Preparation and Characterization of NiTi-Based Implants for Cranio-Maxillo-Facial Surgery

The aim of these studies was to form NiTi and TiNiCo body temperature activated and superelastic staples for clinical joining of mandible and face bone fractures. 

The alloys were obtained by VIM technique. Hot and cold processing were applied to obtain wires with required diameters. The martensitic transformation was studied by DSC, XRD and TEM. The shape memory effects were measured by a bend and free recovery ASTM F2082-06 test. The superelasticity was recorded in the three-point bending cycles in an instrument equipped with a Hottinger force transducer and LVDT. Excellent superelastic behaviour was obtained after cold working and annealing at 400-500^oC. The staples for fixation of bone fractures were formed under the flame of gas burner using the pliers for forming the wires. Compression forces of superelastic staples made from the wires of different diameters were from 10 to 25 N.

The body temperature activated shape memory staples were applied for the fixation of mandibular condyle fractures. The inconveniences connected with the need of cooling the staples in cooled physiological saline or liquid nitrogen and deformation  them at the low temperature, below M_f temperature, before  placing them in the drilled holes in the bone fragments can be avoided by using of superelastic staples which ends can be easily mechanical straighten at the room temperature by using surgical tools.

In experiments on the skull models, fixation the facial fractures by using shape memory and superelastic staples were compared. The superelastic staples were used in osteosynthesis of zygomatico-maxillo-orbital fractures.