In vitro evaluation of different remineralization periods in improving the resistance of previously eroded bovine dentine against tooth-brushing abrasion

One dentine specimen was prepared from each of 90 bovine incisors. The samples were then evenly distributed among nine groups (A-I) and submitted to 10 alternating de- and re-mineralization cycles, including abrasion by tooth brushing. Each cycle started with a demineralization using the erosive soft drink Sprite Light (R) for 1 min, followed by storing the samples in pooled human saliva for a total of 240 min. The specimens were removed from the saliva at different intervals (group A, 0 min; B, 15 min; C, 30 min; D, 45 min; E, 60 min; F, 90 min; G, 120 min) and brushed in an automatic brushing machine. Groups H (erosion, but no brushing) and I (no erosion, but brushing), which were also stored in saliva for 240 min, served as controls. After these cvcles, loss of dentine was determined by profilometry. producing the following values (mean +/- S.D.), which were analysed statistically (P less than or equal to 0.05): group A (5.03 +/- 1.49 mum), B (4.44 +/- 1.09 mum), C (4.91 +/- 0.95 mum), D (5.47 +/- 1.52 mum), E (5.29 +/- 1.45 mum), F (4.76 +/- 0.74 mum), G (5.16 +/- 0.71 mum), H (2.61 +/- 1.31), I (1.11 +/- 0.39). Groups A-G had no significant differences, but they showed a significantly greater loss of dentine than groups H and I. It is concluded that the abrasion resistance of eroded bovine dentine is still decreased after a remineralization period of 120 min. (C) 2001 Elsevier Science Ltd. All rights reserved.