Table 2.
Average person-level FRI scores [count (%) of subjects].
| Tooth Type (Gamma, p-value)* | Mean Person-Level FRI Score Category | Age 9 (n = 282) (Permanent Teeth Only) | Age 13 (n = 282) | Age 17 (n = 282) | Age 23 (n = 282) |
|---|---|---|---|---|---|
| Early-Erupting Teeth (−0.35, < 0.0001) | 0 | 84 (29.8) | 127 (45.0) | 164 (58.2) | 173 (61.4) |
| 0.01–0.50 | 146 (51.8) | 127 (45.0) | 103 (36.5) | 100 (35.5) | |
| 0.51–1.00 | 35 (12.4) | 23 (8.2) | 12 (4.3) | 5 (1.8) | |
| 1.01–3.00 | 17 (6.0) | 5 (1.8) | 3 (1.1) | 4 (1.4) | |
| Late-Erupting Teeth (−0.34, < 0.0001) | (n = 291) | (n = 291) | (n = 291) | ||
| 0 | – | 114 (39.2) | 167 (57.4) | 192 (66.0) | |
| 0.01–0.50 | – | 130 (44.7) | 106 (36.4) | 86 (29.6) | |
| 0.51–1.00 | – | 35 (12.0) | 10 (3.4) | 8 (2.8) | |
| 1.01–3.00 | – | 12 (4.1) | 8 (2.8) | 5 (1.7) | |
| Maxillary Incisors (−0.35, < 0.0001) | (n = 279) | (n = 279) | (n = 279) | (n = 279) | |
| 0 | 100 (35.8) | 141 (50.5) | 181 (64.9) | 192 (68.8) | |
| 0.01–0.50 | 87 (31.2) | 85 (30.5) | 59 (21.2) | 59 (21.2) | |
| 0.51–1.00 | 59 (21.2) | 37 (13.3) | 33 (11.8) | 23 (8.2) | |
| 1.01–3.00 | 33 (11.8) | 16 (5.7) | 6 (2.2) | 5 (1.8) |
*
Gamma statistic for association between age and fluorosis severity. p-value was calculated under the assumption that the sample size was sufficiently large for (gamma statistic/asymptotic standard error) to approximately follow a standard normal distribution.