Anchorage loss due to Herbst mechanics-preventable through miniscrews?

Abstract

Aim: To assess if mandibular incisor proclination and protrusion during treatment with the Herbst/multibracket appliance can be prevented through simple screws (MIs) anchorage.

Material and methods: After a statistical power analysis, 12 Herbst patients with MIs (100% MIs survival) ligated to the Herbst/multibracket appliance to reinforce anchorage were investigated. A control group matched for gender and skeletal maturity treated without MIs anchorage was selected. Pre- and posttreatment cephalograms were analysed for overjet reduction, mandibular incisor proclination (IL/ML), protrusion (Ii-MLp) and intrusion (Ii-ML), as well as occlusal plane inclination (OP/ML) by a single-blinded examiner.

Results: No statistically significant differences between the two groups were found concerning overjet reduction, incisor protrusion- and intrusion or occlusal plane tilt. Although the MIs group generally showed less lower incisor proclination (4.8°) than the group without skeletal anchorage (6.5°), a large interindividual variation was observed.

Conclusion: Interradicular MIs anchorage cannot prevent anchorage loss during Herbst treatment. For the individual patient, the amount of incisor proclination and protrusion remains unpredictable.