Impact of Modified Triple Salt Monolayer Coating on Osseointegration of Endosteal Implants

Background: Improvements in osseointegration and bone healing as a result of surface modifications indicate that the time frame following implantation necessary to achieve biomechanical capacity for functional load-bearing may be reduced. In this context, a potassium peroxymonosulfate-based modified triple salt monolayer could potentially serve as a viable surface coating to further augment bone regenerative capabilities of endosteal implants. Methods: Implants with resorbable blast media textured surface [Tapered Pro 3DS RBT (Laser-Lok), BioHorizons] (CTRL) were treated with a potassium peroxymonosulfate-based modified triple salt coating process to generate a stabilized monolayer (Oxion). Prior to surgical intervention, implants were subjected to surface characterization. Subsequently, implants were evaluated in a large, preclinical sheep model (n = 14 sheep). A total of 12 implants were placed bilaterally in the submandibular ramus (3 implants per group per sheep per side) and allowed to heal for 3- and 12-weeks (7 sheep per time point). Following the allocated healing time, the animals were euthanized, mandibles harvested, and samples isolated for histomorphometric and nanoindentation analysis, along with biomechanical assessment through implant lateral load testing. Results: The Oxion coated implant's surfaces yielded lower contact angle (p < 0.001) and higher surface free energy values (p < 0.001) relative to the CTRL surface. Bone-to-Implant Contact (BIC) and Bone Area Fractional Occupancy (BAFO), which were used to quantify degrees of osseointegration, were statistically homogeneous at both healing times between Oxion and CTRL surfaces. Biomechanical testing, i.e. nanoindentation and lateral loading, demonstrated improved values for Oxion implants at both early and advanced healing time points compared to CTRL (p = 0.001). Conclusion: Implant failures continue to manifest during the initial months following implant insertion due to a variety of reasons, including inadequate osseointegration, or in cases involving clinical diseases and comorbidities. These findings suggest that the time frame following implantation necessary to achieve biomechanical capacity for functional load-bearing can be further reduced due to the Oxion surface coating in addition to the potential for enhanced early biomechanical integration relative to CTRL.