Erosive potentials of brewed teas.
OBJECTIVE
To measure the pH, titratable acidity, fluoride concentration and erosive potential of brewed teas.


METHODS
Bag teas were purchased to represent black, green, citrus, fruity, and floral tea flavors from Tulsi, Bigelow, HyVee, Tazo, and Yogi brands and brewed (1 bag/240 ml) in boiling water for 3 minutes. The pH, titratable acidity, and fluoride concentrations were measured. Following these measurements, a representative tea from each flavor was selected for investigation of erosion potential. Six extracted human molars were randomly assigned to each tea. Teeth were painted with fingernail polish to expose a 1 x 4 mm window and then soaked in tea for a total of 25 hours with teas refreshed every 5 hours. Teeth were then sectioned using a microtome and photographed using a polarized light microscope. Lesion depths (i.e., eroded surfaces) were measured using Image Pro Plus software. Differences in physiochemical properties and lesion depths between beverages were investigated using one-way ANOVA with post-hoc Tukey's HSD test. Relationships among lesion depths and physiochemical properties were evaluated using the Pearson correlation test.


RESULTS
pH, titratable acidity and fluoride concentrations differed between tea flavors (P < 0.05) and between brands (P < 0.05). Lesion depths produced by the citrus tea (83.1 +/- 10.3 microm) were greater than those produced by the fruity tea (56.5 +/- 6.1 microm); both teas produced greater depths than black (30.1 +/- 7.4 microm), floral (25.0 +/- 3.2 microm) or green (22.3 +/- 6.3 microm) teas (P < 0.05). pH (r = -0.96; P = 0.009) was inversely and titratable acidity (r = 0.97; P = 0.006) was positively associated with lesion depths.
Julie L
JL
Hendricks
Department of Preventive & Community Dentistry, College of Dentistry, University of Iowa, N335 Dental Science Building, Iowa City, IA 52340, USA.
Teresa A
TA
Marshall
Dows Institute for Dental Research, College of Dentistry, University of Iowa, Iowa City, Iowa 52340, USA.
Jeffrey D
JD
Harless
Dows Institute for Dental Research, College of Dentistry, University of Iowa, Iowa City, Iowa 52340, USA.
Mary M
MM
Hogan
Dows Institute for Dental Research, College of Dentistry, University of Iowa, Iowa City, Iowa 52340, USA.
Fang
F
Qian
Department of Pediatric Dentistry, College of Dentistry, University of Iowa, Iowa City, Iowa 52340, USA.
James S
JS
Wefel
D000143:Acids / Q000737:chemistry; D001628:Beverages / Q000032:analysis; D028241:Camellia sinensis; D020843:Chamomile; D002957:Citrus; D003743:Dental Enamel / Q000473:pathology; D005459:Fluorides / Q000032:analysis; D005638:Fruit; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008859:Microscopy, Polarization; D008963:Molar / Q000473:pathology; D013662:Tea; D017186:Titrimetry; D014077:Tooth Erosion / Q000209:etiology*
D000143:Acids; D013662:Tea; D005459:Fluorides