Guessing this could be done quite simply. Either just erase all the "Caption" columns and let solarwinds fill it in itself, or maybe a query like this in the database manager?
UPDATE Nodes
SET Caption = SysName
WHERE NOT (Caption = SysName)
Guessing this should work on all versions of Orion even the latest even though the Nodes table is actually gone in 11.5. If not, might need to change "Nodes" to "NodesData"...