Comparing two quantitative methods for studying remineralization of artificial caries

Abstract

Abstract Objectives: To compare the detection of changes after remineralization of artificial enamel caries by microCT radiographic scanning and microradiography. Methods: Twelve extracted premolars were cut into cuboidal tooth blocks and painted with an acid-resistant vanish leaving one enamel surface uncovered. After scanning by a microCT (僔20, SCANCO Medical AG, Switzerland), the tooth blocks were immersed into demineralizing solution for 4 days to produce artificial carious lesions and scanned by 僔20 again. After taking the above measurements, the 12 tooth blocks were randomly allocated into two groups. Six tooth blocks in the first group were cut longitudinally through the exposed surface into 100-150孠thick sections and microradiographs (MRG) were taken. All the tooth blocks and sections were then immersed into remineralizing solution for 5 days. MRG of the tooth sections in the first group were taken again. Depth of the lesion on the MRG was measured. Tooth blocks in the second group were scanned by 僔20. Changes in linear attenuation coefficient (LAC) of the region of interest (ROI) in enamel were used to represent the changes in mineral concentration of the artificial caries lesions. Results: There was no statistically significant difference in the mean LAC of the two groups of tooth blocks before remineralization (paired t-test, P>0.05). Mean lesion depth in the first group reduced from 176孠(SD=58) before remineralization to 143孠(SD=46) after remineralization (paired t-test, P=0.01) which was an 18.8% change. In the second group, LAC increased from 3.59/cm before remineralization to 4.17/cm after remineralization (paired t-test, P=0.011) which was a 16.2% change. Conclusion: Both microCT and microradiography are able to detect a change of similar magnitude in the artificial caries in enamel after remineralization.