Maxillary sinus augmentation using xenogenic bone substitute material Bio-Oss (R) in combination with venous blood - A histologic and histomorphometric study in humans

The aim of the present study was to evaluate bone formation following maxil lary sinus augmentation using bovine bone substitute material Bio-Oss(R) in combination with venous blood by means of histologic and histomorphometric examination of human biopsies. This involved a total of 15 sinus floor ele vation procedures being carried out on 11 patients (average age of 49.6 yea rs) according to the technique described by Tatum (1986). The subantral sin us cavity was augmented using bovine apatite combined with venous blood. Af ter an average healing phase of 6.8 months, trephine burrs were used to tak e 22 bone biopsies from the augmented sinus region. Then 38 Branemark(R) im plants were inserted in both the osteotomies resulting from bone sampling a nd in regular sites in the augmented posterior maxilla. Histomorphometric a nalysis 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 xenoge nic bone substitute material of 29.7% (+/-7.8%). Some 29.1% (+/-8.1%) of th e surface of the Bio-Oss(R) granulate was in direct contact with newly-form ed bone. Histologically, newly-developed bone became evident, partly invagi nating the particles of apatite and forming bridges in the form of trabecul ae between the individual Bio-Oss(R) particles. Despite the absence of oste oclastic activity, the inward growth of bone indicates slow resorption of t he xenogenic bone graft material. When the implants were uncovered, after a n 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 super structure. Thus, the resulting clinical survival rate, prior to prosthetic loading, was 89.5%.