| 摘要 |
A drill is used on a jaw bone with overlying soft tissue and underlying, more solid bone. The drill comprises a first portion which is provided with one or more first cutting edges and with a first width or diameter. Arranged behind the first portion there is a second portion which is provided with one or more second cutting edges and with a second diameter exceeding the first width or diameter. The first portion can cooperate with soft tissues to form an initial hole, and the second portion can cooperate with the soft tissue and the more solid bone in order to enlarge said hole and create a countersunk hole in the more solid bone. The first portion is also depicted to cooperate with the more solid bone, during the second portion's formation of the countersunk hole, in order to provide a guidance hole or marker hole in the bottom of the countersink. |
