Magnitude of beam-hardening artifacts produced by gutta-percha and metal posts on cone-beam computed tomography with varying tube current
Gaeta-Araujo Hugo, Nascimento Eduarda Helena Leandro, Fontenele Rocharles Cavalcante, Mancini Arthur Xavier Maseti, Freitas Deborah Queiroz, Oliveira-Santos Christiano,
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( Gaeta-Araujo Hugo ) - University of Campinas Piracicaba Dental School Department of Oral Diagnosis
( Nascimento Eduarda Helena Leandro ) - University of Campinas Piracicaba Dental School Department of Oral Diagnosis
( Fontenele Rocharles Cavalcante ) - University of Campinas Piracicaba Dental School Department of Oral Diagnosis
( Mancini Arthur Xavier Maseti ) - University of Sao Paulo School of Dentistry of Ribeirao Preto Department of Dental Materials and Prosthodontics
( Freitas Deborah Queiroz ) - University of Campinas Piracicaba Dental School Department of Oral Diagnosis
( Oliveira-Santos Christiano ) - University of Sao Paulo School of Dentistry of Ribeirao Preto Department of Stomatology, Public Oral Health and Forensic Dentistry
Abstract
Purpose: This study was performed to evaluate the magnitude of artifacts produced by gutta-percha and metal posts on cone-beam computed tomography (CBCT) scans obtained with different tube currents and with or without metal artifact reduction (MAR).
Materials and Methods: A tooth was inserted in a dry human mandible socket, and CBCT scans were acquired after root canal instrumentation, root canal filling, and metal post placement with various tube currents with and without MAR activation. The artifact magnitude was assessed by the standard deviation (SD) of gray values and the contrast-to-noise ratio (CNR) at the various distances from the tooth. Data were compared using multi-way analysis of variance.
Results: At all distances, a current of 4 mA was associated with a higher SD and a lower CNR than 8 mA or 10 mA (P<0.05). For the metal posts without MAR, the artifact magnitude as assessed by SD was greatest at 1.5 cm or less (P<0.05). When MAR was applied, SD values for distances 1.5 cm or closer to the tooth were reduced (P<0.05). MAR usage did not influence the magnitude of artifacts in the control and gutta-percha groups (P>0.05).
Conclusion: Increasing the tube current from 4 mA to 8 mA may reduce the magnitude of artifacts from metal posts. The magnitude of artifacts arising from metal posts was significantly higher at distances of 1.5 cm or less than at greater distances. MAR usage improved image quality near the metal post, but had no significant influence farther than 1.5 cm from the tooth.
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Cone-Beam Computed Tomography; Artifacts; Gutta-Percha; Metals
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