“I’ve seen an increase in decay, even with those who have good home care habits and see their dentist twice a year,” Kantor says. “The juice seems to sit at the junction where the tooth meets the gum and in between teeth, so flossing and brushing right after drinking juice is very important.” Basically, the sugar from juice can wear away tooth enamel and ultimately cause cavities. The bacteria can also irritate the gums and eventually could lead to gum disease. “There is a direct association between having an inflammatory response in your mouth, such as gum disease, to having an inflammatory response in the rest of the body, such as heart attack,” Kantor says. Yikes.