| 摘要 |
Two slides are slidably fitted into each of two through openings extending in a parallel relationship through a base block and two opposite holders extend perpendicularly from outer end portions of both slides. A threaded rod loosely extends through one of the slides is screw threaded into the other slide to adjust a spacing between the opposite holders. The base block is disposed opposite another identical one so that the holders on the former are aligned with those on the latter and have occluding models for the jaws held by their serrated end portions.
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