LONG-TERM RESULTS FOLLOWING FRONTAL-SINUS OBLITERATION IN CATS WITH AN IONOMER BASED MICROIMPLANT

Background: Osteoplastic frontal sinus surgery in combination with sin us obliteration may occasionally be performed far indications such as severe sinus inflammations, extensive wall fractures involving the nas ofrontal duct, or osteomas. The material most frequently used for this obliteration is autogenous adipose tissue. Autografts such as muscle, cartilage, and bone chips have been also recommended for this purpose . In order to avoid the surgical procedure required for harvesting an autograft from other body sites, alloplastic materials have been sugge sted for frontal sinus obliteration. Methods: In an animal study using cats, the mucous lining of the frontal sinus was removed, the nasofro ntal duct sealed with semifluid ionomer cement, and the cavity filled up with a solid and porous ionomer-based microimplant. Results: Histol ogical investigations were performed up to two years after surgery. In creasing obliteration of the sinus cavity by bone regeneration, starti ng from the sinus wall, as well as formation of connective tissue betw een the cement grains was detected as early as one month after implant ation. Osteoblasts lining the osteoid layer were considered to be an i ndication of active bone regeneration. Osteogenesis inside the sinus c avity continuously progressed during the following months. Two years a fter implantation, osteoid and newly mineralized bone encircled the mi croimplants leading to an almost complete obliteration. There was no e vidence for mucosal regeneration or foreign body reaction. Conclusion: Because of its osteoconductive effect, biocompatibility, and biostabi lity the ionomer-based microimplant is a suitable alloplastic material for frontal sinus obliteration.