PubMed Health⌕ Search

Biomedical subjects

L Bondemark

Publications and source records attributed to L Bondemark.

20 records · Page 2Linked to original sources

Distalization of maxillary first and second molars simultaneously with repelling magnets.

The aim of this study was to analyse the clinical and the dentofacial effects of using repelling SmCo5 magnets for distalization of maxillary first and second molars simultaneously. Ten consecutive patients, aged 12.0-15.6 years, with Class II malocclusion and moderate space deficiency in the upper jaw were orthodontically treated using prefabricated repelling SmCo5 magnets. The magnets were attached buccally in the premolar and first molar area to a fixed orthodontic applicance. When the magnets were activated, the molars could move freely distally. The tooth movements were analysed by measurements on dental casts, lateral photographs of dental casts, and lateral skull radiographs before and after treatment. The mean treatment time was 16.6 weeks and all maxillary molars could be distalized to a Class I relationship. The mean molar crown movement was 4.2 mm, and the maxillary first molars tipped distally and rotated disto-buccally by 8.0 and 8.5 degrees, respectively. The reciprocal forces resulted in a slightly increased inclination of the upper incisors. It was found that simultaneous distalization of first and second maxillary molars with repelling magnets could be an alternative to ordinary orthodontic treatment methods. As the molar distalization was achieved during a relatively short period, occlusal adjustment, including uprighting and derotation of the maxillary molars as well as post-treatment retention, seems recommendable.

Adolescent↗

Force-distance relation and properties of repelling Sm-Co5 magnets in orthodontic clinical use: an experimental model.

In recent years, magnets and magnetic forces have been suggested as an alternative to traditional orthodontic devices such as elastics, springs and wires. The purpose of this study was to analyze the reliability and the output of forces for prefabricated orthodontic repelling Sm-Co5 magnets and the force conditions for the magnets after 5 months of maximal loading. The test-machine consisted of a jig where the tested pair of repelling magnets was mounted close to the clinical situation. With a cylindrical strain gauge transducer, a micrometer screw, a bridge-amplifier, and a Mingograph jet recorder, force-distance diagrams were constructed. The force-distance diagrams showed that the force-distance curve was hyperbolic and that the mean force when the magnetic pole faces were almost in contact with each other was 214.9 g, SD 13.42 g. The variation of magnetic force between different Sm-Co5 magnets was 6-9%. The difference in force before and after 5 months of maximal loading of the magnets was not significant. The test results indicate that with proper handling of the forces according to the new force diagrams, the system is reliable for orthodontic use.

Cobalt↗