comparison of push-out bond strength of two endodontic sealers to root canal dentin: an in vitro study

Statement of Problem: Adhesion to root canal dentin is one of the necessary characteristics of endodontic sealers. MTA Fillapex [Angelus, Londria, PR, Brazil] is one of the recently introduced MTA-based sealer. Only a limited number of studies have evaluated the bonding of this sealer to the dentin, with conflicting results

Objectives: The purpose of this study was to evaluate the bond strength of MTA Fillapex sealer] to root canal dentin compared to an epoxy resinbased sealer [AH26 sealer]

Materials and Methods: Twenty root blocks [6mm length] were acquired from the middle part of the extracted single-rooted central or lateral maxillary incisor roots and their lumens were enlarged to achieve a diameter of 1.3 mm. MTA Fillapex and AH26 were placed in the lumens of root blocks [n = 10]. The specimens were kept in an incubator for 7 days, the roots were sectioned perpendicular to their long axis to achieve slices with thickness of 1 mm and the push-out test was carried out by a universal testing machine

Results: The mean value of bond strength was 1.84 +/- 0.7 Mpa for AH26 and 0.19 +/- 0.1 Mpa for MTA Fillapex. The difference between the two groups was statistically significant [p < 0.001]

Conclusions: With in the limitation of this study, AH 26 showed significantly higher bond strength in comparison to MTA Fillapex

[Histopathologic effects of methadone on central nervous system of mice newborns in suckling period]

Background and aim: Methadone is a synthetic opioid, used in the treatment of opioid dependence and chronic pain. The aim of this study was to investigate histopathological effects of methadone on central nervous system of mice newborns in suckling period

Methods: In this study, twenty eight mature pregnant mice were randomly divided into four groups of seven each. Three groups were intraperitonealy injected methadone [3, 6, 9 mg/kg per day respectively] from first lactational day until weaning. Control group was injected distilled water saline. At the 27th day, respectively offspring were weighed and anesthetized with choloroform and then their brains removed from their skulls and immersed in the fixative formalin buffer 10% for 24h and samples were stained with Hematoxylin and Eosin stain for the histopathology study. The data were analysed using one way ANOVA and Sheffe tests

Results: Methadone caused a significant reduction in both weight and Crown Rumpa-Length and also an increase in the brain to body mass ratio in experimental groups compared to the control group [P<0.001]. In addition, offsprings who received methadone during lactational period showed changes in the brain neuronal degeneration along with apoptotic cells in the regions of DG and CA3 of the hippocampus

Conclusion: Methadone consumption during lactational period can cause reduction in growth indices and structural disorders in the offspring brains