Reosseointegration Following Regenerative Therapy of Tissue-Engineered Bone in a Canine Model of Experimental Peri-Implantitis

BACKGROUND

Due to the existence of inflammation and limited osteogenesis on the precontaminated implant surface, reosseointegration is difficult to realize by current therapies. Tissue-engineering strategy has been proved quite effective in intractable bone defect situation.

PURPOSE

This study was designed to see whether the adoption of tissue-engineered bone complex of adipose-derived stem cells (ASCs) and bone morphogenetic protein-2 (BMP-2) gene delivery would work efficiently in the correction of experimental peri-implantitis.

METHODS

All premolars in both side of mandibular were removed from six beagle canines three months before implant placement. Typical peri-implantitis were then induced by three month ligature placement. After the implementation of identical anti-bacterial and mechanical debridement therapy, the shaped peri-implant defect were stuffed with four groups of constructs, as A: beta tricalcium phosphate (β-TCP); B: β-TCP with ASCs; C: β-TCP with enhanced green fluorescent protein gene transduced ASCs (AdGFP-ASCs); and D: β-TCP with bone morphogenetic protein-2 gene-modified ASCs (AdBMP-2-ASCs). Systematic radiographic, micro-CT, and histomorphometrical assessments were performed.

RESULTS

After six months of healing, more bone formation and reosseointegration was found around the implant of groups B and C than group A. And group D further promoted the new bone height and reosseointegration percentage. Moreover, sequential fluorescence labeling tells that group D exhibited the quickest and strongest bone formation on the cleaned implant surface during the entire observation period as compared to the other three groups.

CONCLUSIONS

These data demonstrated that tissue engineered bone of ASCs, BMP-2 gene delivery, and β-TCP could exert powerful therapeutic effect on peri-implantitis as expected, which may suggest a feasible way to maintain the stability and masticatory function of dental implant.

Manganese Oxide Nanozyme-Doped Diatom for Safe and Efficient Treatment of Peri-Implantitis

Peri-implantitis is a major cause of dental implant failure. Bacterial biofilm contamination on the implant induces surrounding bone resorption and soft tissue inflammation, leading to severe deterioration of oral health. However, conventional biofilm removal procedures, such as mechanical decontamination and antiseptic application, are not effective enough to induce reosseointegration on decontaminated implant surfaces. This is due to (1) incomplete decontamination of the biofilm from inaccessible areas and (2) physicochemical alteration of implant surfaces caused by decontamination procedures. Herein, a safe and effective therapeutic approach for peri-implantitis is developed, which involves decontamination of implant-bound biofilms using the kinetic energy of microsized oxygen bubbles generated from the catalytic reaction between hydrogen peroxide (H2O2) and manganese oxide (MnO2) nanozyme sheet-doped silica diatom microparticles (Diatom Microbubbler, DM). Rapidly moving microsized DM particles are able to penetrate narrow spaces between implant screws, exerting just the right amount of force to entirely destroy biofilms without harming the surrounding mucosa or implant surfaces, as opposed to conventional antiseptics such as chlorhexidine or 3% H2O2 when used alone. Consequently, decontamination with DM facilitates successful reosseointegration on the peri-implantitis-affected implant surface. In summary, our new DM-based therapeutic approach will become a promising alternative to resolve clinically challenging aspects of peri-implantitis.