Maxillary sinus augmentation with Bio-Oss particles: a light, scanning, and transmission electron microscopy study in man

Abstract: Biological interactions occurring at the bone–biomaterial interface are critical for long-term clinical success. Bio-Oss is a deproteinized, sterilized bovine bone that has been extensively used in bone regeneration procedures. The aim of the present study was a comparative light, scanning, and electron microscopy evaluation of the interface between Bio-Oss and bone in specimens retrieved after sinus augmentation procedures. Under light microscopy, most of the particles were surrounded by newly formed bone, while in a few cases, at the interface of some particles it was possible to observe marrow spaces and biological fluids. Under scanning electron microscopy, in most cases, the particle perimeter appeared lined by bone that was tightly adherent to the biomaterial surface. Transmission electron microscopy showed that the bone tissue around the biomaterial showed all the phases of the bone healing process. In some areas, randomly organized collagen fibers were present, while in other areas, newly formed compact bone was present. In the first bone lamella collagen fibers contacting the Bio-Oss surface were oriented at 243.73 7.12° (mean SD), while in the rest of the lamella they were oriented at 288.05 4.86° (mean SD) with a statistically significant difference of 44.32° (p < 0.001). In the same areas the intensity of gray value was 172.56 18.15 (mean SD) near the biomaterial surface and 158.71 21.95 (mean SD) in the other part of the lamella with an unstatistically significant difference of 13.79 (p 0.071). At the bone–biomaterial interface there was also an electron-dense layer similar to cement lines. This layer had a variable morphology being, in some areas, a thin line, and in other areas, a thick irregular band. The analyses showed that Bio-Oss particles do not interfere with the normal osseous healing process after sinus lift procedures and promote new bone formation. In conclusion, this study serves as a better understanding of the morphologic characteristics of Bio-Oss and its interaction with the surrounding tissues.