Apple juice is widely marketed as a healthy and desirable drink. To a group of six public health dentistry and dental sciences researchers in India, however, apple juice contains certain acids and sugars that can dissolve the hard structure of the teeth. The 3.2 pH and acidity of apple juice make it the perfect negative test subject for the dental erosion, decalcification, and demineralization of teeth. A pilot study decided upon apple juice, as it was the most acidic of India’s three most commonly consumed juices: apple, guava, and “litchi” juices.
What was the perfect positive test subject? The researchers decided upon clove essential oil with two of its constituents eugenol and eugenol acetate. The study1 was published in the August 2012 issue of the International Journal of Dentistry.
Extracted human permanent teeth were exposed to apple juice in beakers for 24 hours, with the juice constantly stirred by a magnetic stir bar. This period of time was longer than exposure from normal juice drinking, but the time was sufficient to cause dental erosion or decalcification. Clove oil and the two constituents were added to individual beakers, as was fluoride. The data was analyzed by third-party technicians who were unaware of the treatment of each of the samples (blinded part of the study).
There was significant leaching of calcium from the teeth into the juice at the end of the 24 hours. The study states that “samples treated with clove essential oil and its two lead molecules showed significant decrease in the calcium content when compared to the control group.” The study showed there was no statistical difference between the fluoride and the clove essential oil groups—both decreased the decalcification of the tooth. Fluoride inhibited the decalcification to only 15 mgL-1of calcium. Clove essential oil decreased the decalcification of the tooth by apple juice to only 17 mgL-1.
A toxicity test of fluoride, clove oil, eugenol, and eugenol acetate on red blood cells for hemolysis (the rupturing of red blood cells releasing hemoglobin into surrounding fluid) reported that clove oil showed 48 percent hemolysis, eugenol 41 percent, and eugenol acetate at 57 percent hemolysis while “fluoride at the same concentration showed 100 percent hemolysis. . . . This indicates that the clove essential oil as well as its lead molecules has low cytotoxic activity,” the researchers concluded.
The scientists reported that “the potential inhibition of the erosion of the teeth by the clove oil and its lead molecules may also be attributed in the same way as was done by the fluoride. However, the higher concentrations of fluoride would be undesirable, as it would be unacceptably toxic and also negatively affect organoleptic taste properties.”
The irreversible tooth enamel damage called fluorosis
On January 7, 2011, the U.S. Health and Human Services2 changed the recommended dosage of fluoride in municipal water from 0.7 to 1.2 ppm (parts per million) to just 0.7 stating this would be “reducing the possibility of receiving too much fluoride.”
What caused this change? What happened to U.S. youth because they received too much fluoride as children? The CDC announced in November 2010 that 41 percent of U.S. adolescents age 12-15 have some form of fluorosis defects on their teeth.3
Most toothpastes contain between 0.22 percent fluoride (1000 ppm) and 0.312 percent fluoride (1450 ppm). A non-fluoride toothpaste seems the safer choice. Toothpaste with clove essential oil would even be better.
Marya CM, et al. In Vitro Inhibitory Effect of Clove Essential Oil and Its Two Active Principles on Tooth Decalcification by Apple Juice, Int J Dent.; 2012:759618. Epub Aug. 21. Full study available at: http://www.ncbi.nlm.nih.gov/pubmed/22997520.
EPA and HHS Announce New Scientific Assessments and Actions on Fluoride, January 7, 2011, http://www.ada.org/5290.aspx.