Date on Master's Thesis/Doctoral Dissertation

5-2014

Document Type

Master's Thesis

Degree Name

M.S.

Department

Oral Biology

Committee Chair

Farman, Allan G.

Committee Co-Chair (if applicable)

Scarfe, William C.

Committee Member

Harris, Bryan T.

Subject

Diagnostic imaging; Teeth--Radiography

Abstract

Artifacts due to high-density objects (HDO) such as metallic dental restorations on maxillofacial cone beam computed tomographic (CBCT) images can render certain areas unsuitable for diagnosis. It was hypothesized that image quality due to HDO artifacts was affected by CBCT acquisition parameters and the number and configuration of HDO. Simulated complete maxillary and mandibular dental arches were constructed using dental stone and extracted teeth. Conservative coronal dental amalgam (MOD) restorations on premolar and molar teeth were used as HDOs. Gray values (GV) measured on uniform dental stone test cylinders at specific levels from the occlusal plane at three tooth locations was used as an index of artifact effect on image quality. Scans with various HDO configurations were taken at several acquisition parameters for three CBCT systems: Accuitomo 170 (J. Morita MFG. Corp, Kyoto, Japan), iCAT Next Generation (Imaging Sciences International Inc., Hatfield, PA, USA) and Carestream 9000 3D (Carestream/KODAK, Atlanta, GA). For all systems, HDOs significantly affected images throughout the field of view, with machine specific beam hardening or scatter artifacts. Worst beam hardening affected areas were within 0mm-4mm of the occlusal plane of the ipsilateral test cylinder. The Accuitomo 170 was unaffected by acquisition parameters. Caution must be exercised when assessing CBCT images for coronal dental caries and other pathologies in the presence of HDOs to prevent errors in diagnosis due to beam hardening or scatter artifacts.

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