Prediction of Tooth Emergence

¹ Forsyth Dental Infirmary-Harvard School of Dental Medicine, Boston, Massachusetts

The association between tooth formation and tooth emergence was determined in 874 Bostonian children (434 males and 440 females) with actual emergence of one or more of the following teeth through the gingival tissues: the permanent maxillary incisors and all permanent mandibular teeth, except third molars. Excluded were individuals with lack of space for the emerging tooth and those with history or evidence of early loss of the deciduous predecessors. Root formation was rated in four stages corresponding to attainment of quarter-segments of the root length. Bone age was assessed with reference to the standards of Greulich and Pyle.¹⁵

Tooth emergence appears to be more closely associated with the stage of root formation than with the chronologic or skeletal age of the child.

The majority of all teeth studied had attained approximately three-quarters of their roots at the time of clinical emergence. The mandibular central incisor and first molar had generally less root development, with half of their roots completed, while the mandibular canine and second molar had just passed the three-quarter stage at emergence.