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                                                                     EXHIBIT 5.1

              [LETTERHEAD OF WALLER LANSDEN DORTCH & DAVIS, PLLC]

                                October 6, 2000

Orthodontic Centers of America, Inc.
3850 N. Causeway Boulevard, Suite 990
Metairie, Louisiana 70002

Re: Registration Statement on Form S-3

Ladies and Gentlemen:

     We are acting as counsel to Orthodontic Centers of America, Inc., a
Delaware corporation (the "Company"), in connection with the registration under
the Securities Act of 1933, as amended (the "Act"), of 4,396,105 shares of the
Company's Common Stock, $.01 par value per share (the "Shares"), pursuant to the
above-referenced Registration Statement (the "Registration Statement"). In
connection with this opinion, we have examined and relied upon such records,
documents and other instruments as in our judgment are necessary or appropriate
in order to express the opinions hereinafter set forth and have assumed the
genuineness of all signatures, the authenticity of all documents submitted to us
as originals and the conformity to original documents of all documents submitted
to us as certified or photostatic copies.

     Based upon the foregoing, we are of the opinion that the Shares that are
currently outstanding and being offered by selling stockholders are duly
authorized, validly issued, fully paid and nonassessable, and the Shares that
are being offered by the Company, when issued and delivered in the manner and on
the terms described in the Registration Statement (after the Registration
Statement is declared effective), will be duly authorized, validly issued, fully
paid and nonassessable.

     We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and further consent to the reference to us under the
caption "Legal Matters" in the prospectus included in the Registration
Statement.

                                         Very truly yours,

                                         /s/ WALLER LANSDEN DORTCH & DAVIS, PLLC