Biocompatibility Study of a New Dental Cement Based on Hydroxyapatite and Calcium Silicates: Focus on Liver, Kidney, and Spleen Tissue Effects.

The effects of a new material based on hydroxyapatite and calcium silicates, named ALBO-MPCA, were investigated on the liver, kidney and spleen. The material was administrated orally for 120 days in an in vivo model in Wistar rats, and untreated animals served as a control. Hematological and biochemical blood parameters were analyzed. Qualitative histological analysis of tissues, change in mitotic activity of cells, and histological characteristics was conducted, as well as quantitative stereological analysis of parenchymal cells, blood sinusoids, and connective tissues. Additionally, the protein expressions of Ki67 and CD68 markers were evaluated. Histological analysis revealed no pathological changes after the tested period. It showed the preservation of the architecture of blood sinusoids and epithelial cells and the presence of mitosis. Additionally, the significantly increased number of the Ki67 in the presence of ALBO-MPCA confirmed the proliferative effect of the material noticed by stereological analysis, while immunoreactive CD68 positive cells did not differ between groups. The study showed non-toxicity of the tested material based on the effects on the hematological, biochemical, and observed histological parameters; in addition, it showed evidence of its biocompatibility. These results could be the basis for further steps toward the application of tested materials in endodontics.

Homo naledi did not have flat foot.

The collection of 1550 Homo naledi fossil remains includes six tarsal and five metatarsal bones from the right foot, forming a nearly complete humanlike flat foot arch. The missing right medial cuneiform, however, raises our interest to explore the true structure of Homo naledi's foot arch. We hypothesize that Homo naledi does not have flat foot. To verify our hypothesis, the left medial cuneiform of Homo naledi was mirrored using three-dimensional reconstruction and virtual model analysis. Then, we defined quantities of Euler, standardized the body coordinate system of foot bone and developed a new foot arch reconstruction method based on discrete bones. The reconstructed transverse foot arch corroborated our hypothesis, thus providing biomechanical evidence for interpreting the evolution of human locomotion and bringing novel ideas to the research of the biomechanical mechanism of ankle stability.

Marginal Gaps between 2 Calcium Silicate and Glass Ionomer Cements and Apical Root Dentin.

INTRODUCTION: The outcome of periapical surgery has been directly improved with the introduction of novel material formulations. The aim of the study was to compare the retrograde obturation quality of the following materials: calcium silicate (Biodentine; Septodont, Saint-Maur-des-Fosses, France), mineral trioxide aggregate (MTA+; Cerkamed Company, Stalowa Wola, Poland), and glass ionomer cement (Fuji IX; GC Corporation, Tokyo, Japan). METHODS: Materials' wettability was calculated concerning the contact angles of the cements measured using a glycerol drop. Cements' porosity was determined using mercury intrusion porosimetry and micro-computed tomographic (µCT) imaging. Extracted upper human incisors were retrofilled, and µCT analysis was applied to calculate the volume of the gap between the retrograde filling material and root canal dentin. Experiments were performed before and after soaking the materials in simulated body fluid (SBF). RESULTS: No statistically significant differences were found among the contact angles of the studied materials after being soaked in SBF. The material with the lowest nanoporosity (Fuji IX: 2.99% and 4.17% before and after SBF, respectively) showed the highest values of microporosity (4.2% and 3.1% before and after SBF, respectively). Biodentine had the lowest value of microporosity (1.2% and 0.8% before and after SBF, respectively) and the lowest value of microgap to the root canal wall ([10 ± 30] × 10-3 mm3). CONCLUSIONS: Biodentine and MTA possess certain advantages over Fuji IX for hermetic obturation of retrograde root canals. Biodentine shows a tendency toward the lowest marginal gap at the cement-to-dentin interface.