Abstract: An improved dental burr and method of preparing a tooth for a porcelain to metal restoration. The method comprises the forming of a test trough of a precise depth in the tooth enamel across a tooth and removing the necessary enamel from the rest of the tooth to a corresponding depth so as to provide the space necessary to accommodate the required thickness of the porcelain restoration. To secure the desired optimum depth, a dental burr is provided with a stop flange to limit the depth of the cut or trough. In one embodiment the stop flange is rendered detachable connected to the burr so as to render the burr useful for other procedures.