| 摘要 |
The base of dental rings (fig.5) is composed of a plastic circular base (fig.1) having inside elastomer material devoid of grooves (fig. 20). At the centre of the base there is placed a plastic cone (fig.3) bearing under construction wax models of crowns or bridges stuck thereto. At four points of the base circumference, there are diametrically located supports whereon there are adapted springs having at their free ends hooks (fig.4) stabilizing the metal rings. This base is used during the fist phase of the bridges and crowns construction. The advantages of the invention are: possibility of using whatever size of rings beyond the standard one, time saving and increase of the service life of the base since mottle body deposition into grooves is abolished, slight displacement of the ring in case of non centered position of the wax model on the plastic cone, and better sticking of same wax models to a plastic cone rather than to an elastomer one. |
