The effect of maternal smoking on the timing of deciduous tooth eruption.

The mean age at the eruption of the first deciduous tooth was calculated for the 10,443 children of a birth cohort in 1966 in Northern Finland. Eruption was advanced by one week on average in the 1,559 children whose mothers had smoked during pregnancy, the difference between these and their controls being statistically significant. A regression analysis on the age at tooth eruption showed highly significant "explanatory" variables, in addition to maternal smoking, to be weight and height at birth and at 6 months, and gestational age, while place of residence on a north-south axis was of lesser significance.