Table 1.

General characteristics of studies.

References	Study type	Participants (n)	Follow-up (weeks)	Probiotic type	Study conclusions
Jamali et al. (20)	Randomized Controlled Clinical Trial	n = 99	12 weeks	SS K12	Probiotic therapy following oral disinfection with chlorhexidine may reduce the severity of halitosis over longer periods.
Benic et al. (21)	Randomized, triple-blind, placebo-controlled trial	n = 64	12 weeks	SS M18	Oral probiotic SS M18 reduced the level of halitosis in patients wearing orthodontic.
He et al. (22)	Randomized, placebo-controlled trial	n = 28	4 weeks	SS K12	The use of SS K12 did not have significant effect on halitosis with tongue coating cause when the tongue coating was not physically or chemically pre-treated, which implies removing tongue coating is required before SS K12 use.
Lee et al. (23)	Randomized, double-blind, placebo-controlled study	n = 92	8 weeks	WC	WC tablets could prove to be a safe and useful oral care product to control bad breath.

SS, Streptococcus salivarius, WC, Weissella cibaria.