BACKGROUND:At present, there are stil differences in the studies of total-etch, self-etch and self-bonding resin cement effect on the coronal microleakage and bonding strength of fiber posts.
OBJECTIVE:To evaluate the coronal microleakage and the bonding strength of fiber posts treated with three kinds of resin cements.
METHODS:Total y 32 upper incisors were randomly divided into five groups, including three experimental groups and two control groups. After the root canal preparation, three kinds of resin cements (EMBRACE WetBond, LuxaCore, Medental Multi-cure) were used to fiber posts with the bond diameter of 1.4 mm. Stereomicroscope was used to observe the microleakage. Then, the specimens were cut into 2 mm wafer along the axis of tooth, and universal testing machine for push-out test was used to observe the failure mode. In the positive control group, no root canal preparation was done, the root was coated with nail polish, and the crown was directly exposed to the dye. In the negative control group, no root canal preparation was done, the root canal orifice was covered with the resin, the tooth was overal coated with nail polish and then embedded 1 mm below the section.
RESULTS AND CONCLUSION:The microleakage was observed in al the three resin cements, Medental Multi-cure showed the least microleakage and LuxaCore showed the largest microleakage, and there was significantly different among the three kinds of resin cements (P<0.05). The bonding strength of three cements had significant differences (P<0.05), and ranked from high to low:Mdental Multi-cure, LuxaCore, and EMBRACE WetBond. The main fracture modes were binder/fiber post fracture and mixed failure. The results suggest that the total-etch resin cement binds tightly with the dentin, and owns a superiority in the microleakage and bonding property as compared with the self-etch resin cements and self-bonding resin cements.

Objective: To explore the clinical efficacy of spine subtle adjusting manipulation for postpartum low back pain (PLBP). Methods: A total of 76 patients with PLBP were randomized into a control group and a treatment group, with 38 cases in each group. The control group was treated with core muscle strengthening exercises, and the treatment group was treated with spine subtle adjusting manipulation. After 3 weeks of treatment, the clinical efficacy was observed, and the visual analog scale (VAS) score and Oswestry disability index (ODI), and the changes of lumbar Cobb angle and pelvic rotation were compared between the two groups. Results: The total effective rate of the treatment group was 92.1％, and that of the control group was 78.9％. The difference between the two groups was statistically significant (P<0.05). After treatment, the VAS score and ODI in both groups decreased, and the intra-group differences were all statistically significant (P<0.05). There were no intra-group statistical differences in the lumbar Cobb angle or pelvic rotation in the two groups (P>0.05). After treatment, there were no statistical differences in the lumbar Cobb angle or pelvic rotation between the two groups (P>0.05); the VAS score and ODI in the treatment group were significantly lower than those in the control group (P<0.05). Conclusion: Spine subtle adjusting manipulation can effectively relieve the pain for patients with PLBP, and improve their daily activity function.