Red Light Therapy for Gum Disease: Scientific Evidence

Blood levels of an inflammation messenger fell from 11.54 to 11.02 picograms per milliliter over 3 months in diabetics whose gum disease treatment included low-level laser therapy (LLLT), against 11.56 to 11.41 without it, in a 2021 clinical trial from Pristina, Kosovo. 80 patients aged 35 to 60 with type 2 diabetes and chronic periodontitis were divided into 40 given conservative periodontal treatment plus LLLT and 40 given the treatment alone. The 660 nm laser at 10 mW was applied to the gums quadrant by quadrant in 5 sessions on 5 consecutive days. Blood was drawn at the first treatment, at 6 weeks, and at 3 months. The trial found the marker significantly lower in the laser group than the control group at both 6 weeks and 3 months, so LLLT alongside conservative treatment reduces this marker of body-wide inflammation in diabetics with periodontitis.

This 2021 single-blind parallel randomized controlled trial at Osmangazi University in Eskişehir, Turkey, assessed an 820 nm diode laser added to scaling and root planing (SRP), the deep cleaning of the roots used to treat gum disease, in smokers and non-smokers with periodontitis. 60 patients, 30 smokers and 30 non-smokers, were divided into SRP alone or SRP plus photobiomodulation therapy (PBMT), with the laser at 50 mW applied to the outer gum surface after cleaning and again 1, 2, and 3 weeks later. Clinical measures were recorded at baseline and 6 weeks, and gum fluid was sampled from the deepest pocket for a reading of oxidative stress, the tissue damage caused by unstable oxygen molecules. PBMT appeared to improve the oxidative stress reading in smokers more than in non-smokers, and no side effects occurred with either treatment. The authors placed the result alongside earlier work showing that laser add-ons to SRP raise treatment effectiveness and support gum tissue recovery, especially in smokers.

Treating 1 side of the mouth with a 940 nm diode laser and the other with a sham, a 2020 double-blind randomized controlled trial at the University of Hong Kong followed 27 adults with treated and controlled chronic periodontitis through 6 months of orthodontic treatment. The aim was to test whether low-level laser irradiation eases orthodontic pain and calms periodontal inflammation in patients whose gums are already compromised. Pairs of displaced single-rooted teeth on both sides of the arch were assigned at random to laser or placebo, with the laser at 800 mW applied over the gum from the central incisor to the first molar. Inflammatory messengers in gum fluid, periodontal clinical measures, and the load of 2 gum disease bacteria were tracked alongside pain scores. The laser side showed a significantly smaller rise in 1 inflammatory messenger at 1 day and 1 month after the first wire was fitted, with no difference between sides in bacterial load.

Published in 2020, this randomized controlled trial at National Taiwan University in Taipei tested 660 nm light-emitting diode (LED) light during non-surgical periodontal therapy, after animal work had shown the light could speed oral wound healing. 19 patients with at least 1 periodontitis-affected tooth in each of 3 quadrants had the quadrants assigned at random to LED light from first assessment until scaling and root planing was complete, LED light from the end of cleaning until re-evaluation, or no light. Clinical measures were taken before and at re-evaluation, and 2 inflammatory markers in gum fluid at 3 points. Every site showed significantly reduced pocket depth, attachment loss, gum bleeding, plaque, and pain by re-evaluation, and in the sites with the deepest pockets and worst attachment both LED schedules cut pocket depth and attachment loss more than no light, the researchers reported. 1 tissue-breakdown marker fell most with light given during cleaning, and LED light was judged a useful add-on, particularly for sites with severe breakdown.

According to a 2020 systematic review and meta-analysis from Tokyo Medical and Dental University in Japan, lasers added to conventional periodontal treatment reduced the pain patients reported afterward. 3 databases were searched for randomized controlled trials up to June 2020, and 10 trials of 13 to 40 patients each were included, 6 on periodontal surgery and 4 on non-surgical pocket treatment. 5 trials used high-power lasers in place of or alongside instruments, 4 used photobiomodulation therapy (PBMT) with diode lasers between 588 and 970 nm, and 1 used both. Pooled results showed that high-power erbium lasers significantly reduced pain immediately after treatment, while PBMT with diode lasers significantly reduced pain 2 to 7 days after surgery. Every trial had weaknesses in blinding, and the authors concluded that the evidence remains insufficient and that more well-designed trials are needed.

2020 brought a single-blind split-mouth randomized controlled trial from an oral health center in Gaziantep, Turkey, on photobiomodulation therapy (PBMT) added to non-surgical periodontal treatment in people with type 2 diabetes and chronic periodontitis. 22 patients, 12 women and 10 men averaging 45 years, had 1 quadrant chosen at random for PBMT plus the deep cleaning and the other for the cleaning alone with a placebo application. The laser was given on the day of treatment and on days 1, 3, and 7 at 7.64 J/cm², with pocket depth, gum inflammation, plaque, and gum attachment measured at baseline and at 1, 3, and 6 months. According to the results, pocket depth fell significantly more on the laser side at every check, gum attachment gained significantly more at 6 months, and gum fluid volume was lower on the laser side throughout, while plaque did not differ. Recovery was uneventful in every patient with no side effects from the laser, so PBMT appeared to add lasting pocket gains for diabetics with gum disease.

In 2018, a prospective randomized controlled trial at the University of Niš in Serbia tested low-level laser therapy (LLLT) as an add-on to periodontal treatment in chronic periodontitis, looking at bacteria, cell changes, and clinical signs together. 60 patients were assigned at random to scaling and root planing alone, the deep cleaning of the roots used to treat gum disease, or to SRP plus LLLT, 30 in each group, with all receiving hygiene instruction and full-mouth treatment first. The laser group then had a 980 nm laser at 0.2 W and 6 J/cm² in 5 sessions, with clinical measures taken before treatment, after the fifth session, and a month later. The trial found better clinical results in the laser group and a significant fall in the prevalence of 5 gum disease bacteria after treatment, including Porphyromonas gingivalis and Treponema denticola. Measures of cell nucleus size in the gum fell in both groups but more strongly with the laser, and the authors concluded that LLLT gives short-term additional bacteriological, cellular, and clinical benefits in gum disease.

When 33 furcation defects, the bone loss between the roots of molars that gum disease causes, were treated in 25 patients, a 2016 randomized controlled trial in Erzurum, Turkey, compared guided tissue regeneration alone against the same surgery plus low-level laser therapy (LLLT). Guided tissue regeneration places a membrane over the defect so bone can regrow; 17 defects received it with a 1064 nm Nd:YAG laser, while 16 received it alone. Pocket depth, gum attachment, horizontal probing depth, and 2 bone-formation markers in the gum crevice fluid were recorded at baseline and at 3 and 6 months. Healing was uneventful in every case, and both groups improved on all clinical measures from baseline. At 6 months, the laser group had improved significantly more in pocket depth, gum attachment, horizontal depth, and 1 bone marker, and the trial concluded that LLLT plus regeneration may be the more effective treatment for these gum disease defects.

90 people took part in a 2016 clinical trial at SRM Dental College in Chennai, India, on low-level laser therapy (LLLT) added to root surface debridement for chronic periodontitis, 30 of them with healthy gums for comparison and 60 with the disease. The trial's main interest was periostin, a protein of the ligament and bone around the tooth that is reduced in gum disease. The 60 patients were assigned at random to debridement alone or debridement plus an 810 nm diode laser at 0.7 W, applied once a week for 6 weeks along the gum margin, with clinical measures and periostin in the gum crevice fluid assessed at baseline and 3 months. Periostin was significantly lower in the patients with gum disease than in the healthy group at the start, and rose significantly in both treated groups by 3 months, more so with the laser. Pocket depth, gum attachment, and gum bleeding also improved significantly more with the laser, and the authors suggested periostin may serve as a marker of how well non-surgical treatment of gum disease has worked.

Among 25 non-smoking adults with chronic periodontitis and pockets of 5 to 7 mm on both sides, a 2016 single-blind split-mouth randomized controlled trial at the University of Gaziantep in Turkey tested low-level laser therapy (LLLT) as an add-on to non-surgical treatment. After the deep cleaning, 1 side of the mouth received a 980 nm diode laser at 400 mW for 15 seconds per tooth in 4 sessions over the first week, at 7.64 J/cm². Pocket depth, gum inflammation, plaque, gum attachment, and gum bleeding were recorded at baseline and at 1, 3, and 6 months, and gum crevice fluid was analyzed for 27 signaling proteins. The trial found pocket depth significantly lower on the laser side at 1 month, and pocket depth, gum attachment, and gum inflammation all significantly better on the laser side at 3 and 6 months, with plaque no different. The signaling proteins did not differ between sides at any time, and no side effects of the laser were reported.

80% of sampled pockets carried Porphyromonas gingivalis, a key gum disease bacterium, before treatment and 20% after laser irradiation in a 2016 randomized controlled trial at King Saud University in Riyadh, Saudi Arabia. 32 patients aged 35 to 60 with chronic periodontitis were assigned at random to scaling and root planing alone, the deep cleaning of the roots used to treat gum disease, or SRP plus a 685 nm diode laser in the pockets at 1.6 J/cm². 30 completed the study: 19 women and 11 men, with plaque samples tested for the bacterium and clinical measures recorded before and 2 months after treatment. Gum inflammation, pocket depth, gum attachment, and gum bleeding improved significantly more with the laser than with SRP alone, while plaque did not differ. The fall from 80% to 20% of pocket sites positive for the bacterium was significant, with no significant change in the SRP group.

Gum inflammation fell 69.3% when low-level laser therapy (LLLT) followed scaling and root planing, against 45.4% with the cleaning alone, according to a 2015 randomized controlled trial at Magna Graecia University in Catanzaro, Italy. 40 patients with periodontal disease were assigned at random to scaling and root planing, the deep cleaning of the roots used to treat gum disease, with or without a 940 nm laser, 20 in each group. Gum measures were taken before and 5 months after treatment, and blood thickness and 3 measures of the carotid artery wall in the neck were taken before, soon after, and at 5 months. In the laser group, the shear stress on the carotid wall, a measure of blood flow along the artery, dipped 5% right after treatment and then rose 11% by 5 months.

Researchers in Bhilai, India, compared modified Widman flap surgery, an operation that opens the gum to clean the roots in gum disease, with and without an 810 nm diode laser in a 2015 randomized controlled trial. 25 patients aged 20 to 50 with generalized chronic periodontitis had 1 side of the mouth chosen by coin flip for surgery alone and the other for surgery plus low-level laser therapy at 4 J/cm² on the gum surface. Plaque, gum bleeding, pocket depth, and gum attachment were recorded at baseline and at 6 and 9 months. Researchers found that bleeding was significantly lower on the laser side at 6 months but not at 9 months, while pocket depth fell more on the laser side by 9 months and attachment gains were greater at 6 and 9 months. Plaque did not differ, and the 810 nm laser was judged to add clinical benefit to the flap surgery.

Whether daily light therapy from a toothbrush adds to professional cleaning in chronic periodontitis was the question a 2014 randomized single-blind controlled trial at Ewha Womans University Mokdong Hospital in Seoul, Korea, set out to answer. 41 patients with mild to moderate chronic periodontitis were divided at random into 2 equal groups after full-mouth scaling and root planing, the deep cleaning of the roots used to treat gum disease. 1 group also used an electric toothbrush with built-in 635 nm light-emitting diodes 3 times a day for a month. Pocket depth and gum attachment improved significantly more in the light group than with cleaning alone, the researchers reported, while 2 major gum disease bacteria fell in that group without a significant difference between groups at the 4-week check. Daily phototherapy seems to bring clinical benefit, but the evidence for an antibacterial effect is not sufficient.

In 2014, a split-mouth randomized controlled trial at Atatürk University in Erzurum, Turkey, tested low-level laser therapy (LLLT) alongside guided tissue regeneration, a surgical repair of bone lost to gum disease using a horse-derived bone graft and a membrane. 13 periodontitis patients with bone defects on both sides of the mouth had 1 defect treated with the graft and membrane plus a 1064 nm laser at 100 mW and 4 J/cm² during and after surgery, and the other with the graft and membrane alone. Pocket depth, gum attachment, gum recession, plaque, and gum bleeding were recorded at surgery and at 3 and 6 months. Both treatments appeared to reduce pocket depth, gain attachment, and lower bleeding significantly by 6 months. The laser-treated defects showed less gum recession, less bleeding, more pocket reduction, and more attachment gain than the graft alone at 6 months, suggesting LLLT may improve the results of regenerative surgery for gum disease defects.

Researchers in periodontology in Turkey tested a diode laser as an add-on to scaling and root planing, the deep cleaning of the roots used to treat gum disease, in a 2014 parallel-group randomized controlled trial in chronic periodontitis. 30 patients were assigned at random to SRP alone or SRP followed by a 940 nm diode laser at 1.5 W, applied to the pockets of the upper front teeth for 20 seconds. Plaque, gum inflammation, gum bleeding, pocket depth, and gum attachment were measured at baseline and at 1, 3, and 6 months, and gum crevice fluid was analyzed for inflammatory signals and tissue-breakdown enzymes. The laser group appeared to do significantly better than the control group on the full-mouth clinical measures. 1 enzyme, MMP-8, was significantly affected by the laser at the first month, which the authors took as a clue to how lasers might enhance non-surgical treatment of gum disease.

200 of the 300 patients in a 2012 clinical trial at the University of Niš in Serbia had diabetes alongside periodontitis, 100 with type 1 and 100 with type 2, and the remaining 100 had periodontitis alone for comparison. After gum smears were taken, all received hygiene instruction and full-mouth scaling and root planing, the deep cleaning of the roots used to treat gum disease. In a split-mouth design the right side of the jaws was then treated with a 670 nm gallium-aluminum-arsenide laser at 5 mW for 14 minutes a day for 5 consecutive days, and smears from both sides were analyzed for cell changes afterward. The measured cell parameters were significantly lower after treatment than before, and on the laser-treated side there was no longer a significant difference between the diabetic patients and the comparison group. The authors concluded that low-level laser therapy as an add-on to periodontal treatment reduces gum inflammation in people with diabetes and gum disease.

22 patients with 27 teeth that had erupted through loose cheek-side tissue with no firm, keratinized gum around them took part in a 2012 observational study at the University of Milano-Bicocca in Italy. Each was treated with self-ligating braces, and at every orthodontic visit the teeth received biostimulation from a 980 nm diode laser at 1 W, according to the protocol columns for 2.5 minutes per session over 180 days. At the end of treatment, the 27 teeth were assessed for the quality and amount of attached gum, with gum bleeding and attachment loss also checked. Every tooth appeared to have gained a band of attached gum around its crown by the time the braces came off, averaging 3.10 mm and growing about 0.49 mm a month. The authors suggested that braces combined with laser biostimulation may help the cells of the tooth's supporting ligament turn into the fibroblasts that build firm gum, protecting teeth that would otherwise sit in loose tissue prone to gum disease.

Published in 2011, this clinical trial from the University of Niš in Serbia tested low-level laser therapy (LLLT) as an add-on for gum inflammation in people with diabetes and periodontal disease. 150 participants were split into 3 groups: 50 with type 1 diabetes, 50 with type 2 diabetes, and the rest with no diabetes; all had plaque and tartar removed and their periodontal pockets cleaned. A 670 nm gallium-aluminum-arsenide laser at 5 mW was then applied to 1 side of the jaw for 5 consecutive days, with the other side left untreated for comparison. Gum inflammation scores and the size of gum cell nuclei fell significantly on both sides, but after the first, third, and fifth sessions, inflammation appeared lower on the laser side. LLLT was efficient at clearing gum inflammation and may serve as an add-on in basic periodontal treatment for diabetics.

60 people with advanced chronic periodontitis took part in a 2009 randomized controlled trial, reported from Loma Linda University in the United States, of low-level laser treatment combined with scaling and root planing (SRP), the deep cleaning of the roots used to treat gum disease. They were assigned at random to 3 groups of 20: SRP alone, given 1 quarter of the mouth per day over 5 days, or the same SRP followed by a 630 to 670 nm diode laser for 5 days or for 10 days. Plaque, gum inflammation, and gum bleeding were recorded throughout. The trial found significant improvement from baseline on every measure in all 3 groups, and both laser groups improved significantly more than SRP alone. These findings suggest that a low-level diode laser can help in treating inflammatory advanced chronic gum disease.

A 2009 randomized controlled trial at a private periodontal clinic in Piraeus, Greece, compared scaling and root planing (SRP), the deep cleaning of the roots used to treat gum disease, with a diode laser alone and with the two combined in aggressive periodontitis. 30 patients had 1 quadrant of the mouth assigned at random to each of SRP alone, SRP plus laser, laser alone, and no treatment, with a 980 nm diode laser run in continuous mode at 2 W. Plaque samples were tested for gum disease bacteria at 2 weeks, 12 weeks, and 6 months, alongside pocket depth, gum attachment, plaque, and gum bleeding. The trial found that bacteria fell with all 3 treatments, but the SRP plus laser quadrants had significantly fewer bacteria at 6 months than either treatment alone, with better pocket depth and gum attachment too. Plaque and gum bleeding did not differ, and the authors concluded that laser-assisted SRP was superior to SRP or laser alone on several measures of aggressive gum disease.

Researchers in 2008 compared low-intensity laser light in pulsed and continuous modes, and in the red and infrared parts of the spectrum, for its effect on blood flow in the gums during full treatment of mild to moderate chronic periodontitis. The observational study measured microcirculation indices in gum tissue under each combination of wavelength band (620 to 780 nm for red and 780 to 1400 nm for infrared) and mode of operation. The aim was to determine which light characteristics matter most for the small blood vessels of the gum. Pulsed laser light in the red part of the spectrum appeared to have a predominantly activating effect on gum microcirculation.

Comparing a helium-neon laser with a diode laser of nearly the same wavelength, a 2007 pilot randomized controlled trial at the Karolinska Institutet in Sweden tested whether coherence length, a property of laser light, matters in laser phototherapy. 20 patients with moderate periodontitis had scaling and root planing, the deep cleaning of the roots used to treat gum disease. 1 side of the upper jaw was then assigned at random to a 632.8 nm helium-neon laser and the other to a 650 nm diode laser, both at 3 mW. According to the trial, all clinical measures improved on both sides, but inflammation fell more clearly after helium-neon treatment, with pocket depth going from 4.6 to 3.5 mm on that side against 4.3 to 4.2 mm on the diode side. Treatment ran once a week for 6 weeks, and 1 tissue-breakdown enzyme was also considerably reduced on the helium-neon side, so coherence length appeared to be an important factor.

A 2005 split-mouth, double-blind randomized controlled trial at the Karolinska Institutet in Sweden studied low-level lasers as an add-on treatment for inflamed gums in moderate periodontitis. 17 patients had all teeth scaled and root planed, the deep cleaning of the roots used to treat gum disease, and 2 weeks later began laser treatment once a week for 6 weeks. 1 side of the upper jaw was treated with 2 lasers at 635 and 830 nm, and the other with a placebo, with gum fluid and plaque sampled before and after for inflammatory markers and 12 bacteria. The trial found pocket depth, plaque, and gum inflammation reduced more on the laser side than on the placebo side, and gum fluid volume fell more there as well. 1 tissue-breakdown enzyme rose on the placebo side but was slightly lower on the laser side, while the other markers and the bacteria showed no significant difference, so the added lasers reduced gum inflammation.

This 2024 review from JSS Dental College in Mysuru, India, traced the history of laser use in medicine from 1960 to low-level laser therapy (LLLT), also called photobiomodulation (PBM), and weighed its place in periodontal care. The review examined how PBM acts on cells and tissues, then gathered the evidence-based recommendations for using it alongside conventional gum disease treatment. According to the review, PBM shows potential to improve periodontal conditions, especially as an adjunct to standard care, and may also support regenerative procedures, speed soft tissue wound healing, reduce periodontal inflammation, and ease discomfort after gum surgery. Whether it can improve gum health in people with other diseases or on long-term medication was left as an open question for future work. The authors called for research to streamline laser procedures, develop antimicrobial photodynamic therapy, run well-designed randomized controlled trials, and secure adequate funding, leaving the laser's effectiveness in gum disease treatment still to be settled.

Whether low-level laser therapy (LLLT) changes the level of interleukin-37, an anti-inflammatory signal thought to help control periodontal inflammation, was the question a 2024 clinical trial at the University of Foggia in Italy set out to answer in chronic periodontitis. 30 patients were treated with scaling and root planing alone, the deep cleaning of the roots used to treat gum disease, or with SRP plus LLLT from a diode laser in the 600 to 1000 nm range at 0.04 to 60 J/cm². Pocket depth and gum bleeding were recorded before treatment, and plaque and gum crevice fluid were sampled before treatment and at 10, 30, and 60 days. Pocket depth, gum bleeding, and interleukin-37 all appeared to improve with healing in every patient. Although LLLT is widely recommended for its stimulating and anti-inflammatory effects, it showed additional short-term merit only in reducing pocket depth after SRP, and its long-term value in gum disease remains unclear.

Doses, wavelengths, and session counts varied so widely across 17 randomized controlled trials that a 2021 systematic review from the University of Genoa in Italy could not pool them, and instead appraised each in turn. The review gathered human trials of photobiomodulation therapy (PBMT) as an add-on to non-surgical periodontal therapy for periodontitis, judging them on pocket depth, gum attachment, gum bleeding, plaque, and gum inflammation, as well as bacterial and immune measures. According to the review, current evidence lacks adequate information on light dosing, which is fundamental to a standard, repeatable protocol. Substantial differences in study methods and a high risk of bias in most included papers further lowered the quality of the evidence. The review concluded that well-designed trials are still needed to determine whether PBMT is effective once those confounding factors are accounted for.

According to a 2020 randomized controlled trial from King Saud University in Riyadh, Saudi Arabia, photobiomodulation therapy (PBMT) added to scaling and root planing (SRP) improved the surface signs of gum disease in people who chew gutka, a smokeless tobacco. 64 self-reported gutka users had SRP with or without a 940 nm laser at 300 mW, with plaque, gum bleeding, pocket depth, attachment loss, jawbone loss, and missing teeth recorded before treatment and at 3 and 6 months. The trial found plaque, bleeding, and pocket depth significantly lower at 3 and 6 months than at baseline in the laser group, and higher in the control group than the laser group at both follow-ups. Attachment loss and bone loss did not differ between the groups at 3 or 6 months. The laser therefore appeared to help clear surface inflammation without changing the underlying loss of support.

68.43% was the fall in a pain-and-inflammation messenger in gum fluid 3 days after photobiomodulation (PBM)-aided cleaning, compared with 47.68% with cleaning alone, in a 2020 split-mouth randomized controlled trial from Genoa, Italy. 20 non-smoking patients with chronic periodontitis had 1 premolar site with a pocket over 5 mm treated with scaling and root planing (SRP), the deep cleaning of the roots, and a matching site with SRP plus a 645 nm diode laser. 20 people without gum disease served as a comparison group, and 3 healing-related messengers in gum fluid were tracked along with pocket depth, gum inflammation, and gum bleeding. The trial found that a blood-vessel growth signal fell more with PBM by day 7, and a tissue-repair signal rose slightly more by day 21. Clinical measures improved significantly in both groups, pocket depth from 5.6 to 4.5 mm on average, with no significant difference between them.

19 patients with type 2 diabetes who had 1 periodontal pocket treated with photobiomodulation (PBM) and 1 with cleaning alone showed no difference in mean pocket depth or gum attachment at 12 months, in a 2019 randomized controlled trial in São Paulo State, Brazil. 38 pockets of at least 5 mm, 2 per patient, were assigned at random to debridement alone or debridement plus a 660 nm laser at 30 mW, with pocket depth, attachment, bleeding, and plaque compared at baseline and at 3, 6, and 12 months. According to the results, the share of moderate pockets of 5 to 6 mm was significantly lower with PBM at 6 months. Pockets of 7 mm or more improved significantly from baseline at every check with PBM, but only at 6 months with cleaning alone. So the laser added nothing to mean pocket depth or attachment, but was more effective at reducing moderate pockets at 6 months in people with type 2 diabetes.

3 of 4 clinical studies showed significantly better periodontal outcomes when low-level laser therapy (LLLT) was added to scaling and root planing, the deep cleaning of the roots used to treat gum disease, according to a 2018 systematic review from Riyadh, Saudi Arabia. 3 databases were searched through March 2018 for trials of LLLT plus SRP against SRP alone, and 4 studies of 13 to 31 patients each, all using diode lasers between 810 and 980 nm, were included. Pooled, the gain in gum attachment with the laser was not significant, while the reduction in pocket depth was. The fourth study found the 2 approaches comparable. According to the review, whether LLLT adds to SRP in aggressive gum disease remains debatable, and randomized trials with longer follow-up and standard laser settings are needed.

Across 7 randomized controlled trials in 8 publications, a 2017 meta-analysis from the University of Hong Kong weighed whether low-level laser therapy (LLLT) adds anything to scaling and root planing (SRP), the deep cleaning of the roots used to treat gum disease. 3 databases were searched to August 2015 and 354 records screened, with 6 of the 8 included papers rated at high risk of bias for weak allocation concealment and blinding. The analysis found significant short-term benefits from laser-aided SRP over SRP alone, in pocket depth at 1 and 2 months and in an inflammatory marker in gum fluid at 1 month. No significant additional effect remained at 3 and 6 months for clinical measures or jawbone density. LLLT therefore offers only short-term extra benefit after conventional SRP, the authors concluded, with its longer-term effects unclear until better-designed trials with longer follow-up are run.

Deep pockets alone appeared to benefit, and only for a month, when low-level laser therapy (LLLT) was added to non-surgical periodontal treatment in people with type 2 diabetes, according to a 2017 split-mouth randomized controlled trial at Istanbul University in Turkey. 22 patients with chronic periodontitis and type 2 diabetes had 2 quadrants treated with scaling and root planing, the deep cleaning of the roots, and the other 2 with SRP plus an 808 nm diode laser at 4.46 J/cm². The laser sites showed significant improvement in plaque and gum bleeding in deep pockets at the 1-month check. No other periodontal measure differed between the laser and control sites. The authors concluded that LLLT during periodontal treatment offered minimal short-term additional benefit in deep pocket healing for diabetics with gum disease.

Comparing quadrants treated with scaling and root planing (SRP), the deep cleaning of the roots used to treat gum disease, against quadrants that also had a 980 nm diode laser, a 2013 split-mouth randomized controlled trial in Zagreb, Croatia, tested the laser in chronic periodontitis. 35 patients had 2 quadrants deep cleaned and the other 2 deep cleaned and then irradiated in the periodontal pockets on days 1, 3, and 7 after SRP, at 2 W. Plaque, gum bleeding, pocket depth, and gum attachment were recorded at baseline and at 6 and 18 weeks, with pockets analyzed separately as moderate, 4 to 6 mm, or deep, 7 to 10 mm. The 2 sides were similar in plaque, bleeding, attachment, and deep pocket depth. Only moderate pockets gained significantly more depth reduction on the laser side by 18 weeks, so repeated laser applications with SRP improved gum disease pockets of 4 to 6 mm and nothing else, the authors reported.

A single session versus 5 sessions over 2 weeks was the comparison in a 2013 randomized controlled trial at the Complutense University of Madrid in Spain of laser phototherapy added to scaling and root planing for chronic periodontitis. Researchers divided 27 patients into 3 groups of 9: SRP alone, SRP plus 1 laser session, and SRP plus 5 sessions over 11 days, using a 670 nm diode laser at 200 mW applied into the gum crevice for 60 seconds per tooth. Plaque, gum bleeding, pocket depth, and gum attachment were recorded, and gum crevice fluid was sampled at baseline, 4 weeks, and 8 weeks for inflammatory and bone-turnover signals. The trial found no significant change in the clinical measures with either laser schedule. Interleukin-1β fell significantly with both schedules, while only the 5-session group also lowered tumor necrosis factor and the bone-loss ratio at 4 weeks, suggesting repeated sessions calmed gum disease inflammation faster and more fully.

A split-mouth, double-blind design, with each patient's mouth divided between treated and untreated quadrants, was used in a 2012 randomized controlled trial at a laser institute in Cairo, Egypt, on low-level laser therapy (LLLT) added to scaling and root planing for chronic periodontitis. 16 patients with pockets of 4 to 6 mm in every quadrant had all quadrants deep cleaned, and those chosen at random then received 10 sessions of an 830 nm laser at 100 mW, 3 J per point, and 3 J/cm². Sites treated with SRP plus LLLT appeared to have greater reductions in pocket depth at 5 weeks and 3 months than sites with SRP alone, but not at 6 months. Bone density on radiographs rose significantly at the laser sites between 6 and 12 months and over the whole year. The inflammatory signal interleukin-1β tended to fall with the laser without reaching significance, and neither gum inflammation nor plaque changed, so the added benefit in gum disease was short-lived for pockets and lasting for bone.

When infrared laser light was added to standard treatment for mild to moderate chronic periodontal disease in a 2011 clinical trial, a marker of bone breakdown in the gums fell 6.7-fold from its pre-treatment level. 36 patients were divided into 2 groups of 18, 1 receiving conventional periodontal treatment alone and the other receiving the same plus phototherapy with an infrared laser in the 780 to 1400 nm range, while 10 people free of gum disease served as a comparison group. Treatment was judged by a panel of immune messengers in the gum tissue that rise with inflammation or govern bone loss. Before treatment, the gum disease patients showed raised inflammation messengers and a lower bone-protective factor than the healthy group. The trial found that 2 inflammation messengers fell in both treated groups while a third did not change, and only the laser group showed the dramatic drop in the bone breakdown marker.

Among 36 patients with moderate to advanced chronic periodontitis, a 2011 randomized controlled trial at Istanbul University in Turkey tested low-level laser therapy (LLLT) as an add-on to non-surgical periodontal treatment. All 36 had the standard treatment, and 18 also received an 808 nm diode laser at 4 J/cm² on the gum surface on days 1, 2, and 7 afterward, with each group divided into smokers and non-smokers. Gum fluid was sampled and clinical measures recorded at baseline and at 1, 3, and 6 months, with 4 healing and tissue-breakdown markers measured. According to the results, the laser group showed significantly more improvement in gum bleeding, gum attachment, and pocket depth at every check, and laser-treated smokers improved more than untreated smokers in pocket depth and bleeding. The markers changed similarly in both groups, and the authors concluded that LLLT alongside non-surgical treatment improves periodontal healing in gum disease.

A split-mouth design gave each of 24 nonsmoking adults with untreated chronic periodontitis both treatments in a 2011 randomized controlled trial at the University of Hong Kong, China. 1 side had scaling and root debridement, the deep cleaning of the roots used to treat gum disease, and the other had the same cleaning plus 1 course of photodynamic therapy, a light-activated dye that kills bacteria, with low-level laser therapy (LLLT) within 5 days. Plaque, gum bleeding, pocket depth, and gum recession were recorded at baseline and at 1 and 3 months, with gum fluid collected for an inflammatory marker at baseline, 1 week, and 1 month. Bleeding sites and mean pocket depth fell more on the laser-treated teeth at 1 month, and gum fluid volume and the inflammatory marker also dropped further there, the researchers reported, but by 3 months no significant differences remained. The combined course could be a useful short-term add-on to non-surgical treatment of chronic gum disease, with longer studies still needed.

A 2022 randomized controlled trial at Rio Grande do Norte Federal University in Natal, Brazil, tested laser light shone through the skin onto the blood, a technique called modified intravascular laser irradiation of blood (ILIB), in people with periodontitis and type 2 diabetes. 21 patients were divided into a control group given conventional periodontal therapy and a test group given the same therapy plus 10 applications of a 660 nm laser at 100 mW by the modified ILIB technique. Fasting blood sugar, long-term blood sugar, visible plaque, gum bleeding, and periodontal clinical measures were evaluated at baseline and after 4 months. Plaque, bleeding, pocket depth, and gum attachment all improved significantly within each group over the 4 months, but the laser group appeared no better than the control group on any of them. Neither blood sugar measure changed significantly in either group, and the modified ILIB did not improve periodontal measures or blood sugar control in people with type 2 diabetes.

A 2021 double-blind randomized controlled trial at the University of Freiburg in Germany tested visible light plus water-filtered infrared-A (VIS + wIRA), a lamp treatment rather than a laser, added to subgingival instrumentation (the cleaning below the gum line) in 40 patients with untreated periodontitis. 1 quadrant of the upper jaw was assigned at random to 4 sessions of 20 minutes of the light within 2 weeks on top of the cleaning, and the opposite quadrant to cleaning alone. Pocket depth, gum attachment, gum bleeding, tooth mobility, and plaque were re-evaluated at 3 and 6 months, patients rated discomfort on each side on a 1 to 10 scale, and no adverse events were recorded. The authors concluded that the light gave no significant additional healing over instrumentation alone at either check, though patients reported less pain on the irradiated side.

Blood flow in the gum and the gum's sensitivity to touch, heat, and cold were the measures a 2020 randomized controlled trial in Nanjing, China, used to test laser therapy added to scaling and root planing (SRP), the deep cleaning of the roots. In a single visit, 24 patients with periodontitis were randomly assigned one side of the mouth to SRP plus a 1064 nm laser and the other to SRP alone. Pocket depth and bleeding improved significantly after treatment, blood flow readings fell on both sides at every check, and sensitivity fell for every measure except warmth detection. Gum temperature rose only on the laser side. The authors concluded that the added laser gave no significant clinical advantage and no extra effect on the recovery of gum sensation or blood flow.

Researchers in Turkey asked whether a diode laser, known for killing bacteria in periodontal treatment, adds anything against the 3 main gum disease bacteria in people with type 2 diabetes, in a 2020 single-blind parallel-group randomized controlled trial. 60 patients aged 35 to 60 with chronic periodontitis and diabetes were assigned at random to scaling and root planing, the deep cleaning of the roots, or to SRP plus pocket irradiation with a 940 nm diode laser at 1.5 W. Plaque from the 3 deepest pockets was tested for Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia at baseline and at 1 and 3 months. All 3 bacteria fell significantly at 1 and 3 months with both treatments. The conclusion drawn was that the laser gave no additional benefit in reducing these bacteria in diabetics with gum disease, and that its effect on other periodontal bacteria remains to be clarified.

2017 brought a split-mouth randomized controlled trial at Yeditepe University in Istanbul, Turkey, on low-level laser therapy (LLLT) added to scaling and root planing (SRP), the deep cleaning of the roots used to treat gum disease, in smokers and non-smokers with chronic periodontitis. 30 patients, 15 smokers and 15 non-smokers, had SRP with a 940 nm laser at 300 mW on 1 side of the mouth and a sham on the other, on the day of cleaning and on days 2 and 7. 30 healthy people served as controls, with clinical measures recorded at baseline and day 30 and gum fluid sampled for 3 proteins involved in healing. Every clinical measure improved significantly by day 30 with SRP, but the laser side appeared no better than the sham side in smokers or non-smokers. The proteins did not differ between sides either, though both laser groups showed a falling ratio of 2 of them over time, so LLLT may modulate tissue repair, particularly in smokers.

No added clinical benefit was observed with a low-power helium-neon laser in a 2009 pilot randomized controlled trial at the University of Hong Kong on moderate to advanced chronic periodontitis. 16 patients with pockets of 5 mm or more on both sides of the mouth had non-surgical periodontal treatment, after which test sites chosen at random were irradiated at 0.2 mW for 10 minutes, 8 times over 3 months, and control sites were left untreated. Plaque, gum bleeding, pocket depth, and gum attachment were recorded for 12 months, with gum fluid samples and radiographs at 6 time points. Plaque fell from 83% to 16% and gum bleeding from 95% to 34% over the year, and pockets, attachment, and gum fluid improved significantly at both test and control sites. The conclusion drawn was that no measure differed between laser and control sites, so the helium-neon laser did not seem to add to the treatment of gum disease.

No significant difference between the laser-treated and untreated sides of the mouth followed low-intensity laser use during scaling and root planing in a 2008 randomized controlled trial at the University of São Paulo in Bauru, Brazil. 10 patients had 6 sites on each of 4 teeth per half-jaw measured, 960 sites in all, before every tooth received scaling and root planing, the deep cleaning of the roots used to treat gum disease. On the test side, a 780 nm laser at 70 mW was applied for 20 seconds per site for pain relief before and during cleaning, and a 630 nm laser at 35 mW for 10 seconds for healing, repeated at 24 and 48 hours. Pocket depth, gum attachment, gum inflammation, and pain during the procedure were assessed, with a final check at 3 days. Gum inflammation fell on both sides, and the authors concluded that the diode laser, as an aid to deep cleaning, gave no apparent clinical benefit for teeth with shallow to moderate pockets.

Rinsing the gums with methylene blue dye before applying a soft laser, a 2002 randomized controlled trial in Turkey, tested whether the combination added anything to mechanical cleaning in periodontal disease. 10 patients had each quarter of the mouth assigned at random to 1 of 4 treatments: scaling and root planing (SRP), a 685 nm laser alone, SRP plus laser, or oral hygiene instruction only. 1 tooth per quarter with a 4 mm pocket was tracked for the share of oxygen-avoiding bacteria and for plaque, gum inflammation, gum bleeding, and pocket depth over 32 days. Only the SRP and SRP plus laser groups appeared to reduce the bacteria significantly, with no difference between them, and both gave similar clinical improvement. The laser alone had a limited effect similar to hygiene instruction, and within the study's limits the dye-and-laser treatment gave no extra microbiological or clinical benefit.