• sinus augmentation;
  • endosseous implant;
  • bone grafting;
  • bone substitute;
  • xenograft

The aim of the present study was to evaluate bone formation following maxillary sinus augmentation using bovine bone substitute material Bio-Oss® in combination with venous blood by means of histologic and histomorphometric examination of human biopsies. This involved a total of 15 sinus floor elevation procedures being carried out on 11 patients (average age of 49.6 years) according to the technique described by Tatum (1986). The subantral sinus cavity was augmented using bovine apatite combined with venous blood. After an average healing phase of 6.8 months, trephine burrs were used to take 22 bone biopsies from the augmented sinus region. Then 38 Brånemark® implants were inserted in both the osteotomies resulting from bone sampling and in regular sites in the augmented posterior maxilla. Histomorphometric analysis of ground sections from the bone biopsies prepared according to the standard method of Donath & Breuner (1982) produced an average percentage of newly-formed bone of 14.7% (±5.0%) and a proportion of residual xenogenic bone substitute material of 29.7% (±7.8%). Some 29.1% (±8.1%) of the surface of the Bio-Oss® granulate was in direct contact with newly-formed bone. Histologically, newly-developed bone became evident, partly invaginating the particles of apatite and forming bridges in the form of trabeculae between the individual Bio-Oss® particles. Despite the absence of osteoclastic activity, the inward growth of bone indicates slow resorption of the xenogenic bone graft material. When the implants were uncovered, after an average healing phase of 6 months, 4 of the 38 implants had become loose. Of these 4 implants, 1 had to be subsequently explanted, while the others remained as “sleeping implants” and were not included in the implants superstructure. Thus, the resulting clinical survival rate, prior to prosthetic loading, was 89.5%.