n research appearing in the journal General Dentistry, tea was found to be similar to water in regards of erosion potential on teeth, with both green and black varieties offering a less acidic alternative to beverages like soft drinks.
Researchers stressed though that while tea appeared to induce tooth erosion of levels closely resembling those of tap water, long-term exposure to tea did by comparison induce low-grade damage to teeth. “This damage may be related to the tannic acid in tea that slightly decreases the pH at the tooth surfaces,” stated the group.
Dental concerns
According to the researchers, increasing levels of soft drink consumption in markets like the US and the seemingly longer life of teeth are expected to lead to growing incidence of dental erosion, particularly in elderly consumers.
The report claims that more regular intake of acidic drinks can therefore lead to increasing need for treatment, particularly in older consumers, who may face increased expenses as a result.
“Dental treatment of this magnitude could be burdensome financially to these individuals, their families, the health care system, or society in general,” the researchers stated.
The study conceded that while independently testing beverage ingredients in a lab environment did supply vital information, the findings may not be directly applicable ‘clinically’ though.
Methodology
The study was conducted over a twenty week period in what the researchers said were ‘strictly controlled’ vitro conditions, comparing changes in colour, translucency, texture, and presence of enamel on teeth. His change was measured visually through radio-graphs and sequential photographs.
Using this methodology, which the study says has been previously employed effectively in other trials, 36 healthy premolar teeth - all recently extracted and stored in the sterilisation product Cidex for a week - were selected for testing.
The teeth, which were all cleaned to remove hard and soft deposits from their surfaces and polished with slurry, were then selected at random before being exposed into one of either four trial beverage formulations or two control fluids.
The teeth were immersed at the crown and root portions of each specimens at room temperature, the researchers said.
In terms of the control fluids tested, vinegar of five per cent acetic acid with a pH value of 2.4 was used as the active sample and tap water with a pH of 6.8 was the passive sample.
Trial beverages
These four beverages included:
- Orange juice with a pH value of 2.8
- A caramelised carbonated cola beverage with a pH value of 2.7
- 200ml of boiling water infused with 2.5g of green tea for three minutes
- 200ml of boiling water infused with 2.5g of black tea for three minutes
Tea difference
“Green and black teas contain similar amounts of proteins; amino acids; carbohydrates; lipids; minerals; pigments; caffeine; vitamins A, C, and E; and fibers,” stated the researchers.
However, there were some differences in the presence of flavonoids present during the study, according to the group.
Findings
Conclusions were based on the geometrical changes between the different samples through quantitative radiographic findings that evaluated loss of cusp tip height, vertical cervical enamel, enamel cap height, and radius of enamel cap.
For the control fluids, researchers said that there was maximum enamel loss at cusp tip height and the cervical region in the vinegar sample. The study suggests that this was a ‘drastic reduction’ compared to other fluids.
In terms of the soft drink specimens, soda was found to have resulted in greater cusp tip height reduction than orange juice. However, the fruit-based drink proved to have led to higher levels of cervical enamel loss.
“Within the scope of the 20-week test, both the soda and orange juice exhibited similar losses of enamel cap height,” said the researchers.
In studying tea, both green and black varieties produced mostly similar results in how they affected tooth erosion.
As such, both samples were found to have stained enamel. Researchers calculated that the average loss of cervical enamel by the end of the study was less than half in tea of what had been found in the soda and orange juice specimens.
Source: General Dentistry
July-August 2008, 451-461“Topographic and radiographic profile assessment of dental erosion—Part III: Effect of green and black tea on human dentition.”Authors: Mohamed A. Bassiouny, Shuntaro Kuroda, Jie Yang