Ligature-Induced Peri-Implantitis in Minipigs Revisited

Aim: The ligature-induced defect model still remains the model of first choice to experimentally investigate the cause, effect and treatment approaches of periimplantitis. It was the aim of the present in-vivo trail to revisit the ligature-induced peri-implantitis minipig model regarding its current scientific value and ethical justification in implant research. Materials and methods: Six minipigs were used for the analysis of peri-implant hard and soft tissue structures. Animals were randomly allocated to an experimental silk ligature-induced peri-implantitis group (n=4 animals) and a reference healthy group (n=2 animals). After six weeks mean pocket depths (PD) and bleeding on probing (BOP) measurements were performed just before animals were sacrificed. Results: Overall, ligature-induced peri-implantitis provoked a local inflammation around the experimental implants. Additionally, a loss of crestal bone surrounding the implants could be detected. Mean pocket depths (PD) were 2.2 ± 1.1 mm for healthy animals and 5.4 ± 1.9 mm for peri-implantitis sites. Healthy sites showed a BOP of 60%, whereas peri-implantitis sites disclosed a BOP of 90% within 10 s after probing. Conclusion: Clinical, radiological and histological findings of the present animal experiment supported the overall applicability of the ligature-induced periimplantitis minipig model. A rapid breakdown of peri-implant hard tissues could be detected mainly on the buccal side.