Development of secondary palate requires strict regulation of ECM remodeling: sequential distribution of RECK, MMP-2, MMP-3, and MMP-9

We have evaluated RECK (reversion-inducing-cysteine-rich protein with Kazal motifs), MMP-2 (matrix metalloproteinase-2), MMP-3, and MMP-9 involvement during palate development in mice by using various techniques. Immunohistochemical features revealed the distribution of RECK, MMP-2, and MMP-3 in the mesenchymal tissue and in the midline epithelial seam at embryonic day 13 (E13), MMPs-2, -3, and -9 being particularly expressed at E14 and E14.5. In contrast, RECK was weakly immunostained at these times. Involvement of MMPs was validated by measuring not only their protein expression, but also their activity (zymograms). In situ hybridization signal (ISH) for RECK transcript was distributed in mesenchymal and epithelial regions within palatal shelves at all periods evaluated. Importantly, the results from ISH analysis were in accord with those obtained by real-time polymerase chain reaction. The expression of RECK was found to be temporally regulated, which suggested possible roles in palatal ontogeny. Taken together, our results clearly show that remodeling of the extracellular matrix is finely modulated during secondary palate development and occurs in a sequential manner.

The use of a setting accelerator and its effect on pH and calcium ion release of mineral trioxide aggregate and white Portland cement

The aim of this study was to evaluate the influence of adding 10% calcium chloride (CaCl2) indicated as setting accelerator on pH and release of calcium ions of commercially available materials: ProRoot MTA (tooth-colored formula), MTA Branco, and White Portland cement. The products were mixed for 30 seconds in previously established ratios. To estimate the values of pH and release of calcium ion, polyethylene tubes were filled with the materials and immersed in containers with 10 ml of deionized water. The analyses were performed baseline, 30 minutes, 60 minutes, and 24 hours after the mixing process. A pHmeter (MicroNal B 371, Sao Paulo, SP, Brazil) and an atomic absorption spectrophotometer (Model GBC 904; CG Corp, Melbourne, Australia) equipped with a hollow cathode lamp were used to determine the data. According to the Student's t-test, the comparison between the pure and the CaCl2-added products indicated that the presence of this substance increased immediately the pH, although the results were very similar when they were analyzed in the other intervals. In addition, products with CaCl2 released more calcium ions than pure materials in the 24-hour period (p<0.05). The results revealed that the addition of CaCl2 to MTA enhanced the physicochemical properties of this product. Thus, materials mixed with CaCl2 became easier to handle and needed lower amounts of water in the mixing process.

pH and calcium ion release of 2 root-end filling materials

OBJECTIVE

The purpose of this study was to evaluate the pH and calcium ion release of 2 materials used for root-end fillings and perforation repair.

STUDY DESIGN

ProRoot and MTA-Angelus were placed in plastic tubes and immersed in glass flasks containing deionized water. After 3, 24, 72, and 168 hours, the water in which each had been immersed was tested to determine the pH changes and released calcium.

RESULTS

The values for pH and calcium ion release were slightly higher for MTA-Angelus than ProRoot. The calcium release and pH of both materials were initially higher.

CONCLUSION

The results suggest that both materials release calcium and promote alkaline pH.