There are several reports on the extraction of lower deciduous canines for treatment of crowded lower incisors. In these cases, many clinicians recognized a change in dental arch form resulting from lingual tipping of the lower incisors and a lack of space for the erupting lower premolars.
The present study attempted to evaluate the influence on dental arch form caused by the early extraction of the canines.
The subjects were 28 children, who showed a lack of space for the erupting lower incisors at dental stages TIC or IIIA, and were divided into three groups as follows:
1. The group maintains space by utilizing lingual arch after extraction of lower deciduous canines.
2. The group not utilizing a space maintainer after extraction of lower deciduous canines.
3. The disking group on the approximal surface of the lower canines. Dental plaster models and lateral roentgenographic cephalograms of each child were taken just prior to and 12 months after extraction, with shedding or disking on approximal surface of the lower deciduous canines. The results were shown as follows:
1) Lingual tipping arose in the lower incisors and first deciduous molars in the group not utilizing a space maintainer.
2) Available arch length decreased in both groups with extracted lower deciduous canines.
3) Buccal movement of deciduous molars was observed just in the disking group.
4) Buccal movement of the first molars was observed in all groups.