Table 2.

Patients and parameters measured in the included studies.

References	Type of patient	Parameters measured	Age range (years)	Measurement system	Outcomes
Jamali et al. (20)	Children	OLT	6–9	Judge examiner	A significant and stable number of participants showed moderate levels of improvement in organoleptic tests in the experimental group (probiotic + chlorhexidine) vs. the control group.
Benic et al. (21)	Children/ Adults	VSCLs	10–30	Halimeter®	VSCLs decreased significantly in the probiotic-treated group at 3-month follow-up, while in the placebo-treated group, VSCLs returned to baseline levels.
He et al. (22)	Adults	OLT and VSCLs	23–44	Halimeter®	Both groups (test and control) showed a significantly lower OLT score compared to baseline values. VSCLs in the test group the decrease was statistically significant.
Lee et al. (23)	Adults	OLT, VSCLs and BB	20–39	Judge examiner	A significant decrease in OLT and VSCLs scores was observed in the test group, while BB scores decreased significantly.

OLT, Organoleptic test; VSCLs, Volatile Sulfur Compound Levels; BB, Bad Breath.