With the exception of Churches of the Armenian Rite and the Maronite Church, Orthodox Churches and Eastern Catholic Churches use leavened bread for the Eucharist. Thus, the sacramental bread symbolizes the Resurrected Christ.

What kind of bread does the Orthodox Church use?

A prosphoron (Greek: πρόσφορον, offering) is a small loaf of leavened bread used in Orthodox Christian and Greek Catholic (Byzantine) liturgies. The plural form is prosphora (πρόσφορα).

Did the East or West use unleavened bread?

For the east, using leavened bread symbolized the Risen Christ, but for the Latins in the west unleavened bread was used just as Jesus had at the Last Supper.