The history of orthodontics has been intimately linked with the history of dentistry for more than 2000 years. Dentistry had its origins as a part of medicine.
Addressing an envelope to a post office box address is just like addressing envelopes to any other type of address. Of course, before you can address the envelope, you need the name of the recipient, the post office box number and the city, state and ZIP code.
How Zip + 4 Works The extra 4-digit added on to the regular ZIP Code identifies a geographic segment within the 5-digit delivery area, such as a city block, office building, or individual high-volume receiver of mail (e.g., the phone company bill center, the White House), or any other delivery location that would aid efficient mail sorting and delivery.