Dear Antell

I have read Liane Beam Wansbrough’s article on the topic of cosmetic plastic surgery, and I am writing to express my viewpoint and feelings as I feel so strongly about this subject. Whilst I can appreciate why you would choose to help young teenagers who have a facial or body disfigurement to have cosmetic surgery; however encouraging healthy young adults to have unnecessary surgery can have devastating results.
Or should I say dear Dr antell,I have read Liane Beam Wansbrough’s article on the topic of cosmetic plastic surgery.....
Without any space?

In a formal letter, the spacing is necessary. The salutation is also followed by a comma: "Dear Dr. Antell," And I would point out that "whilst" is not proper. The correct word is "while".

http://owl.english.purdue.edu/owl/resource/653/01/

Thank you

Both while and whilst are ancient, though while is older. There's no difference in meaning between them. For reasons that aren't clear, whilst has survived in British English but has died out in the US. However, in Britain it is considered to be a more formal and literary word than its counterpart.

Btw I live in the uk:)))

Dear Antell,

I have read Liane Beam Wansbrough’s article on the topic of cosmetic plastic surgery, and I am writing to express my viewpoint and feelings as I feel so strongly about this subject. Whilst I can appreciate why you would choose to help young teenagers who have a facial or body disfigurement to have cosmetic surgery; however encouraging healthy young adults to have unnecessary surgery can have devastating results.
like so?

You're right, "whilst" is more commonly used in the U.K. It is a perfectly good word. I was wrong to say it's not proper. It does seem strange (uncommon) to American ears and eyes.

You refer to "Antell" as Dr. once. Is that a first name or a surname? In the salutation in a letter, a title (Mr., Ms., Mrs., Dr., etc.) is customary unless it is a personal letter to someone you know and are addressing by his/her "given" name or whatever name you use in interpersonal exchange.

To answer your question, yes, the salutation "Or should I say dear Dr. Antell" should be followed by a comma or a colon, not without any space. The correct formatting for the sentence would be:

Or should I say, dear Dr. Antell, I have read Liane Beam Wansbrough’s article on the topic of cosmetic plastic surgery...

By adding the comma after "say," it separates the introductory phrase ("Or should I say") from the rest of the sentence, making it clearer for the reader.