Can we grow mandibles with bone-anchored plates for class 2 correction? 6 MINUTE SUMMARY

orthodontics In summary

Join me for a summary exploring an innovation of the use of bone-anchored plates in class 2 correction. This was a clinically novel idea presented by Hugo De Clerck, who has been an innovator in the use of bone-anchored plates and has published seminal papers on the topic for class 3 treatment. Hugo explores the use of bone-anchored plates in the mandible, combined with a Herbst appliance. He presents his data of 90 patients treated in Brussels by his research team. PROTOCOL Customised bone anchored plates in lower anterior mandible – digitally designed per patient with surgical guide Transmucosal between lower canine and 1st premolar Herbst: modified to attach from upper 1st molar to the lower bone anchored plates Procline upper incisors prior to fitting Bone anchored-Herbst Expansion of the upper arch 2-3 modifications to Herbst piston to lengthen during treatment Duration 10 months HOW DOES IT WORK Growth of the mandibular body: mainly, bone modelling. Average growth 5-7mm, whereas conventional herbst 2-2.5mm of chin projection. New growth of bone as ramus moves backwards, resulting in lengthening of the mandible Force generation: in similar to the conventional functional appliance, with contraction of medial and lateral pterygoid and stretching of the suprahyoid and temporalis muscle Lower incisor proclination: No lower incisor proclination: There is a distal force on the mandibular dentition instead of a forward force from conventional functional appliances, due to the appliance attaching to the mandibular body, not the dentition Condylar displacement: Longer duration, of up to 10 months which results in stimulation of growth of the body of the mandible, conventionally this stops with a herbst as the lower incisors procaine, resulting in only 2 months of condylar displacement and therefore less stimulation of growth Glenoid fossa remodelling. The glenoid fossa remodelled in a forwards direction, however it was small and unpredictable, with some posterior remodelling Rotation of mandible – similar to the conventional functional appliance, a posterior rotation reduces the effects, anterior rotation enhances, for every 1 degree 1.1mm increase projection. Achieve via expansion and removable appliance Upper molar distalisation: Hugo saw this as unfafourable and advised lengthening the herbst piston to reduce upper molar distalisation, therefore maximising mandibular lengthening Age 13-15 Not possible with miniscrews, due to the quantity of force Breakages of Herbst still occur Is growth maintained long term – unable to state No control as requirement for cbct of untreated patients. Contributions Contents: Farooq Ahmed Edited and produced: Farooq Ahmed