oracle database corrupt block recovery

Error:

Corrupt block relative dba: 0x1a0975d9 (file 104, block 619993)
Bad check value found during user buffer read
Data in bad block:
 type: 6 format: 2 rdba: 0x1a0975d9
 last change scn: 0x0726.9a3a3fc5 seq: 0x1 flg: 0x06
 spare1: 0x0 spare2: 0x0 spare3: 0x0
 consistency value in tail: 0x3fc50601
 check value in block header: 0x287e
 computed block checksum: 0xfe81
Reread of rdba: 0x1a0975d9 (file 104, block 619993) found same corrupted data
Tue Feb 18 20:17:59 IST 2014
Corrupt Block Found
         TSN = 47, TSNAME = EVENT_TAB
         RFN = 104, BLK = 619993, RDBA = 436827609
         OBJN = 141322, OBJD = 141322, OBJECT = EVENT_PK, SUBOBJECT =
         SEGMENT OWNER = EVA_ADMIN, SEGMENT TYPE = Index Segment


Background: