Evaluation of force systems from a "free-end" force system.

Introduction: The purpose of this study was to investigate the biomechanical characteristics of a V-bend wire configuration in a free-end system, ie, with 1 end mounted in an orthodontic tube and the other loosely ligated to a bracket. The effects of V-bend position and size, wire dimension, method of ligation, and the inclusion of a second wire in the system were examined.

Methods: Samples of various wire configurations were mounted in a bench testing machine to measure moments and forces at both ends in a standardized configuration resembling a 2-premolar extraction clinical case incorporating a special bracket with a second, frictionless slot.

[The morphology of the facial skull in patients with active acromegaly based on lateral-view teleroentgenograms].

Measurements of skull base, maxilla and mandible were carried out from lateral teleroentgenograms of the skull made in 27 patients with active acromegaly. Total anterior facial height and mandibular branch height were found the most increased both in men and women. Bone changes of the skull base and facial skeleton in patients with active acromegaly did not depend on the disease duration.

[Assessment of the condition of the parodontium in children undergoing maxillary-orthopaedic treatment with reference to malocclusion, groups of teeth and duration of treatment with orthodontic devices].

The condition of the parodontium was studied in 281 children. Group I comprised children with malocclusion treated by maxillary orthopaedic methods, group II--children with non-treated malocclusion, group III--children with normal occlusion. The condition of the parodontium was assessed in various types of malocclusion, in groups of teeth and in relation to the duration of treatment with maxillary-orthopaedic devices.