Root repair after injury from mini-screw

Mini-implants and mini-screws are commonly used in orthodontics to provide extra anchorage. One potential insertion site is between the roots in the alveolar process, which results in a risk of damaging the roots of neighbouring teeth. In an animal-experimental study, 20 mini-screws (bracket screw bone anchors, BSBAs) were inserted into the mandible of five beagle dogs. Each dog received two BSBAs in each lower quadrant, between the roots of the second and third, and third and fourth premolars. Sequential point labelling was performed every 6 weeks with vital stains, and apical X-rays were taken every 6 weeks. Radiographic examination demonstrated damage at three roots because of insertion of the BSBAs. Histological examination at these three roots demonstrated an almost complete repair of the periodontal structure (e.g. cementum, periodontal ligament and bone) in a period of 12 weeks, following removal of the screws.