Bone growth in rapid prototyped porous titanium implants

Abstract

Two porous titanium implants with a pore size diameter of 800 and 1200 microm (Ti800 and Ti1200) and an interconnected network were manufactured using rapid prototyping. Their dimensions and structure matched those of the computer assisted design. The porosity of the implants was around 60%. Their compressive strength and Young's modulus were around 80 MPa and 2.7 GPa, respectively. These values are comparable to those of cortical bone. The implants were implanted bilaterally in the femoral epiphysis of 15 New Zealand White rabbits. After 3 and 8 weeks, abundant bone formation was found inside the rapid prototyped porous titanium implants. For the Ti1200 implants, bone ingrowth was (23.9 +/- 3.5)% and (10.3 +/- 2.8)%, respectively. A significant statistical difference (p < 0.05) was found for bone ingrowth in the Ti1200 between the two delays. The percentage of bone directly apposited on titanium was (35.8 +/- 5.4)% and (30.5 +/- 5.0)%. No significant difference was found for bone-implant contact between the different time periods and pore sizes. This work demonstrates that manufacturing macroporous titanium implants with controlled shape and porosity using a rapid prototyping method is possible and that this technique is a good candidate for orthopedic and maxillofacial applications.

Porous titanium scaffolds fabricated using a rapid prototyping and powder metallurgy technique

“…By pouring molten CoCr into porous ceramic moulds that had been fabricated using a three-dimensional printing technique, textures with five layers of distinct geometric definition were created. Using a similar investment casting technique, LopezHeredia et al created a porous titanium scaffold with 100% interconnected structure and porosity of around 60% [27,28]. Abundant bone formation was found inside the rapid prototyped titanium scaffolds after 3 and 8 weeks of implantation in the femoral epiphysis of New Zealand White rabbits [27].…”

Open Celled Porous Titanium

“…An example of this is the use of investment casting with rapid prototyping methods, such as multijet modelling [85] , used to produce a complex porous structured wax or polymer pattern to a CAD design which is used as the investment [86] . This method has been used to produce Ti with a total porosity of 60 % and a compressive strength of 80 MPa, though it should be noted that the surface contamination of carbon was very significant (being measured by XPS at 62.7 at%) which is unlikely to be optimal for titanium or its alloys.…”

Selective laser-melted fully biodegradable scaffold composed of poly(d,l-lactide) and β-tricalcium phosphate with potential as a biodegradable implant for complex maxillofacial reconstruction:In vitroandin vivoresults

“…Therefore, the design of porosity is integrated during the planning of the virtual model to enhance possible cell and vascular supply and bone ingrowth. 12 Porosity attributable to process parameters cannot be controlled and is therefore not predictable. Parameters involving maximum temperatures during the process have also been established to minimize thermal damage to the materials caused by decreased molecular mass.…”