Green tea, or any real tea made from the Camellia sinensis plant, has many advantages as a go-to beverage.
It itself does not contain significant amounts of sugar, it has an enamel preserving pH level (that is: it is non-acidic). Some compounds (like the poyphenols) have shown some activity against harmful bacteria causing gingivitis or caries.
The most significant part plays the sometimes enormous amount of fluoride tea contains. Fluoride hardens the enamel against acids from bacteria metabolising around. In fact tea has often so much fluoride that this is much more likely to be a health concern than the caffeine content some hysterics worry about. (Or not? Since everyone should only buy tea that was tested for pesticides, radioactivity, and other contaminations, why not demand a chemical analysis sheet as well?)
Green tea is tooth friendly. It does not cause or aggravate tooth decay. On the contrary, it usually makes your teeth stronger (and stains them, alas) – Green tea will not stop or reverse caries.
Every sugar drink replaced by tea helps. How much tea is needed for the effects of fluoride to be significant depends on other dietary factors, water fluoridation and tooth paste used. The amount of tea is therefore impossible to gauge exactly but an upper limit is dependent on how much tea a user can take (if the fluoride content is kept well below a dosage causing problems like fluorosis) since caffeine and tannins are not equally well tolerated by everyone.
Inhibition of Streptococcus mutans biofilm formation using extracts from Assam tea compared to green tea:
Assam tea has stronger biofilm inhibition activity against S. mutans than green tea. A substance of <10kDa in mass in Assam tea had a high concentration of galloylated catechins and a stronger biofilm inhibiting activity than green tea. In contrast, substances >10kDa in mass from green tea included higher concentrations of polysaccharides composed of galacturonic acid, such as pectin, that enhance biofilm formation.
The higher concentrations of galloylated catechins in Assam tea may assist in prevention of dental caries, whereas in green tea, this mode of inhibition was likely offset by the presence of pectin. Purification of catechins in partially fermented Assam tea with lower-molecular-weight polysaccharide than pectin may be useful for developing oral care products such as toothpaste and oral care gel pastes.
Inhibition of salivary amylase by black tea in high-caries and low-caries index children: A comparative in vivo study:
Results: The average ratio of maltose to sucrose ratio percentage reduction in high-caries group was 43.63% and 41.17% in no caries group which was highly significant (P < 0.005) while the intergroup comparison was found statistically insignificant.
Tea decoction has inhibitory effect on salivary amylase activity thus dental caries. The effect was statistically insignificant in children with high- and no-caries index.
An In vitro Study to Compare the Effect of Different Types of Tea with Chlorhexidine on Streptococcusmutans:
The mean zone of inhibition of the aqueous extracts of green tea, black tea, oolong tea and chlorhexidine was found to be 16.33 mm, 10.33 mm, 19.66 mm and 22 mm respectively. The mean zone of inhibition of the ethanol extracts of green tea, black tea, oolong tea and chlorhexidine was found to be 14 mm, 9 mm, 20.66 mm and 22 mm respectively. The study result state that the inhibitory effect of chlorhexidine is almost similar to that of oolong tea followed by green tea and black tea.
Conclusion: From the present study, it can be concluded that the aqueous and ethanol extracts of oolong tea showed highest antimicrobial activity compared to green tea and black tea.
Green Tea (Camellia Sinensis): Chemistry and Oral Health:
Green tea is a widely consumed beverage worldwide. Numerous studies have suggested about the beneficial effects of green tea on oral conditions such as dental caries, periodontal diseases and halitosis. However, to date there have not been many review articles published that focus on beneficial effects of green tea on oral disease. The aim of this publication is to summarize the research conducted on the effects of green tea on oral cavity. Green tea might help reduce the bacterial activity in the oral cavity that in turn, can reduce the aforementioned oral afflictions. Furthermore, the antioxidant effect of the tea may reduce the chances of oral cancer. However, more clinical data is required to ascertain the possible benefits of green tea consumption on oral health.
A more comprehensive overview with a lot of references are in each:
Yukihiko Hara: "Green Tea: Health Benefits and Applications", (Food science and technology ; 106), Marcel Dekker: New York, Basel, 2001.
Helen Mckinley & Mark Jamieson: "Handbook of Green Tea and Health Research", Food and Beverage Consumption and Health Series, Nova Science Publishers, New York, 2009.
Chi-Tang Ho & Jen-Kun Lin & Fereidoon Shahidi: "Tea and Tea Products. Chemistry and Health-Promoting Properties", CRC Press: Boca Raton, 2009.