title: Enamel lesion parameter correlations between polychromatic micro-CT and TMR.
abstract: Transverse microradiography (TMR) is considered as the gold standard technique for the evaluation of enamel lesions. Micro-computed tomography (µCT) has the advantage of non-destructive measurements, but the beam-hardening effect with polychromatic x-rays is a major drawback. To date, no study has validated µCT against TMR. The objective of this study was to validate µCT measurements of enamel lesions under various x-ray conditions and software beam-hardening correction (BHC) against TMR. Human molars with natural white-spot lesions were scanned for 5 min by µCT at 100 kV in different conditions: 50 µA (0.5-mm Al filter), 165 µA (0.5-mm Al/0.3-mm Cu), and 200 µA (0.5-mm Al/0.4-mm Cu), with or without BHC. Grayscale values were converted into mineral density values using phantoms. Thin sections at the same positions were then prepared for TMR. Lesion depth (LD; µm) and mineral loss (ΔZ; vol%µm) were compared between µCT and TMR by Pearson's correlations. µCT measurements correlated well with TMR under all conditions (p < 0.001, r > 0.86 for LD and ΔZ), except for 0.5-mm Al without BHC (p > 0.05). Even without BHC, combined Al/Cu filters successfully reduced the beam-hardening effect. µCT can be used as a non-destructive alternative to TMR with comparable parameters for the study of enamel lesions.
authors.affiliation: Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Hamba
authors.forename: T
authors.initials: T
authors.lastname: Nikaido
authors.forename: A
authors.initials: A
authors.lastname: Sadr
authors.forename: S
authors.initials: S
authors.lastname: Nakashima
authors.forename: J
authors.initials: J
authors.lastname: Tagami
mesh_terms: D000328:Adult; D000535:Aluminum; D016477:Artifacts; D003300:Copper; D003731:Dental Caries / Q000000981:diagnostic imaging*; D003743:Dental Enamel / Q000000981:diagnostic imaging*; D005374:Filtration / Q000379:methods; D006801:Humans; D008852:Microradiography; D008964:Molar, Third / Q000473:pathology; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D055114:X-Ray Microtomography; D055815:Young Adult
chemical_list: D003300:Copper; D000535:Aluminum