Table 4.

Summary of findings for the main comparison: healing time

Comparisons	Number of participants (studies)	Quality of the evidence (GRADE)	Anticipated mean difference (95% CI)
Low-level laser therapy (LLLT) vs conventional therapy (topical medication and placebo)	121 (3 studies)	⊕⊕◯◯ Low	− 2.55 [95% CI − 4.67, − 0.43]; I2 = 98%
CO2 vs placebo	70 (2 studies)	⊕⊕⊕◯ Moderate	− 3.72 [95% CI − 4.18, − 3.25]; I2 = 0%

High quality further research is very unlikely to change our confidence in the estimate of effect, Moderate quality further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate, Low quality further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate, Very low quality we are very uncertain about the estimate