Best practice to shrink Tempdb in a production environment What is best practice to use when shrinking Temporary db in SQL Server 2008?

Is it risky to use the following?

use tempdb
GO

DBCC FREEPROCCACHE -- clean cache
DBCC DROPCLEANBUFFERS -- clean buffers
DBCC FREESYSTEMCACHE ('ALL') -- clean system cache
DBCC FREESESSIONCACHE -- clean session cache
DBCC SHRINKDATABASE(tempdb, 10); -- shrink tempdb
dbcc shrinkfile ('tempdev') -- shrink db file
dbcc shrinkfile ('templog') -- shrink log file
GO

-- report the new file sizes
SELECT name, size
FROM sys.master_files
WHERE database_id = DB_ID(N'tempdb');
GO
It is a best practice to proactively monitor the normal usage of Tempdb and set the size accordingly.
If this is one off case where the Tempdb has grown to such a size and its a PROD env, I would restart SQL Server Services during weekly maintenance. There after Tempdb would go back to its configured size.

Shrinking the file is fine as long as Tempdb is not being used, else existing transactions may be impacted from performance point of view due to blockings and deadlocks.

Cleaning procedure cache, buffer caches etc will have negative impact on the database performance itself until those are not re-created. I would not do this on PROD.

Hope that helps!