B&W negative scans

[daz]

PLease advice,

I have scanned some Tri-X 400 B&W negatives using Minolta Dmage DualScan III. The scans turn out quite grainy on screen. and highlights are washed-out. I am not sure if this has got to do with the oveerexposure of my shots, around 1 stops over.

Will it be better to send the negatives to a pro lab for drum scan?

THanks in advance for any advice