Résumé
Objective: To investigate low intensity pulsed ultrasound (LIPUS) on the expression of L-type calcium ion channels(cav1. 2) and Na +-Ca2 + exchangers(NCX1) during dentin-pulp complex injury and repair in rats. Methods: Cavity preparation was made on the upper right first molar of 40 male adult SD rats,20 of them and the upper left first molar of the other 20 were randomly chosen for LIPUS irradiation(frequency: 1. 5 MHz,200 μs pulses,pulse repetition frequency: 1 KHz,ISATA 30 mW/cm2,20 min /d),so the animals were randomly allocated into 4 groups(n = 10): Control group,LIPUS group,cavity preparation group and cavity preparation + LIPUS group. At 1,3,7,14 d post-irradiation the rats were sacrificed respectively for HE stain and immunohistochemical analysis. Results: Reparative dentin formation was observed at 14 days after cavity preparation and LIPUS irradiation,the expression of Cav1. 2(L-type) and NCX1 in this group were increased significantly at day 1 and day 3. Compared with the control group, the expression of Cav1. 2 in LIPUS group increased at day 1 post-irradiation. Conclusion: LIPUS may enhance tertiary dentin formation and up-regulate the expression of Cav1. 2 and NCX1 at the early period of dentin injury.