Introduction: The use of a partially saturated acidic buffer system to create subsurface carious lesions in bovine enamel is long established. Previous work has suggested however, that immersion for 72 hours brings about significant surface mineral loss and erosive changes, thereby confounding subsequent investigation.
Objective: To define the production of carious demineralisation (D) in bovine enamel that excludes erosion.
Method: Five bovine upper incisors were sectioned into six and randomly allocated into one of six groups (1-6). Tooth sections were varnished to leave a 5x5 mm window and exposed to a partially saturated acidic buffer (pH 4.5) for 12(1), 18(2), 24(3), 30(4), 36(5) or 42(6) hours at room temperature. Sections were imaged with quantitative light induced fluorescence (QLF) before, during and after D. Analysis was carried out using QLF V.2.00 software (Inspektor Research Systems, Netherlands). All samples were examined using transverse microradiography (TMR).
Results: D, measured as ΔF, showed reduced fluorescence for all samples with increasing time of immersion (p<0.001). TMR confirmed progressive mineral loss as well as increased depth and width of subsurface lesions. Groups 1 and 6 showed mean mineral loss of 1479.7±223.8 and 2400.5±739.7vol%.μm respectively with lesion width progressing from 46.9±2.6μm to 68.8±17.2μm and depth from 60.4±3.8μm to 82.4±20.3μm. No surface mineral loss was seen for any samples
Conclusion: The production of carious demineralisation with the absence of erosion can be achieved in bovine enamel under defined conditions. Time of immersion in the partially saturated acidic buffer system is suggested as 42 hours or less at room temperature to exclude surface mineral loss.