IADR Abstract Archives
Development of a Novel Rat Model of Polymicrobial Peri-implantitis
Objectives: Peri-implantitis is a complex polymicrobial biofilm-induced inflammatory osteolytic gingival infection that results in orofacial implant failures. No in vivo studies in implant dentistry investigated the inflammatory response to known microbial biofilms observed in humans. The aim of this study was to develop a novel peri-implant rat model by using an established rat model of polymicrobial periodontitis.
Methods: Wistar rats were used for experimental peri-implantitis study. One month following extraction of first maxillary (M1) molars, mini-titanium implants (Grade IV, machined-surfaced implants) were implanted. Two months following implant healing, implants uncovered, and abutments were fixed using cyanoacrylate in order to prevent abutment loosening. Rats were divided into two groups (Group A: polymicrobial–infected and Group B: Sham-infected, n=6). One week following healing of abutment, rats were infected with Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia for 12 weeks. Bacterial colonization around infected implants was evaluated by PCR, alveolar bone resorption (ABR) by microCT and implant inflammation by histology.
Results: Three rats with 4 implants in infection (Group A) and 2 rats with 3 implants in sham-infection (Group B) were available at 13th week for analysis. PCR analysis of infected implanted rats showed bacterial genomic DNA indicating bacterial colonization around implants and infection-induced significant serum IgG and IgM antibodies against all bacteria. Infection-induced enhanced mean distance from the implant platform to the first bone to implant contact in maxilla and also induced horizontal ABR in mandibles. Polymicrobial-infected implants showed extensive peri-implantitis with advanced ABR and extensive inflammation with granulation tissue and PMN infiltration.
Conclusions: This is the first study to develop a novel rat model for peri-implantitis with polymicrobial infection with human pathogens and could serve as a model for studies of initiation and progression of peri-implantitis. Support: Dentsply Implants, Sweden, R01 DE020820 NIH/NIDCR, and Department of Periodontology, University of Florida, Gainesville, Florida, USA.
Methods: Wistar rats were used for experimental peri-implantitis study. One month following extraction of first maxillary (M1) molars, mini-titanium implants (Grade IV, machined-surfaced implants) were implanted. Two months following implant healing, implants uncovered, and abutments were fixed using cyanoacrylate in order to prevent abutment loosening. Rats were divided into two groups (Group A: polymicrobial–infected and Group B: Sham-infected, n=6). One week following healing of abutment, rats were infected with Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia for 12 weeks. Bacterial colonization around infected implants was evaluated by PCR, alveolar bone resorption (ABR) by microCT and implant inflammation by histology.
Results: Three rats with 4 implants in infection (Group A) and 2 rats with 3 implants in sham-infection (Group B) were available at 13th week for analysis. PCR analysis of infected implanted rats showed bacterial genomic DNA indicating bacterial colonization around implants and infection-induced significant serum IgG and IgM antibodies against all bacteria. Infection-induced enhanced mean distance from the implant platform to the first bone to implant contact in maxilla and also induced horizontal ABR in mandibles. Polymicrobial-infected implants showed extensive peri-implantitis with advanced ABR and extensive inflammation with granulation tissue and PMN infiltration.
Conclusions: This is the first study to develop a novel rat model for peri-implantitis with polymicrobial infection with human pathogens and could serve as a model for studies of initiation and progression of peri-implantitis. Support: Dentsply Implants, Sweden, R01 DE020820 NIH/NIDCR, and Department of Periodontology, University of Florida, Gainesville, Florida, USA.