A novel method of assessment of BMD using CBCT for implant placement: A retrospective study

Nowadays, dental implant evolves as an alternative treatment modality for oral rehabilitation. The success of dental implants is largely dependent on bone density; Cone-beam computed tomography (CBCT) is a well-known modus operandi for the volumetric measurement of bone mineral density (BMD), which measures Grayscale values on 3-D images. This study was conducted with the aim to analyze bone density with CBCT and also test its reliability and reproducibility using Galileos Sirona CBCT Viewer Software and Philips digital imaging and communications in medicine (DICOM) Viewer. A total of 75, CBCT images were obtained from the Department of Oral Radiology, retrospectively, and, BMD in Hounsfield units (HUs) was evaluated in a standardized implant area superimposed on the images. Bone density was also calculated by 2 different independent observers. The estimation of sample size was achieved to attain a power of 90% with 0.5 alpha error and 0.2 effect size as per a previous study. Statistical analysis was performed by statistical package for the social sciences version 22.0; data were presented as mean and standard deviation and Kappa correlation test was applied to check the reproducibility of values. The mean and standard deviation of grayscale values and HUs attained from the interdental area of front teeth were 1837 (288.76) and 270 (125.4), respectively, with a conversion factor of 6.8. Whereas the mean and standard deviation of grayscale values and HUs acquired from posterior interdental spaces were 2880 (489.99) and 640 (204.6), respectively, with a conversion factor of 4.5. To verify the reproducibility Kappa correlation test was applied, which showed correlation values of 0.68 and 0.79. The conversion or exchange factors for grayscale values to HUs determined at the frontal, posterior interdental space area and from the highly radio-opaque area were exceedingly reproducible and consistent. Hence, CBCT can be used as one of the valuable techniques in the estimation of bone density.