Orange juice, lemonade and other acidic fruit juices increase the risk for tooth decay the most among mass-produced drinks, a study showed Monday.

A research team at Seoul National University Hospital’s School of Dentistry studied the relationship between the level of acid and the possibility of tooth erosion with eight types of drinks, such as lemonade, soda, sports, drinks and kids’ beverages, for eight days.

Orange juice had the worst effect of teeth erosion and decreased enamel hardness, the study found.

The hardness of dental enamel exposed to orange juice sharply fell from 318.4 to 99.8 in the Vickers Hardness Number, a method for measuring the hardness of a material. Lemonade also decreased the hardness of tooth enamel by nearly 50 percent from 322.9 to 165.2 VHN. Other types of acidic drinks such as apple-flavored soda and drinks targeting kids reduced dental hardness by nearly 30 percent, from 319.7 to 181.5 and from 316.7 to 183, respectively. Cider, a clear soft drink popular in Korea, had lower impact on dental hardness, with the number dropping by less than 30 percent, from 309 to 226.8.

The study concluded that drinks with a higher level of acidity can cause more severe tooth erosion.

Orange juice topped the list in terms of the level of acidity while cider was the lowest of the eight beverages tested in the study.

The team will conduct follow-up studies to show exactly what substances in acidic fruit juices cause tooth erosion more severely than others and define their reasons.

The team also recommended consumers to finish drinks quickly or drink water afterward to wash acidic substances away from the teeth.

By Cho Chung-un (christory@heraldcorp.com)