaw. 27 children aged 8 to 12, average age 10.2, were split into a laser group of 14 and a no-laser group of 13, the expander was turned a full turn on day 1 and half a turn daily until slightly over-widened, and the laser group received 780 nm light at 40 mW and 10 J/cm² over 10 seconds at each of 10 points around the join in the roof of the mouth, on days 1 to 5 of turning, on 3 further days once the screw was locked, and again 1, 2 and 3 weeks later, 11 sessions in all, with bone density read from X-rays at 5 time points. The researchers reported that the laser improved join opening and sped up bone regrowth across it. The trial concluded that the laser, alongside widening, opened the join effectively and accelerated healing.

Published in 2010, this clinical trial in Brazil tested whether low level laser therapy (LLLT) speeds bone regrowth at the join in the middle of the roof of the mouth after the upper jaw is widened surgically. 13 patients aged 18 to 33 with an upper jaw at least 7 mm too narrow had jaw surgery and an expander fitted, with 7 then receiving 830 nm light at 100 mW, 8.4 J and 140 J/cm² per point over 84 seconds at each of 3 points on the join, 25.2 J and 420 J/cm² per session, in 8 sessions 48 hours apart, and 6 receiving no laser, with bone density read from X-rays before surgery and at 1, 2, 3, 4 and 7 months. Bone density in the laser group rose at a 26.3% higher rate than in the control group, a statistically significant difference. The authors concluded that the laser accelerates bone regrowth after this surgery, though at 7 months the density readings in both groups were still below the pre-surgery level.

When researchers in Türkiye looked back at 89 patients wearing clear aligners for crowded lower front teeth, a 2025 observational study found that only the combination of light and vibration did better than aligners alone. Patients with mild to moderate crowding were grouped as control with 19, low-frequency vibration with 26, photobiomodulation (PBM) with 21, and both together with 23, with the vibration at 30 Hz and 0.25 N and the PBM from an 850 nm LED array at about 9.5 J/cm² for 20 minutes a day in contact with the mouth, over 62 days. Crowding fell significantly more in the combined group than in every other group, while vibration alone and PBM alone did not differ from the control. The authors concluded that combining the 2 gave greater short-term acceleration than either alone, and called for trials with random assignment to confirm the long-term effect and safety.

A double-blind, parallel design was used in a 2025 randomized controlled trial in Türkiye of low-level laser therapy (LLLT) for straightening crowded lower front teeth. 30 patients with 4 to 8 mm of crowding between the lower front teeth had thin nickel-titanium wires changed every 2 weeks. The laser group received 810 nm light at 100 mW and 8 J/cm² for 10 seconds per point in contact with the teeth on day 0, days 3, 7, and 14, and then every 2 weeks until the teeth were straight, with pain rated on a standard scale at 8 points over the first 3 weeks. Straightening took no less time with laser than without, about 112 days against about 138, a difference that was not statistically significant. The authors concluded that LLLT does not shorten straightening but does significantly reduce pain at 6 hours and on day 1 after the wire is fitted.

According to a 2024 narrative review from Greece, laser techniques used alongside widening of the upper jaw, whether by expander alone or with surgery, consistently improved bone regrowth in patients with malocclusion. A search of 1 database up to September 2024 produced 78 publications, of which 17 were included: 11 clinical trials and 6 systematic reviews, plus 1 more found by hand, covering 450 to 980 nm light at 1.5 to 140 J/cm² in sessions of 2 minutes to 37 minutes 20 seconds. Despite varied protocols, the included studies agreed that laser techniques improved bone regrowth after widening, and the review judged them a promising way to ease pain during the procedure as well. Some studies found no faster regrowth and similar pain, and the reviewers called for longer randomized trials before a reliable protocol can be set.

Comparing low level laser therapy against placebo for bone regrowth after the upper jaw is widened, a 2023 systematic review and meta-analysis from Brazil pooled placebo-controlled trials in patients with a narrow upper jaw. 5 trials met the criteria and 3 supplied bone density readings for pooling, with wavelengths from 660 to 1440 nm, power outputs from 10 to 300 mW and fluences from 10 to 238.85 J/cm², measured at the join in the roof of the mouth over up to 6 months. The authors concluded that the pooled change in bone density did not differ significantly between light and placebo, that the trials disagreed with each other to a high degree, and that removing 1 trial from the pool swung the result towards a benefit for the light. A test for publication bias was positive on 1 of 2 measures.

A 2022 randomized controlled trial in Egypt evaluated whether low-level laser therapy (LLLT) improves the results of widening the upper jaw with an expander anchored on screws in the palate, in girls whose upper back teeth bit inside the lower ones on both sides. 24 girls aged 10 to 13 were randomly split into 2 groups of 12: expander alone and expander plus LLLT, with the 7 mm expander turned twice a day for about 2 weeks and then locked as a retainer for 6 months. The laser was delivered at 780 nm, 40 mW, 10 J/cm², and 32 J for 8 seconds during widening and retention, with photographs, 3D scans, and digital models taken before and 6 months after. The trial found that both groups showed a significant increase in nose and upper jaw width and face height, and that only the laser group showed significant increases in 2 upper jaw angles and the distance between the premolar roots. The authors concluded that at these settings, LLLT does not make a practical difference to the efficiency of this expander in girls before and around puberty.

60.8% was the increase in the speed at which the upper eye tooth moved back into an extraction gap with low-level laser therapy (LLLT), in a 2021 randomized controlled trial in Iran that also tested an LED device in young adults with malocclusion. 60 patients needing an upper first premolar removed were assigned to 3 groups: an LED group using a custom device at 640 nm and 40 mW/cm² for 5 minutes, a laser group receiving 810 nm light at 100 mW and 4 to 10 J/cm² for 3 to 18 seconds per point, and a control group, over 60 days. According to the trial, the laser increased the rate of tooth movement significantly, while the LED's 26% increase did not reach significance. Neither light affected how the tooth rotated or how much pain patients felt.

Whether low-level laser therapy shortens the time elastic bands need to correct a Class II malocclusion was the question a 2021 randomized controlled trial in France put to 42 patients. The 41 analyzed, 28 girls and 13 boys aged 10 to 16, had 1 side of the upper jaw treated with an active 970 nm diode laser and the other with a placebo, while elastic bands linking the upper and lower braces pulled the bite into the correct position over 6 months, with the time to a correct bite, the distance the upper eye tooth moved, and pain in the first 3 days recorded. Researchers found that the time to a correct bite was the same on both sides, 2.46 months with laser and 2.48 months with placebo, but the eye tooth moved further on the laser side, 2.27 mm against 1.64 mm, and faster, 1.1 mm per month against 0.74. Pain in the first 3 days did not differ between the sides.

According to a 2017 review from the United States, the evidence that low-level laser therapy (LLLT) speeds orthodontic tooth movement in malocclusion is low to moderate in quality. The review surveyed the techniques and materials proposed to shorten braces treatment, from bone surgery and vibration to light at 600 to 1000 nm, and weighed the level of evidence for each. There was some evidence that LLLT and a form of bone surgery that lifts the gum away were associated with faster tooth movement, the review found, while vibration devices had no significant effect in the higher-quality trials. The single trial of an intraoral light device was rated very low quality because of its design and incomplete reporting, and the review advised against routine use of any of the techniques until better research exists.

In 2015, a meta-analysis from China pooled trials of low-level laser therapy for speeding tooth movement during braces in patients with malocclusion. Searches from 1990 to June 2013 yielded 5 studies, 4 randomized and 1 controlled, of 11 to 20 patients each aged 12 to 23, all measuring how far the eye tooth moved into an extraction gap, with wavelengths of 650, 780, 800 and 860 nm, power outputs of 0.25, 20 and 100 mW and fluences of 5 and 25 J/cm², over up to 90 days. According to the analysis, the pooled extra distance moved with laser was 0.33 mm within 1 month, 0.76 mm within 2 months, and 0.43 mm within 3 months, but the results were unstable and differed widely between studies, with signs of publication bias at 3 months. The reviewers judged there was weak evidence that 780 nm light at 5 J/cm² or 20 mW could speed tooth movement within 2 to 3 months, and none they could rely on within 1 month.

This 2023 clinical trial in Saudi Arabia asked whether low-level laser therapy (LLLT) during braces changes the bone between the tooth roots in patients with malocclusion. 32 patients aged 14 to 25, treated with fixed braces and scanned in 3D before and after, were assigned to a laser group, receiving 940 nm light at 100 mW, 7.5 J/cm², and 75 J for 3 seconds per point in contact with the gum over the roots after each wire change, or to a control group without laser, over about 600 days. Bone width between the roots at 4 depths appeared unchanged, with mostly insignificant differences between the groups. The authors rejected their hypothesis that the laser would alter the bone.

Comparing a reversed forward-holding appliance with and without photobiomodulation therapy (PBMT), a 2022 randomized controlled trial in Syria examined the jaw joint in children with Class III malocclusion. 40 children aged 9 to 11, 28 boys and 12 girls, were randomly assigned to appliance plus PBMT or appliance alone, with the light delivered at 808 nm, 150 to 250 mW, and 5 J/cm² over the jaw joint on days 1, 3, 7, and 14 of the first month and then every fifteen days to the end of treatment, and 3D scans were taken before and after. The rounded top of the lower jawbone appeared to grow significantly, by an average of 287.97 mm³, only in the group without light. Neither group differed from the other in the position of the joint after treatment.

Among 14 children with Class II malocclusion caused by a lower jaw set too far back, a 2022 clinical trial in Egypt tested whether low-level laser therapy aimed at the jaw joint adds anything to a removable appliance that holds the lower jaw forward. The children, 9 boys and 5 girls with an average age of 11.4, were split into an appliance-plus-laser group and an appliance-only group, with the laser group receiving 940 nm light at 100 mW, 2.5 J and 3.94 J/cm² for 25 seconds in contact with the skin over the jaw joint, over 9 months. According to the trial, the lower jaw lengthened by 3.6 mm with laser and 4.3 mm without, with no significant difference between the groups at any point. The trial concluded that the laser at these settings added nothing to the appliance's effect on the bones or the teeth.

No difference in bone growth or pain separated the laser group from the sham group in a 2021 randomized controlled trial in Brazil of photobiomodulation therapy (PBMT) after the upper jaw is widened in children with a narrow upper jaw. 40 children aged 6 to 12 were enrolled and 34 completed, 18 in the laser group and 16 in the sham group, with the laser group receiving 980 nm light at 300 mW and 238.85 J/cm² over 10 seconds at each of 6 points spread along both sides of the join in the roof of the mouth, 4 times during the 2 to 3 weeks of active widening and then once a week for 8 weeks, 12 sessions in all, and the sham group treated with the laser on standby, with bone formation read from X-rays and pain rated on a faces scale. Bone formation appeared no different between the groups and was still incomplete in both at 3 months. Pain was similar in both groups, though higher in the first week than on day 14, and the laser group was on average 1 year older than the sham group.

No meaningful difference in the size or position of the jaw joint separated the laser group from the control group in a 2020 randomized controlled trial in Egypt of low level laser therapy (LLLT) added to a removable appliance that holds the lower jaw forward, in children with Class II malocclusion. 28 children aged 9 to 12, 14 girls and 14 boys, were enrolled and 24 completed, all wearing the appliance, with the laser group also receiving 635 nm light at 50 mW, 4.5 J/cm² and 11.25 J over 45 seconds at each of the 2 jaw joints, in contact with the skin, once a week for 3 months, and 3D scans taken before and after. The trial found that the rounded top of the lower jawbone grew by 213.3 mm³ on the right and 231 mm³ on the left with laser, against 244.2 mm³ and 225.2 mm³ without, differences that were not statistically significant. The appliance itself produced clear changes in jaw shape and position in both groups, which the authors could not attribute to the laser.