Two different techniques of manufacturing TMJ replacements - A technical report.

Area of Science:

• Maxillofacial Surgery
• Biomaterials Engineering
• Orthopedic Implants

Background:

• Custom-made implants, utilizing CAD/CAM technology, are increasingly used in maxillofacial surgery.
• This study focuses on custom implants for temporomandibular joint (TMJ) reconstruction, presenting novel clinical data.

Purpose of the Study:

• To report clinical outcomes of custom TMJ implants manufactured using two distinct techniques: direct metal laser sintering (DMLS) and computer numerical control (CNC) milling.
• To compare the efficacy and safety of DMLS versus CNC milled implants in TMJ reconstruction.

Main Methods:

• Eleven patients (average age 54) underwent TMJ reconstruction with either DMLS (4 patients) or CNC milled (7 patients) custom implants.
• Patients presented with TMJ hypomobility, facial asymmetry, pain, and swelling, with diagnoses including malignancy and benign conditions.

Main Results:

• Both DMLS and CNC techniques yielded successful TMJ reconstruction with uneventful healing over an average 26.8-month follow-up.
• Significant improvement in maximal interincisal opening was observed post-operation (p < 0.01) with no significant correlation to patient-specific factors.
• No post-operative complications such as facial nerve palsy, infections, or re-ankylosis were reported.

Conclusions:

• Both DMLS and CNC milling are successful techniques for manufacturing custom TMJ implants, suitable for neoplastic lesions and other TMJ disorders.
• A key difference lies in surface finishing: DMLS implants require more subtractive finishing than CNC implants.
• While both methods achieve similar clinical results, DMLS implants exhibit a higher vulnerability to fracture.