Objective: The aim of the present study was to compare the histomorphometrically evaluated
new bone formation (NB), the radiographically measured graft stability and the clinical
implant outcome for maxillary sinus augmentation grafted with deproteinized bovine bone
mineral (DBBM) with either small (Bio-Oss-S.) or large (Bio-Oss-L.) particles.
Materials and Methods: By using a split-mouth study design bilateral maxillary sinus
augmentation was performed in 13 patients either with Bio-Oss-S. particles (0.25-1 mm) or
with Bio-Oss-L. (1-2 mm). After a healing period of 6 months bone biopsies were axially
retrieved in the molar region for histologic/histomorphometric analysis of new bone formation
including subsequent staged-implant placement. For determining graft stability the maxillary
sinus augmentation vertical graft heights were radiographically measured immediately after
sinus augmentation, at implant placement and at the 2- and 4-year post-augmentation follow
ups. In addition, the clinical implant-prosthodontic outcome (survival/success/marginal bone
loss) was assessed at year 1 and year 3post-loading.
Results: 22 sinuses of 11 patients with split-mouth evaluation were ultimately available for
data and statistical analysis. Histomorphometric analysis of the axially retrieved bone biopsies
revealed new bone formation (S.:25.5Å}7.0% vs. L.:23.6Å}11.9%; p=0.640), residual graft
(S.:19.6Å}9.2% vs. L.:17.5Å}6.3%; p=0.365) as well as connective tissue (S.:54.9Å}9.2% vs.
L.: 58.9Å}12.5%; p=0.283) without differences between the use of small (Bio-Oss-S.) and
large (Bio-Oss-L.) particles. However, there was significantly (p=0.021) higher graft-to-bone
contact (BGC) for the small-particle ( 27.9Å}14.8%) than for the large-particle size
(19.9Å}12.9%) representing a significantly higher osteoconductivity. Both particles showed
significant (p<0.01) vertical graft height reduction over time (4 years) of about 10% with
predominant graft reduction in the time-period between sinus augmentation and implant
placement compared to the time-period of the follow-ups post implant placement. At the 3-
year post-loading implant evaluation all implants and prostheses survived (100%) and the
peri-implant marginal bone loss (S.:0.52Å}0.19 mm; L.:0.48Å}0.15 mm) as well as the periimplant
health conditions (S.:87.5%, L.:81.2%) also did not differ between implants
inserted with the two different xenograft particles used.
Conclusions: The use of small and large bovine xenograft particles for maxillary sinus
augmentation provides for comparable bone formation ensuring stable graft dimensions
combined with high implant success and healthy peri-implant conditions. However, small
particle size resulted in a higher bone-to-graft contact providing for higher osteoconductivity
than with the larger particle size.