Aim: Considering that the use of intracanal medicaments in teeth with necrotir; pulp, periapical lesion, or exudating canals is evident, this study was performed to evaluate the ca ++ and OH- diffusion through root dentin using calcium hydroxide paste as intracanal dressing.Method & Materials: 52 single - rooted teeth were selected. The canals were enlarged to size 60 master apical file and flared to size 1ra. External defects were created on the coronal one- third of the root surface. 17%EDTA and 5% sodium hypochlorite were used to eliminate the smear layer.Ali surfaces except the external defects were sealed and the teeth were, placed in normal saline. Ten teeth were selected as th.e control group and after three days, ca+2 concentrations and the pH in the saline were determined. 42 remaining teeth were divided to three groups with 14 teeth in each one (A,B, C groups).Calcium hydroxide powder and distilled water were mixed to make calcium hydroxide paste. This paste was placed in root. cenal of 42 teeth. Ca++ concentration and pH of normal saline were determined after 24 hoursin group A, after 48 haul's in group B and after one week in group C.Results: The ca++ concentration and pH in all three groups (A, Band C) were significantly .different from control group. The most ca++ release and pH was seen in group C that was significantly different from groups A and B.Conclusion: In order to gain the maximum effect of calcium hydroxide as an intracanal dressing it is recommended to be used for 1 week.

Calcium channels are cell membrane proteins that play an important role in control the Ca ion flux through the membrane. In this study, the effect of external constant electric field on the dynamics of calcium ions in a L-type channel, located within a stochastically fluctuating medium, is modeled via the application of the molecular dynamics (MD) simulation method. The obtained results show that application of constant field of 0. 03 V/nm did not show significant effect on the ions motion. On the other hand, when the channel is exposed to a constant electric field of strength 0. 3 V/nm, the ions directional motion along the applied field is observed. Furthermore, it is found that no net motion is observed when the field direction is changed.

Introduction: Endodontic cements are essential materials for achieving successful root canal treatment. Therefore, they must present adequate physicochemical properties to ensure optimal clinical performance. This study aimed to evaluate radiopacity, pH, and calcium ion release of calcium silicate- and epoxy resin-based cements/sealers. Materials and Methods: Four materials were evaluated: Vioseal, AH-Plus, AH-Plus Bioceramic Sealer, and MTA Angelus. Ten cylindrical specimens (10 mm diameter, 1 mm height) per group were prepared for each tested property, totaling 80 samples. The same specimens were used for pH and calcium ion release, while separate specimens were used for radiopacity. All samples were stored at 37°C and 95% humidity. Radiopacity was assessed by digital radiography using an aluminum step wedge (1-10 mm). pH was measured at 1, 7, and 14 days using a calibrated digital pH meter. Calcium ion release was determined using atomic absorption spectrophotometry. Data were analyzed using Kruskal-Wallis and Dwass-Steel-Critchlow-Fligner post hoc tests (P<0.05). Results: Vioseal and AH-Plus showed the highest radiopacity values (9.98±0.42 mm Al and 10.00±0.38 mm Al, respectively), while AH-Plus Bioceramic Sealer (9.04±0.28 mm Al) and MTA Angelus (4.72±0.40 mm Al) showed lower values. Regarding pH, AH-Plus Bioceramic presented the highest and most sustained alkaline value (up to 12.5), and AH-Plus the lowest (6.25±0.26). In calcium ion release, Vioseal showed the highest release on day 7 (29.4±3.12 ppm), while AH-Plus Bioceramic Sealer also peaked on day 7 (18.60±5.54 ppm); MTA Angelus presented its highest release on day 1 (11.80±1.00 ppm). Conclusion: All evaluated cements/sealers met the ISO 6876 standard for radiopacity. Calcium silicate-based cements showed an alkaline pH and sustained calcium ion release, whereas Vioseal presented an initially high and transient release.

Natural elemental impurities are recognized as a threat for safety and quality of edible salt and have adverse effects on public health. In the current study, fiftysamples of packages containing 1 kg of salt from 25 different brands were collected from retailers in Semnan city (Iran). The concentrations of main impurities of edible salt including magnesium (Mg), calcium (Ca), and sulphate (SO4-2) ions were quantified by the aid of an Ion Chromatography with conductivity detector. According to findings, the maximum concentrations of Mg, Ca, and SO4-2 ions in salt samples were 0. 067, 0. 226, and 0. 888 % w/w (dry matter basis), respectively. In addition, the concentration of Mg in 16%, Ca in 4%, and SO4-2 in 28% of samples suppressed the acceptable limit proposed by the Institute of Standards and Industrial Research of Iran (ISIRI) (0. 15% for Ca, 0. 03% for Mg, and 0. 46% for SO4-2). Moreover, the maximum and minimum levels of purity in the salt samples were recorded as 99. 940 and 97. 730%, respectively. Moreover, the purity in 12% of the investigated samples was lower than that of the minimum acceptable limit suggested by ISIRI, while the purity of 97% samples met the acceptable Codex Alimentarius limit (97% Min). Based on results of the current investigation, the routine purification processes used in some factories of Iran did not reduce impurities. Hence, purification process bedsides constant monitoring and safety management should be improved to promote the health quality of edible salt.

Aspartame (N- (L-Aspartyl) -L-phenylalanine, 1-methyl ester) is an artificial sweetener and because of high sweetness and low calorie has wide use in food industries. Experimental studies show that aspartame affects the amount of calcium in the body and cause osteoporosis in long time. In this study interaction of aspartame with calcium ions was investigated via molecular dynamics simulation.MD simulation was carried out using a model of Ca2+ and other ions enclosed in a fully hydrated simulation box with aspartame. The results showed that aspartame was capable to sequestering calcium ions for a long time. The theoretical results are consistent with experimental results.

Wheat being a glycophyte crop, responds differently to saline-sodic soil environmental conditions. The application of calcium is multidimensional with respect to sodium ion and plant part response. This study was conducted to record the response of shoot and root to sodium and calcium interaction under saline environment. Wheat seed of variety Punjab 85 were raised in quartz sand. Later on the seedlings were transplanted to pots containing Hoagland’s nutrient solution along with NaCl at 0 mM. and 50 mM. Calcium was applied as CaSO4 2H2O at 3 mM. and 6 mM. Under saline conditions shoot showed positive response to sodium ion in the presence of higher calcium. Relative water contents were higher in the root system at 6 mM of CaSO4. 2H2O under saline condition. Growth responses to potassium and Magnesium in the presence of sodium induced salinity with calcium ion interaction remained variable.