[Retrospective evaluation and experimental radiographic study on bone reaction concomitant with orthodontic tooth movement].

Concomitant with orthodontic tooth movement a radiographically dense zone of high mineralisation can be observed on the periodontal tension side. This zone consists of the alveolar cortical bone and mineralized osteoid. This bone reaction has not evoked much interest in orthodontic literature in the past. In a retrospective study, orthopantomograms of children in orthodontic treatment were evaluated, and the discussed reaction was studied in relation with different treatment parameters. Opaque bone layers were found in cases in whom the orthopantomogram was made within 6 months after initiating tooth movement. When using elastics for tooth movement the bone reaction under discussion was comparatively rare. There is no proneness to root resorption in teeth showing the described adjacent bone reaction. Bone reaction was also studied with a densitometric radiological procedure. In all 9 cases the bone reaction was observed.