ABSTRACT
Calcium hydroxide which is commonly used as an intracanal medicament, changes the pH of dentin and periradicular tissues to an alkaline pH. In some clinical situations, endodontic reparative cements like calcium enriched mixture cement are used after calcium hydroxide therapy. However, the alkaline pH may affect the physical properties of this cement. This study was designed to evaluate the effect of alkaline pH on the push-out bond strength of calcium enriched mixture. 80 root slices were prepared from single-rooted human teeth and their lumens were instrumented to achieve a diameter of 1.3mm. Calcium enriched mixture [CEM] was mixed according to the manufacturer's instruction and introduced into the lumens of root slices. The specimens were then randomly divided into 4 groups [n = 20] and wrapped in pieces of gauze soaked in synthetic tissue fluid [STF] buffered in potassium hydroxide at pH values of 7.4, 8.4, 9.4, or 10.4. The samples were incubated for 4 days at 37 degree C. The push-out bond strengths were then measured using a universal testing machine. Failure modes were examined under a light microscope at ×20 magnification. The data were analyzed using one-way analysis of variance and Tukey's post hoc tests. The greatest [1.41 +/- 0.193 MPa] and lowest [0.8 +/- 0.06 MPa] mean push-out bond strengths were observed after exposure to pH values of 7.4 and 8.4, respectively. There were significant differences between the neutral group and the groups with pH of 8.4 [p = 0.008] and 10.4 [p = 0.022]. The bond failure was predominantly of cohesive type for all experimental groups. Under the condition of this study, alkaline pH adversely affected the Push-out bond strength of CEM cement
ABSTRACT
Statement of Problem: The pH of the human abscess has been measured as low as 5.0. This low pH could potentially inhibit setting reactions, affect adhesion, or increase the solubility of root end filling materials hence affect the compressive strength. Moreover, root end filling materials might expose or even mix with lidocaine HCL during periapical surgery
Objective: The aim of this in vitro study was to evaluate the effect of acidic pH and lidocaine on the compressive strength of calcium-enriched mixture [CEM]
Materials and Methods: CEM was mixed according to the manufacturer's instructions or with lidocaine [L], and condensed into 6 × 4 mm split moulds. The samples were exposed to phosphate buffered saline [PBS] at pH 5 or 7.4 for 7 or 28 days. Cylindrical blocks of CEM [total number = 120 and 15 for each group] were subjected to compressive strength test using a universal testing machine. Data were analysed using three-factor analysis of variance [ANOVA]
Results: Regardless of pH and time, significant differences were not found between lidocaine groups and the groups that were mixed according to the manufacturer's instruction [p = 0.083]. For both mixing agents, regardless of time, there were no significant differences between the two pH levels [p = 0.157]. Regardless of the material and pH, there was a significant increase in the compressive strength from days 7 to 28 [p < 0.001]
Conclusion: Mixtures with lidocaine and exposure to an acidic environment had no adverse effects on the compressive strength of CEM Cement
ABSTRACT
Statement of Problem: Sealing the perforation defect is an important factor to reduce inflammation in the area and to perform healing. Selecting the appropriate material to repair the defect is an important concern. Among the various available materials, MTA and CEM are used recently for achieving this purpose. In the current study we compare the sealing ability of these materials by evaluating their microleakage by fluid filtration method
Purpose: The purpose of this study was to compare the microleakage of MTA and CEM cement in furcal perforation in different periods of time
Materials and Method: Forty one mandibular molars were selected for this experimental study. The perforation defects were created perpendicular to the long axis of the teeth, on the furcation of the teeth and the samples were divided into 2 experimental and two control groups. The defects were sealed by CEM and MTA in each experimental group. The samples were undergone the fluid filtration test with 20 cm H2O pressure. The amount of fluid filtration was measured for each sample at 24, 72 and 168 hrs and the data were analyzed by using ANOVA and T test
Results: The experimental groups which were sealed with CEM exhibited significantly less microleakage in all determined periods of time [24, 72 and 168 hrs] than MTA groups [p< 0.001]
Conclusion: Based on the results of this study, CEM cement has a better sealing ability compared with MTA using fluid filtration method