A hydroxyapatite-coated thin titanium disc which sits on and is osseointegrated with the palatal cortical bone beneath the periosteum, and used as a means of anchorage during orthodontic treatment. It is placed surgically and about 10 weeks later, after osseointegration has taken place, it is surgically exposed. It is removed on completion of orthodontic treatment under local anaesthetic. Onplants have advantages over implants in that they are less invasive, can be removed on completion of treatment, and are less expensive.
Skeggs R. M., Benson P. E., Dyer F. Reinforcement of anchorage during orthodontic brace treatment with implants or other surgical methods. Cochrane Database of Systematic Reviews 2007, Issue 3. Art. No.: CD005098. DOI: 10.1002/14651858.CD005098.pub2Kalha A. S. Is anchorage reinforcement with implants effective in orthodontics? Evidence-Based Dentistry 2008;9:13–14.