Table 1.
Linear regression analyses of log‐RP against log‐enamel growth
| Enamel | n | Intercept | Slope | r | r 2 | P | Residual |
|---|---|---|---|---|---|---|---|
| Thickness: RP vs. EA | |||||||
| All | 40 | 0.755 | 0.569 | 0.697 | 0.486 | < 0.001* | 55% |
| M1 | 25 | 0.826 | 0.489 | 0.615 | 0.378 | 0.001* | 64% |
| M2 | 15 | 0.639 | 0.703 | 0.806 | 0.650 | < 0.001* | 43% |
| Thickness: RP vs. AET | |||||||
| All | 40 | −0.426 | 0.432 | 0.604 | 0.365 | 0.002* | 63% |
| M1 | 25 | −0.391 | 0.384 | 0.577 | 0.333 | 0.004* | 68% |
| M2 | 15 | −0.542 | 0.580 | 0.720 | 0.519 | 0.002* | 44% |
| Rate: RP vs. DSR | |||||||
| M1 | 15 | 0.817 | −0.098 | 0.009 | 0.000 | 0.714 | 98% |
Tooth types: M1, permanent first molar; M2, permanent second molar. *Significant. AET, average enamel thickness; DSR, daily secretion rate; EA, enamel area; RP, Retzius periodicity. RP vs. EA: lower M1 (n = 13): r 2 = 0.491, P = 0.007*.Upper M1 (n = 12): r 2 = 0.633, P = 0.001*.Lower M2 (n = 12): r 2 = 0.603, P = 0.002*.RP vs. AET: lower M1 (n = 13): r 2 = 0.338, P = 0.037*.Upper M1 (n = 12): r 2 = 0.482, P = 0.012*.Lower M2 (n = 12): r 2 = 0.287, P = 0.072. Upper M2 excluded from separate analysis as n = 3.