Quantification of Osseointegration of Plasma-Polymer Coated Titanium Alloyed Implants by means of Microcomputed Tomography versus Histomorphometry

Abstract

A common method to derive both qualitative and quantitative data to evaluate osseointegration of implants is histomorphometry. The present study describes a new image reconstruction algorithm comparing the results of bone-to-implant contact (BIC) evaluated by means of µCT with histomorphometry data. Custom-made conical titanium alloyed (Ti6Al4V) implants were inserted in the distal tibial bone of female Sprague-Dawley rats. Different surface configurations were examined: Ti6Al4V implants with plasma-polymerized allylamine (PPAAm) coating and plasma-polymerized ethylenediamine (PPEDA) coating as well as implants without surface coating. After six weeks postoperatively, tibiae were explanted and BIC was determined by µCT (3D) and afterwards by histomorphometry (2D). In comparison to uncoated Ti6Al4V implants demonstrating low BIC of 32.4% (histomorphometry) and 51.3% (µCT), PPAAm and PPEDA coated implants showed a nonsignificant increase in BIC (histomorphometry: 45.7% and 53.5% and µCT: 51.8% and 62.0%, resp.). Mean BIC calculated by µCT was higher for all surface configurations compared to BIC detected by histomorphometry. Overall, a high correlation coefficient of 0.70 (p < 0.002) was found between 3D and 2D quantification of BIC. The μCT analysis seems to be suitable as a nondestructive and accurate 3D imaging method for the evaluation of the bone-implant interface.

Novel application and validation of in vivo micro‐CT to study bone modelling in 3D

“…Bone is multifunctional, playing roles in mechanical support, protection, mineral homeostasis and hematopoiesis. Bone histomorphometry has been an essential technique for understanding tissue‐level events and bone adaptation physiology in basic and applied biomedical research . Histomorphometry on a bone biopsy specimen has been the gold standard for clinical and pathologic evaluation .…”

“…Several limitations have been associated with bone histology such as time and cost‐effectiveness, difficulties with specimen preparation and sectioning. Additionally, the results are often limited to two‐dimensional (2D) interpretations of the bone tissue …”

“…The use of three‐dimensional (3D) technologies in biological and radiological imaging research has been advocated to replace 2D systems . However, newer systems need to be validated prior to broader acceptance.…”

“…Although this mathematical method of histomorphometry and stereology can be extrapolated with diagnostic significance in mineralized bone tissue experiments, bone imaged in 3D can be better understood . New imaging techniques and corresponding analysis such as micro‐computed tomography can offer superior visualization and also overcome the limitations of 2D methodologies .…”

“…New imaging techniques and corresponding analysis such as micro‐computed tomography can offer superior visualization and also overcome the limitations of 2D methodologies . Furthermore, micro‐CT data sets can be subjected to traditional 2D analysis should that be desired …”