Résumé
We developed an animal model to recreate the condition of an open fracture in communication with the maxillary sinus. We then studied wound healing of the sinus wall structures following fracture in the presence of autogenous bone and alloplastic implant. This model is designed to simulate the repair of an orbital floor fracture in humans. The New Zealand White rabbit was used as the animal model. Standardized 8mm defects were made bilaterally in the maxillary sinuses to include bone and mucosa in 36 rabbits. Two different implants and autogenous calvarial bone graft were placed in the soft-tissue pockets to obturate the defects, exposing one surface of the implant to the open sinus. Medpor porous polyethylene, silicone and calvarial bone implant were compared. Animals were killed at 1, 2 and 8 weeks after implantation. Gross examination of the specimens for the amount of mucosal closure and implant tissue fixation was performed. Histological sections were evaluated for bone and soft-tissue morphology juxtaposed to the implant. Complete closure of the mucosal defect was demonstrated with each type of implant. Medpor implants showed both vascular and soft-tissue ingrowth into pores by week 1. Bone ingrowth was seen by week 2. Closure of the Medpor obturated defects occurred more rapidly than in the silicone group. The Medpor implants and calvarial bone demonstrated bone and soft-tissue fixation, callus formation and maturation, while mature overlying mucosa was reconstituted over the defects. Silicone implants demonstrated a fibrous tissue reaction within 1 week of implantation and they never became fixed to bone or soft tissue. Maxillary sinus wall regeneration occurred in all defects. This study supports clinical observations of maxillary sinus wall regeneration in humans.