Quantitative measurements obtained by micro-computed tomography and confocal laser scanning microscopy

To compare measurements obtained by micro-CT with those obtained by confocal laser scanning microscope in simulative internal resorption cavities.

An extracted human maxillary central incisor tooth was divided into two in the coronal plane. Four artificial internal resorption cavities were prepared with standardized burs on each section, and diameters and volumes were measured using a laser scanning electron confocal microscope and a desktop cone beam micro-CT-40. Differences between means of quantitative measurements for both methods were tested using the paired t-test; the correlation between quantitative measurements was tested by regression analysis.

Mean diameter and volume differences between the two methods were 0.061 mm and 0.004 mm(3), respectively. Average diameter and volume calculations obtained by micro-CT were significantly lower (P < 0.001 for diameter and P < 0.01 for volume). A significantly strong relationship was found in the average diameters (R(2) = 92.9%) and calculated volumes (R(2) = 91%), (P < 0.001).

Although a strong correlation between both methods was found, micro-CT significantly underestimated the diameters and volumes.