Enamel lesion parameter correlations between polychromatic micro-CT and TMR

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. © 2012 international & american associations for dental research.