I do not know enough about Visual Basic to tell you how to actually print a Word document. However, I have messed with some databases where I had a need to interact with Word. I used the hyperlink command.
FollowHyperlink "C:/Document.doc"
It will then open the document and you can use the print button in Word.
I have used the same tactic with MailMerge documents. Setup the MailMerge using Words Mail Merge Wizard. Then use the FollowHyperlink command to open the document you created. Word will automatically run the merge on opening. You can get even more sophisticated by basing the query underlying the mail merge off of the form that opens the document. Then the user can manipulate the data (maybe select the appropriate names) and open the Word Document with your button.