The use of titanium implants and prosthodontic techniques in the preparation of non-human primates for long-term neuronal recording studies

Investigators that require the chronic implantation of hardware on the non-human primate skull are often challenged with the possible failure of head implants. To improve the success rate of our head implants, titanium anchor screws, referred to as titanium endosseous implants, were implanted in the skulls of six macaques. Techniques adapted from the processing of dentures were utilized to pre-fabricate an acrylic "skull cap", which provided the mechanical support structure for our study-specific hardware. A two-stage procedure adapted from dentistry (Brånemark et al., 1977) was employed for the placement of titanium endosseous implants in the skull. This two-stage technique incorporates the principles of osseointegration and a healing period. Of the six skull-anchored implants prepared implementing the methods described in this paper, we have not experienced any failures. Additionally, all of the titanium endosseous implants examined post mortem were functionally successful (n=30). Histology results confirmed that there was healthy bone in direct contact with the titanium endosseous implants. The dense cortical bone of the macaque skull is ideal for the implantation of titanium endosseous implants. Titanium endosseous implants have provided secure, functional anchor points for the attachment of hardware to the macaque skull and have resulted in healthy, stable head implants that can remain on the skull for extended periods of time.