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.

Background: Microbial irritation is the major etiologic cause of pulp and periapical lesions. Therefore the main goal of endodontic treatment is complete elimination or inimizing acteria with chemo-mechanical preparation. CALCIUM HYDROXIDE is one of the chemical substances, which are used, in endodontic treatment and its antimicrobial effect on various bacteria has extensively has been studied and researched. Recently Gutta-percha point containing CALCIUM HYDROXIDE has been offered to dentistry.The purpose this study was to examine the antimicrobial effects of this substance in infected root canals.Material and Methods: In this study ninty extracted human maxillary central incisors, which had been extracted to various reasons, were selected. After canal preparation and root sterilization, all the samples (excluding 10 negative control samples) were contaminated by bacillus subtillis. Then these eighty roots were randomly divided into 3 groups, which were 10 roots as positive control group (non medicated), 35 roots medicated with Gutta-percha point containing CALCIUM HYDROXIDE as group A, 35 roots medicated with CALCIUM HYDROXIDE as group B. after 1, 2, 3, 5 and 7 days in these three groups , antimicrobial effect was assessed.Result: The result showed no significant difference (p=0.35) between antimicrobial effect of Gutta-percha point containing CALCIUM HYDROXIDE and CALCIUM HYDROXIDE past.Conclusion: Since there is no significant difference between antimicrobial effect of Gutta-percha point containing CALCIUM HYDROXIDE and CALCIUM HYDROXIDE past, it seems that the usage of this product as an intracanal medication should be more investigated.

Background and Aim: During root canal therapy, it is necessary to remove as many bacteria as possible from the root canal. The use of medicaments is recommended t6 reduce the microbial population prior to root filling. CALCIUM HYDROXIDE pastes have been used because of their antibacterial effects and the ability of tissue dissolving. The aim of this study was to evaluate the effect of CALCIUM HYDROXIDE/glycerine mixture, CALCIUM HYDROXIDE/normal saline mixture and CALCIUM HYDROXIDE/distilled water mixture on root dentin microhardness in storage times of 7 and 14 days.Materials and Methods: In this in vitro study, fifteen extracted maxillary canines and central incisors were selected. The crowns of the teeth were removed and the canals were prepared. Teeth were sectioned transversally to produce a total of 30 dentin discs from the middle third of the roots. Specimens were divided into three groups of 10 discs each. Dentin samples were subjected to CALCIUM HYDROXIDE/glycerine, CALCIUM HYDROXIDE/normal saline and CALCIUM HYDROXIDE/distilled water' mixtures for 7 and 14 days. Dentin microhardness was measured by a Vickers indenter with a load of 200 g for IS seconds. Data were analyzed using ANOVA, Paired t-test and LSD with p<0.05 as the level of significance.Results: Statistical analysis showed that all three mixtures decreased dentin microhardness. After 7 days, reduction in dentin microhardness by CALCIUM HYDROXIDE/glycerine combination was significantly higher than CALCIUM HYDROXIDE/normal saline and CALCIUM HYDROXIDE/distilled water combinations. After 14 days, reduction in dentin microhardness by CALCIUM HYDROXIDE/distilled water combination was significantly higher than the other two groups.Conclusion: Based on the results of this study, the use of CALCIUM HYDROXIDE combinations for intracanal dressing reduces dentin microhardness. After 7 days CALCIUM HYDROXIDE/glycerine combination and after 14 days CALCIUM HYDROXIDE/distilled water combination are the most effective combinations.

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.

Background and Aim: CALCIUM HYDROXIDE plays an important role in endodontics by its ability to induce hard tissue formation, its antibacterial action, and its tissue dissolving capability. Different vehicles have been added to CALCIUM HYDROXIDE in an attempt to enhance its antimicrobial activity, biocompatibility, ionic dissociation, and diffusion. The purpose of this study was to investigate the efficacy of various CALCIUM HYDROXIDE pastes against enteroccocus faecalis in vitro.Method and Material: A total of 20 blood agar plates were prepared for this experimental study. Five holes were made in each plate. Three experimental pastes (CALCIUM HYDROXIDE/chlorhexidine, CALCIUM HYDROXIDE/saline, CALCIUM HYDROXIDE/xylocaine) were placed in 3 holes. Ampicillin and distilled water were placed in the other 2 holes as positive and negative controls. Plates were stored room temperature for 2 hours and then were incubated at 37 degrees centigrade for 48 hours. The antimicrobial effect was determined by ADT method. Blood agar plates were infected with pure enteroccocus faecalis suspensions. The diameter of growth inhibition was measured and recorded after incubation. Statistical analysis was performed using the one-way ANOVA and LSD tests.Results: In all plates all 3 experimental pastes and ampicillin showed growth inhibition. Mean diameter of growth inhibition was the greatest for the ampicillin group. The negative control showed no growth inhibition. The growth inhibition for CALCIUM HYDROXIDE/chlorhexidine was significantly more than the other two groups (P<0.05).The growth inhibition between CALCIUM HYDROXIDE/saline and CALCIUM HYDROXIDE/xylocaine was not significant.Conclusion: The antimicrobial properties of CALCIUM HYDROXIDE can be influenced by the vehicles used to make the paste form. Based on the results of this study, CALCIUM HYDROXIDE/chlorhexidine is a better vehicle than CALCIUM HYDROXIDE/saline and CALCIUM HYDROXIDE/xylocaine to improve CALCIUM HYDROXIDE antimicrobial properties.

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 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.