Medical instrument assembly and a method of manufacturing the same

A method of manufacturing a medical instrument assembly by MIM technology comprising:

• a) providing a mold including a sprue and at least two mold cavities connected via an interconnecting runner, each of the mold cavities at least partially corresponding to or approximating the shape of a medical instrument;
• b) injecting a molding material including a metal powder via the sprue and the runner into the mold cavities to form a green body including at least two connected green body portions corresponding to the mold cavities and the connective runner;
• c) removing the green body from the mold,
• d) debinding the green body, and
• e) densifying the green body by sintering at a temperature above 1050° C. to a final density of more than 90% of the theoretical density, so as to provide a metal structure including at least two interconnected medical instruments corresponding to the shape of the cavities.

A metal injection molded endodontic instrument comprising in weight %:

• 15-30 Cr,
• 8-16 Ni,
• 0.01-5 Mo,
• 0.01-1 Cu,
• 0.09-1 Mn,
• less than 0.14 C,
• less than 0.12 O,
• balance Fe and incidental impurities;
• and
• said endodontic instrument having a hardness in the range of 55-75 HRB and a yield strength in the range of 150-240 MPa.

A method of cleaning an apical portion of a root canal of a tooth, comprising:

• a) providing a metal injection molded endodontic instrument including a gripping portion configured for gripping the instrument with a hand piece, and a cutting portion sized for the apical part of the root canal, the endodontic instrument comprising in weight %:
• 15-30 Cr,
• 8-16 Ni,
• 0.01-5 Mo,
• 0.01-1 Cu,
• 0.09-1 Mn,
• less than 0.14 C,
• less than 0.12 O,
• balance Fe and incidental impurities, and
• having a hardness in the range of 55-75 HRB and a yield strength in the range of 150-240 MPa;
• b) gripping the gripping portion of the endodontic instrument with a hand piece;
• c) inserting at least a part of the cutting portion in the apical part of the root canal;
• and
• d) powering the hand piece for cutting tissue and thereby cleaning the apical part of the root canal.

A method of cleaning a root canal of a tooth, comprising:

• a) cleaning the root canal until an apical part of the root canal is reached;
• b) providing a metal injection molded endodontic instrument including a gripping portion configured for gripping the instrument with a hand piece, and a cutting portion sized for the apical part of a root canal, the endodontic instrument comprising in weight %:
• 15-30 Cr,
• 8-16 Ni,
• 0.01-5 Mo,
• 0.01-1 Cu,
• 0.09-1 Mn,
• less than 0.14 C,
• less than 0.12 O,
• balance Fe and incidental impurities, and
• said endodontic instrument further having a hardness in the range of 55-75 HRB and a yield strength in the range of 150-240 MPa;
• c) gripping the gripping portion of the endodontic instrument with a hand piece;
• and
• d) powering the hand piece and advancing the cutting portion in the apical part of the root canal for cutting tissue and thereby cleaning the apical part of the root canal.