Rosehip tea and Coca-Cola appeared to weaken the bonds that attach orthodontic brackets in a study posted online March 31 in the European Journal of Orthodontics.
In the study, the researchers from Gazi and Ankara Universities in Turkey attached brackets to 90 extracted human premolars with Transbond XT (3M Unitek). They divided the teeth equally into six groups and soaked them in different liquids: black tea, mint-mate herbal tea, mint-lemon herbal tea, rosehip herbal tea, Coca-Cola, and distilled water.
For 90 days, they soaked the teeth for three five-minute-sessions, removing them for five minutes between sessions. They measured the initial pH, shear bond strength (SBS), and adhesive remnant index (ARI) of the groups.
The researchers found that the lowest pH values were for rosehip tea (2.4 ± 0.07) and Coca-Cola (2.5 ± 0.05). They found that Coca-Cola reduced the SBS of the brackets by 6.04 ± 1.11 MPa, and rosehip tea reduced the SBS by (7.26 ± 1.11 MPa). The change was statistically significant (p < 0.001).
They didn't find a statistically significant change in SBS for the other liquids. Teeth soaked in Coca-Cola had an ARI of 0, whereas all the other ARI scores were 1.
"Although this experiment could not completely replicate the complex oral environment, it seems to confirm that Coca-Cola and rosehip fruit tea may be a causative factor in bracket-enamel bonding failure," the researchers concluded.
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