Bone classification: clinical-histomorphometric comparison.

This study was aimed to correlate the hand clinical assessment of the bone quality to the histologic structure quantified by histomorphometric evaluation of bone density. Small bone biopsies were harvested in 56 patients during oral implant surgery, and were utilized for histomorphometric evaluation. The bone scoring was recorded during drilling of the implant bed, based on the hand-felt perception of the drilling resistance. The bone biopsies were then processed to obtain thin ground sections. The results of histomorphometric analysis were expressed as percentage of bony trabeculae over the total biopsy area, and the Spearman's rank correlation test, was applied to calculate the statistical differences of the clinically assessed classes of bone density and linear regression was calculated. Samples from the D1 showed a mean histomorphometric density of 76.54% +/- 16.19. Samples from D2 showed a mean value of 66.78% +/- 15.82. D3 specimens had a mean histomorphometric density scoring 59.61% +/- 19.55%. D4 samples had a mean value of 28.28% +/- 12.02. The interclass correlation analysis of the variance, showed that the clinically assessed classes D1 (P = 0.01) and D4 (P = 0.0006) were significantly different from the population. On the other hand, the classes D2 (P = 0.6) and D3 (P = 0.4) were not significantly different. This study demonstrated that hand feeling allows to distinguish, with statistically significant confidence, D1 and D4 bone, but failed to distinguish between the intermediate classes of bone quality.