Background: The permeability feature of conventional CALCIUM HYDROXIDE (CH) and nanoparticle CH (NCH) was compared to show the desired effects of this new material and in case of confirmation of its other properties; CH can be used as a safe alternative. Materials and Methods: This in vitro was carried out in two phases: First phase: measurement and comparison of the permeability rate of conventional CH and NCH in the dentinal tubules employing a fluorescence microscope were carried out. Second phase: measurement and comparison of the permeability rate of NCH and conventional CH in L929 fibroblast cells using a fluorescence microscope were carried out. Kruskal– Wallis analysis was used for overall comparisons. A series of Mann– Whitney U tests were used for pair‑ wise comparisons (P < 0. 05). Results: Based on the results of Kruskal– Wallis test, in all three regions of the cervical third, middle third, and apical third of the root, mean values of the percentage difference of the fluorescence and color change in NCH were more than the conventional CH, and the difference was statistically significant (P < 0. 001). the percentage of fluorescence color change in drug with the concentration of 1 g/cc was more than the one with the concentration of 0. 1 g/cc and the difference was statistically significant (P < 0. 001). Conclusion: The nanoparticle drug compared with the conventional drug has a more penetration depth in all regions of the root of the dentinal tubules.

Introduction: The goal of this paper was to determine the impact of CALCIUM HYDROXIDE (CH) and nano-CALCIUM HYDROXIDE (NCH) on the push-out bond strength of an epoxy resin-based sealer. Materials and Methods: A total of 48 mandibular premolars were decoronated in vitro and instrumented by a ProTaper rotary system up to F4. The specimens then were randomly allocated into 3 groups (n=16). The two intervention groups were treated with either CH or NCH and one control group which did not receive any intracanal medicament. After one week of medicament placement, the specimens were irrigated by 10 mL 17% EDTA, followed by 10 mL 2. 5% NaOCl and an ultimate flushing by 5 mL sterile saline. The samples were obturated using AH-Plus Jet sealer and gutta-percha by lateral condensation technique. Push-out test was done by a universal test machine to evaluate the bond strength among the sealer and the root canal dentin. Repeated measurement analysis followed by Tukey’ s HSD and Bonferroni post-hoc tests were used for data analysis. Results: The control group showed a higher push-out bond strength in comparison to the specimens in the CH and NCH groups (P<0. 05). In spite of the greater push-out bond strength of the samples treated with NCH in comparison to those in CH group, no statistically notable difference was found among them (P>0. 05). Additionally, irrespective of the kind of medicament, the bonding at the apical level of the root canal was stronger compared to the coronal third (P<0. 001). Conclusion: According to the present in vitro study, application of CH and NCH resulted in a significant reduction of the bond strength between the epoxy resin-based sealer and dentinal walls. Although, application of these medicaments resulted in reduction of bonding of epoxy resin-based sealers root canal dentin significantly.

Background and Aim: Therapeutic effects of CALCIUM HYDROXIDE as an intra-canal medicament depend on its decomposition into hydroxyl and CALCIUM ions. The aim of this study was to determine the diffusion amount of CALCIUM ion and ph changes around the tooth root in the application of conventional CALCIUM HYDROXIDE and Nano particle CALCIUM HYDROXIDE at different times. Material and Methods: In this in vitro experimental study, 50 human single rooted and single canal teeth were divided into two experimental groups of 20 (conventional CALCIUM HYDROXIDE and Nano particle CALCIUM HYDROXIDE with a size of 23±, 5 nm after confirmation by X-ray Powder Diffraction) and a control group of ten (distilled water). After applying these materials using a K file ISO # 55, seal the coronal part of the canals and transfer to normal saline, the concentration of CALCIUM ions and the ph of normal saline in all groups was measured After 3, 24, 96, 360 and 720 hours. Data were analyzed by one-way ANOVA, Tukey Post Hoc, Bonferroni Post Hoc statistical tests and SPSS 22 software. Results: There was a significant difference between the three groups at different times and in total in comparing the mean ph and mean concentration of CALCIUM ions around the tooth roots (P <0. 001). These values for both parameters, in the group of nanoparticle CALCIUM HYDROXIDE were significantly higher than conventional CALCIUM HYDROXIDE and in the group of conventional CALCIUM HYDROXIDE, higher than the control group (P <0. 05). Also, the mean concentration of CALCIUM ions in the group of normal CALCIUM HYDROXIDE and nanoparticle CALCIUM HYDROXIDE incresaed. Conclusion: Nanoparticle CALCIUM HYDROXIDE can be a suitable alternative to achieve the desired therapeutic goals due to its ability to emit more CALCIUM ions and higher ph than the conventional type.

CALCIUM HYDROXIDE (CH) is commonly employed as intracanal medicament in endodontics. In order to maximize its therapeutic effects, it is essential to develop new approaches for preparing the controlled drug release systems which, in turn, facilities the dissociation of CH into CALCIUM and hydroxyl ions. This work studies the sustained-controlled release of CALCIUM ions and the effect of pH changes on the different formulation of CH with hydrophilic natural polymers over a period of 30 days. Various formulations were prepared by combining CH with gelatin, aloe vera and gum tragacanth. Root canals of 60 human teeth were instrumented and filled with a different formulation of CH and suspended in plastic tubes containing distilled water. Three formulas of polymer/CH were evaluated, and pure CH powder was used as a control. At specific time intervals, the CALCIUM ions release and the pH changes of the medium in different formulations were analyzed. The main interactions between the studied polymers and CH were investigated using FTIR spectra. The antibacterial activity of formulations against Enterococcus faecalis was also studied. Faster release of CH was observed for aloe vera/CH. Gum tragacanth/CH showed a slow-release during the first 15 days. In contrast, only Gelatin/CH formulation showed a prolonged release with statistically significant differences (P < 0. 05). The pure CH showed significantly higher pH values than the other formulations. The Gelatin/CH formulation was a better sustained-release system than the pure CH, and it can be used as a promising vehicle for CH in the root canal treatment.