The aim of this study was to investigate the proper time to restore composite resin over mineral trioxide aggregate (MTA).
samples of MTA blocks were divided into 7 groups with 3 different times
(10 minutes, 1 day, and 7 days) selected for restoring the composite
resin over MTA with and without bonding resin, and a control group was
included for comparison. After 21 days, the distances between MTA and
the composite resin or between MTA and the bonding agent on sectioned
planes along the long axis were measured using a scanning electron
microscope (×2,000 magnification). The hardness of the MTA near the
composite resin was presented as the Vickers microhardness.
were no gaps at the interface in the 10-minute groups, the 1-day group
with a bonding agent, and the 7-day group with a bonding agent. The
groups without a bonding agent at 1 and 7 days presented a separation or
gap at the interface. The value of the Vickers microhardness in the
1-day groups was significantly decreased compared with those of the
other groups regardless of the presence or absence of a bonding agent.
findings suggest that composite resin with a bonding agent over MTA can
be restored almost immediately after MTA mixing during a single visit.