RESUMEN
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.
RESUMEN
Objective:To explore the effect of low intensity pulsed ultrasound (LIPUS) on TGF-β1/Smad 2,3 signal pathway during the dentin injury and repair.Methods:Among 25 Sprague-Dawley rats,5 rats served as a blank control group without treatment.The remaining 20 rats received modified caries preparation inbilateral maxillary first molars to establish a model of dentin-pulp injury and repair.The right maxillary first molars served as a LIPUS group,which received LIPUS irradiation (frequency:1.5 MHz,pulse width:200 μs,pulse repetition frequency:1 kHz,spatial averaged temporal averaged intensity:30 mW/cm2,20 min/d),and the left maxillary first molars served as a cavity-prepared group,which received fake LIPUS irradiation.The rats were sacrificed at 1,3,5,7 and 14 days after LIPUS irradiation.Immunohistochemical staining and Image-pro plus 6.0 were applied to detect the expression and distribution of transforming growth factor-beta1 (TGF-β1) and small mothers against decapentaplegic 2/3(Smad 2 and Smad 3).Results:Immunohistochemical staining showed that the expression of TGF-β1 and Smad 2,3were low innormal pulp,but they were increased in different degree after dentin injury.The result of image analysis showed that the expression of TGF-β1 in the cavity-prepared group gradually increased at the first day and peaked at day 5,and then it returned to normal level at day 14.However,the expression of TGF-β 1 in the LIPUS group were significantly higher than that in the cavity-prepared group at day 3 and 5 (bothP＜0.05).The expressions of Smad 2,3 in both the LIPUS group and the cavity-prepared group were consistently increased all the way, but the expressions in the LIPUS group were higher compared with that in the cavity-prepared group (P＜0.05).Conclusion:The TGF-β1/Smad 2,3 signal pathway can be activated during the dentin injury and repair.LIPUS can up-regulate the expression of TGF-β1 and Smad 2,3 in the early period,which may take part in the dentin-pulp complex injury and repair process.
RESUMEN
0.05).Conclusion: For teeth with perforation in root canal therapy,the Propex,Raypex 5 and Root ZX electronic apex locators can detect the perforation with high accuracy.