Characterization of the mineral trioxide aggregate-resin modified glass ionomer cement interface in different setting conditions.
BACKGROUND
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 microanalyzer (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.
Department of Dental and Biomedical Material Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan. ashraf.abulfotooh@gmail.com
Ashraf A
AA
Eid
Takashi
T
Komabayashi
Etsuko
E
Watanabe
Takanobu
T
Shiraishi
Ikuya
I
Watanabe
D017607:Aluminum Compounds / Q000737:chemistry*; D002118:Calcium / Q000032:analysis; D017610:Calcium Compounds / Q000737:chemistry*; D004338:Drug Combinations; D004577:Electron Probe Microanalysis; D005461:Fluorine / Q000032:analysis; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006244:Hardness; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D008768:Methylmethacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D010087:Oxides / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry*; D012117:Resins, Synthetic / Q000737:chemistry; D012387:Root Canal Filling Materials / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors; D014867:Water / Q000737:chemistry; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry
D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; C079765:Fuji II LC cement; D005899:Glass Ionomer Cements; D008768:Methylmethacrylates; D010087:Oxides; D019279:Resin Cements; D012117:Resins, Synthetic; D012387:Root Canal Filling Materials; D017640:Silicates; D015035:Zinc Oxide-Eugenol Cement; C086631:mineral trioxide aggregate; D014867:Water; D005461:Fluorine; C031667:IRM cement; D002118:Calcium