A Validated Method for Titanium Implant Anchorage Analysis using MicroCT and Biomechanical Testing

The use of uncemented titanium endosseous implants for restorative dentistry and orthopaedic surgery has been the standard of care for several decades. Endosseous implantation using uncemented titanium prostheses is commonly performed in trabecular bone sites such as the jaws, vertebrae and ileum. Still, the mechanisms involved in this fascinating and unique interaction between a living tissue and foreign substance are poorly understood. An important reason for the absence of sufficient mechanistic information is the lack of robust experimental models combined with solid tools to analyze structurefunction relationships of the implant-bone system. Qualitative and quantitative ex vivo analysis of peri-implant tissues is typically done by means of light microscopy using thin histological sections following implant removal or thicker ground sections which contain the implant and undecalcified bone [1,2]. These techniques are labor-intensive and thus time-consuming. Moreover, they allow tissue quantification in only a limited number of two-dimensional images, and therefore exhibit inherent deficits in representativeness and/or accuracy. Furthermore, since all of these techniques are destructive, the specimens could not be further subjected to biomechanical testing, precluding correlative analyses to decipher the underlying causative microstructural changes. By contrast, micro-computed tomography (μCT) is nondestructive, relatively fast and produces full, high-resolution three-dimensional (3-D) images of the implant and surrounding bone. Over the last 15 years, high-resolution micro-CT has set new gold-standards for the morphometric analysis of bone microarchitecture. Expectedly, this technology is also increasingly used in the experimental evaluation of endosseous implants. It does not require any specimen preparation and facilitates relatively rapid quantification based on three-dimensional (3D) reconstruction of the entire specimen rather than a limited number of planes typically sampled using 2D methods. The reliability of this technology in assessing 360o PIB is now well-established. It does not expose the specimen to any destructive procedures, a feature enabling combined microstructural-biomechanical evaluation thus attaining unrivaled insights into structure-function relationships of the bone-implant system.