ABSTRACT

Objective: This study aims to evaluate the antibacterial effect and flow of a bioceramic sealer modified by different concentrations of nano magnesium hydroxide (NMH). 

Methods: NMH were characterized using transmission electron microscope and X-ray diffraction analysis. Then, added to Ceramoseal HBC by 0.025%, 0.05% and 0.1% in weight. for direct contact antibacterial test (DCT), the tested materials were added to wells of a 96-well plate. Bacterial suspension was added to each well, incubated for 1hour and 24 hours and transferred to agar plates for colony forming unit to be counted. Flow test was applied according to ISO standards and the diameters of compressed discs of tested materials were measured. The data were statistically analyzed using One way ANOVA test and Student t-test.

Results: For DCT test, all tested groups showed antibacterial effect compared to the positive control. At 1 hour, group Ⅰ showed the highest antibacterial effect. At 24 hours, group Ⅰ and Ⅳ were the same antibacterial effect that is higher than group Ⅱ and Ⅲ. Regarding flow, group Ⅰ was highest flow and group Ⅳ was the lowest but all results were more than 17 mm.

Conclusion: NMH modified sealers showed antibacterial efficacy and their flow still according to ISO requirements

ABSTRACT

Objective: This study evaluated the push out bond strength of a bioceramic sealer modified by nano
magnesium hydroxide with different concentrations (NMH).

Methods: NMH was characterized using
transmission electron microscope and X-ray diffraction analysis. Then, added to Ceramoseal HBC by
0.025%, 0.05% and 0.1% in weight. For push out bond strength test; 40 extracted upper central
incisors were collected and prepared for endodontic treatment. The teeth were decronated, their root
canals were mechanically cleaned and shaped then, grouped randomly into four groups according to
the percentages of added nanoparticles. Group Ⅰ: Bioceramic sealer without added nanoparticles.
Group Ⅱ: Bioceramic sealer + 0.025% NMH. Group Ⅲ: Bioceramic sealer + 0.05% NMH. Group Ⅳ:
Bioceramic sealer + 0.1% NMH. Obturation was performed using gutta percha and the tested
materials. Specimens were placed in 100% relative humidity for 7 days for sealer setting. After that,
2mm coronal slices were cut from each root to be tested for push out bond strength by applying a
deponding force through a computer controlled testing machine till bond failure and bond strength
was calculated in MPa. The data were statistically analyzed using One way ANOVA test and Student
t-test.

Results: The results showed that highest mean bond strength value was recorded for group Ⅳ
(9.72 ± 1.66), while the lowest value was recorded for group I (5.97 ± 1.28). Conclusion: Addition of
NMH to bioceramic sealers enhanced their bond strength.

Abstract

Objective: To decipher the role of locally injected bone marrow mesenchymal stem cells (BM-MSCs) in the tongue of hypothyroid rats.

Design: A total 24 male Wister rats were utilized and allocated into 3 groups (n = 8). As for the control group, rats received distilled water via oral gavage. In the hypothyroid group, rats administered carbimazole 5 mg/ 250 g/ day for 6 successive weeks, for hypothyroidism induction. The BM-MSC treated hypothyroid group (BM-MSC group); hypothyroid rats received local injection of 0.5 million BM-MSCs in tongue. Six weeks after BM-MSC injection, tongue samples were processed for Hematoxylin and eosin (H and E) staining, Ki67-immunohistochemistry and histomorphometric analysis.

Results: The hypothyroid group revealed degenerative alterations in the lingual papillae, and apparent thinning of the inferior lingual epithelium compared to their controls. Tongues of the BM-MSC group depicted restoration of the normal tongue histology. The Ki67 immunoreaction was apparently decreased in the lingual epithelium of hypothyroid group compared to their controls, however the BM-MSC group regained Ki67 immunostaining.

Conclusion: Our data suggest that administration of BM-MSCs rescued the degenerative changes in the lingual mucosa and one of the possible underlying mechanisms could be the restoration of cellular proliferation in the lingual epithelium.