[Follow-up study of the reaction of the marginal and apical periodontium under the continuous application of force].

Radiological findings and clinical data from existing treatment records have been examined using X2-test for clarification of possible relationships between pathological reaction of the periodontal ligament to continuous application of force and different patient-specific and therapeutic factors. It was shown that 70% of the total group have pathological changes following fixed appliance therapy. Apical root resorption usually could be diagnosed five times more frequently than marginal bone loss. No age-specific relationship was noted. The findings confirmed that active intrusion, extensive tooth movement, interruption of treatment, and in particular the anatomical configuration of the roots codetermine the quality of the periodontal reaction.