In this article we studied two types of teeth, spherical and conical one. We compared the results with a previous study for the flat tooth. the study of stresses field under these three teeth show that in the soft rocks we prefer to use conical tooth because it is easy to be Implanted in the rock, and this was confirmed by the values of stresses under the tooth. Either in hard rock and due to our need for big values of pressure to shatter the rock we prefer to use spherical tooth because of its property of forming tow cons of stresses under tooth and therefore can be good in drilling hard rock..