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Endosseous implant surface topography directly affects adherent cell responses following implantation. The aim of this study was to examine the impact of nanoscale topographic modification of titanium implants on Osterix gene expression since this gene has been reported as key factor for bone formation. Titanium implants with smooth and nanoscale topographies were implanted in the femurs of Osterix-Cherry mice for 1-21 days. Implant integration was evaluated using scanning electron microscopy (SEM) to evaluate cell adhesion on implant surfaces, histology, and nanotomography (NanoCT) to observe and quantify the formed bone-to-implant interface, flow cytometry to quantify of Osterix expressing cells in adjacent tissues, and real-time PCR (qPCR) to quantify the osteoinductive and osteogenic gene expression of the implant-adherent cells. SEM revealed topography-dependent adhesion of cells at early timepoints. NanoCT demonstrated greater bone formation at nanoscale implants and interfacial osteogenesis was confirmed histologically at 7 and 14 days for both smooth and nanosurface implants. Flow cytometry revealed greater numbers of Osterix positive cells in femurs implanted with nanoscale versus smooth implants. Compared to smooth surface implants, nanoscale surface adherent cells expressed higher levels of Osterix (Osx), Alkaline phosphatase (Alp), Paired related homeobox (Prx1), Dentin matrix protein 1 (Dmp1), Bone sialoprotein (Bsp), and Osteocalcin (Ocn). In conclusion, nanoscale surface implants demonstrated greater bone formation associated with higher levels of Osterix expression over the 21-day healing period with direct evidence of surface-associated gene regulation involving a nanoscale-mediated osteoinductive pathway that utilizes Osterix to direct adherent cell osteoinduction.

Endosseous implant surface topography directly affects adherent cell responses following implantation. The aim of this study was to examine the impact of nanoscale topographic modification of titanium implants on Osterix gene expression since this gene has been reported as key factor for bone formation. Titanium implants with smooth and nanoscale topographies were implanted in the femurs of Osterix‐Cherry mice for 1–21 days. Implant integration was evaluated using scanning electron microscopy (SEM) to evaluate cell adhesion on implant surfaces, histology, and nanotomography (NanoCT) to observe and quantify the formed bone‐to‐implant interface, flow cytometry to quantify of Osterix expressing cells in adjacent tissues, and real‐time PCR (qPCR) to quantify the osteoinductive and osteogenic gene expression of the implant‐adherent cells. SEM revealed topography‐dependent adhesion of cells at early timepoints. NanoCT demonstrated greater bone formation at nanoscale implants and interfacial osteogenesis was confirmed histologically at 7 and 14 days for both smooth and nanosurface implants. Flow cytometry revealed greater numbers of Osterix positive cells in femurs implanted with nanoscale versus smooth implants. Compared to smooth surface implants, nanoscale surface adherent cells expressed higher levels of Osterix (Osx), Alkaline phosphatase (Alp), Paired related homeobox (Prx1), Dentin matrix protein 1 (Dmp1), Bone sialoprotein (Bsp), and Osteocalcin (Ocn). In conclusion, nanoscale surface implants demonstrated greater bone formation associated with higher levels of Osterix expression over the 21‐day healing period with direct evidence of surface‐associated gene regulation involving a nanoscale‐mediated osteoinductive pathway that utilizes Osterix to direct adherent cell osteoinduction. [ABSTRACT FROM AUTHOR]

Objectives: The objective of this study was to determine the relative osteogenic behavior of titanium implants with or without a porous tantalum modification when placed with a gap between the implant and existing bone. Materials and Methods: A gap‐healing model in the rabbit tibia was used for placement of titanium implants. Forty‐eight rabbits received 96 implants, with 48 of the implants containing a porous tantalum middle section and the remaining 48 implants were composed of solid titanium. After 4, 8, and 12 weeks of healing, biomechanical stability was measured with removal torque testing, implant‐adherent cells were isolated for analysis of osteogenic gene expression, and histomorphometric analysis was performed on sections of the implants and surrounding bone. Results: Increased osteogenic activity at 4 weeks was demonstrated by upregulation of key osteogenic genes at implants containing porous tantalum which was accompanied by greater bone–implant contact at 4, 8, and 12 weeks and significantly greater removal torque at 8 and 12 weeks. Conclusions: Implants containing porous tantalum demonstrated increased peri‐implant bone formation within this gap‐healing model as shown by significant differences in biomechanical and histomorphometric outcomes. Such implants may represent an alternative to influence bone healing in surgical sites with an existing gap. [ABSTRACT FROM AUTHOR]