While Dead sessions aren't inherently problematic, they consume unnecessary space in your database. In this Teamcenter resource article, we guide you through the process of purging dead sessions within the Teamcenter Rich Client.  

In the Rich Client (RAC), log in as infodba (or another member of the DBA group).                                                                         Go to View > Current Users...
In the Current Login Users window that opens, there will be a message stating there are Dead Sessions, asking if you would like to Purge them. Click Yes.
Dead processes have been cleared and valid sessions are shown... Click Close.