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Evaluating Maxilla Bone Quality Through Clinical Investigation of Voxel Grey Scale Values from Cone-Beam Computed Tomography for Dental Use.

BACKGROUND
During the study the relative bone density thickness in maxilla was evaluated in 20 patients.


OBJECTIVES
The aim of the study was to investigate relative bone density in maxilla by means of voxel value measurements.


MATERIAL AND METHODS
The study comprised of 20 patients in whom cone beam computed tomography scans were made for diagnostic purposes. The horizontal scans of the maxilla were used for analysis. The measurements of density of both cortical plates and trabecular bone were taken in interdental spaces. To eliminate negative values a modified grey scale was introduced in which radiological density of the air was determined as "0". For every patient relative bone density was calculated separately for anterior and posterior maxilla.


RESULTS
Mean values of relative radiological density for cortical plates and trabecular bone were 0.849 for palatal cortical plate, 0.8978 for vestibular cortical plate and 0.5988 for trabecular bone in anterior maxilla with standard deviation (SD) 0.0931 - 0.0971 - 0.1091 respectively. In posterior maxilla the mean values were 0.5274 for palatal cortical plate, 0.6047 for vestibular cortical plate and 0.3307 for trabecular bone with SD 0.1635 - 0.1515 - 0.126 respectively. The statistically significant difference (p < 0.001) was found for radiological density of dental alveolus in anterior and posterior maxilla.


CONCLUSIONS
The mean of radiological densities of vestibular cortical plate is higher than that of palatal cortical plate. The mean radiological density of trabecular bone is × 2 lower than the mean radiological density of vestibular cortical plate in posterior region and × 1.5 lower in anterior region of the maxilla. The clinical use of CBCT radiological bone density measurement tool with modified grey scale voxel values creates possibility to evaluate the relative bone density of dental alveolus.