This study aimed to investigate the effects of fluoride-containing acidic tea beverages on bovine teeth surfaces.
The pH values and fluoride concentrations of 11 kinds of mineral water and 23 kinds of tea were measured. The fluoride-containing Seopyenje black tea beverages with pH 3.48 were chosen for the experimental group. Distilled water that did not contain fluoride and had the same pH value as that of the Seopyenje black teas served as the positive control. The Jeju Samdasoo mineral waters with neural pH (pH 7.52) and no fluoride were chosen as the negative control. Bovine teeth in each group were submerged for 10 minutes. Thereafter, surface microhardness of each bovine teeth was measured and the results were analyzed.
The pH value range was 6.94-8.09 (mean=7.37±0.08) for the 11 kinds of mineral water and 3.48-6.74 (5.62±0.05) for the 23 tea beverages. Titratable acidity of the Seopyenje black tea beverages was higher than that of the distilled water mixed with citric acid, and the pH was 5.5 and 7.0, respectively. The fluoride content of the 11 kinds of mineral water was 0-1.09 ppm (mean=0.44±0.02 ppm) that of the 23 tea beverages was and 0-0.74 ppm (0.64±0.06 ppm). In terms of enamel microhardness reduction of the bovine teeth, the tea beverages had the largest effects. There was no significant difference in microhardness reduction between the tea beverages and distilled water mixed with citric acid (
Acidic tea beverages appeared to erode the surfaces of bovine teeth. The amount of fluoride in the tea beverages was not enough to inhibit erosion. Therefore, frequent intakes of acidic tea beverage are likely to increase erosion on the surfaces of bovine teeth, by affecting the enamel microhardness of teeth.
Materials used in the experiment
| Group | pH | Fluoride (ppm) | Titratable acidity (ml) |
Brand name | |
|---|---|---|---|---|---|
| pH 5.5 | pH 7.0 | ||||
| Mineral water | 7.52±0.10 | − | − | − | Jeju samdasoo |
| (Negative control) | |||||
| Distilled water mixed with citric acid | 3.48±0.00 | − | 0.03±0.00 | 0.03±0.00 | − |
| (Positive control) | |||||
| Tea beverage (Experimental group) | 3.48±0.02 | 0.50±0.06 | 0.28±0.00 | 0.39±0.00 | Seopyeonje hongcha |
The pH and fluoride concentration of mineral waters
| Brand name | Manufacturer | pH | Fluoride (ppm) |
|---|---|---|---|
| Sparkle | Sparkle | 6.94±0.19 | 0.35±0.00 |
| Baeksansu | Nongshim | 6.98±0.05 | 0.69±0.08 |
| ICIS pyeonghwagongwon | Lotte | 6.99±0.15 | − |
| sanrimsu | |||
| Pulmuonesaemmul by nature | Pulmuone | 7.00±0.06 | 0.11±0.00 |
| Malgeun saemmul | Lotte | 7.00±0.13 | − |
| Gangwon pyeongchangsu | Hai-Tai | 7.14±0.04 | 0.14±0.02 |
| Hwio sunsu | Coca-Cola | 7.27±0.02 | 0.25±0.02 |
| Jeju samdasoo | Kwangdong | 7.52±0.10 | − |
| ICIS 8.0 (by gyeongsangdo) | Lotte | 8.05±0.08 | 1.09±0.00 |
| ICIS 8.0 (by chungcheongdo) | Lotte | 8.08±0.02 | − |
| Baekdusan haneulsaem | Lotte | 8.09±0.07 | 0.43±0.04 |
Values are presented as mean±standard deviation.
The pH and fluoride concentration of tea beverages
| Brand name | Manufacturer | pH | Fluoride (ppm) |
|---|---|---|---|
| Seopyeonje hongcha | Boseong | 3.48±0.02 | 0.50±0.06 |
| Hongsseonin | Nonghyup | 4.20±0.02 | − |
| Ueongcha | Kwangdong | 4.54±0.05 | − |
| Boricha | Dongsuh | 4.99±0.01 | − |
| Yawang bisuricha | Kwangdong | 5.35±0.20 | − |
| Condition heotgaesu | CJ | 5.41±0.15 | − |
| Oksususuyeomcha soon | Dongwon | 5.47±0.07 | − |
| Heotgaesu | CJ | 5.56±0.16 | − |
| Heotgaecha | Kwangdong | 5.67±0.02 | − |
| Haneulbori | Woongjin | 5.70±0.02 | − |
| Dunggulrecha | Dongsuh | 5.78±0.02 | − |
| Bosungnokcha | Boseong | 5.81±0.06 | 0.68±0.03 |
| Hwanggeumbori | Lotte | 5.91±0.06 | − |
| Achim heotgae | Lotte | 5.93±0.11 | − |
| V line oksususuyeomcha | Kwangdong | 5.95±0.02 | − |
| Oksususuyeomcha | Dongsuh | 6.01±0.01 | − |
| Bosungnokcha soon | Dongwon | 6.03±0.03 | 0.74±0.09 |
| Momi malgajineun sigan | Namyang | 6.03±0.03 | − |
| 17cha | |||
| Chogaeul ueongcha | Lotte | 6.08±0.02 | − |
| Chahwanokcha | Heysong | 6.11±0.05 | 0.59±0.04 |
| Taeyang-ui matecha | Coca-Cola | 6.28±0.02 | − |
| Oksususuyeomcha | Lotte | 6.30±0.04 | − |
| Seopyeonje oksususu- | Boseong | 6.74±0.04 | − |
| yeomcha |
Values are presented as mean±standard deviation.
The average pH of experiment beverages
| Beverage | N | pH (Min-Max)* |
|---|---|---|
| Mineral waters | 11 | 7.37±0.08 (6.94-8.09) |
| Tea beverages | 23 | 5.62±0.05 (3.48-6.74) |
Values are presented as mean±standard deviation. *
Difference in surface microhardness after treatment for 10 minutes Unit: VHN
| Group | N | Time |
Difference |
|
|---|---|---|---|---|
| Before | After | |||
| Mineral water | 10 | 292.73±13.68 | 292.63±13.18 | ―0.96±18.07 |
| Distilled water mixed with citric acid* | 10 | 294.12±15.31 | 273.07±13.97 | ―21.05±15.65b |
| Tea beverage* | 10 | 293.26±14.38 | 254.98±13.44 | ―38.28±15.03b |
Values are presented as mean±standard deviation. *
The same letter indicates no significant difference by Tukey test at a=0.05.