evaluation of the effect of green tea extract on mouth bacterial activity in the presence of propylene glycol

background compounds present in green tea have proved to inhibit the growth and activity of bacteria associated with infections. objectives to assess the effects of green tea leaves extract in presence of propylene glycol on the aerobic mouth bacteria load. materials and methods saliva of 25 volunteer girl students aging 20-25 years were selected and evaluated by a mouthwash sample containing 1% tannin, as the most effective antibacterial complex in green tea. comparative studies were also conducted between green tea mouthwashes containing 1% tannin and a similar sample with 10% propylene glycol added during extraction. this comparison was applied for a chlorhexidine 0.2% sample as a chemical mouthwash brand, too. results there was a meaningful difference between the green tea mouthwashes containing 10% propylene glycol and the simple green tea extract (p < 0.05). significant difference was also seen between the herbal and chemical mouthwashes (p < 0.05). the extract 1% tannin containing 10% propylene glycol reduced the aerobic mouth bacterial load of the student salvia about 64 percent. the ph monotonousness in different days and temperatures approved the stability of tannin in liquid water medium. conclusions using green tea extract as a herbal mouthwash is safe and harmless specially for children and pregnant women. this result led us to suppose that green tea may prevent plaque formation on teeth, coming over halitosis due to mouth infection, too. these effects need to be approved in an in vivo trial as a second study.