Dental erosion from acid drinks is known; in vitro with in vivo evidence that apple and grape juices cause erosion is rare.
i) To test acidity (pH and buffering capacity) in vitro; ii) And assess if these juices leach calcium from teeth in vivo.
First: Six commercially available potable apple and grape juices were measured (six times each drink) for pH and buffering using 0.5 Molar NaOH with a Mettler DL 25 Automatic Titrator. The apple and grape juices were measured separately, using a 50 mL bolus for measures, 6 times for each. Second: Two volunteer cohorts; (One fully dentate WITH TEETH (mean age 20, M:F 6:6, n = 12) the second edentulous WITHOUT TEETH (mean age 61, M:F 6:6, n = 12)), were used to swish with 50 mL aliquots of Apple and/or Grape juices for 30 seconds. Each sample was analyzed six times with Inductively Coupled Plasma with Optical Emission Spectroscopy (ICP-OES) for Calcium, and Phosphorous. Juices from source were analyzed for Calcium, and Phosphorous, and post-swish expectorate samples were analyzed for Calcium and Phosphorous. Data were analyzed 'blind' by technicians unaware of the source of procured samples.
Analysis reveals apple and grape juices have pH below 5.5. Statistics consistently show significant (p < 0.01 Student-t paired data) increases in Calcium and Phosphorous leeched from dentate (WITH TEETH) subjects after swishing with apple and grape juices tested. Results provide strong evidence that rinsing with Apple or Grape juices will erode teeth. Grape is more erosive than apple juice.
Apple and grape juices have acidity below critical pH 5.5; Both have strong buffering capacities and will decalcify teeth by erosion, when exposed to these drinks in diets.