| 摘要 |
A maxillary protraction device (12) characterized with a chin-cup (1); one or more front hook-levers (2) on the front section of said chin-cup (1) to exert a force horizontally and forwards to the maxilla; at least two lateral linear hooks (5) located at the sides of the chin-cup (1) to exert an upwards force to the mandible, front recess (6) to be used for engaging the hooks (2 and 5) to the chin-cup (1) to which the front hook is engaged in a length-adjustable manner, in the same number as that of hooks; and fixing members (9) in the same number as that of hooks.
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