Three-dimensional ultrasound imaging of the jawbone for ridge width determination: A pre-clinical ex-vivo porcine study

Abstract

ObjectiveTwo-dimensional (2D) ultrasound can conveniently evaluate focal regions of interest intraorally. When a larger field of view to spatially reference remote anatomical structures is needed, 3D ultrasound (US) is desirable but not currently available. The aim of this study was to demonstrate the feasibility of constructing 3D US jawbone for ridge width determination. MethodsSeven porcine hemi-mandibles with the overlying soft tissues secured by a holding frame with fiducial markers were US scanned on the facial and lingual sides separately. The facial and lingual volumes were combined into a single volume, which was registered with the matched cone beam computed tomography (CBCT) scan. On 8 to 11 cross-sections, 4 measurements of the facio-lingual ridge width at 3, 6, 9 and 12 mm from the bone crest were performed by two calibrated examiners. A mixed model was used to estimate the differences between US and CBCT readings. ResultsInter-examiner correlation was 0.978 and 0.987 for US and CBCT measurements, respectively. The ICCs between the US and CBCT was between 0.890 and 0.988 at the defined sites. The estimated mean differences ranged from -0.38 ± 0.69 (95% CI: -0.66 to -0.11) mm to 0.07 ± 0.93 (95% CI: -0.23 to 0.38) mm. The normalized root mean square deviation ranged between 4.50% and 7.89% for all levels except the 3 mm level, which ranged between 5.51% (in molars) and 11.16% (in premolars). ConclusionsThis study demonstrates the feasibility of generating US jawbone in 3D for ridge width measurements. Clinical SignificanceCommonly applied 2D ultrasound images are limited by a small field of view and an unknown coordinate system due to the nature of free hand scans. Novel 3D ultrasound acquisition enables referencing anatomical structures in a larger field of view and could become a promising tool to supplement CBCT.