Table 3.
Average age of molar formation stages.
| Tooth stage | Upper | Lower | |||||
|---|---|---|---|---|---|---|---|
| Male | Female | Sex difference | Male | Female | Sex difference | ||
| Mean ± SD (years) | Mean ± SD (years) | Mean ± SD (years) | Mean ± SD (years) | ||||
| First molar | Cr3/4 | 3.7 ± 0.5 | 3.7 ± 0.5 | p = 0.89 | 3.5 ± 0.3 | – | – |
| Crc | 4.6 ± 0.7 | 4.5 ± 0.7 | p = 0.48 | 3.9 ± 0.5 | 3.7 ± 0.5 | p = 0.019 | |
| R1/4 | 5.5 ± 0.8 | 5.2 ± 0.7 | p = 0.013 | 4.9 ± 0.6 | 4.6 ± 0.5 | p = 0.0012 | |
| R1/2 | 6.3 ± 0.7 | 5.7 ± 0.8 | p < 0.001 | 5.6 ± 0.8 | 5.5 ± 0.6 | p = 0.28 | |
| R3/4 | 7.2 ± 0.8 | 6.8 ± 0.9 | p = 0.042 | 6.7 ± 0.8 | 6.3 ± 0.7 | p = 0.0020 | |
| Rc | 8.5 ± 1.1 | 7.8 ± 1.0 | p < 0.001 | 8.3 ± 1.0 | 7.8 ± 1.0 | p < 0.001 | |
| Second molar | O | 3.8 ± 0.4 | 3.8 ± 0.6 | p = 0.72 | 3.6 ± 0.3 | 3.6 ± 0.4 | p = 0.86 |
| Ci | 4.2 ± 0.6 | 4.4 ± 0.7 | p = 0.20 | 4.4 ± 0.7 | 4.3 ± 0.7 | p = 0.42 | |
| Cco | 5.1 ± 0.8 | 5.3 ± 1.1 | p = 0.48 | 5.2 ± 0.7 | 5.1 ± 0.8 | p = 0.44 | |
| Cr1/2 | 6.0 ± 0.8 | 6.1 ± 0.7 | p = 0.42 | 6.2 ± 1.0 | 6.2 ± 0.8 | p = 0.99 | |
| Cr3/4 | 7.3 ± 0.8 | 7.0 ± 0.8 | p = 0.043 | 7.4 ± 0.8 | 7.1 ± 0.8 | p = 0.026 | |
| Crc | 8.5 ± 1.0 | 8.2 ± 0.9 | p = 0.049 | 8.6 ± 0.8 | 8.1 ± 0.9 | p < 0.001 | |
| R1/4 | 9.9 ± 0.9 | 9.6 ± 1.1 | p = 0.062 | 9.5 ± 1.1 | 9.4 ± 1.0 | p = 0.45 | |
| R1/2 | 11.1 ± 1.0 | 10.8 ± 0.9 | p = 0.082 | 10.6 ± 1.0 | 10.4 ± 0.9 | p = 0.26 | |
| R3/4 | 12.1 ± 1.1 | 12.0 ± 1.4 | p = 0.56 | 11.6 ± 1.0 | 11.7 ± 1.1 | p = 0.55 | |
| Rc | 13.8 ± 1.2 | 13.6 ± 1.4 | p = 0.20 | 13.4 ± 1.1 | 13.3 ± 1.4 | p = 0.60 | |
| Third molar | O | 9.8 ± 1.5 | 10.3 ± 1.2 | p = 0.32 | 10.0 ± 2.0 | 9.9 ± 1.4 | p = 0.15 |
| Ci | 10.4 ± 1.4 | 10.5 ± 1.7 | p = 0.96 | 10.7 ± 1.3 | 10.5 ± 1.3 | p = 0.69 | |
| Cco | 11.3 ± 1.4 | 10.8 ± 1.5 | p = 0.11 | 11.6 ± 1.8 | 11.6 ± 2.0 | p = 0.47 | |
| Cr1/2 | 12.2 ± 1.4 | 12.1 ± 1.7 | p = 0.79 | 13.1 ± 1.6 | 13.3 ± 1.9 | p = 0.83 | |
| Cr3/4 | 13.3 ± 1.3 | 13.6 ± 1.6 | p = 0.33 | 14.0 ± 1.6 | 14.0 ± 1.7 | p = 0.50 | |
| Crc | 14.9 ± 1.5 | 14.3 ± 1.8 | p = 0.038 | 14.9 ± 1.2 | 15.6 ± 1.6 | p = 0.89 | |
| R1/4 | 15.7 ± 1.4 | 16.3 ± 1.6 | p = 0.044 | 15.8 ± 1.1 | 16.2 ± 1.4 | p = 0.012 | |
| R1/2 | 16.7 ± 1.2 | 16.6 ± 1.4 | p = 0.76 | 16.4 ± 1.3 | 16.9 ± 1.5 | p = 0.19 | |
| R3/4 | 16.8 ± 0.9 | 17.2 ± 1.2 | p = 0.17 | 17.3 ± 1.1 | – | – | |
| Rc | 17.8 ± 0.8 | – | – | 17.5 ± 0.9 | – | – | |
SD standard deviation, O crypt, no calcification, Cco coalescence of cusps, Ci initial calcification, Cr1/2 crown 1/2 complete, Cr3/4 crown 3/4 complete, Crc crown complete, R1/4 root length 1/4, R1/2 root length 1/2, R3/4 root length 3/4, Rc root length complete.