Comparison 2. Laser versus placebo/no treatment. Outcome: changes in intensity of pain (VAS with value range from 0 to 10) when tested through tactile stimuli.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
2.1 Short term ‐ all types of laser	8		Mean Difference (IV, Random, 95% CI)	‐0.67 [‐1.31, ‐0.03]
2.1.1 Split‐mouth design	4		Mean Difference (IV, Random, 95% CI)	‐0.89 [‐1.68, ‐0.11]
2.1.2 Parallel design	4		Mean Difference (IV, Random, 95% CI)	‐0.44 [‐1.50, 0.62]
2.2 Short term ‐ Nd:YAG	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
2.2.1 Parallel design	1		Mean Difference (IV, Fixed, 95% CI)	‐0.25 [‐0.91, 0.41]
2.3 Short term ‐ diode: visible red (630 nm to 700 nm)	4		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
2.3.1 Split‐mouth design	4		Mean Difference (IV, Fixed, 95% CI)	‐0.81 [‐1.16, ‐0.45]
2.4 Short term ‐ diode: near infrared (700 nm to 850 nm)	2		Mean Difference (IV, Random, 95% CI)	0.27 [‐0.60, 1.14]
2.4.1 Parallel design	2		Mean Difference (IV, Random, 95% CI)	0.27 [‐0.60, 1.14]
2.5 Short term ‐ diode: near infrared (850 nm to 980 nm)	1		Mean Difference (IV, Random, 95% CI)	‐2.17 [‐2.80, ‐1.54]
2.5.1 Parallel design	1		Mean Difference (IV, Random, 95% CI)	‐2.17 [‐2.80, ‐1.54]
2.6 Medium term ‐ all types of laser	9		Mean Difference (IV, Random, 95% CI)	‐1.73 [‐3.17, ‐0.30]
2.6.1 Split‐mouth design	3		Mean Difference (IV, Random, 95% CI)	‐3.75 [‐6.15, ‐1.35]
2.6.2 Parallel design	6		Mean Difference (IV, Random, 95% CI)	‐0.67 [‐1.77, 0.42]
2.7 Medium term ‐ Nd:YAG	2		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
2.7.1 Parallel design	1		Mean Difference (IV, Fixed, 95% CI)	‐1.06 [‐2.15, 0.03]
2.7.2 Parallel design	1		Mean Difference (IV, Fixed, 95% CI)	‐2.17 [‐2.80, ‐1.54]
2.8 Medium term ‐ diode: visible red (630 nm to 700 nm)	4		Mean Difference (IV, Random, 95% CI)	‐2.95 [‐5.14, ‐0.75]
2.8.1 Split‐mouth design	3		Mean Difference (IV, Random, 95% CI)	‐3.75 [‐6.15, ‐1.35]
2.8.2 Parallel design	1		Mean Difference (IV, Random, 95% CI)	‐0.19 [‐1.98, 1.60]
2.9 Medium term ‐ diode: near infrared (700 nm to 850 nm)	2		Mean Difference (IV, Random, 95% CI)	‐0.68 [‐3.57, 2.21]
2.9.1 Parallel design	2		Mean Difference (IV, Random, 95% CI)	‐0.68 [‐3.57, 2.21]
2.10 Medium term ‐ diode: near infrared (850 nm to 980 nm)	1		Mean Difference (IV, Random, 95% CI)	‐1.83 [‐2.36, ‐1.30]
2.10.1 Parallel design	1		Mean Difference (IV, Random, 95% CI)	‐1.83 [‐2.36, ‐1.30]
2.11 Medium term ‐ Er,Cr:YSGG	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
2.11.1 Parallel design	1		Mean Difference (IV, Fixed, 95% CI)	0.38 [‐0.13, 0.89]
2.12 Long term ‐ all types of laser	2		Mean Difference (IV, Random, 95% CI)	‐3.52 [‐10.37, 3.33]
2.12.1 Split‐mouth design	2		Mean Difference (IV, Random, 95% CI)	‐3.52 [‐10.37, 3.33]
2.13 Long term ‐ diode: visible red (630 nm to 700 nm)	2		Mean Difference (IV, Fixed, 95% CI)	‐4.67 [‐5.38, ‐3.96]
2.13.1 Split‐mouth design	2		Mean Difference (IV, Fixed, 95% CI)	‐4.67 [‐5.38, ‐3.96]