How Accurate Is <scp>CBCT</scp> in Measuring Bone Density? A Comparative <scp>CBCT‐CT</scp> In Vitro Study

<jats:title>Abstract</jats:title><jats:sec><jats:title>Purpose</jats:title><jats:p>Recently, cone beam computed tomography (<jats:styled-content style="fixed-case">CBCT</jats:styled-content>) has become widely used for oral and maxillofacial imaging. Twenty dry mandibles were <jats:styled-content style="fixed-case">CBCT</jats:styled-content> and conventional multislice <jats:styled-content style="fixed-case">CT</jats:styled-content> scanned to evaluate if there is a statistically significant difference between the bone density values they produce, defined as gray density values, and to determine any correlation between them.</jats:p></jats:sec><jats:sec><jats:title>Materials and Methods</jats:title><jats:p>Using software and a radiographic template, the <jats:styled-content style="fixed-case">CT</jats:styled-content> and <jats:styled-content style="fixed-case">CBCT</jats:styled-content> scan images were overlapped, and two data sets were created, each one giving the respective gray values (voxel value [<jats:styled-content style="fixed-case">VV</jats:styled-content>] or <jats:styled-content style="fixed-case">H</jats:styled-content>ounsfield unit [<jats:styled-content style="fixed-case">HU</jats:styled-content>]) of the same area with the same spatial coordinates. For the statistical analysis, <jats:italic>t</jats:italic>‐test, <jats:styled-content style="fixed-case">P</jats:styled-content>earson's correlation, and <jats:styled-content style="fixed-case">P</jats:styled-content>earson's <jats:italic>r</jats:italic> were used.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>The differences between the <jats:styled-content style="fixed-case">CBCT</jats:styled-content> (<jats:styled-content style="fixed-case">VV</jats:styled-content>) and <jats:styled-content style="fixed-case">CT</jats:styled-content> (<jats:styled-content style="fixed-case">HU</jats:styled-content>) gray density values were statistically significant (<jats:italic>p</jats:italic> ≤ .05), whereas the <jats:styled-content style="fixed-case">P</jats:styled-content>earson's correlation coefficients and <jats:styled-content style="fixed-case">P</jats:styled-content>earson's <jats:italic>r</jats:italic>‐values demonstrated a statistically significant linear correlation between <jats:styled-content style="fixed-case">VV</jats:styled-content> and <jats:styled-content style="fixed-case">HU</jats:styled-content> gray density values.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>The lower radiation dose and reduced costs of <jats:styled-content style="fixed-case">CBCT</jats:styled-content> make this a useful substitute for <jats:styled-content style="fixed-case">CT</jats:styled-content>; however, this study has shown that, in order to more accurately define the bone density with <jats:styled-content style="fixed-case">CBCT</jats:styled-content>, a conversion ratio needs to be applied to the <jats:styled-content style="fixed-case">VV</jats:styled-content>.</jats:p></jats:sec>