Characterization of the Mineral Trioxide Aggregate–Resin Modified Glass Ionomer Cement Interface in Different Setting Conditions

Abstract

Introduction Mineral trioxide aggregate (MTA) has been used successfully for perforation repair, vital pulpotomies, and direct pulp capping. However, little is known about the interactions between MTA and glass ionomer cement (GIC) in final restorations. In this study, 2 null hypotheses were tested: (1) GIC placement time does not affect the MTA-GIC structural interface and hardness and (2) moisture does not affect the MTA-GIC structural interface and hardness. Methods Fifty cylinders were half filled with MTA and divided into 5 groups. The other half was filled with resin-modified GIC either immediately after MTA placement or after 1 or 7 days of temporization in the presence or absence of a wet cotton pellet. The specimens were then sectioned, carbon coated, and examined using a scanning electron microscope and an electron probe micro-analyzer (SEM-EPMA) for interfacial adaptation, gap formation, and elemental analysis. The Vickers hardness numbers of the interfacial MTA were recorded 24 hours after GIC placement and 8 days after MTA placement and analyzed using the analysis of variance test. Results Hardness testing 24 hours after GIC placement revealed a significant increase in hardness with an increase of temporization time but not with a change of moisture conditions (P < .05). Hardness testing 8 days after MTA placement indicated no significant differences among groups. SEM-EPMA showed interfacial adaptation to improve with temporization time and moisture. Observed changes were limited to the outermost layer of MTA. The 2 null hypotheses were not rejected. Conclusions GIC can be applied over freshly mixed MTA with minimal effects on the MTA, which seemed to decrease with time.

Evaluation of Calcium Aluminate/Calcium Phosphate Based Bio-Cements as Root-End Filling Material

“…Immediately after molding, the samples were cured in a humidity chamber at 100% relative humidity at a constant temperature of 37 °C for 24 h. At the end of the moist curing period the samples were demoulded and then cured under the two types of aqueous solutions (distilled water and saliva) until the time of testing such as 1, 3, 7and 14 days at a constant temperature of 37°C. The hardness test 20 was carried out on three cubes of each case of the hardened cement pastes. The test was performed with a Vickers indentation hardness tester at five points on one side of each sample.…”

“…Since this material sets and harden in vivo there is always a certain amount of ion leakage. Earlier studies reported that the leakage and hardness of root end filling materials were all affected over time 20 . The conversion process that is occurred during hydration of CA phase has an adverse effect on physicomechanical properties of hardened CA pastes, namely, bulk density and micro-hardness measurements (Figs.…”

“…13, however, this layer was not observed in CA Fig. 12, indicating that the increasing of HA content to 50wt% facilitated the precipitation of a hydroxyapatite-like active layer, suggesting that the HA feature favorable in vitro bioactivity 20,[27][28][29] . On the other hand,CA group specimens adhesive separation had shown between the CA cement and the tooth surface among all samples.It is obvious that the CA/HA contains a rather large proportion of entrained air.…”

In vitro bonding effectiveness of new self-adhering flowable composite to calcium silicate-based material

“…In vital pulp therapy using MTA, the choice of restorative material to be applied over MTA is important. Previous studies have emphasized that glass-ionomer cement can be used as intermediate material and that composites can be used for final restoration over MTA [11][12][13] . However, acid etching before composite placement reduces the compressive strength and surface microhardness of MTA 14) .…”

Mineral Trioxide Aggregate: A review of clinical usage and investigations of the effects of modifying particle size

“…127 After placing MTA, clinicians can place a wet cotton pellet, dry cotton pellet, 367 or a restorative material above the newly placed MTA. 368 The results of the present study illustrates that using a dry cotton pellet could be detrimental to the strength of the MTA.…”