Orthodontic Bone Anchor
The technique of using a fixed anchorage point for precise orthodontic alignment of posterior teeth has become a standard procedure in orthodontics mainly in Asian countries for more than a decade and is now gaining more popularity in other parts of the world. For the development of the system, feedbacks were collected from more than 100 oral and maxillofacial surgeons and orthodontists working in US , Japan, Canada, Europe and Hong Kong were obtained.
The newly designed orthodontic bone anchor (OBA) system is aimed to be implanted into the jaw bone via an intraoral approach and used as a stable fixation point for the orthodontic procedures. This system eliminates the need for headgear or similar extra-oral anchorage and able to offer more control than the traditional techniques. The system is composed of a variety of screw anchors, plate anchors, and respective instruments for implementation.
The anchor devices of OBA system provide fixed anchorage for improved orthodontic control of tooth movement and enable immediate loading of anchorage force for the teeth to be moved. They can be used in combination with a variety of orthodontic arch wires, elastics and springs.
The screw anchors are available with thread lengths of 6 and 8mm (self-drilling) as well as 10mm and they are all designed for self-tapping. A 1.5 mm non-threaded gingival collar beneath the head was added to protect the soft tissue from compression and prevent burying of the screw heads. All anchor screws have through-holes that accommodate orthodontic wire with a cross section of 0.022 x 0.028 in. The thread diameter of the screws is only1.55mm and this allows for placement into the alveolar bone between the tooth roots.
In cases where a strong fixation is required or more favorable orthodontic vectors are needed, plate anchors are included in the set as well. They can be adapted to the patients bony anatomy and position further away from the tooth roots. The anchor plates can be fixed with self-drilling screws (1.55mm). It is recommended to use at least three screws per plate for optimal fixation. If any screw gets loose upon insertion in the bone, emergency screws (1.85mm) are available in the set for use. The plate anchor neck is malleable to allow for later adjustments if necessary.
All implants are manufactured from commercially pure (CP) titanium and titanium alloy (Ti-6Al-7Nb). The set contains a screw driver handle with hex coupling and the new Matrix Midface screwdriver blade as well as bending pliers and plate cutters.
Not intended for use in:
- Less than 5mm bone thickness or insufficient bone quality
- Deciduous or mixed dentition
- Active or chronic infection
- Abnormal habits of mastication or bruxism
Figure Plate anchor
Case images courtesy of Lim K Cheung, Hong Kong, HK
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