Experimental Peri-implantitis Versus Experimental Periodontitis. Characterization of Mice Model

Objectives: Dental implants have been a common solution for missing teeth for the last decades, however this treatment also carries the risk of peri-implantitis. Peri-implantitis is a rapidly emerging disease characterized by inflammation of both soft tissue and progressive alveolar bone loss.
The aim of this study was to develop a murine model for bacteria-induced alveolar bone loss around titanium implants and compare it to the alveolar bone loss around teeth.

Methods: Screw-shaped titanium implants, SLA based (Ø 0.5 mm and 1.5 mm of length Ditron. Israel), were inserted immediately after extraction of the first upper left molar, in 5-6-week-old BALB/c mice. Seven days after implantation, the mice were infected with Porphyromonas gingivalis and Fusobacterium nucleatum. Six weeks later, bone volume around the inserted implants was measured using micro-CT, and was compared to alveolar bone level around the right molar. Histological analysis was performed.
Results: Histologically, the implants were well Osseo-integrated in bone. Through micro-CT analysis, we found a significant difference in alveolar bone loss around infected implants (about 45% compared to non-infected implants) compared to infected teeth (25% compared to non-infected teeth). The infected mice showed a mean ofµ 275 m of alveolar bone loss at the distal site and a mean of 214µm at the mesial site of the implant, while the control group showed significantly lower level of resorption : a mean of 123µm loss at the distal site and 126µm at the mesial site of the implants.
Conclusions: The results show that the alveolar bone resorption around implant was significantly higher compared to the resorption around teeth, which may indicate a severe infection around implants by the same pathogens. This new model of peri-implantitis in mice open new possibilities towards studying peri-implantitis pathogenesis looking for new modalities for prevention and treatments.