Osteocyte lacunar density and area in newly formed bone of the augmented sinus

Objectives Osteocytes, the most common cells of the bone, are buried in lacunae. Density and area of the osteocyte lacunae change with increasing maturation of the newly formed bone. Evaluation of osteocyte lacunae can therefore provide insights into the process of graft consolidation. Materials and Methods Here, we determined the osteocyte lacunar density (number of osteocyte lacunae per bone area; N.Ot/BAr) and the osteocyte lacunar area in m2 (Lac.Ar) in histological specimens 6 and 12weeks after the sinuses of 10 minipigs were augmented with Bio-Oss (R), a deproteinized bovine bone mineral, and Ostim (R), an aqueous paste of synthetic nanoparticular hydroxyapatite. The region of interest was defined by the following criteria: (i) >1mm from the host bone, (ii) >0.5mm from the sinus mucosa, (iii) minimum area of 0.2mm2, and (iv) bone tissue spanning at least two bone substitute particles. Results The overall osteocyte lacunar density was significantly higher in the Bio-Oss (R) group than in the Ostim (R) group and decreased during the observation period at a similar range in both groups. The osteocyte lacunar area was smaller in the Bio-Oss (R) group than the Ostim (R) group but there was no significant change within the groups over time. Conclusions These results suggest that bone substitutes affect the osteocyte lacunar density and the osteocyte lacunar area in the newly formed bone within the augmented sinus in this particular model situation. These measures can provide insights into the maturation of newly formed bone in the augmented sinus.