Hi Zerandib,
Go to Se14
put table name for which index is missing
Select "indexes" tab from the menu bar
Look out for the index which does not exists in oracle database
Once you select the index , click on "Create Database index" using the option background.
Monitor the progress in SM37.
Once the job is completed, you may check the index active in SE14 / SE11.
Regards,
Deepak Kori