You could call the dentist and tell them the address is not valid for him.
This is from usps.com:
Reporting/Returning misdelivered mail
Despite our best efforts, occasionally mail is mis-delivered, or is delivered to an old location for an individual. If you are receiving mail for the previous resident and do not know their address, simply return the mail piece back to the mailstream (by leaving in a Collection Box® or other mail receptacle) with the notation "Not at this address" marked on the envelope.
Important: If the misdelivered item meets any of the following criteria
The Express Mail service item,
An unknown applicant submits proper ID.
The applicant provides a verifiable point of contact (e.g., place of employment, shelter, charitable institution, or social services office).
Please contact the Delivery Supervisor at your local Post Office facility:
For Express Mail items only, you can obtain the number of the Express Mail Reporting Unit by calling:
1-800-ASK-USPS (1-800-275-8777)
For other misdelivered mail items (such as letters):
If the mailpiece is delivered to the wrong location:
Don't erase or mark over the information, or write any type of endorsement on the mailpiece.
Place the item back in the mailbox or hand the item back to your mailperson.
If the mailpiece is delivered to the correct location but the recipient on the mailpiece does not reside at the address:
Write"Not at this address" on mailpiece.
Don't erase or mark over the address.
Provide the mailpiece to your mailperson or drop into a Collection Box receptacle.
Destroying mail that was not intended for you may be prohibited by US laws.
Willfully destroying mail is an act that may be punishable by the Federal Government.
If you have any questions about the legality of doing this, please contact your local law enforcement.
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They also have a phone number for customer support, but they will probably tell you the same thing as what's on the website.
Call 1-800-ASK-USPS® (800-275-8777)
M-F - 8:00am-8:30pm ET
Sat - 8:00am-6:00pm ET
Sun/Holidays* - Closed
- Gray 2010 carbon WSD road bike, Rivet Independence saddle
- Red hardtail 26" aluminum mountain bike, Bontrager Evoke WSD saddle
- Royal blue 2018 aluminum gravel bike, Rivet Pearl saddle
Gone but not forgotten:
- Silver 2003 aluminum road bike
- Two awesome worn out Juliana saddles