CT-Density and CT-Volumetry after Sinuslift with Gdf-5 Coated Beta-TCP

Objective:

The aim of this study was to evaluate the effect of beta-tricalciumphosphate(beta-TCP) coated with rh-GDF-5 in sinus augmentation. Non-invasive computer tomography(CT) was used to determine the density and volume of the augmented area.

Methods:

A bilateral sinus augmentation procedure and a simultaneous implantation of dental implants were performed in 12 minipigs. In one maxillary sinus beta-TCP coated with rh-GDF-5 was implanted, with 2 different amounts of rh-GDF-5: 400µg(low concentration) or 800µg(high concentration)/g beta-TCP. The contralateral sinus served as control group(beta-TCP without coating). The minipigs were divided into 2 groups: group 1 were put down and evaluated after 4, group 2 after 12 weeks.

After the indicated intervals, ct-measurements were performed to evaluate volume and density of the augmented area.

Results:

Volume: after 4 weeks the mean volumes revealed no significant differences between all groups. After 12 weeks both the volume of the low (5.1ml) and the high concentration (4.4ml) lay above the volumes of the control (3.7ml). Despite the difference the statistical evaluation revealed no significance.

Comparing the results after 4 and 12 weeks, the volume of the augmentations with rh-GDF-5 revealed no noticeable differences. Only the control showed a smaller volume after 12 weeks.

Density: After 4 weeks the highest density was noted for low concentrations (mean: 616HU; p=0.013), whereas high concentrations and the controls definitely showed lower densities (means: 457HU, 456HU). After 12 weeks the mean density of all groups revealed nearly no differences (mean: 854HU, 790HU, 823HU).

Compared to the density at 4 weeks the densities of all groups were much higher after 12 weeks.

Conclusion:

Rh-GDF-5/beta-TCP has proved itself as useful material in sinus augmentation. High concentrations of rh-GDF-5 doesn`t have better effects on the augmentation than lower concentrated allografts. The non-invasive ct appears to be a useful method in evaluating sinus augmentations.