Drill bit, drill kit and method for drilling a cavity or a recess into a skull

A method for drilling a cavity or a recess into a skull, wherein the cavity or the recess is configured to receive an implantable fixture screw unit of a hearing aid system, wherein the method comprises:

• applying an incision hole to a bone layer of the skull by using a first tool;
• cleaning the incision hole by using a cleaning tool;
• arranging a guiding tool into the cleaned incision hole, wherein the guiding tool includes a hollow tube;
• and
• applying a drill bit into the hollow tube and drilling the cavity or the recess in a single step,
• wherein the drill bit comprises:
• a first part including a drill tip with a first drill diameter, wherein the drill tip comprises a tip angle of between 137 degrees to 143 degrees along a longitudinal axis of the drill bit and wherein the drill tip comprises a back rake angle of between-1 degree and +1 degree,
• a second part including a plurality of flute blades with a second drill diameter, wherein the second drill diameter is greater than the first drill diameter and
• a transition part which is arranged between the first part and the second part and along the longitudinal axis, wherein the transition part includes a body clearance, and wherein a diameter of the hollow tube is greater than the second drill diameter.