A SERIAL STUDY OF THE EFFECTS OF FINGER-SUCKING

¹ University of Michigan, Ann Arbor, Mich.

The maxillary arch form is modified in thumb and finger suckers by elongation of the anterior segment. This acts to produce spacing, labial inclination, and protrusion of the maxillary incisors. There is a definite opening action in the anterior region. True and apparent overjet are increased strongly, although apparent overjet shows a tendency to increase in the nonhabit, as well as the habit, series.

Sucking habits act in opposition to any inherent tendency for a transition from maxillary deciduous anterior spacing to crowding of the permanent anterior teeth. This effect is not evident in the mandibular interiors.

The frequency of distortion of the maxillary arch width at the permanent canine level is limited. In a few cases, however, where a distortion does occur it progresses to a rather marked degree.

Modification of the mandibular arch width at the deciduous first molar and the permanent first molar merely approaches statistical significance. Clinical utility of this fact, however, is questionable.

Maxillary arch width, with the infrequent exception of the permanent canine area, is unaffected.

Contrary to most publications, the effect of thumb and finger habits on the molar occlusion merely approaches statistical significance, and does not attain clinical utility.