| Factors | Element | ||
| Al | Ca | ||
| Total subjects (n) | 104 | 108 | |
| Sex (n) | Male | 62 | 65 |
| Female | 42 | 43 | |
| Age (years) | Mean ± S.D. | 9.1 ± 2.0 | 9.1 ± 2.0 |
| Range | 5-14 | 5-14 | |
| Tooth types (n) | Incisors | 18 | 21 |
| Canines | 17 | 18 | |
| Molars | 69 | 69 | |
| Tooth condition (n) | Sound | 38 | 41 |
| Caries experience | 66 | 67 | |
| Untreated | 23 | 21 | |
| Treated | 43 | 46 | |