1. Overview of included studies.
| Studies | Countries | Study designs | Sample sizes | Age ranges | Experimental groups | Control groups | Outcome assessment | Outcome time pointsa | Notes |
| Alencar 2020 | Brazil | RCT (Patient as unit) | 32 patients with 83 teeth | 18 to 50 years | 1. Diode laser 2. Diode laser + nHAP toothpaste |
Placebo (Placebo laser + nHAP‐free toothpaste) | Tactile + evaporative | ‐ Baseline ‐ After the 1st session (short term) ‐ After the 2nd session (medium term) ‐ 1 month after the 2nd session (medium term) |
The treatments were performed in 2 sessions with a 24‐hour interval |
| Bal 2015 | Turkey | RCT (Split‐mouth design) | 21 patients with 156 teeth | 19 to 60 years (Mean 37 years) | Diode laser (685 nm) | Placebo (Saline) | Air blast | ‐ Baseline ‐ Immediate (short term) ‐ 10 days (medium term) ‐ 30 days (medium term) ‐ 60 days (medium term) ‐ 90 days (long term) |
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| Doshi 2014 | India | RCT (Split‐mouth design) | 30 patients with 60 teeth | 23 to 56 years | Diode laser (660 nm) | Placebo laser | Air blast | ‐ Baseline ‐ Day 1 (short term) ‐ Day 3 (medium term) ‐ Day 5 (medium term) ‐ Day 7 (medium term) |
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| Flecha 2013 | Italy | RCT (Split‐mouth design) | 62 patients with 434 teeth | 12 to 60 years | Diode laser (795 nm) | Cyanoacrylate (Toothpaste) | Air blast | ‐ Baseline ‐ 1 day (short term) ‐ 1 month (medium term) ‐ 3 months (long term) ‐ 6 months (long term) |
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| García 2017 | Spain | RCT (Split‐mouth design) | 30 patients with 120 teeth | 19 to 67 years | Diode laser (660 nm) | Placebo laser | 1. Tactile 2. Thermal (air jet from the syringe, isolating adjacent teeth) |
‐ Baseline ‐ Immediately after treatment (short term) ‐ 2 weeks (medium term) ‐ 1 month (medium term) ‐ 2 months (medium term) |
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| Gentile 2004 | Brazil | RCT (Patient as unit) | 32 patients with 68 teeth | 20 to 52 years | Diode laser (670 nm) | Placebo laser | 1. Tactile 2. Air blast |
‐ Baseline ‐ 6 to 8 weeks (medium term) |
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| Gerschman 1994 | Australia | RCT (Patient as unit) | 71 patients | 15 to 69 years (Mean 37.5 years) | 1. Diode laser (830 nm) | Placebo laser | 1. Tactile 2. Air blast |
‐Baseline ‐ 1 week (medium term) ‐ 2 weeks (medium term) ‐ 8 weeks (medium term) |
Participants of experimental intervention group (GaAlAs laser) were re‐assigned into subgroups according to the measurements (tactile and air blast) respectively |
| Lee 2015 | South Korea | RCT (Patient as unit) | 82 patients | 20 to 65 years | Er,Cr:YSGG laser | Strontium chloride (SC) toothpaste | 1. Tactile 2. Air blast |
‐ Baseline ‐ 1 week (medium term) ‐ 2 weeks (medium term) ‐ 1 month (medium term) |
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| Lier 2002 | Norway | RCT (Split‐mouth design) | 17 patients with 34 teeth | 26 to 66 years | Nd:YAG laser | Placebo laser | Air blast | ‐ Baseline ‐ Immediate (short term) ‐ 1 week (medium term) ‐ 4 weeks (medium term) ‐ 16 weeks (long term) |
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| Lizarelli 2007 | Brazil | RCT (Split‐mouth design) | 60 patients with144 teeth | Minimum 18 years | 1. Diode laser (780 nm and 660 nm) 2. Diode laser (630nm) |
Placebo | 1. Cold and heat 2. Air blast |
‐ After 1sttreatment ‐ After 2nd treatment ‐ After 3rd treatment ‐ 15 days ‐ 30 days ‐ 60 days |
3 irradiation procedures at 7‐day intervals and 3 follow‐up sessions at 15, 30, and 60 days after the last application were carried out |
| Lund 2013 | Brazil | RCT (Split‐mouth design) | 13 patients with 117 teeth | 19 to 58 years (Mean 35.75 ±15.05 years) | Diode laser (780 nm) | Placebo (Carbomer gel) | Air blast | ‐ Baseline ‐ 5 minutes (short term) ‐ 1 week (medium term) ‐ 2 weeks (medium term) ‐ 1 month (medium term) ‐ 3 months (long term) |
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| Maximiano 2019 | Brazil | RCT | 70 patients | 18 to 65 years | Nd:YAG laser | 1. Placebo laser 2. CSP paste |
1. Air blast 2. Tactile stimuli |
‐ Baseline ‐ 5 minutes (short term) ‐ 1 week (medium term) ‐ 4 weeks (medium term) |
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| Naghsh 2020 | Iran | RCT (Patient as unit) | 7 patients with 96 teeth | 25 to 45 years | 1. Diode laser (660 nm) 2. Diode laser (810 nm) |
Placebo laser | Tactile | ‐ Baseline ‐ Immediate (short term) ‐ 1 week (medium term) ‐ 30 days (medium term) ‐ 60 days (long term) |
Treatment was rendered in 4 sessions with a 1‐week interval. Outcome measures following the first treatment session were considered for meta‐analysis |
| Orhan 2011 | Turkey | RCT (Patient as unit) | 16 patients with 64 teeth | 21 to 51 years (Mean 34.31 years) | Diode (655 nm) | 1. Distilled water 2. Placebo laser | Air blast | ‐ Baseline ‐ 24 hours (short term) ‐ 7 days (medium term) |
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| Ortiz 2019 | Brazil | RCT (Patient as unit) | 24 patients were enrolled. 21 participants with 80 teeth completed all phases of the study | 18 to 50 years (Mean age 30 years) | Photobiomodulation (PBM) 808 nm diode laser | Placebo laser | 1. Tactile 2. Air blast |
‐ Baseline ‐ Immediate ‐ 24 hours (short term) ‐ 48 hours (medium term) ‐ 1 month (medium term) |
3 desensitizing treatment sessions were performed with a 24‐hour interval between each session. Outcome measures following the 1st treatment session were considered for meta‐analysis |
| Pantuzzo 2020 | Brazil | RCT (Patient as unit) | 28 patients | Mean age 48.4 (older than 18 years) | Diode laser (808 nm) | Placebo laser | Tactile + evaporative | ‐ Immediate ‐ 6 hours (short term) ‐ 12 hours (short term) ‐ 24 hours (medium term) |
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| Suri 2016 | India | RCT (Split‐mouth design) | 30 patients with 120 teeth | 20 to 59 years | Diode laser (980 nm) | Placebo (Distilled water) | 1. Tactile 2. Air blast |
‐ Baseline ‐ 24 hours (short term) ‐ 1 week (medium term) ‐ 1 month (medium term) ‐ 2 months (medium term) |
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| Tevatia 2017 | India | RCT | 120 patients | 18 to 55 years (mean age 36.5 years) | 1. Diode laser (980 nm) 2. Diode laser (980 nm) + 5% KNO3 |
1. 5% KNO3 2. Placebo | 1. Tactile 2. Air blast 3. Cold water |
‐ Baseline ‐ Immediately after treatment (short term) ‐ 2 weeks (medium term) ‐ 4 weeks (medium term) ‐ 6 weeks (medium term) |
Commercial toothpaste was applied for 60 s as placebo control |
| Vieira 2009 | Brazil | RCT (Split‐mouth design) | 30 patients with 164 teeth | 24 to 68 years | Diode laser (660 nm) | Placebo (laser + gel) | 1. Tactile 2. Air blast |
‐ Baseline ‐ Immediate (short term) ‐ 3 months (long term; 6/30 patients lost to follow‐up) |
The 3‐month dropout rate was 20% |
| Yilmaz 2011a | Turkey | RCT (Split‐mouth design) | 51 patients with 174 teeth | 18 to 60 years (Mean 44 years) | 1. Diode laser (810 nm) 2. Er,Cr:YSGG laser |
No treatment | Air blast | ‐ Baseline ‐ Immediate (short term) ‐ 1 week (medium term) ‐ 1 month (medium term) ‐ 3 months (long term) |
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| Yilmaz 2011b | Turkey | RCT (Split‐mouth design) | 42 patients with 146 teeth | 18 to 64 years (from author's reply) (Mean 33.8 years) | Er,Cr:YSGG laser | Placebo laser | Air blast | ‐ Baseline ‐ Immediate (short term) ‐ 1 week (medium term) ‐ 1 month (medium term) ‐ 3 months (long term) |
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| Yilmaz 2011c | Turkey | RCT (Split‐mouth design) | 48 patients with 244 teeth | 18 to 58 years (Mean 41 years) | Diode laser (810 nm) | Placebo laser | Air blast | ‐ Baseline ‐ Immediate (short term) ‐ 1 week (medium term) ‐ 1 month (medium term) ‐ 3 months (long term) ‐ 6 months (long term) |
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| Yilmaz 2014 | Turkey | RCT (Split‐mouth design) | 20 patients with 60 teeth | 18 to 60 years (Mean 46.3 ± 8.4 years) | 1. Er,Cr:YSGG laser at 0.25 W 2. Er,Cr:YSGG laser at 0.5 W |
Placebo laser | Air blast | ‐ Baseline ‐ Immediately after treatment (short term) |
All teeth were extracted for SEM evaluation after VAS assessment |
aOutcome time points: 'Immediate' is short for 'Immediate after intervention,' '1 week' is short for '1 week after intervention,' '1 month' is short for '1 month after intervention,' and so forth. CSP = calcium sodium phosphosilicate; Er,Cr:YSGG = erbium,chromium:yttrium‐scandium‐gallium‐garnet; Nd:YAG = neodymium‐doped:yttrium‐aluminum‐garnet; nHAP = nano‐hydroxyapatite; nm = nanometers; RCT = randomized controlled trial; s = second; SEM = scanning electron microscopy; VAS = visual analogue scale; W = watt.