RELATIONSHIP BETWEEN THE SEQUENCE OF CALCIFICATION AND THE SEQUENCE OF ERUPTION OF THE MANDIBULAR MOLAR AND PREMOLAR TEETH

¹ The Fels Research Institute, Antioch College, Yellow Springs, Ohio

1. The relationship between the sequence of calcification and the sequence of eruption of the mandibular molar and premolar teeth was investigated in 36 boys and girls who were definitely either P₂M₂ or M₂P₂ in tooth formation and tooth eruption.

2. Twenty-one out of 22 children with the P₂M₂ sequence of formation continued to be P₂M₂ in eruption.

3. Half of 14 children M₂P₂ in formation shifted to the P₂M₂ sequence in eruption.

4. Analysis of individual cases shows that in all cases the M₂P₂ formation sequence was characterized by early formation of M₂ but in the children who shifted to the P₂M₂ sequence the early advantage in formation was not held.

5. The dangers of extrapolating from the sequence of formation to the sequence of eruption were emphasized, particularly in relationship to fossil finds.