Implant functionalization with mesoporous silica: A promising antibacterial strategy, but does such an implant osseointegrate?

Objectives: New strategies for implant surface functionalization in the prevention of peri-implantitis while not compromising osseointegration are currently explored. The aim of this in vivo study was to assess the osseointegration of a titanium-silica composite implant, previously shown to enable controlled release of therapeutic concentrations of chlorhexidine, in the Göttingen mini-pig oral model.
Material and Methods: Three implant groups were designed: macroporous titanium implants (Ti-Porous); macroporous titanium implants infiltrated with mesoporous silica (Ti-Porous + SiO ₂ ); and conventional titanium implants (Ti-control). Mandibular last premolar and first molar teeth were extracted bilaterally and implants were installed. After 1 month healing, the bone in contact with the implant and the bone regeneration in the peri-implant gap was evaluated histomorphometrically.
Results: Bone-to-implant contact and peri-implant bone volume for Ti-Porous versus Ti-Porous + SiO ₂ implants did not differ significantly, but were significantly higher in the Ti-Control group compared with Ti-Porous + SiO ₂ implants. Functionalization of titanium implants via infiltration of a SiO ₂ phase into the titanium macropores does not seem to inhibit implant osseointegration. Yet, the importance of the implant macro-design, in particular the screw thread design in a marginal gap implant surgery set-up, was emphasized by the outstanding results of the Ti-Control implant.
Conclusions: Next-generation implants made of macroporous Ti infiltrated with mesoporous SiO ₂ do not seem to compromise the osseointegration process. Such implant functionalization may be promising for the prevention and treatment of peri-implantitis given the evidenced potential of mesoporous SiO ₂ for controlled drug release.
(© 2020 The Authors. Clinical and Experimental Dental Research published by John Wiley & Sons Ltd.)