Introduction: Microleakage is one of the most important factors in the failure of root canal treatment. Microhardness is one of the physical properties of bioceramics that can be affected by various environmental factors such as enviromental humidity. The aim of this study was to evaluation the effect of adding water to semi-setting cement on the microhardness and microleakage of CEM cement. Methods: 50 single-rooted teeth were selected. Teeth were cut from the CEJ region and the apical 3 mm of the root were trimmed and dentinal blocks with 5 mm height were prepared Peeso reamer size 2 was used to prepare the canal. The teeth were divided into two groups of 23 cases and two groups of 2 positive and negative controls. In the first group, CEM-cement prepared according to the manufacturer's instructions was placed in the canal. In the second group, after adding water to the semi-setting CEM cement mixture, the canal was filled with this cement. The samples were placed in 1% methylene blue for 3 days and then cut. Microleakage was recorded under a stereomicroscope. The microhardness of the samples was measured with Vickers device after mounting in acrylic resin. Statistical analysis was performed using SPSS19 software and Mann-Whitney Kruskal-Wallis and one-way ANOVA tests. Results: There was a statistically significant difference between the two groups in microleakage (P-Value <0. 008) and microhardness (P-Value <0. 001). Conclusion: According to the results of the present study, adding water to the semi-setting CEM cement not only does have a very bad clinical effect, but also may even increase sealling ability.

Introduction: Sealing ability of root-end filling materials is of great importance. It can be investigated by measuring microleakage. The purpose of this in vitro study was to evaluate microleakage of calcium enriched mixture (CEM) cement in two different media including phosphate buffer solution (PBS) and distilled water.Materials and Methods: Twenty single-rooted human teeth were selected. All teeth were root-end filled with CEM cement. Samples were divided into two groups of 10 each and were placed in PBS or distilled water. The microleakage was measured after 12 and 24 h, 14 and 30 days with Fluid Filtration device. Data were statistically analyzed by repeated measures test.Results: Sealing ability of CEM cement was significantly superior in PBS compared to distilled water (P<0.05). This study also showed that time had no significant effect on the sealing ability of CEM cement.Conclusion: Media can significantly affect the microleakage of CEM cement. PBS can provide more phosphorous ions for hydroxyapatite formation of CEM cement; therefore, CEM cement can seal more effectively with PBS.

Introduction: It is difficult and sometimes impossible to predict the degree of damage and prognosis of tooth vitality after a carious dental pulp exposure. This predicament is exacerbated by the fact that clinical signs and symptoms do not correlate closely with the histopathological status of the pulp. As clinicians, we are keen to be conservative to maintain pulp vitality; however we must also remove all the infected tissue. Vital pulp therapy (VPT) aims to remove infected dentin, and bacteria, and at the same time to maintain pulp vitality by using a biocompatible material to seal off the pulp and restore the tooth’s strength and function. In the past, calcium hydroxide was used as a biocompatible pulp capping/pulpotomy agent. This has now been generally replaced with either MTA or Calcium Enriched Mixture (CEM) cement. These new biomaterials have good sealability and regenerative abilities, even superior to the traditional material used for VPT; for example, they can induce the production of greater and better quality reparative dentine. CEM cement has been clinically assessed for different VPT treatments such as direct pulp capping and pulpotomy treatments and therefore, its use for different VPT treatments is recommended.

Objective: This study aimed to assess the surface microhardness of calcium-enriched mixture cement (CEM) and cold ceramic (CC) cement after being cured in environments with different pH values. Methods: Sixty maxillary canines were obtained. Their roots were cut below the cementoenamel junction (CEJ) to create root dentin blocks with a height of 3 mm. The internal space of the canal was then prepared with a Peeso reamer. The specimens were filled with either CEM (Group 1) or CC (Group 2) cement (n=30). The groups were further divided into three subgroups (n=10), each was wrapped in gauze soaked in one of the following solutions: A) distilled water (pH=7.4), B) buffered butyric acid (pH=4.4), or C) potassium hydroxide (pH=10.4). The samples were incubated at 37°C for one week. Afterwards, the Vickers surface microhardness of specimens was measured and compared between groups and subgroups using a two-way ANOVA (α=0.05). Results: The microhardness values of both cements showed significant differences depending on the environmental conditions (P<0.05). The highest microhardness was observed in the alkaline environment, with CC cement measuring 60.32 ± 3.16 and CEM cement measuring 53.57 ± 2.09. The microhardness of both materials reduced significantly in the acidic environment (P<0.05). CC cement demonstrated significantly higher surface microhardness than CEM cement in neutral and alkaline environments (P=0.001 for both), but the two groups showed comparable microhardness in the acidic environment (P=0.51). Conclusions: CC cement showed greater microhardness than CEM cement in neutral and alkaline environments. Both cements exhibit reduced hardness in the acidic condition.

Introduction: Root mineral trioxide aggregate (MTA) is a type of MTA that has been introduced in the Iranian market. There have been few studies on this substance. This study compared the push-out bond strength of Root MTA and CEM cement, which were both Iranian products. Materials & Methods: This in vitro study was performed on 20 extracted maxillary incisors. Samples were divided in two groups. The canals of the first group were filled with Root MTA and the second group by CEM cement. In order to investigate the push-out bond strength, the device applied a force in the direction parallel to the longitudinal axis of the sample so that the desired materials would fail. Each sample was classified into one of three types of failureincluding adhesive (failure in the material and dentin interface), cohesive (failure in the material itself) or a combination of both. Results: There was no significant difference between the mean pressure on teeth for the two groups (P>0. 05). There was no significant difference between the frequencies of different types of failure between the two groups (P>0. 05). Cohesive failure in the CEM group was twice as high as in the MTA group (P>0. 05). Conclusion: There was not any significant difference between the push-out bond strength of CEM cement and Root MTA cement. These findings demonstrated that Root MTA material showed a satisfactory result in the bond strength test compared to CEM material, and could be used as an alternative to CEM cement.

Introduction: Most of the materials used in endodontic procedures may lead to discoloration. This study compared the discolorations induced following treatment by MTA, CEM, and Biodentine using a spectrophotometric analysis. Material & Methods: In this experimental study Forty extracted mandibular anterior teeth were selected and sectioned from 2 mm below Cemento Enamel Junction (CEJ) using a disc. A retrograde method was used for drilling cavities 2 mm away from incisal edge. Then the cavities were washed using 5. 25% NaOCL and normal saline and the samples were divided randomly into 4 groups. The cavities in groups 1, 2, and 3 were filled by MTA Angleus, Cem cement, and Biodentine, respectively as deep as CEJ level and they were sealed by 2mm of A3 composite color. All of cavities of group 4/control, were all filled by composite A3. Then the samples were stored in a glass incubator with 100% humidity and under laboratory light. they were exposed to a spectrophotometric analysis within 6 periods from placement including base line, 1 week, 2 weeks, 1 month, 3 months, 6 months. The data were analyzed by SPSS 17, Tukey HSD and ANOVA statistical test. Results: The results showed no statistically significant difference in discoloration rate during measurement periodsin each group. However, the discoloration rate varied in various materials. The minimum and maximum discolorations occurred in Biodentine and MTA, respectively and their difference was statistically significant. (p=0. 033)Other groups showed no statistically significant difference. Conclusion: The biodentinehad minimum discolorations compared with other two materials; thus, it seems that it can be recommended for cosmetic areas.

Introduction: the aim of the present study was to evaluate the influence of propylene glycol (PG) on the flowability, microhardness, pH and calcium ion release of calcium-enriched mixture (CEM). Methods and Materials: CEM cement was mixed with different proportions of PG, as follows: group 1, 100% CEM liquid (CL); group 2, 100% PG; group 3, 50% PG and group 4, 20% PG. For assessment of flowability, methodology of ADA Specification No. 57 was applied. For measuring microhardness, 80 cylindrical molds (6×4 mm) were filled with CEM cement and divided into 2 subgroups (4, 21 days) and tested using Vickers Test. Data were analyzed using the one-way ANOVA test and Tukey’ s post hoc and student’ s t test. In order to check pH and calcium release, the mixed cements were placed in cylindrical molds (5×2 mm). After 3, 24, 72 and 168 h, pH determined by a pH meter and the calcium release was measured by an atomic absorption spectrophotometer. Data were analyzed using the repeated measure ANOVA, one way ANOVA test and Tuckey’ s post hoc test. Results: The present study showed that the presence of PG did not affect the flowability. With the elapse of time, microhardness was significantly increased in all groups except CL group. Regardless of time, samples with 50% PG showed the lowest pH value which was significantly different from other groups (P<0. 05) and samples with 100% and 20% PG showed significantly higher calcium ion release compared to other group. Conclusion: addition of PG did not have any positive or negative effect on the flowability and pH of CEM cement but increased its microhardness in long term. Calcium ion release also increased in the concentration of 20% and 100%.