Rotary drive cutter for dentistry

A reamer, comprising:

• a peeso reamer comprising a cutting portion formed on a tip side,
• a shank formed in a base, and
• a neck part formed between the cutting portion and the shank;
• wherein the neck part comprises a tapered portion, which is wider on the tip side and narrower on a side closer to the base, and the neck part includes a straight portion, which has a constant thickness along the length of the straight portion and a smooth surface;
• wherein the straight portion has a diameter equal to a diameter of an end of the tapered portion on the side closer to the base, and the neck part includes a connecting part between the straight portion and the shank, which gradually becomes thicker towards the shank,
• wherein a length of the straight portion is at least 0.5 mm and at most 2.0 mm.

A drill, comprising:

• a gates drill comprising a cutting portion formed on a tip side,
• a shank formed in a base and having a whirl-stop formed therein, and
• a neck part formed between the cutting portion and the shank;
• wherein the neck part comprises a tapered portion, which is wider on the tip side and narrower on a side closer to the base, and the neck part includes a straight portion, which has a constant thickness along the length of the straight portion and a smooth surface;
• wherein the straight portion has a diameter equal to a diameter of an end of the tapered portion on the side closer to the base, and the neck part includes a connecting part between the straight portion and the shank, which gradually becomes thicker towards the shank,
• wherein a length of the straight portion is at least 0.5 mm and at most 2.0 mm.