Computer assisted analysis of bone volume for sinus augmentation procedure
The objectives of this study were to determine the volume of bone required prior to a sinus graft using two different methods, to compare it to the actual volume used during surgery and to evaluate a segmentation technique in quantifying the volume of a xenograft on the post operative cone beam computed tomography (CBCT) slices. CBCT data from 11 CBCT scans for 11 patients (6 males, 5 females) requiring 13 lateral augmentation procedures were imported to Simplant Pro 15(r) (Materialise, Leuven, Belgium) in DICOM format. Residual ridge height (RRH) was measured for each implant site as well as mucosal thickness (MT) MT was classified by grades (1 to 4) Simulation of implant placement for each site was realized and the graft volume was pre operatively calculated by a semi automatic segmentation (SAS) technique and another automatic Simplant sinus graft (SSG) technique. All patients underwent a lateral sinus augmentation surgery 3 to 12 weeks after the initial CBCT scan. The volume of the bovine bone grafting material (BBM) particles was quantified during the surgery (Vr) for all patients and on immediate post operative CBCT scans (CBCT V) for 7 patients. With a mean augmentation of 9.45 1.72 mm, the calculated volumes were 2.243 0.962 mm3 and 2032 0.843 mm3 for the SAS and SSG methods, respectively. Percent variation between Vr and SAS volume was significant (22.4% and non significant (4.5% between Vr and SSG volume. In cases with MT grade 1 2, no difference was found between Vr and SAS volume. No difference was found between Vr (1.918 1.118 mm3) and CBCT V (1.979 1.108) In conclusion, the results showed that the use of the Simplant(r) software was effective in determining the required graft volume for the surgery, the volume measurements with the SSG were more accurate than the SAS and the quantification of BBM particles on CBCT data sets was reliable and accurate with the segmentation technique used.