Premolar extraction in orthodontics and its effect on mandibular kinematics: Axiographic data
Description
The purpose of this study was to test whether orthodontic premolar teeth extraction had an influence on mandibular kinematics. Forty-five orthodontically treated patients (P4ex group) with premolar teeth extraction were compared with 45 paired untreated controls (P4 group). Symmetric movements were registered in 3D for both right and left sides, using a diagnostic computerised axiograph CADIAX. We measured condyle symmetric movements, specially mandibular lateral translation during protrusion/retrusion (∆Y) and speech (SP-∆Y), and the amount of rotation (SP-G) and length of the movement during speech (SP-3D). Finally the amount of Retral stability was measure (R-ST). All the mmeasurements were taken for the right (R) and left (L) sides . We found that orthodontic extraction of first premolars might disrupt jaw kinematics by increasing the amount of lateral deviations of the tracings describing the condylar movements in 25% of the cases