| 摘要 |
<p>The orthodontic support has a square-section groove to take a square-section straightening wire. The groove is lined along its whole length with metal insert mounted immovably in the plastic. The edges of the insert make only a thin line on the plastic surface. The metal insert may be held fast in te plastics either by making it of dovetail section, and in addition tapering from the ends to the middle of its length, or by making it of square section with roughened sides to which the plastics can adhere.</p> |
