Erosive characteristics and fluoride content of cola-type drinks

Excessive consumption of carbonated soft drinks is detrimental to general and oral health. This study determined endogenous pH, titratable acidity (TA) and fluoride (F) ion concentration of cola-type drinks available in the UK. Subsidiary aims were to compare: (i) endogenous pH and TA of drinks upon opening (T0) and after 20 minutes (T20); (ii) endogenous pH, TA and F ion concentration of diet vs regular and plastic bottle vs canned drinks.

Endogenous pH, TA (mls 0.1M NaOH) and F ion (mg/L) of 71 products were measured using a pH meter and F-ISE. A Wilcoxon Signed Ranks Test compared pH and TAs at T0 and T20; a Mann-Whitney U test compared pH, TAs and F ion concentration for; a) regular vs diet drinks; and b) plastic bottle vs canned drinks.

Mean (±SD) pH for regular and diet drinks was 2.44 ± 0.12 and 2.83 ± 0.33 respectively (p = 0.001). Mean NaOH (ml) to raise pH to 5.5 and 5.7 was 5.49 ± 0.76 and 6.40 ± 0.78 (regular drinks); 5.17 ± 1.03 and 6.03 ± 1.07 (diet drinks). Diet (p = 0.040) and regular (p = 0.041) drinks had higher TA to pH 5.7 at T0 compared with T20; at T20 regular drinks had higher TA to pH 5.5 (p = 0.026) and pH 5.7 (p = 0.030) than diet drinks. There was no difference in F ion concentration between regular vs diet drinks (p = 0.754) and no significant container effect.

Erosive characteristics were similar between manufacturers, but higher erosive potentials were evident at T0 compared with 20 minutes later and for regular compared with diet drinks. F ion concentration of drinks was low.